Current understanding of glucose transporter 4 expression and functional mechanisms

Table 3 Recent studies of effects of bioactive compounds and chemical drugs on glucose transporter 4 expression and translocation in adipocytes

Methods	Materials	Comparisons	Conclusions	Ref.
Immunoprecipitation, dual fluorescence immunostaining, Western blot.	3T3-L1, anti-GLUT4 from Santa Cruz Biotechnology (1:200).	Treatments without or with kaempferitrin.	Kaempferitrin treatment upregulates total GLUT4 expression and its translocation in 3T3-L1 cells.	[95]
Subcellular fractionations, Western blot.	3T3-L1, anti-GLUT4 from Cell Signaling Technology (1:1000).	Treatments without or with epigallocatechin gallate.	Green tea epigallocatechin gallate suppresses insulin-like growth factor-induced-glucose uptake via inhibition of GLUT4 translocation in 3T3-L1 cells.	[96]
Western blot.	3T3-L1, anti-GLUT4 from Santa Cruz Biotechnology.	Treatments without or with GW9662.	GW9662 increases the expression of GLUT4 protein in 3T3-L1 cells.	[97]
Immunoprecipitation, Western blot.	3T3-L1, anti-GLUT4 from Chemicon.	Treatments without or with p38 inhibition.	Inhibition of p38 enhances glucose uptake through the regulation of GLUT4 expressions in 3T3-L1 cells.	[98]
Western blots, Real-time PCR, Electrophoretic mobility shift assay, Immunofluorescence.	Adipose tissues of Esr1 deletion and wild type female mice, 3T3-L1, anti-GLUT4 from Merck/Millipore for Western blot (1:4000), and for immunofluorescence (1:100).	Tissue and cells without or with gene deletion.	Estradiol stimulates adipocyte differentiation and Slc2a4 mRNA and GLUT4 protein expressions in an ESR1/CEBPA mediated manner in vitro and in vivo.	[99]
Real-time PCR, Solid-phase ELISA.	3T3-L1, anti-GLUT4 antibody from Pierce (1:1000).	Treatments without or with the extract.	The crude extract of stevia leaf can enhance Slc2a4 mRNA and GLUT4 protein levels in 3T3-L1 cells.	[100]
GeXP multiplex for mRNA, Western blot.	3T3-L1, anti-GLUT4 from Millipore (1:20).	Treatments without or with indicated reagents.	Curculigoside and ethyl acetate fractions increase glucose transport activity of 3T3-L1 adipocytes via GLUT4 translocation.	[101]
Real-time PCR, Western blot.	3T3-L1, anti-GLUT4 from Cell Signaling Technology.	Treatments without or with luteolin	Luteolin treatment decreases Slc2a4 mRNA and GLUT4 protein levels in 3T3-L1 cells.	[102]
Western blot.	3T3-L1, anti-GLUT4 from Abcam (ab654-250).	Treatments without or with extract.	Shilianhua extract treatment decreases GLUT4 protein level in 3T3-L1 cells.	[103]
Western blot.	3T3-L1, and male C57BL/6J mice fed a normal-fat or high-fat diet, anti-mouse GLUT4 from AbD SeroTec (1:1000).	Treatments without or with fargesin.	Fargesin treatment increases GLUT4 protein expression in 3T3-L1 cells and adipose tissues of mice.	[104]
Western blot.	3T3-L1, antibody no mentioned.	Treatments without or with phillyrin.	Phillyrin treatment increases the expression levels of GLUT4 protein in 3T3-L1 cells.	[105]
Real-time PCR, Western blot.	3T3-L1, anti-GLUT4 from Santa Cruz Biotechnology.	Treatments without or with 6Hydroxydaidzein.	6Hydroxydaidzein facilitates GLUT4 protein translocation, but did not affect Slc2a4 mRNA level in 3T3-L1 cells.	[106]
Western blot.	3T3-L1, and C57BL/6J mice with SirT1 and Ampkα1 knockdown, anti-GLUT4 from Signalway Antibody.	Treatments without or with indicated reagents.	Seleniumenriched exopolysaccharides produced by Enterobacter cloacae Z0206 increase the expression of GLUT4 protein in mice, but not in 3T3-L1 cells.	[107]
Western blot.	3T3-L1, anti-GLUT4 from Cell Signaling Technology	Treatments without or with extract.	Aspalathin-enriched green rooibos extract increases GLUT4 protein expression in 3T3-L1 cells.	[108]
Transient expression of myc-GLUT4-GFP and fluorescence microscopy.	3T3-L1, fusion protein only.	Treatments without or with indicated reagents.	Gallic acid can increase GLUT4 translocation and glucose uptake in 3T3-L1 cells.	[109]
Real-time PCR, Western blot.	3T3-L1, anti GLUT4 from Santa Cruz Biotechnology (1: 1000).	Treatments without or with Ginsenoside Re.	Ginsenoside Re promotes the translocation of GLUT4 by activating PPAR-γ2. Slc2a4 mRNA is not affected in 3T3-L1 cells.	[110]
Real-time PCR, GLUT4-myc7-GFP from retroviral vector, flow cytometry, fluorescence microscopy.	3T3-L1 with knockdown of PPARγ, fusion protein.	Cells without or with knockdown.	Bone morphogenetic proteins 2 and 6 inhibit PPARγ expression, which increases total GLUT4 levels, but not GLUT4 translocation3T3-L1 cells.	[111]
Western blot, real-time PCR.	3T3-L1, anti-GLUT4 antibody from Santa Cruz Biotechnology (sc-1608).	Treatments without or with pulse or manipulations.	Glucose pulse (25 mM) increases GLUT4 expression. GLUT4 level is partially restored by increasing intracellular NAD/P levels. A liver X receptor element on Slc2a4 promoter is responsible for glucose-dependent transcription.	[112]

GLUT4: Glucose transporter 4; AMPK: AMP-activated protein kinase; CEBPA and C/EBP: CCAAT/enhancer-binding protein alpha; ESR1: Estrogen receptor 1.