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Cell adhesion regulates the interaction between Nck and p21-activated kinase
1Department of Pharmacology and the Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599-7365, USA. Alan_Howe@med.unc.edu
The Journal of Biological Chemistry
|March 30, 2001
Summary
Cell adhesion dynamically regulates p21-activated kinases (PAKs) interaction with Nck. This reversible regulation, tied to PAK phosphorylation, influences cell anchorage-dependence and localization.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- p21-activated kinases (PAKs) are crucial for cytoskeletal dynamics and cell motility.
- PAKs are regulated by Rho family GTPases (Rac, Cdc42) and are activated by serum components.
- Cell adhesion to the extracellular matrix (ECM) is critical for PAK activation, which binds the Nck adapter protein.
Purpose of the Study:
- To investigate the dynamic regulation of PAK-Nck interaction by cell adhesion.
- To elucidate the role of cell adhesion in controlling PAK activity and localization.
Main Methods:
- Studied the binding of PAK to Nck in adherent versus detached cells.
- Analyzed PAK phosphorylation status using electrophoretic mobility shift assays.
- Investigated the effect of fibronectin re-adhesion on PAK-Nck interaction.
Main Results:
- PAK-Nck binding is rapidly lost upon cell detachment and restored upon re-adhesion to fibronectin.
- Loss of Nck binding correlates with altered PAK phosphorylation in nonadherent cells.
- Identified specific phosphorylation changes in a sequence mediating Nck interaction.
Conclusions:
- Cell adhesion provides a rapidly reversible regulatory mechanism for PAK-Nck interaction.
- Adhesion-dependent regulation of PAK phosphorylation and Nck binding contributes to anchorage-dependence of PAK activation.
- This mechanism likely influences the spatial localization of activated PAK within the cell.