Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2011 Jan 7;286(1):480-90. doi: 10.1074/jbc.M110.173526. Epub 2010 Oct 28.

Structural basis for c-KIT inhibition by the suppressor of cytokine signaling 6 (SOCS6) ubiquitin ligase.

Author information

  • 1Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-17177 Stockholm, Sweden.

Abstract

The c-KIT receptor tyrosine kinase mediates the cellular response to stem cell factor (SCF). Whereas c-KIT activity is important for the proliferation of hematopoietic cells, melanocytes and germ cells, uncontrolled c-KIT activity contributes to the growth of diverse human tumors. Suppressor of cytokine signaling 6 (SOCS6) is a member of the SOCS family of E3 ubiquitin ligases that can interact with c-KIT and suppress c-KIT-dependent pathways. Here, we analyzed the molecular mechanisms that determine SOCS6 substrate recognition. Our results show that the SH2 domain of SOCS6 is essential for its interaction with c-KIT pY568. The 1.45-Å crystal structure of SOCS6 SH2 domain bound to the c-KIT substrate peptide (c-KIT residues 564-574) revealed a highly complementary and specific interface giving rise to a high affinity interaction (K(d) = 0.3 μm). Interestingly, the SH2 binding pocket extends to substrate residue position pY+6 and envelopes the c-KIT phosphopeptide with a large BG loop insertion that contributes significantly to substrate interaction. We demonstrate that SOCS6 has ubiquitin ligase activity toward c-KIT and regulates c-KIT protein turnover in cells. Our data support a role of SOCS6 as a feedback inhibitor of SCF-dependent signaling and provides molecular data to account for target specificity within the SOCS family of ubiquitin ligases.

PMID:
21030588
[PubMed - indexed for MEDLINE]
PMCID:
PMC3013007
Free PMC Article

Images from this publication.See all images (7)Free text

FIGURE 1.
FIGURE 2.
FIGURE 3.
FIGURE 4.
FIGURE 5.
FIGURE 6.
FIGURE 7.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk