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Trihydrophobin 1 Interacts with PAK1 and Regulates ERK/MAPK Activation and Cell Migration
Chunming Cheng1, Xiangfei Kong, Hanzhou Wang
1Gene Research Center, Shanghai Medical College, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China.
The Journal of Biological Chemistry
|January 13, 2009
Summary
Trihydrophobin 1 (TH1) interacts with p21-activated kinase 1 (PAK1), inhibiting its activity and negatively regulating MAPK signaling. This interaction impacts cell migration by affecting actin and adhesion dynamics.
Area of Science:
- Cell biology
- Molecular signaling
- Biochemistry
Background:
- p21-activated kinase (PAK) regulates cell proliferation and motility, and is crucial for RAF-MEK-MAPK cascade activation.
- Trihydrophobin 1 (TH1) was previously identified as a negative regulator of A-RAF kinase.
Purpose of the Study:
- To investigate the interaction between TH1 and PAK1.
- To elucidate the role of TH1 in PAK1-mediated signaling and cell migration.
Main Methods:
- Confocal microscopy to assess colocalization of TH1 and PAK1.
- GST pulldown and coimmunoprecipitation to confirm direct interaction.
- In vitro kinase activity assays and Western blot to evaluate kinase inhibition.
- Cell migration assays to assess the effect of TH1 on cell motility.
Main Results:
- TH1 directly interacts with PAK1, preferentially binding to its kinase domain, with binding enhanced upon PAK1 activation.
- TH1 inhibits PAK1 kinase activity and negatively regulates MAPK signaling.
- TH1 localizes to focal adhesions and filopodia, reducing cell migration by impacting actin and adhesion dynamics.
Conclusions:
- TH1 acts as an inhibitor of PAK1 and MAPK signaling.
- TH1 influences cell migration through modulation of actin and adhesion dynamics at the leading edge.
- A model is proposed where TH1 restricts MAPK module activation upstream, affecting cell migration.
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