Regulation of signal transducers and activators of transcription (STATs) by effectors of adipogenesis: coordinate regulation of STATs 1, 5A, and 5B with peroxisome proliferator-activated receptor-gamma and C/AAAT enhancer binding protein-alpha.
We have recently demonstrated that three signal transducers and activators of transcription (STAT) family members are induced during adipocyte differentiation (Stephens et al., J. Biol. Chem. 271 (1996) 10441-10444). Since STATs 1, 5A, and 5B are induced during adipocyte differentiation, we have examined the ability of these proteins to be regulated by components of the differentiation cocktail. In addition, we have examined the effects of potent effectors of differentiation on STAT protein expression during adipogenesis. A negative effector, tumor necrosis factor-alpha (TNFalpha), and a positive effector, a thiazolidinedione, were used in these experiments. Our results demonstrate that the expression of STATs 1, 5A, and 5B is not dramatically influenced by individual components of the differentiation cocktail. However, the expression of these three STAT family members tightly correlates with lipid accumulation. Moreover, the expression of STATs 1, 5A, and 5B, but not STATs 3 and 6, are regulated in an identical fashion to both C/AAAT enhancer binding proteins alpha and peroxisome proliferator-activated receptor-gamma by TNFalpha and a thiazolidinedione. Furthermore, the expression of adipocyte-expressed JAK kinases are unaffected by effectors of differentiation. These findings suggest that three STAT family members may play a role in the regulation of adipocyte gene expression.
Stewart
W C
WC
Middle Tennessee State University, Department of Biology, Murfreesboro, TN, USA.
Morrison
R F
RF
Young
S L
SL
Stephens
J M
JM
D016475:3T3 Cells; D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology; D022762:CCAAT-Enhancer-Binding Proteins; D002454:Cell Differentiation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D008055:Lipids / Q000032:analysis; D051379:Mice; D008894:Milk Proteins; D009687:Nuclear Proteins / Q000378:metabolism*; D020025:Peroxisome Proliferators / Q000378:metabolism*; D050794:STAT1 Transcription Factor; D050799:STAT5 Transcription Factor; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D045162:Thiazolidinediones; D015534:Trans-Activators / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D001578:Benzopyrans; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D008055:Lipids; D008894:Milk Proteins; D009687:Nuclear Proteins; D020025:Peroxisome Proliferators; D050794:STAT1 Transcription Factor; D050799:STAT5 Transcription Factor; C494080:Stat1 protein, mouse; D013844:Thiazoles; D045162:Thiazolidinediones; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; C066021:englitazone