Transactivation of Abl by the Crk II adapter protein requires a PNAY sequence in the Crk C-terminal SH3 domain

Charles Reichman, Kamalendra Singh, Yan Liu, Sukhwinder Singh, Hong Li, J. Eduardo Fajardo, Andras Fiser, Raymond B. Birge

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


To gain a better understanding of how Crk II regulates the function of the Abl tyrosine kinase, we explored the function of the C-terminal linker and SH3 domain, a region of Crk II that is still poorly understood. Molecular modeling, tryptophan fluorescence, and covariation sequence alignment indicate that the Crk-SH3-C has a unique binding groove and RT loop not observed in typical SH3 domains. Based on these models, we made a series of mutations in the linker and in residues predicted to destabilize the putative binding pocket and RT loop. In Abl transactivation assays, Y222F and P225A mutations in the linker resulted in strong transactivation of Abl by Crk II. However, mutations predicted to be at the surface of the Crk SH3-C were not activators of Abl. Interestingly, combinations of activating mutations of Crk II with mutations in the highly conserved PNAY sequence in the SH3-C inactivated the activating mutations, suggesting that the SH3-C is necessary for activation. Our data provide insight into the role of highly conserved residues in the Crk-SH3-C, suggesting a mechanism for how the linker and the Crk-SH3-C function in the transactivation of the Abl tyrosine kinase.

Original languageEnglish (US)
Pages (from-to)8187-8199
Number of pages13
Issue number55
StatePublished - Dec 8 2005


  • Abl
  • Atypical
  • Covariation
  • Crk
  • Kinase activation
  • Protein modeling
  • SH3 domain

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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