A kinase-independent function of PAK is crucial for pathogen-mediated actin remodelling

PLoS Pathog. 2021 Aug 30;17(8):e1009902. doi: 10.1371/journal.ppat.1009902. eCollection 2021 Aug.

Abstract

The p21-activated kinase (PAK) family regulate a multitude of cellular processes, including actin cytoskeleton remodelling. Numerous bacterial pathogens usurp host signalling pathways that regulate actin reorganisation in order to promote Infection. Salmonella and pathogenic Escherichia coli drive actin-dependent forced uptake and intimate attachment respectively. We demonstrate that the pathogen-driven generation of both these distinct actin structures relies on the recruitment and activation of PAK. We show that the PAK kinase domain is dispensable for this actin remodelling, which instead requires the GTPase-binding CRIB and the central poly-proline rich region. PAK interacts with and inhibits the guanine nucleotide exchange factor β-PIX, preventing it from exerting a negative effect on cytoskeleton reorganisation. This kinase-independent function of PAK may be usurped by other pathogens that modify host cytoskeleton signalling and helps us better understand how PAK functions in normal and diseased eukaryotic cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry*
  • Cytoskeleton / chemistry*
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Phosphorylation
  • Rho Guanine Nucleotide Exchange Factors / genetics
  • Rho Guanine Nucleotide Exchange Factors / metabolism
  • Salmonella Infections / metabolism
  • Salmonella Infections / microbiology*
  • Salmonella Infections / pathology
  • Salmonella enterica / physiology*
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism
  • p21-Activated Kinases / genetics
  • p21-Activated Kinases / metabolism*

Substances

  • ARHGEF7 protein, human
  • Actins
  • Membrane Proteins
  • Rho Guanine Nucleotide Exchange Factors
  • SCRIB protein, human
  • Tumor Suppressor Proteins
  • p21-Activated Kinases