1yvh
Crystal Structure of the c-Cbl TKB Domain in Complex with the APS pTyr-618 Phosphopeptide
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| , resolution 2.05Å | |||||||
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| Ligands: | , | ||||||
| Gene: | CBL, CBL2, RNF55 (Homo sapiens) | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
The Cbl adapter proteins typically function to down-regulate activated protein tyrosine kinases and other signaling proteins by coupling them to the ubiquitination machinery for degradation by the proteasome. Cbl proteins bind to specific tyrosine-phosphorylated sequences in target proteins via the tyrosine kinase-binding (TKB) domain, which comprises a four-helix bundle, an EF-hand calcium-binding domain, and a non-conventional Src homology-2 domain. The previously derived consensus sequence for phosphotyrosine recognition by the Cbl TKB domain is NXpY(S/T)XXP (X denotes lesser residue preference), wherein specificity is conferred primarily by residues C-terminal to the phosphotyrosine. Cbl is recruited to and phosphorylated by the insulin receptor in adipose cells through the adapter protein APS. APS is phosphorylated by the insulin receptor on a C-terminal tyrosine residue, which then serves as a binding site for the Cbl TKB domain. Using x-ray crystallography, site-directed mutagenesis, and calorimetric studies, we have characterized the interaction between the Cbl TKB domain and the Cbl recruitment site in APS, which contains a sequence motif, RA(V/I)XNQpY(S/T), that is conserved in the related adapter proteins SH2-B and Lnk. These studies reveal a novel mode of phosphopeptide interaction with the Cbl TKB domain, in which N-terminal residues distal to the phosphotyrosine directly contact residues of the four-helix bundle of the TKB domain.
About this StructureAbout this Structure
1YVH is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structural characterization of a novel Cbl phosphotyrosine recognition motif in the APS family of adapter proteins., Hu J, Hubbard SR, J Biol Chem. 2005 May 13;280(19):18943-9. Epub 2005 Feb 28. PMID:15737992
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