Determination of the substrate-docking site of protein tyrosine kinase C-terminal Src kinase

Sungsoo Lee, Xiaofeng Lin, Nguyen Hai Nam, Keykavous Parang, Gongqin Sun

Research output: Contribution to journalArticle

Abstract

Protein tyrosine kinases (PTK) are key enzymes of mammalian signal transduction. For the fidelity of signal transduction, each PTK phosphorylates only one or a few proteins on specific Tyr residues. Substrate specificity is thought to be mediated by PTK-substrate docking interactions and recognition of the phosphorylation site sequence by the kinase active site. However, a substrate-docking site has not been determined on any PTK. C-terminal Src kinase (Csk) is a PTK that specifically phosphorylates Src family kinases on a C-terminal Tyr. In this study, by sequence alignment and site-specific mutagenesis, we located a substrate-docking site on Csk. Mutations in the docking site disabled Csk to phosphorylate, regulate, and complex with Src but only moderately affected its general kinase activity. A peptide mimicking the docking site potently inhibited (IC50 = 21 μM) Csk phosphorylation of Src but only moderately inhibited (IC50 = 422 μM) its general kinase activity. Determination of the substrate-docking site provides the structural basis of substrate specificity in Csk and a model for understanding substrate specificity in other PTKs.

Original languageEnglish (US)
Pages (from-to)14707-14712
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume100
Issue number25
DOIs
StatePublished - Dec 9 2003
Externally publishedYes

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Protein-Tyrosine Kinases
Substrate Specificity
Phosphotransferases
Inhibitory Concentration 50
Signal Transduction
Phosphorylation
src-Family Kinases
Sequence Alignment
Site-Directed Mutagenesis
Catalytic Domain
CSK tyrosine-protein kinase
Peptides
Mutation
Enzymes
Proteins

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Determination of the substrate-docking site of protein tyrosine kinase C-terminal Src kinase. / Lee, Sungsoo; Lin, Xiaofeng; Nam, Nguyen Hai; Parang, Keykavous; Sun, Gongqin.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 100, No. 25, 09.12.2003, p. 14707-14712.

Research output: Contribution to journalArticle

Lee, Sungsoo ; Lin, Xiaofeng ; Nam, Nguyen Hai ; Parang, Keykavous ; Sun, Gongqin. / Determination of the substrate-docking site of protein tyrosine kinase C-terminal Src kinase. In: Proceedings of the National Academy of Sciences of the United States of America. 2003 ; Vol. 100, No. 25. pp. 14707-14712.
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