title: 4E-BP1 regulates the differentiation of white adipose tissue.
abstract: 4E Binding protein 1 (4E-BP1) suppresses translation initiation. The absence of 4E-BP1 drastically reduces the amount of adipose tissue in mice. To address the role of 4E-BP1 in adipocyte differentiation, we characterized 4E-BP1(-/-) mice in this study. The lack of 4E-BP1 decreased the amount of white adipose tissue and increased the amount of brown adipose tissue. In 4E-BP1(-/-) MEF cells, PPARγ coactivator 1 alpha (PGC-1α) expression increased and exogenous 4E-BP1 expression suppressed PGC-1α expression. The level of 4E-BP1 expression was higher in white adipocytes than in brown adipocytes and showed significantly greater up-regulation in white adipocytes than in brown adipocytes during preadipocyte differentiation into mature adipocytes. The amount of PGC-1α was consistently higher in HB cells (a brown preadipocyte cell line) than in HW cells (a white preadipocyte cell line) during differentiation. Moreover, the ectopic over-expression of 4E-BP1 suppressed PGC-1α expression in white adipocytes, but not in brown adipocytes. Thus, the results of our study indicate that 4E-BP1 may suppress brown adipocyte differentiation and PGC-1α expression in white adipose tissues.
authors.affiliation: Department of Experimental Phylaxiology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto-City, Kumamoto 860-8556, Japan. kkohara@agri.kagoshima-u.ac.jp
authors.forename: Kyoko
authors.initials: K
authors.lastname: Tsukiyama-Kohara
authors.forename: Asao
authors.initials: A
authors.lastname: Katsume
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saito
authors.forename: Michinori
authors.initials: M
authors.lastname: Kohara
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D052436:Adipose Tissue, White / Q000166:cytology* / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D002478:Cells, Cultured; D039642:Eukaryotic Initiation Factors; D005260:Female; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010750:Phosphoproteins / Q000096:biosynthesis / Q000172:deficiency / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C499527:Eif4ebp1 protein, mouse; D039642:Eukaryotic Initiation Factors; D010750:Phosphoproteins