Title of article :
Novel mechanism of regulation of the non-receptor protein tyrosine kinase csk: insights from NMR mapping studies and site-directed mutagenesis
Author/Authors :
Alexander Shekhtman، نويسنده , , Ranajeet Ghose، نويسنده , , Dongxia Wang، نويسنده , , Philip A. Cole، نويسنده , , David Cowburn، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2001
Pages :
10
From page :
129
To page :
138
Abstract :
Csk (C-terminal Src kinase), a protein tyrosine kinase, consisting of the Src homology 2 and 3 (SH2 and SH3) domains and a catalytic domain, phosphorylates the C-terminal tail of Src-family members, resulting in downregulation of the Src family kinase activity. The Src family kinases share 37 % homology with Csk but, unlike Src-family kinases, the catalytic domain of Csk alone is weakly active and can be stimulated in trans by interacting with the Csk-SH3 domain, suggesting a mode of intradomain regulation different from that of Src family kinases. The structural determinants of this intermolecular interaction were studied by nuclear magnetic resonance (NMR) and site-directed mutagenesis techniques. Chemical shift perturbation of backbone nuclei (H′ and 15N) has been used to map the Csk catalytic domain binding site on the Csk-SH3. The experimentally determined interaction surface includes three structural elements: the N-terminal tail, a small part of the RT-loop, and the C-terminal SH3-SH2 linker. Site-directed mutagenesis revealed that mutations in the SH3-SH2 linker of the wild-type Csk decrease Csk kinase activity up to fivefold, whereas mutations in the RT-loop left Csk kinase activity largely unaffected. We conclude that the SH3-SH2 linker plays a major role in the activation of the Csk catalytic domain.
Keywords :
Protein tyrosine kinase , SH3 domain , Src-family kinases , heteronuclear NMR
Journal title :
Journal of Molecular Biology
Serial Year :
2001
Journal title :
Journal of Molecular Biology
Record number :
1241249
Link To Document :
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