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07:09
Myeloid Innate Signaling Pathway Regulation by MALT1 Paracaspase Activity
Published on: January 7, 2019
c-Maf interacts with c-Myb to down-regulate Bcl-2 expression and increase apoptosis in peripheral CD4 cells
Siying Peng1, Saif Lalani, Jianmei W Leavenworth
1Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794, USA.
European Journal of Immunology
|September 8, 2007
Summary
The transcription factor c-Maf increases CD4 cell susceptibility to apoptosis by reducing Bcl-2 expression. This interaction with c-Myb impacts T cell survival and immune responses.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- The transcription factor c-Maf is essential for Interleukin-4 (IL-4) production and T helper 2 (Th2) cell development.
- c-Maf's specific functions within CD4 cells beyond Th2 differentiation remain largely unexplored.
Purpose of the Study:
- To investigate the novel role of c-Maf in regulating CD4 cell apoptosis.
- To elucidate the molecular mechanisms by which c-Maf influences T cell survival.
Main Methods:
- Overexpression of c-Maf in CD4 cells.
- Induction of apoptosis using various stimuli (growth factor withdrawal, dexamethasone, irradiation, TCR engagement).
- Immunoprecipitation, Western blot, chromatin immunoprecipitation, and reporter assays to analyze protein interactions and gene regulation.
- Analysis of Bcl-2 and c-Myb expression and promoter activity.
Main Results:
- Overexpression of c-Maf significantly increases CD4 cell apoptosis susceptibility, independent of Fas or p53.
- c-Maf overexpression leads to reduced Bcl-2 expression in CD4 cells.
- Enhanced c-Maf-c-Myb complex formation and decreased c-Myb binding to the Bcl-2 promoter were observed in c-Maf transgenic T cells.
- Reporter assays confirmed c-Maf's dose-dependent reduction of Bcl-2 promoter activity.
- Restoration of Bcl-2 expression corrected the apoptosis defect in c-Maf transgenic CD4 cells.
Conclusions:
- c-Maf plays a critical role in regulating CD4 cell apoptosis.
- c-Maf interacts with c-Myb to suppress Bcl-2 expression, thereby limiting CD4 cell survival.
- This mechanism impacts T cell survival following T cell receptor (TCR) engagement and may influence immune responses.
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