A Dimeric Kinase Assembly Underlying Autophosphorylation in the p21 Activated Kinases

Michelle Pirruccello, Holger Sondermann, Jeffrey G. Pelton, Patricia Pellicena, André Hoelz, Jonathan Chernoff, David E. Wemmer, John Kuriyan

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

The p21-activated kinases (PAKs) are serine/threonine kinases that are involved in a wide variety of cellular functions including cytoskeletal motility, apoptosis, and cell cycle regulation. PAKs are inactivated by blockage of the active site of the kinase domain by an N-terminal regulatory domain. GTP-bound forms of Cdc42 and Rac bind to the regulatory domain and displace it, thereby allowing phosphorylation of the kinase domain and maximal activation. A key step in the activation process is the phosphorylation of the activation loop of one PAK kinase domain by another, but little is known about the underlying recognition events that make this phosphorylation specific. We show that the phosphorylated kinase domain of PAK2 dimerizes in solution and that this association is prevented by addition of a substrate peptide. We have identified a crystallographic dimer in a previously determined crystal structure of activated PAK1 in which two kinase domains are arranged face to face and interact through a surface on the large lobe of the kinase domain that is exposed upon release of the auto-inhibitory domain. The crystallographic dimer is suggestive of an engagement that mediates trans-autophosphorylation. Mutations at the predicted dimerization interface block dimerization and reduce the rate of autophosphorylation, supporting the role of this interface in PAK activation.

Original languageEnglish
Pages (from-to)312-326
Number of pages15
JournalJournal of Molecular Biology
Volume361
Issue number2
DOIs
StatePublished - Aug 11 2006

Keywords

  • NMR
  • P21 activated kinase
  • autophosphorylation
  • kinase
  • protein kinase substrate

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