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Mechanism of Regulation of Adipocyte Numbers in Adult Organisms Through Differentiation and Apoptosis Homeostasis
Published on: June 3, 2016
O-linked N-acetylglucosamine modification on CCAAT enhancer-binding protein beta: role during adipocyte
Xi Li1, Henrik Molina, Haiyan Huang
1Key Laboratory of Molecular Medicine, Ministry of Education, Fudan University Shanghai Medical College, Shanghai 200032, China.
The Journal of Biological Chemistry
|May 30, 2009
Summary
CCAAT enhancer-binding protein beta (C/EBPbeta) undergoes O-GlcNAc modification, which inhibits its phosphorylation and DNA binding. This sugar modification delays adipocyte differentiation, revealing a new regulatory mechanism for C/EBPbeta activity.
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- CCAAT enhancer-binding protein beta (C/EBPbeta) is a transcription factor involved in adipocyte differentiation.
- C/EBPbeta activity is regulated by post-translational modifications, including phosphorylation.
Purpose of the Study:
- To investigate the role of O-GlcNAc modification in regulating C/EBPbeta activity.
- To determine how O-GlcNAcylation affects C/EBPbeta phosphorylation and DNA binding during adipocyte differentiation.
Main Methods:
- In vitro and ex vivo experiments were used to analyze C/EBPbeta modification.
- Site-directed mutagenesis was employed to study the function of specific O-GlcNAcylation sites.
Main Results:
- O-GlcNAcylation occurs at Ser180 and Ser181 of C/EBPbeta.
- GlcNAcylation inhibits phosphorylation at key sites (Thr188, Ser184, Thr179), reducing DNA binding activity.
- Mutation of O-GlcNAcylation sites enhances C/EBPbeta transcriptional activity.
- C/EBPbeta O-GlcNAcylation delays adipocyte differentiation.
Conclusions:
- O-GlcNAcylation is a novel regulator of C/EBPbeta phosphorylation and DNA binding.
- This sugar modification plays a critical role in controlling adipocyte differentiation.
- The interplay between O-GlcNAcylation and phosphorylation modulates C/EBPbeta function.
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