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Feedback control of MKP-1 expression by p38.
Jun-Hao Hu1, Ting Chen, Zi-Heng Zhuang
1Signal Transduction Lab of Institute of Health Sciences, Shanghai Institutes for Biological Sciences [corrected] Chinese Academy of Sciences & [corrected] Shanghai Jiao-Tong University School of Medicine, China.
Cellular Signalling
|September 19, 2006
Summary
p38 MAP kinase signaling regulates the expression of MAP kinase phosphatase-1 (MKP-1) post-transcriptionally. This pathway is crucial for controlling innate immune responses to microbial components like LPS and PGN.
Area of Science:
- Immunology
- Molecular Biology
- Cell Signaling
Background:
- Mitogen-activated protein (MAP) kinases are vital for innate immunity, controlling cytokine production during microbial infections.
- MAP kinase phosphatase-1 (MKP-1) deactivates MAP kinases, and its induction can attenuate responses to lipopolysaccharide (LPS) and peptidoglycan (PGN).
- The precise regulation of MKP-1 expression remains incompletely understood.
Purpose of the Study:
- To elucidate the regulatory mechanisms governing MKP-1 expression in response to microbial stimuli.
- To investigate the role of p38 MAP kinase signaling in controlling MKP-1 induction.
- To determine the impact of p38 inhibition on innate immune responses and LPS tolerance.
Main Methods:
- Utilized specific p38 inhibitor (SB 203580) and RNA interference (RNAi) to modulate p38 MAP kinase and MAPKAP kinase 2 (MK2) activity.
- Assessed MKP-1 expression levels in LPS- or PGN-treated macrophages.
- Examined mRNA levels and cycloheximide treatment to differentiate transcriptional and post-transcriptional regulation.
- Investigated MKP-1 expression in LPS-tolerized macrophages and subsequent MAP kinase activation.
Main Results:
- Inhibition of p38 MAP kinase or MK2 significantly reduced MKP-1 expression in stimulated macrophages.
- p38 inhibition prolonged p38 and JNK activation and affected MKP-1 expression at a post-transcriptional level.
- Blocking p38 prevented MKP-1 induction in LPS-tolerized macrophages, restoring MAP kinase activation upon restimulation.
Conclusions:
- p38 MAP kinase signaling, via MK2, critically mediates the post-transcriptional induction of MKP-1.
- The p38-MK2-MKP-1 pathway plays a significant role in regulating innate immune responses.
- Understanding this pathway offers insights into controlling inflammatory responses during microbial infections.
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