Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1997 Feb 13;385(6617):650-3.
doi: 10.1038/385650a0.

Activation of the Src-family tyrosine kinase Hck by SH3 domain displacement

Affiliations

Activation of the Src-family tyrosine kinase Hck by SH3 domain displacement

I Moarefi et al. Nature. .

Abstract

The protein Hck is a member of the Src family of non-receptor tyrosine kinases which is preferentially expressed in haematopoietic cells of the myeloid and B-lymphoid lineages. Src kinases are inhibited by tyrosine-phosphorylation at a carboxy-terminal site. The SH2 domains of these enzymes play an essential role in this regulation by binding to the tyrosine-phosphorylated tail. The crystal structure of the downregulated form of Hck has been determined and reveals that the SH2 domain regulates enzymatic activity indirectly; intramolecular interactions between the SH3 and catalytic domains appear to stabilize an inactive form of the kinase. Here we compare the roles of the SH2 and SH3 domains in modulating the activity of Hck in an investigation of the C-terminally phosphorylated form of the enzyme. We show that addition of the HIV-1 Nef protein, which is a high-affinity ligand for the Hck SH3 domain, to either the downregulated or activated form of Hck causes a large increase in Hck catalytic activity. The intact SH3-binding motif in Nef is crucial for Hck activation. Our results indicate that binding of the Hck SH3 domain by Nef causes a more marked activation of the enzyme than does binding of the SH2 domain, suggesting a new mechanism for regulation of the activity of tyrosine kinases.

PubMed Disclaimer

Comment in

  • New impressions of Src and Hck.
    Pawson T. Pawson T. Nature. 1997 Feb 13;385(6617):582-3, 585. doi: 10.1038/385582b0. Nature. 1997. PMID: 9024653 No abstract available.

Similar articles

Cited by

Publication types

MeSH terms

Substances

LinkOut - more resources