Abstract
CCAAT/enhancer-binding protein (C/EBP) β plays an important role in proliferation and differentiation of 3T3-L1 preadipocytes. C/EBPβ is sequentially phosphorylated during the 3T3-L1 adipocyte differentiation program, first by MAPK/Cyclin A/cdk2 on Thr 188 and subsequently by GSK3β on Ser 184 or Thr 179. Dual phosphorylation is critical for the gain of DNA binding activity of C/EBPβ. In this manuscript, we found that phosphorylation also contributed to the stability of C/EBPβ. Both ex vivo and in vitro experiments showed that phosphorylation by MAPK/Cyclin A/cdk2 and GSK3β protected C/EBPβ from μ-calpain-mediated proteolysis, while phosphorylation on Thr 188 by MAPK/Cyclin A/cdk2 contributed more to the stabilization of C/EBPβ, Further studies indicated that phosphorylation mimic C/EBPβ was insensitive to both calpain accelerator and calpain inhibitor. Thus, phosphorylation might contribute to the stability as well as the gain of DNA binding activity of C/EBPβ.
Original language | English (US) |
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Pages (from-to) | 550-555 |
Number of pages | 6 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 419 |
Issue number | 3 |
DOIs | |
State | Published - Mar 16 2012 |
Externally published | Yes |
Keywords
- C/EBPβ
- Calpain
- Degradation
- Phosphorylation
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Cell Biology
- Molecular Biology