Novel mechanism of regulation of the non-receptor protein tyrosine kinase Csk: insights from NMR mapping studies and site-directed mutagenesis.
J Mol Biol
; 314(1): 129-38, 2001 Nov 16.
Article
em En
| MEDLINE
| ID: mdl-11724538
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 (15)N) 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.
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Base de dados:
MEDLINE
Assunto principal:
Mutagênese Sítio-Dirigida
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Quinases da Família src
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Domínios de Homologia de src
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Ressonância Magnética Nuclear Biomolecular
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Domínio Catalítico
Limite:
Humans
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Estados Unidos