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Published on: July 17, 2019

p21-activated kinase 1 (PAK1) interacts with the Grb2 adapter protein to couple to growth factor signaling

Lorena A Puto1, Kersi Pestonjamasp, Charles C King

  • 1Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.

The Journal of Biological Chemistry
|January 11, 2003
PubMed

Insights

The adapter protein Grb2 links p21-activated kinase 1 (PAK1) to the epidermal growth factor receptor (EGFR) signaling pathway. This interaction is crucial for regulating cell membrane extensions, impacting cytoskeletal dynamics.

Area of Science:

  • Cell Biology
  • Molecular Signaling
  • Signal Transduction

Background:

  • Intracellular signaling pathways connect to cell surface receptors via adapter molecules containing Src homology 2 (SH2) and SH3 domains.
  • p21-activated kinase 1 (PAK1) is a key effector of Rac/Cdc42 GTPases involved in cytoskeletal dynamics, proliferation, and cell survival.

Purpose of the Study:

  • To investigate the interaction between PAK1 and the Grb2 adapter protein.
  • To elucidate the role of Grb2 in mediating PAK1 signaling in response to epidermal growth factor receptor (EGFR) stimulation.

Main Methods:

  • In vitro and in vivo biochemical assays to detect protein-protein interactions.
  • Identification of the specific binding site between PAK1 and Grb2.
  • Use of cell-permeant peptides to block protein interactions.
  • Assessment of cellular responses, such as membrane lamellae extension.

Main Results:

  • A direct interaction between PAK1 and Grb2 was confirmed both in vitro and in vivo.
  • The second proline-rich SH3 binding domain of PAK1 was identified as the interaction site for Grb2.
  • Epidermal growth factor receptor (EGFR) stimulation enhanced PAK1 and Grb2 association with EGFR.
  • Blocking the PAK1-Grb2 interaction with a specific peptide inhibited EGFR-induced membrane lamellae extension.

Conclusions:

  • Grb2 acts as a crucial adapter protein, linking PAK1 to activated EGFR signaling pathways.
  • The Grb2-mediated interaction is essential for regulating EGFR-induced cytoskeletal rearrangements, specifically membrane lamellae extension.
  • This study reveals a novel mechanism by which Grb2 integrates downstream PAK signaling with upstream receptor tyrosine kinase pathways.

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