Delta-interacting protein A, a new inhibitory partner of CCAAT/enhancer-binding protein beta, implicated in adipocyte differentiation.
CCAAT/enhancer-binding protein beta (C/EBP beta) is expressed early during the adipocyte differentiation program and plays an important role in this process. In an attempt to identify novel proteins that interact with C/EBP beta, we performed a yeast two-hybrid screen with a preadipocyte cDNA library and identified a new co-regulator, delta-interacting protein A (DIPA). DIPA mRNA is expressed during adipocyte differentiation of clonal cell lines. DIPA interacts with C/EBP beta and -delta proteins in intact cells and inhibits their transcriptional activity but not that of C/EBP alpha. Stable overexpression of DIPA in preadipocytes partially inhibits adipocyte differentiation, whereas its gene silencing enhances this process. DIPA and C/EBP beta co-localize in the nucleus, and overexpression of DIPA in preadipocytes results in a partial inhibition of the mitotic clonal expansion which is critical for differentiation. Thus, DIPA is a novel partner of C/EBP beta that down-regulates early events of adipogenesis.
Bezy
Olivier
O
Institute of Signaling, Developmental Biology, and Cancer Research, Centre de Biochimie, UMR 6543 CNRS, Faculté des Sciences, Parc Valrose, 06108 Nice cedex 2, France.
Elabd
Christian
C
Cochet
Olivia
O
Petersen
Rasmus K
RK
Kristiansen
Karsten
K
Dani
Christian
C
Ailhaud
Gérard
G
Amri
Ez-Zoubir
EZ
D048868:Adaptor Proteins, Signal Transducing; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000037:antagonists & inhibitors* / Q000235:genetics; D002352:Carrier Proteins / Q000502:physiology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D020868:Gene Silencing; D051379:Mice; D008938:Mitosis; D041681:NIH 3T3 Cells; D047495:PPAR gamma / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D022782:CCAAT-Enhancer-Binding Protein-beta; C101409:CCDC85B protein, human; D002352:Carrier Proteins; C575862:DIPA protein, mouse; D047495:PPAR gamma; D012097:Repressor Proteins