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JAK2 tyrosine kinase phosphorylates PAK1 and regulates PAK1 activity and functions

Leah Rider1, Alla Shatrova, Edward P Feener

  • 1Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606-3390, USA.

The Journal of Biological Chemistry
|August 30, 2007
PubMed

Insights

The tyrosine kinase JAK2 phosphorylates PAK1 at specific sites, enhancing its activity. This phosphorylation is crucial for cell survival and motility, offering new insights into PAK1 regulation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The serine-threonine kinase PAK1 regulates cell survival through various mechanisms.
  • The role of tyrosyl phosphorylation in PAK1 regulation is not well understood.

Purpose of the Study:

  • To investigate the role of tyrosine kinase JAK2 in PAK1 phosphorylation and function.
  • To identify specific sites of JAK2-mediated tyrosyl phosphorylation on PAK1.

Main Methods:

  • In vivo and in vitro kinase assays using wild type and kinase-dead JAK2.
  • Mass spectrometry and two-dimensional peptide mapping to identify phosphorylation sites.
  • Site-directed mutagenesis of PAK1 tyrosines to phenylalanines.

Main Results:

  • JAK2 directly phosphorylates PAK1 at tyrosines 153, 201, and 285.
  • This tyrosyl phosphorylation significantly increases PAK1 kinase activity.
  • Phosphorylation of PAK1 by JAK2 enhances cell survival and motility while reducing apoptosis.

Conclusions:

  • JAK2-mediated tyrosyl phosphorylation of PAK1 at Y153, Y201, and Y285 is a key regulatory mechanism.
  • This phosphorylation event plays a critical role in promoting cell survival and motility.

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