The eukaryotic initiation factor 5A2 gene (EIF5A2) is a highly conserved and multifunctional gene that significantly influences various cellular processes, including translation elongation, RNA binding, ribosome binding, protein binding and post-translational modifications. Overexpression of EIF5A2 is frequently observed in multiple cancers, where it functions as an oncoprotein. Additionally, EIF5A2 is implicated in drug resistance through the regulation of various molecular pathways. In the review, we describe the structure and functions of EIF5A2 in normal cells and its role in tumorigenesis. We also elucidate the molecular mechanisms associated with EIF5A2 in the context of tumorigenesis and drug resistance. We propose that the biological roles of EIF5A2 in regulating diverse cellular processes and tumorigenesis are clinically significant and warrant further investigation.

Collagen XII (COL12A1) is a type of FACIT collagen that plays an important role in the extracellular matrix structuring, participating in the regulation of collagen fiber size, and serves as a link between different components of the extracellular matrix. However, it is still unclear whether exogenous administration of collagen XII has a direct regulatory effect. In this study, we successfully produced recombinant human XII-type collagen (rh12C) through genetic engineering approach, which is composed of different functional domains. A Pichia pastoris host cell strain was constructed based on the intracellular translation regulatory mechanism of collagen, achieving a maximum yield of 4.89 g/L. After purification and structural characterization of the protein, its potential biological efficacy was evaluated through in vitro cell experiments.

Polyamines (putrescine, spermidine, and spermine) are aliphatic compounds ubiquitous in prokaryotes and eukaryotes. Positively charged polyamines bind to negatively charged macromolecules, such as nucleic acids and acidic phospholipids, and are involved in physiological activities including cell proliferation, differentiation, apoptosis and gene regulation. Intracellular polyamine levels are regulated by biosynthesis, catabolism and transport. Polyamines in the body originate from two primary sources: dietary intake and intestinal microbial metabolism. These polyamines are then transported into the bloodstream, through which they are distributed to various tissues and organs to exert their biological functions. Polyamines synthesized by intestinal microorganisms serve dual critical roles. First, they are essential for maintaining polyamine concentrations within the digestive tract. Second, through transcriptional and post-transcriptional mechanisms, these microbial-derived polyamines modulate the expression of genes governing key processes in intestinal epithelial cells-including proliferation, migration, apoptosis, and cell-cell interactions. Collectively, these regulatory effects help maintain intestinal epithelial homeostasis and ensure the integrity of the gut barrier. In addition, polyamines interact with the gut microbiota to maintain intestinal homeostasis by promoting microbial growth, biofilm formation, swarming, and endocytosis vesicle production, etc. Supplementation with polyamines has been demonstrated to be important in regulating host intestinal microbial composition, enhancing nutrient absorption, and improving metabolism and immunity. In this review, we will focus on recent advances in the study of polyamine metabolism and transport in intestinal microbes and intestinal epithelial cells. We then summarize the scientific understanding of their roles in intestinal homeostasis, exploring the advances in cellular and molecular mechanisms of polyamines and their potential clinical applications, and providing a rationale for polyamine metabolism as an important target for the treatment of intestinal-based diseases.

Defining the proteoform landscape of breast cancer can provide unique insights into the signaling pathways driving disease progression. While bottom-up proteomics has been utilized to profile breast cancer, it lacks the ability to capture intact proteoforms that may underpin the disease. Top-down proteomics is ideally suited to characterize intact proteoforms; however, most top-down proteomics studies have been limited to low molecular weight (MW) proteins (<50 kDa). Herein, we employed a two-dimensional (2D) liquid chromatography combining size exclusion chromatography (SEC) with reverse phase chromatography (RPC) followed by high-resolution mass spectrometry (MS) to expand the coverage for high MW proteoforms. Using this 2D-SEC-RPC-MS approach, we observed a 5-fold increase in the detection of high MW proteoforms (>50 kDa) compared to the conventional 1D-RPC-MS. SEC separation significantly enhanced the detection of high MW proteoforms (>104 kDa), including intermediate filament proteins, vimentin and keratins. Based on accurate mass measurements and MS/MS data, we identified 775 proteoforms from both TFA and HEPES extracts and detected PTMs, such as acetylation, glutathionylation, and myristoylation. Pathway analysis uncovered many proteoforms involved in processes dysregulated in cancer progression. Overall, our findings illustrate the power of top-down proteomics in defining the proteoform landscape of breast carcinoma.

The biochemical and transcriptional regulatory mechanisms of chlorophyll metabolism have been extensively studied, but the translational regulatory mechanisms remain poorly understood. In this study, we found that Nt DHS1 deficiency in N. tabacum resulted in smaller leaves and increased leaf chlorophyll content. Protein content determination experiments revealed that the global protein synthesis of the Ntdhs1 mutant was decreased. A ribosome profiling sequence (Ribo-seq) assay showed that the translation level of genes related to cell growth was significantly reduced, while the translation level of chlorophyll metabolism related genes was significantly increased in Ntdhs1 mutant. Biochemical analysis further demonstrated that Nt DHS interacts with the translation initiation factor Nt eIF5A. Moreover, the Nteif5a1 mutant exhibited phenotypes similar to the Ntdhs1 mutant, including a reduced translation level of cell growth related genes and increased translation level of chlorophyll metabolism related genes. Our studies suggest that the Nt DHS-Nt eIF5A complex regulates leaf senescence by modulating the translation of specific genes.

Polyamines are critically important for protein synthesis. Through their positive ionic charge, polyamines readily bind to ribosomes, as well as to mRNAs and tRNAs. Moreover, the polyamine spermidine serves as a substrate for the synthesis of hypusine, an essential post-translational modification on the translation factor eIF5A. Though originally thought to function in translation initiation, eIF5A is now known to generally promote translation elongation and termination. Moreover, translation of certain motifs like polyproline show a greater dependency on eIF5A. In this chapter, we describe the biochemical assays we use to study eIF5A and its regulation. Owing to the complex nature of protein synthesis, these assays require the purification of over 10 translation factors plus ribosomes, tRNAs, and aminoacyl-tRNA synthetases. We describe the methods used to purify these components, to synthesize the mRNA templates for translation, and to resolve the translation products by electrophoretic thin-layer chromatography. With the recent identification of eIF5A as a key target for regulating the synthesis of polyamine synthesis and transport, and the recent identification of mutations in eIF5A causing a neurodevelopmental disorder, the assays described in this chapter will be useful in further elucidating the function and regulation of this enigmatic protein.

The production of cellulases by filamentous fungi is a crucial aspect of sustainable bioproduction from renewable lignocellulosic biomass. Following the transcription of cellulase genes in the nucleus, a complex pathway involving translation, folding, and secretion is required to produce extracellular cellulases. Most studies about cellulase production have focused on examining transcriptional regulatory mechanisms and enhancement of enzyme gene levels; comparatively, little is known about protein translation and secretion for cellulase production.

A translation-machinery-associated (TMA) protein PoTma15 was identified in cellulosic Penicillium oxalicum. The PoTma15 is conserved in various filamentous fungi, but not in yeast, plants, or animals. All homologous proteins of PoTma15 have previously been uncharacterized. PoTma15 was initially thought to be one of the putative interactors of transcription factor PoXlnR, as it was preyed by tandem affinity purification (TAP) coupled with the mass spectrometry (TAP-MS) technique using PoXlnR as the bait. Subsequent research revealed that PoTma15 is associated with the translation machinery. The top three proteins associated with PoTma15 are orthologs of Saccharomyces cerevisiae translation-machinery-associated protein (Tma19), translation elongation factor eIF5A, and ribosomal protein S28, respectively. PoTma15 is widely distributed in fungal hyphae and positively correlates with the production of cellulases and extracellular proteins. Deleting the Potma15 gene (Δtma15) decreased cellulase production, while overexpressing the Potma15 gene (OEtma15) increased cellulase production. However, the Δtma15 mutant was not observed to have downregulated transcript levels of major (hemi)cellulase and amylase genes, compared to the P. oxalicum wild type (WT). The production of extracellular cellulases and extracellular proteins of the Δtma15 mutant was less affected by cycloheximide, an inhibitor of eukaryotic translation elongation, compared to the WT strain and OEtma15 mutant, suggesting a stronger resistance to the translation-inhibiting effects of cycloheximide in the Δtma15 mutant. The results demonstrate that PoTma15 is a translation-machinery-associated protein that affects translation elongation and, consequently, the production of enzyme proteins.

PoTma15 is the first TMA protein characterized in cellulosic filamentous fungi and the first TMA protein used in fungi to increase cellulase production. PoTma15's role in the production of cellulases and total extracellular proteins suggests that not only can it be used to widen the cellulase production pathway, but can even be engineered as a target to improve the production of other heterologous protein or bioproducts using filamentous fungi as cell factories in the future.

Translation is the process of decoding an mRNA transcript to permit the synthesis of a protein. This process occurs in three steps: initiation, elongation, and termination. Each step of translation is regulated by translation factors. By regulating translation, the quantity and quality of proteins can be controlled. When translation becomes dysfunctional, disease can ensue, making translational regulation an important avenue of research. Polysome profiling and puromycin incorporation are experimental techniques used in concert to analyze the translational state of cells or tissues. Polysome profiling evaluates the state of translation by quantifying mRNAs based on the abundance of associated ribosomes. Puromycin incorporation measures the amount of newly synthesized protein. Together these methodologies can decipher stark and subtle changes in the rate and efficiency of translation, and provide the opportunity to dissect alterations to the translation of specific transcripts.

Neuroblastoma is a common childhood malignancy, and high-risk presentations, including an MYCN amplified status, continue to result in poor survival. Difluoromethylornithine (DFMO) is a new and well-tolerated treatment for high-risk neuroblastoma. This review article discusses preclinical and clinical data that resulted in the establishment of DFMO as a treatment for neuroblastoma. The review of preclinical data includes a summary of the contribution of polyamine synthetic pathways to high-risk neuroblastoma, the effect that MYCN has on polyamine synthetic pathways, and the proposed mechanism by which DFMO inhibits tumorigenesis. This understanding has led to the discussion of various preclinical combination therapies that may result in a synergistic therapeutic response for high-risk neuroblastoma. We review the clinical trials that show the successful treatment of high-risk neuroblastoma with DFMO, including comparative analysis and traditional neuroblastoma trials using propensity score matching. We review the regulatory path by which DFMO gained approval from the Federal Drug Administration for use as a maintenance therapy following the traditional high-risk neuroblastoma therapy. Finally, we discuss the role of DFMO in future clinical research for neuroblastoma and additional pediatric cancers.

Assembly of functional ribosomal subunits and successfully delivering them to the translating pool is a prerequisite for protein synthesis and cell growth. In S. cerevisiae, the ribosome assembly factor Reh1 binds to pre-60S subunits at a late stage during their cytoplasmic maturation. Previous work shows that the C-terminus of Reh1 inserts into the polypeptide exit tunnel of the pre-60S subunit. Here, we show that Reh1-bound nascent 60S subunits associate with 40S subunits to form actively translating ribosomes. Using selective ribosome profiling, we found that Reh1-bound ribosomes populate open reading frames near start codons. Reh1-bound ribosomes are also strongly enriched for initiator tRNA, indicating they are associated with early elongation. Using cryo-electron microscopy to image Reh1-bound 80S ribosomes, we found they contain A site peptidyl tRNA, P site tRNA and eIF5A, indicating that Reh1 does not dissociate from 60S until translation elongation. We propose that Reh1 is displaced by the elongating peptide chain, making it the last assembly factor released from the nascent 60S subunit during its initial round of translation.

Natural products have a long history of providing probes into protein biosynthesis, with many of these compounds serving as therapeutics. The marine natural product girolline has been described as an inhibitor of protein synthesis. Its precise mechanism of action, however, has remained unknown. The data we present here suggests that girolline is a sequence-selective modulator of translation factor eIF5A. Girolline interferes with ribosome-eIF5A interaction and induces ribosome stalling where translational progress is impeded, including on AAA-encoded lysine. Our data furthermore indicate that eIF5A plays a physiological role in ribosome-associated quality control and in maintaining the efficiency of translational progress. Girolline helped to deepen our understanding of the interplay between protein production and quality control in a physiological setting and offers a potent chemical tool to selectively modulate gene expression.

MYC is one of the most deregulated oncogenic transcription factors in human cancers. MYC amplification/or overexpression is most common in Group 3 medulloblastoma and is positively associated with poor prognosis. MYC is known to regulate the transcription of major components of protein synthesis (translation) machinery, leading to promoted rates of protein synthesis and tumorigenesis. MTOR signaling-driven deregulated protein synthesis is widespread in various cancers, including medulloblastoma, which can promote the stabilization of MYC. Indeed, our previous studies demonstrate that the key components of protein synthesis machinery, including mTOR signaling and MYC targets, are overexpressed and activated in MYC-amplified medulloblastoma, confirming MYC-dependent addiction of enhanced protein synthesis in medulloblastoma. Further, targeting this enhanced protein synthesis pathway with combined inhibition of MYC transcription and mTOR translation by small-molecule inhibitors, demonstrates preclinical synergistic anti-tumor potential against MYC-driven medulloblastoma in vitro and in vivo. Thus, inhibiting enhanced protein synthesis by targeting the MYC indirectly and mTOR pathways together may present a highly appropriate strategy for treating MYC-driven medulloblastoma and other MYC-addicted cancers. Evidence strongly proposes that MYC/mTOR-driven tumorigenic signaling can predominantly control the translational machinery to elicit cooperative effects on increased cell proliferation, cell cycle progression, and genome dysregulation as a mechanism of cancer initiation. Several small molecule inhibitors of targeting MYC indirectly and mTOR signaling have been developed and used clinically with immunosuppressants and chemotherapy in multiple cancers. Only a few of them have been investigated as treatments for medulloblastoma and other pediatric tumors. This review explores concurrent targeting of MYC and mTOR signaling against MYC-driven medulloblastoma. Based on existing evidence, targeting of MYC and mTOR pathways together produces functional synergy that could be the basis for effective therapies against medulloblastoma.

Amino acid metabolism in breast cancer cells is unique for each molecular biological subtype of breast cancer. In this review, the features of breast cancer cell metabolism are considered in terms of changes in the amino acid composition due to the activity of transmembrane amino acid transporters. In addition to the main signaling pathway PI3K/Akt/mTOR, the activity of the oncogene c-Myc, HIF, p53, GATA2, NF-kB and MAT2A have a direct effect on the amino acid metabolism of cancer cells, their growth and proliferation, as well as the maintenance of homeostatic equilibrium. A distinctive feature of luminal subtypes of breast cancer from TNBC is the ability to perform gluconeogenesis. Breast cancers with a positive expression of the HER2 receptor, in contrast to TNBC and luminal A subtype, have a distinctive active synthesis and consumption of fatty acids. It is interesting to note that amino acid transporters exhibit their activity depending on the pH level inside the cell. In the most aggressive forms of breast cancer or with the gradual progression of the disease, pH will also change, which will directly affect the metabolism of amino acids. Using the cell lines presented in this review, we can trace the characteristic features inherent in each of the molecular biological subtypes of breast cancer and develop the most optimal therapeutic targets.

The protein synthesis within eukaryotic cells is a complex process involving various translation factors. Among these factors, eukaryotic translation initiation factor 5 A (eIF5A) emerges as a crucial translation factor with high evolutionary conservation. eIF5A is unique as it is the only protein in eukaryotic cells containing the hypusine modification. Initially presumed to be a translation initiation factor, eIF5A was subsequently discovered to act mainly during the translation elongation phase. Notably, eIF5A facilitates the translation of peptide sequences containing polyproline stretches and exerts a universal regulatory effect on the elongation and termination phases of protein synthesis. Additionally, eIF5A indirectly affects various physiological processes within the cell by modulating the translation of specific proteins. This review provides a comprehensive overview of the structure, physiological functions, various post-translational modifications of eIF5A, and its association with various human diseases. The comparison between eIF5A and its bacterial homolog, EF-P, extends the discussion to the evolutionary conservation of eIF5A. This highlights its significance across different domains of life.

Deoxyhypusine synthase (DHPS) catalyzes the initial step of hypusine incorporation into the eukaryotic initiation factor 5A (eIF5A), leading to its activation. The activated eIF5A, in turn, plays a key role in regulating the protein translation of selected mRNAs and therefore appears to be a suitable target for therapeutic intervention strategies. In the present study, we analyzed the role of DHPS-mediated hypusination in regulating neuronal homeostasis using lentivirus-based gain and loss of function experiments in primary cortical cultures from rats. This model allows us to examine the impact of DHPS function on the composition of the dendritic and synaptic compartments, which may contribute to a better understanding of cognitive function and neurodevelopment in vivo. Our findings revealed that shRNA-mediated DHPS knockdown diminishes the amount of hypusinated eIF5A (eIF5AHyp), resulting in notable alterations in neuronal dendritic architecture. Furthermore, in neurons, the synaptic composition was also affected, showing both pre- and post-synaptic changes, while the overexpression of DHPS had only a minor impact. Therefore, we hypothesize that interfering with the eIF5A hypusination caused by reduced DHPS activity impairs neuronal and synaptic homeostasis.

Discovering new treatments for melanoma will benefit human health. The mechanism by which deoxyhypusine synthase (DHPS) promotes melanoma development remains elucidated. Multi-omics studies have revealed that DHPS regulates m6A modification and maintains mRNA stability in melanoma cells. Mechanistically, DHPS activates the hypusination of eukaryotic translation initiation factor 5A (eIF5A) to assist METTL3 localizing on its mRNA for m6A modification, then promoting METTL3 expression. Structure-based design, synthesis, and activity screening yielded the hit compound GL-1 as a DHPS inhibitor. Notably, GL-1 directly inhibits DHPS binding to eIF5A, whereas GC-7 cannot. Based on the clarification of the mode of action of GL-1 on DHPS, it is found that GL-1 can promote the accumulation of intracellular Cu2+ to induce apoptosis, and antibody microarray analysis shows that GL-1 inhibits the expression of several cytokines. GL-1 shows promising antitumor activity with good bioavailability in a xenograft tumor model. These findings clarify the molecular mechanisms by which DHPS regulates melanoma proliferation and demonstrate the potential of GL-1 for clinical melanoma therapy.

The unique amino acid hypusine [Nε-(4-amino-2-hydroxybutyl)lysine] is exclusively formed on the translational regulator eukaryotic initiation factor 5A (eIF5A) via a process coined hypusination. Hypusination is mediated by two enzymes, deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH), and hypusinated eIF5A (eIF5AHyp) promotes translation elongation by alleviating ribosome pauses at amino acid motifs that cause structural constraints, and it also facilitates translation initiation and termination. Accordingly, eIF5AHyp has diverse biological functions that rely on translational control of its targets. Homozygous deletion of Eif5a, Dhps, or Dohh in mice leads to embryonic lethality, and heterozygous germline variants in EIF5A and biallelic variants in DHPS and DOHH are associated with rare inherited neurodevelopmental disorders, underscoring the importance of the hypusine circuit for embryonic and neuronal development. Given the pleiotropic effects of eIF5AHyp, a detailed understanding of the cell context-specific intrinsic roles of eIF5AHyp and of the chronic versus acute effects of eIF5AHyp inhibition is necessary to develop future strategies for eIF5AHyp-targeted therapy to treat various human health problems. Here, we review the most recent studies documenting the intrinsic roles of eIF5AHyp in different tissues/cell types under normal or pathophysiological conditions and discuss these unique aspects of eIF5AHyp-dependent translational control.

Dormancy or hibernation is a non-proliferative state of cells with low metabolic activity and gene expression. Dormant cells sequester ribosomes in a translationally inactive state, called dormant/hibernating ribosomes. These dormant ribosomes are important for the preservation of ribosomes and translation shut-off. While recent studies attempted to elucidate their modes of formation, the regulation and roles of the diverse dormant ribosomal populations are still largely understudied. The mechanistic details of the formation of dormant ribosomes in stress and especially their disassembly during recovery remain elusive. In this review, we discuss the roles of dormant ribosomes and their potential regulatory mechanisms. Furthermore, we highlight the paradigms that need to be answered in the field of ribosomal dormancy.

Rationale: The ubiquitous polyamine spermidine is essential for cell survival and proliferation. One important function of spermidine is to serve as a substrate for hypusination, a posttranslational modification process that occurs exclusively on eukaryotic translation factor 5A (eIF5A) and ensures efficient translation of various gene products. Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by progressive obliteration of the small pulmonary arteries (PAs) caused by excessive proliferation of PA smooth muscle cells (PASMCs) and suppressed apoptosis. Objectives: To characterize the role of hypusine signaling in PAH. Methods: Molecular, genetic, and pharmacological approaches were used both in vitro and in vivo to investigate the role of hypusine signaling in pulmonary vascular remodeling. Measurements and Main Results: Hypusine forming enzymes-deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH)-and hypusinated eukaryotic translation factor 5A are overexpressed in distal PAs and isolated PASMCs from PAH patients and animal models. In vitro, inhibition of DHPS using N1-guanyl-1,7-diaminoheptane or shRNA resulted in a decrease in PAH-PASMC resistance to apoptosis and proliferation. In vivo, inactivation of one allele of Dhps targeted to smooth muscle cells alleviates PAH in mice, and its pharmacological inhibition significantly decreases pulmonary vascular remodeling and improves hemodynamics and cardiac function in two rat models of established PAH. With mass spectrometry, hypusine signaling is shown to promote the expression of a broad array of proteins involved in oxidative phosphorylation, thus supporting the bioenergetic requirements of cell survival and proliferation. Conclusions: These findings support inhibiting hypusine signaling as a potential treatment for PAH.

Given their highly polarized morphology and functional singularity, neurons require precise spatial and temporal control of protein synthesis. Alterations in protein translation have been implicated in the development and progression of a wide range of neurological and neurodegenerative disorders, including Huntington's disease (HD). In this study we examined the architecture of polysomes in their native brain context in striatal tissue from the zQ175 knock-in mouse model of HD. We performed 3D electron tomography of high-pressure frozen and freeze-substituted striatal tissue from HD models and corresponding controls at different ages. Electron tomography results revealed progressive remodelling towards a more compacted polysomal architecture in the mouse model, an effect that coincided with the emergence and progression of HD related symptoms. The aberrant polysomal architecture is compatible with ribosome stalling phenomena. In fact, we also detected in the zQ175 model an increase in the striatal expression of the stalling relief factor EIF5A2 and an increase in the accumulation of eIF5A1, eIF5A2 and hypusinated eIF5A1, the active form of eIF5A1. Polysomal sedimentation gradients showed differences in the relative accumulation of 40S ribosomal subunits and in polysomal distribution in striatal samples of the zQ175 model. These findings indicate that changes in the architecture of the protein synthesis machinery may underlie translational alterations associated with HD, opening new avenues for understanding the progression of the disease.

We have performed a functional in vivo mutagenesis screen to identify genes that, when altered, cooperate with a heterozygous Pten mutation to promote prostate tumour formation. Two genes, Bzw2 and Eif5a2, which have been implicated in the process of protein translation, were selected for further validation. Using prostate organoid models, we show that either Bzw2 downregulation or EIF5A2 overexpression leads to increased organoid size and in vivo prostate growth. We show that both genes impact the PI3K pathway and drive a sustained increase in phospho-AKT expression, with PTEN protein levels reduced in both models. Mechanistic studies reveal that EIF5A2 is directly implicated in PTEN protein translation. Analysis of patient datasets identified EIF5A2 amplifications in many types of human cancer, including the prostate. Human prostate cancer samples in two independent cohorts showed a correlation between increased levels of EIF5A2 and upregulation of a PI3K pathway gene signature. Consistent with this, organoids with high levels of EIF5A2 were sensitive to AKT inhibitors. Our study identified novel genes that promote prostate cancer formation through upregulation of the PI3K pathway, predicting a strategy to treat patients with genetic aberrations in these genes particularly relevant for EIF5A2 amplified tumours.

Tumor-associated macrophages (TAMs) are vital contributors to the growth, metastasis, and therapeutic resistance of various cancers, including hepatocellular carcinoma (HCC). However, the exact phenotype of TAMs and the mechanisms underlying their modulation for therapeutic purposes have not been determined. Here, we present compelling evidence that glutamine-derived aspartate in TAMs stimulates spermidine production through the polyamine synthesis pathway, thereby increasing the translation efficiency of HIF-1α via eIF5A hypusination. Consequently, augmented translation of HIF-1α drives TAMs to undergo an increase glycolysis and acquire a metabolic phenotype distinct from that of M2 macrophages. Finally, eIF5A levels in tumor stromal lesions were greater than those in nontumor stromal lesions. Additionally, a higher degree of tumor stromal eIF5A hypusination was significantly associated with a more advanced tumor stage. Taken together, these data highlight the potential of inhibiting hypusinated eIF5A by targeting glutamine metabolism in TAMs, thereby opening a promising avenue for the development of novel therapeutic approaches for HCC.

Aneuploidy produces myriad consequences in health and disease, yet models of the deleterious effects of chromosome amplification are still widely debated. To distinguish the molecular determinants of aneuploidy stress, we measured the effects of duplicating individual genes in cells with varying chromosome duplications, in wild-type cells and cells sensitized to aneuploidy by deletion of RNA-binding protein Ssd1. We identified gene duplications that are nearly neutral in wild-type euploid cells but significantly deleterious in euploids lacking SSD1 or SSD1+ aneuploid cells with different chromosome duplications. Several of the most deleterious genes are linked to translation; in contrast, duplication of other translational regulators, including eI5Fa Hyp2, benefit ssd1Δ aneuploids over controls. Using modeling of aneuploid growth defects, we propose that the deleterious effects of aneuploidy emerge from an interaction between the cumulative burden of many amplified genes on a chromosome and a subset of duplicated genes that become toxic in that context. Our results suggest that the mechanism behind their toxicity is linked to a key vulnerability in translation in aneuploid cells. These findings provide a perspective on the dual impact of individual genes and overall genomic burden, offering new avenues for understanding aneuploidy and its cellular consequences.

Bachmann-Bupp syndrome (BABS) is a neurodevelopmental disorder characterized by developmental delay, hypotonia, and varying forms of non-congenital alopecia. The condition is caused by 3'-end mutations of the ornithine decarboxylase 1 (ODC1) gene, which produce carboxy (C)-terminally truncated variants of ODC, a pyridoxal 5'-phosphate-dependent enzyme. C-terminal truncation of ODC prevents its ubiquitin-independent proteasomal degradation and leads to cellular accumulation of ODC enzyme that remains catalytically active. ODC is the first rate-limiting enzyme that converts ornithine to putrescine in the polyamine pathway. Polyamines (putrescine, spermidine, spermine) are aliphatic molecules found in all forms of life and are important during embryogenesis, organogenesis, and tumorigenesis. BABS is an ultra-rare condition with few reported cases, but it serves as a convincing example for drug repurposing therapy. α-Difluoromethylornithine (DFMO, also known as eflornithine) is an ODC inhibitor with a strong safety profile in pediatric use for neuroblastoma and other cancers as well as West African sleeping sickness (trypanosomiasis). Patients with BABS have been treated with DFMO and have shown improvement in hair growth, muscle tone, and development.

As professional secretory cells, β-cells require adaptable mRNA translation to facilitate a rapid synthesis of proteins, including insulin, in response to changing metabolic cues. Specialized mRNA translation programs are essential drivers of cellular development and differentiation. However, in the pancreatic β-cell, the majority of factors identified to promote growth and development function primarily at the level of transcription. Therefore, despite its importance, the regulatory role of mRNA translation in the formation and maintenance of functional β-cells is not well defined. In this study, we have identified a translational regulatory mechanism mediated by the specialized mRNA translation factor eukaryotic initiation factor 5A (eIF5A), which facilitates the maintenance of β-cell identity and function. The mRNA translation function of eIF5A is only active when it is posttranslationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS). We have discovered that the absence of β-cell DHPS in mice reduces the synthesis of proteins critical to β-cell identity and function at the stage of β-cell maturation, leading to a rapid and reproducible onset of diabetes. Therefore, our work has revealed a gatekeeper of specialized mRNA translation that permits the β-cell, a metabolically responsive secretory cell, to maintain the integrity of protein synthesis necessary during times of induced or increased demand.

Programmed ribosomal frameshifting (PRF) exists in all branches of life that regulate gene expression at the translational level. The eukaryotic translation initiation factor 5A (eIF5A) is a highly conserved protein essential in all eukaryotes. It is identified initially as an initiation factor and functions broadly in translation elongation and termination. The hypusination of eIF5A is specifically required for +1 PRF at the shifty site derived from the ornithine decarboxylase antizyme 1 (OAZ1) in Saccharomyces cerevisiae. However, whether the regulation of +1 PRF by yeast eIF5A is universal remains unknown. Here, we found that Sc-eIF5A depletion decreased the putrescine/spermidine ratio. The re-introduction of Sc-eIF5A in yeast eIF5A mutants recovered the putrescine/spermidine ratio. In addition, the Sc-eIF5A depletion decreases +1 PRF during the decoding of Ty1 retrotransposon mRNA, but has no effect on -1 PRF during the decoding of L-A virus mRNA. The re-introduction of Sc-eIF5A in yeast eIF5A mutants restored the +1 PRF rate of Ty1. The inhibition of the hypusine modification of yeast eIF5A by GC7 treatment or by mutating the hypusination site Lys to Arg caused decreases of +1 PRF rates in the Ty1 retrotransposon. Furthermore, mutational studies of the Ty1 frameshifting element support a model where the efficient removal of ribosomal subunits at the first Ty1 frame 0 stop codon is required for the frameshifting of trailing ribosomes. This dependency is likely due to the unique position of the frame 0 stop codon distance from the slippery sequence of Ty1. The results showed that eIF5A is a trans-regulator of +1 PRF for Ty1 retrotransposon and could function universally in yeast.

Initiating translation of most eukaryotic mRNAs depends on recruitment of methionyl initiator tRNA (Met-tRNAi) in a ternary complex (TC) with GTP-bound eukaryotic initiation factor 2 (eIF2) to the small (40S) ribosomal subunit, forming a 43S preinitiation complex (PIC) that attaches to the mRNA and scans the 5'-untranslated region (5' UTR) for an AUG start codon. Previous studies have implicated mammalian eIF2A in GTP-independent binding of Met-tRNAi to the 40S subunit and its recruitment to specialized mRNAs that do not require scanning, and in initiation at non-AUG start codons, when eIF2 function is attenuated by phosphorylation of its α-subunit during stress. The role of eIF2A in translation in vivo is poorly understood however, and it was unknown whether the conserved ortholog in budding yeast can functionally substitute for eIF2. We performed ribosome profiling of a yeast deletion mutant lacking eIF2A and isogenic wild-type (WT) cells in the presence or absence of eIF2α phosphorylation induced by starvation for amino acids isoleucine and valine. Whereas starvation of WT confers changes in translational efficiencies (TEs) of hundreds of mRNAs, the eIF2AΔ mutation conferred no significant TE reductions for any mRNAs in non-starved cells, and it reduced the TEs of only a small number of transcripts in starved cells containing phosphorylated eIF2α. We found no evidence that eliminating eIF2A altered the translation of mRNAs containing putative internal ribosome entry site (IRES) elements, or harboring uORFs initiated by AUG or near-cognate start codons, in non-starved or starved cells. Thus, very few mRNAs (possibly only one) appear to employ eIF2A for Met-tRNAi recruitment in yeast cells, even when eIF2 function is attenuated by stress.

The eukaryotic translation initiation protein eIF5A is a highly conserved and essential factor that plays a critical role in different physiological and pathological processes including stress response and cancer. Different proteomic studies suggest that eIF5A may be a small ubiquitin-like modifier (SUMO) substrate, but whether eIF5A is indeed SUMOylated and how relevant is this modification for eIF5A activities are still unknown.

SUMOylation was evaluated using in vitro SUMOylation assays, Histidine-tagged proteins purification from His6-SUMO2 transfected cells, and isolation of endogenously SUMOylated proteins using SUMO-binding entities (SUBES). Mutants were engineered by site-directed mutagenesis. Protein stability was measured by a cycloheximide chase assay. Protein localization was determined using immunofluorescence and cellular fractionation assays. The ability of eIF5A1 constructs to complement the growth of Saccharomyces cerevisiae strains harboring thermosensitive mutants of a yeast EIF5A homolog gene (HYP2) was analyzed. The polysome profile and the formation of stress granules in cells expressing Pab1-GFP (a stress granule marker) by immunofluorescence were determined in yeast cells subjected to heat shock. Cell growth and migration of pancreatic ductal adenocarcinoma PANC-1 cells overexpressing different eIF5A1 constructs were evaluated using crystal violet staining and transwell inserts, respectively. Statistical analysis was performed with GraphPad Software, using unpaired Student's t-test, or one-way or two-way analysis of variance (ANOVA).

We found that eIF5A is modified by SUMO2 in vitro, in transfected cells and under endogenous conditions, revealing its physiological relevance. We identified several SUMO sites in eIF5A and found that SUMOylation modulates both the stability and the localization of eIF5A in mammalian cells. Interestingly, the SUMOylation of eIF5A responds to specific stresses, indicating that it is a regulated process. SUMOylation of eIF5A is conserved in yeast, the eIF5A SUMOylation mutants are unable to completely suppress the defects of HYP2 mutants, and SUMOylation of eIF5A is important for both stress granules formation and disassembly of polysomes induced by heat-shock. Moreover, mutation of the SUMOylation sites in eIF5A abolishes its promigratory and proproliferative activities in PANC-1 cells.

SUMO2 conjugation to eIF5A is a stress-induced response implicated in the adaptation of yeast cells to heat-shock stress and required to promote the growth and migration of pancreatic ductal adenocarcinoma cells.

The silkworm is a lepidopteran domesticated from the wild silkworm, mostly valued for its efficient synthesis of silk protein. This species' ability to spin silk has supported the 5500-year-old silk industry and the globally known "Silk Road", making the transformation of mulberry leaves into silk of great concern. Therefore, research on the silk-related genes of silkworms and their regulatory mechanisms has attracted increasing attention. Previous studies have revealed that domestic silk gland cells are endoreduplication cells, and their high-copy genome and special chromatin conformation provide conditions for the high expression of silk proteins. In this study, we systematically investigate the expression pattern of eukaryotic initiation factors (eIFs) and identified the eIF6 as a eukaryotic translation initiation factor involved in the synthesis of silk proteins. We generated an eIF6 gene deletion mutant strain of silkworm using the CRISPR/Cas9 system and investigated the function of eIF6 in silk gland development and silk protein synthesis. The results showed that deletion of eIF6 inhibited the individual development of silkworm larvae, inhibited the development of silk glands, and significantly reduced the cocoon layer ratio. Therefore, we elucidated the function of eIF6 in the development of silk glands and the synthesis of silk proteins, which is important for further elucidation of the developmental process of silk glands and the mechanism underlying the ultra-high expression of silk proteins.

Programmed ribosomal frameshifting (PRF) exists in all branches of life that regulate gene expression at the translational level. The single-celled eukaryote Euplotes exhibit high frequency of PRF. However, the molecular mechanism of modulating Euplotes PRF remains largely unknown. Here, we identified two novel eIF5A genes, eIF5A1 and eIF5A2, in Euplotes octocarinatus and found that the Eo-eIF5A2 gene requires a -1 PRF to produce complete protein product. Although both Eo-eIF5As showed significant structural similarity with yeast eIF5A, neither of them could functionally replace yeast eIF5A. Eo-eIF5A knockdown inhibited +1 PRF of the η-tubulin gene. Using an in vitro reconstituted translation system, we found that hypusinated Eo-eIF5A (Eo-eIF5AH) can promote +1 PRF at the canonical AAA_UAA frameshifting site of Euplotes. The results showed eIF5A is a novel trans-regulator of PRF in Euplotes and has an evolutionary conserved role in regulating +1 PRF in eukaryotes.

The discovery of new therapeutic strategies for diseases is essential for drug research. Deoxyhypusine synthase (DHPS) is a critical enzyme that modifies the conversion of the eukaryotic translation initiation factor 5A (eIF5A) precursor into physiologically active eIF5A (eIF5A-Hyp). Recent studies have revealed that the hypusine modifying of DHPS on eIF5A has an essential regulatory role in human diseases. The hypusination-induced DHPS/eIF5A pathway has been shown to play an essential role in various cancers, and it could regulate immune-related diseases, glucose metabolism-related diseases, neurological-related diseases, and aging. In addition, DHPS has a more defined substrate and a well-defined structure within the active pocket than eIF5A. More and more researchers are focusing on the prospect of advanced development of DHPS inhibitors. This review summarizes the regulatory mechanisms of the hypusination-induced DHPS/eIF5A pathway in a variety of diseases in addition to the inhibitors related to this pathway; it highlights and analyzes the structural features and mechanisms of action of DHPS inhibitors and expands the prospects of future drug development using DHPS as an anticancer target.

Eukaryotic initiation factor 5A2 (eIF5A2) is overexpressed in many types of cancer, and spermidine-mediated eIF5A hypusination (eIF5Ahpu) appears to be essential to most of eIF5A's biological functions, including its important role in regulating cancer cell proliferation, epithelial-mesenchymal transition (EMT), and cancer stem cell (CSC) properties as well as immune cell functions. Here we investigated the role of eIF5Ahpu in the growth of oral squamous cell carcinoma cells (OSCCs) and OSCC-induced polarization of M2-like tumor-associated macrophages (TAMs). TCGA dataset analysis revealed an overall upregulation in the mRNA expression of eIF5A2 and several key enzymes involved in polyamine (PA) metabolism in HNSCC, which was confirmed by Western blot and IHC studies. Blocking eIF5Ahpu by GC-7 but not the upstream key enzyme activities of PA metabolism, remarkably inhibited cell proliferation and the expression of EMT- and CSC-related genes in OSCC cells. In addition, blocking eIF5Ahpu robustly inhibited OSCC-induced M2-like TAM polarization in vitro. More Importantly, blocking eIF5Ahpu dramatically retarded tumor growth and infiltration/polarization of M2-like TAM in a syngeneic orthotopic murine tongue SCC model. Thus, eIF5Ahpu plays dual functions in regulating tumor cell growth and polarization of M2-TAMs in OSCC.

DHPS deficiency is a rare genetic disease caused by biallelic hypomorphic variants in the Deoxyhypusine synthase (DHPS) gene. The DHPS enzyme functions in mRNA translation by catalyzing the post-translational modification, and therefore activation, of eukaryotic initiation factor 5A (eIF5A). The observed clinical outcomes associated with human mutations in DHPS include developmental delay, intellectual disability, and seizures. Therefore, to increase our understanding of this rare disease, it is critical to determine the mechanisms by which mutations in DHPS alter neurodevelopment. In this study, we have generated patient-derived lymphoblast cell lines and demonstrated that human DHPS variants alter DHPS protein abundance and impair enzyme function. Moreover, we observe a shift in the abundance of the post-translationally modified forms of eIF5A; specifically, an increase in the nuclear localized acetylated form (eIF5A^AcK47) and concomitant decrease in the cytoplasmic localized hypusinated form (eIF5A^HYP). Generation and characterization of a mouse model with a genetic deletion of Dhps in the brain at birth shows that loss of hypusine biosynthesis impacts neuronal function due to impaired eIF5A^HYP-dependent mRNA translation; this translation defect results in altered expression of proteins required for proper neuronal development and function. This study reveals new insight into the biological consequences and molecular impact of human DHPS deficiency and provides valuable information toward the goal of developing treatment strategies for this rare disease.

The neuronal RNA-binding protein Ptbp2 regulates neuronal differentiation by modulating alternative splicing programs in the nucleus. Such programs contribute to axonogenesis by adjusting the levels of protein isoforms involved in axon growth and branching. While its functions in alternative splicing have been described in detail, cytosolic roles of Ptbp2 for axon growth have remained elusive. Here, we show that Ptbp2 is located in the cytosol including axons and growth cones of motoneurons, and that depletion of cytosolic Ptbp2 affects axon growth. We identify Ptbp2 as a major interactor of the 3' UTR of Hnrnpr mRNA encoding the RNA-binding protein hnRNP R. Axonal localization of Hnrnpr mRNA and local synthesis of hnRNP R protein are strongly reduced when Ptbp2 is depleted, leading to defective axon growth. Ptbp2 regulates hnRNP R translation by mediating the association of Hnrnpr with ribosomes in a manner dependent on the translation factor eIF5A2. Our data thus suggest a mechanism whereby cytosolic Ptbp2 modulates axon growth by fine-tuning the mRNA transport and local synthesis of an RNA-binding protein.

The MYC oncoprotein is activated in a broad spectrum of human malignancies and transcriptionally reprograms the genome to drive cancer cell growth. Given this, it is unclear if targeting a single effector of MYC will have therapeutic benefit. MYC activates the polyamine-hypusine circuit, which posttranslationally modifies the eukaryotic translation factor eIF5A. The roles of this circuit in cancer are unclear. Here we report essential intrinsic roles for hypusinated eIF5A in the development and maintenance of MYC-driven lymphoma, where the loss of eIF5A hypusination abolishes malignant transformation of MYC-overexpressing B cells. Mechanistically, integrating RNA sequencing, ribosome sequencing, and proteomic analyses revealed that efficient translation of select targets is dependent upon eIF5A hypusination, including regulators of G1-S phase cell-cycle progression and DNA replication. This circuit thus controls MYC's proliferative response, and it is also activated across multiple malignancies. These findings suggest the hypusine circuit as a therapeutic target for several human tumor types.

Elevated EIF5A and the polyamine-hypusine circuit are manifest in many malignancies, including MYC-driven tumors, and eIF5A hypusination is necessary for MYC proliferative signaling. Not-ably, this circuit controls an oncogenic translational program essential for the development and maintenance of MYC-driven lymphoma, supporting this axis as a target for cancer prevention and treatment. See related commentary by Wilson and Klein, p. 248. This article is highlighted in the In This Issue feature, p. 247.

Protein synthesis is essential to support homeostasis, and thus, must be highly regulated during cellular response to harmful environments. All stages of translation are susceptible to regulation under stress, however, the mechanisms involved in translation regulation beyond initiation have only begun to be elucidated. Methodological advances enabled critical discoveries on the control of translation elongation, highlighting its important role in translation repression and the synthesis of stress-response proteins. In this article, we discuss recent findings on mechanisms of elongation control mediated by ribosome pausing and collisions and the availability of tRNAs and elongation factors. We also discuss how elongation intersects with distinct modes of translation control, further supporting cellular viability and gene expression reprogramming. Finally, we highlight how several of these pathways are reversibly regulated, emphasizing the dynamics of translation control during stress-response progression. A comprehensive understanding of translation regulation under stress will produce fundamental knowledge of protein dynamics while opening new avenues and strategies to overcome dysregulated protein production and cellular sensitivity to stress.

Investigation on the interactions between enantiomers of chiral drugs and biomolecules can help precisely understand their biological behaviors in vivo and provide insights into the design of new drugs. Herein, we designed and synthesized a pair of optically pure, cationic, double-stranded dinuclear Ir(III)-metallohelices (Λ₂R₄-H and Δ₂S₄-H), and their dramatic enantiomer-dependent photodynamic therapy (PDT) responses were thoroughly studied in vitro and in vivo. Compared to the mononuclear enantiomeric or racemic [Ir(ppy)₂(dppz)][PF₆] (Λ-/Δ-Ir, rac-Ir) that with high dark toxicity and low photocytotoxicity index (PI) values, both of the optically pure metallohelices displayed negligible toxicity in the dark while exhibiting very distinctive light toxicity upon light irradiation. The PI value of Λ₂R₄-H was approximately 428, however, Δ₂S₄-H significantly reached 63,966. Interestingly, only Δ₂S₄-H was found to migrate from mitochondria to nucleus after light irradiation. Further proteomic analysis verified that Δ₂S₄-H activated the ATP-dependent migration process after light irradiation, and subsequently inhibited the activities of the nuclear proteins such as superoxide dismutase 1 (SOD1) and eukaryotic translation initiation factor 5A (EIF5A) to trigger the accumulation of superoxide anions and downregulate mRNA splicing processes. Molecular docking simulations suggested that the interactions between metallohelices and nuclear pore complex NDC1 dominated the migration process. This work presents a new kind of Ir(III) metallohelices-based agent with the highest PDT efficacy, highlights the importance of metallohelices' chirality, and provides inspirations for the future design of chiral helical metallodrugs.

Eukaryotic initiation factor 5A hypusine (eIF5A^Hyp) stimulates the translation of proline repeat motifs. Salt inducible kinase 2 (SIK2) containing a proline repeat motif is overexpressed in ovarian cancers, in which it promotes cell proliferation, migration, and invasion.

Western blotting and dual luciferase analyses showed that depletion of eIF5A^Hyp by GC7 or eIF5A-targeting siRNA downregulated SIK2 level and decreased luciferase activity in cells transfected with a luciferase-based reporter construct containing consecutive proline residues, whereas the activity of the mutant control reporter construct (replacing P825L, P828H, and P831Q) did not change. According to the MTT assay, GC7, which has a potential antiproliferative effect, reduced the viability of several ovarian cancer cell lines by 20-35% at high concentrations (ES2 > CAOV-3 > OVCAR-3 > TOV-112D) but not at low concentrations. In a pull-down assay, we identified eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and 4E-BP1 (p4E-BP1) phosphorylated at Ser 65 as downstream binding partners of SIK2, and we validated that the level of p4E-BP1(Ser 65) was downregulated by SIK2-targeting siRNA. Conversely, in ES2 cells overexpressing SIK2, the p4E-BP1(Ser 65) level was increased but decreased in the presence of GC7 or eIF5A-targeting siRNA. Finally, the migration, clonogenicity, and viability of ES2 ovarian cancer cells were reduced by GC7 treatment as well as by siRNA for eIF5A gene silencing and siRNA for SIK2 and 4E-BP1 gene silencing. Conversely, those activities were increased in cells overexpressing SIK2 or 4E-BP1 and decreased again in the presence of GC7.

The depletion of eIF5A^Hyp by GC7 or eIF5A-targeting siRNA attenuated activation of the SIK2-p4EBP1 pathway. In that way, eIF5A^Hyp depletion reduces the migration, clonogenicity, and viability of ES2 ovarian cancer cells.

Metabolic programs contribute to hematopoietic stem and progenitor cell (HSPC) fate, but it is not known whether the metabolic regulation of protein synthesis controls HSPC differentiation. Here, we show that SLC7A1/cationic amino acid transporter 1-dependent arginine uptake and its catabolism to the polyamine spermidine control human erythroid specification of HSPCs via the activation of the eukaryotic translation initiation factor 5A (eIF5A). eIF5A activity is dependent on its hypusination, a posttranslational modification resulting from the conjugation of the aminobutyl moiety of spermidine to lysine. Notably, attenuation of hypusine synthesis in erythroid progenitors, by the inhibition of deoxyhypusine synthase, abrogates erythropoiesis but not myeloid cell differentiation. Proteomic profiling reveals mitochondrial translation to be a critical target of hypusinated eIF5A, and accordingly, progenitors with decreased hypusine activity exhibit diminished oxidative phosphorylation. This affected pathway is critical for eIF5A-regulated erythropoiesis, as interventions augmenting mitochondrial function partially rescue human erythropoiesis under conditions of attenuated hypusination. Levels of mitochondrial ribosomal proteins (RPs) were especially sensitive to the loss of hypusine, and we find that the ineffective erythropoiesis linked to haploinsufficiency of RPS14 in chromosome 5q deletions in myelodysplastic syndrome is associated with a diminished pool of hypusinated eIF5A. Moreover, patients with RPL11-haploinsufficient Diamond-Blackfan anemia as well as CD34+ progenitors with downregulated RPL11 exhibit a markedly decreased hypusination in erythroid progenitors, concomitant with a loss of mitochondrial metabolism. Thus, eIF5A-dependent protein synthesis regulates human erythropoiesis, and our data reveal a novel role for RPs in controlling eIF5A hypusination in HSPCs, synchronizing mitochondrial metabolism with erythroid differentiation.

As professional secretory cells, beta cells require adaptable mRNA translation to facilitate a rapid synthesis of proteins, including insulin, in response to changing metabolic cues. Specialized mRNA translation programs are essential drivers of cellular development and differentiation. However, in the pancreatic beta cell, the majority of factors identified to promote growth and development function primarily at the level of transcription. Therefore, despite its importance, the regulatory role of mRNA translation in the formation and maintenance of functional beta cells is not well defined. In this study, we have identified a translational regulatory mechanism in the beta cell driven by the specialized mRNA translation factor, eukaryotic initiation factor 5A (eIF5A), which facilitates beta cell maturation. The mRNA translation function of eIF5A is only active when it is post-translationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS). We have discovered that the absence of beta cell DHPS in mice reduces the synthesis of proteins critical to beta cell identity and function at the stage of beta cell maturation, leading to a rapid and reproducible onset of diabetes. Therefore, our work has revealed a gatekeeper of specialized mRNA translation that permits the beta cell, a metabolically responsive secretory cell, to maintain the integrity of protein synthesis necessary during times of induced or increased demand.

Pancreatic beta cells are professional secretory cells that require adaptable mRNA translation for the rapid, inducible synthesis of proteins, including insulin, in response to changing metabolic cues. Our previous work in the exocrine pancreas showed that development and function of the acinar cells, which are also professional secretory cells, is regulated at the level of mRNA translation by a specialized mRNA translation factor, eIF5A ^HYP . We hypothesized that this translational regulation, which can be a response to stress such as changes in growth or metabolism, may also occur in beta cells. Given that the mRNA translation function of eIF5A is only active when the factor is post-translationally modified ("hypusinated") by the enzyme deoxyhypusine synthase (DHPS), we asked the question: does DHPS/eIF5A ^HYP regulate the formation and maintenance of functional beta cells? We discovered that in the absence of beta cell DHPS in mice, eIF5A is not hypusinated (activated), which leads to a reduction in the synthesis of critical beta cell proteins that interrupts pathways critical for identity and function. This translational regulation occurs at weaning age, which is a stage of cellular stress and maturation for the beta cell. Therefore without DHPS/eIF5A ^HYP , beta cells do not mature and mice progress to hyperglycemia and diabetes. Our findings suggest that secretory cells have a mechanism to regulate mRNA translation during times of cellular stress. Our work also implies that driving an increase in mRNA translation in the beta cell might overcome or possibly reverse the beta cell defects that contribute to early dysfunction and the progression to diabetes.