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09:11
Assays for Validating Histone Acetyltransferase Inhibitors
Published on: August 6, 2020
p300-mediated acetylation stabilizes the Th-inducing POK factor
Min Zhang1, Jiali Zhang, Jinxiu Rui
1Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.
Journal of Immunology (Baltimore, Md. : 1950)
|September 3, 2010
Summary
The protein Th-inducing POK (ThPOK) is stabilized by acetylation, a process crucial for CD4 T cell differentiation. This acetylation prevents ThPOK degradation, impacting T cell lineage specification.
Area of Science:
- Immunology
- Molecular Biology
- Cellular Differentiation
Background:
- Th-inducing POK (ThPOK) is a key transcription factor for CD4 T cell development.
- Transcriptional regulation of ThPOK is well-studied, but posttranslational modifications remain unclear.
Purpose of the Study:
- To investigate posttranslational modifications of ThPOK.
- To determine the role of acetylation in ThPOK stability and function.
- To elucidate the mechanism of ThPOK regulation in CD4/CD8 T cell lineage differentiation.
Main Methods:
- Protein stability assays comparing CD4 and CD8 T cells.
- Co-immunoprecipitation to identify binding proteins.
- Mass spectrometry to identify acetylation sites.
- Site-directed mutagenesis to assess the impact of acetylation-deficient mutations.
Main Results:
- ThPOK is less stable and more rapidly degraded in CD8 T cells than in CD4 T cells.
- Acetyltransferase p300 acetylates ThPOK at K210, K216, and K339, stabilizing the protein by inhibiting ubiquitination.
- Reduced p300-mediated acetylation leads to ThPOK degradation in CD4 T cells.
- Mutating these lysines to arginines stabilizes ThPOK and enhances its suppressive function in CD8 T cells.
Conclusions:
- p300-mediated acetylation is essential for ThPOK stability.
- Regulation of ThPOK stability via acetylation plays a critical role in CD4/CD8 T cell lineage determination.
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