Article
- The EMBO Journal (2008) 27, 804 - 816
- doi:10.1038/emboj.2008.18
Published online: 14 February 2008
Subject Categories:
Structural basis for a novel intrapeptidyl H-bond and reverse binding of c-Cbl-TKB domain substrates
Cherlyn Ng1,3, Rebecca A Jackson2,3, Jan P Buschdorf2, Qingxiang Sun1, Graeme R Guy2 and J Sivaraman1
- Department of Biological Sciences, National University of Singapore, Singapore
- Institute of Molecular and Cell Biology, Proteos, Singapore
Correspondence to:
J Sivaraman, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore. Tel.: +65 6516 1163; Fax: +65 6779 5671; E-mail: dbsjayar@nus.edu.sg
Graeme R Guy, Institute of Molecular and Cell Biology, Proteos, Singapore, Singapore. Tel.: +65 6586 9614; Fax: +65 6779 1117; E-mail: mcbgg@imcb.a-star.edu.sg
3These authors contributed equally to this work
Received 20 November 2007; Accepted 17 January 2008
Abstract
The c-Cbl tyrosine kinase binding domain (Cbl-TKB), essentially an 'embedded' SH2 domain, has a critical role in targeting proteins for ubiquitination. To address how this domain can bind to disparate recognition mofits and to determine whether this results in variations in substrate-binding affinity, we compared crystal structures of the Cbl-TKB domain complexed with phosphorylated peptides of Sprouty2, Sprouty4, epidermal growth factor receptor, Syk, and c-Met receptors and validated the binding with point-mutational analyses using full-length proteins. An obligatory, intrapeptidyl H-bond between the phosphotyrosine and the conserved asparagine or adjacent arginine is essential for binding and orientates the peptide into a positively charged pocket on c-Cbl. Surprisingly, c-Met bound to Cbl in the reverse direction, which is unprecedented for SH2 domain binding. The necessity of this intrapeptidyl H-bond was confirmed with isothermal titration calorimetry experiments that also showed Sprouty2 to have the highest binding affinity to c-Cbl; this may enable the selective sequestration of c-Cbl from other target proteins.
Keywords:
- c-Cbl,
- EGFR,
- Met,
- reverse binding,
- Sprouty,
- TKB domain,
- X-ray crystallography
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated
REVIEWS
From Tpr-Met to Met, tumorigenesis and tubes
Oncogene Review
Cbl: many adaptations to regulate protein tyrosine kinases
Nature Reviews Molecular Cell Biology Review (01 Apr 2001)
Phosphotyrosine-binding domains in signal transduction
Nature Reviews Molecular Cell Biology Review (01 Mar 2002)
Positive and negative regulation of t-cell activation by adaptor proteins
Nature Reviews Immunology Review (01 Nov 2001)
