Structural framework of c-Src activation by integrin β3

• Published in: Blood Vol. 121; no. 4; pp. 700 - 706
• Main Authors: Xiao, Run, Xi, Xiao-Dong, Chen, Zhu, Chen, Sai-Juan, Meng, Guoyu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 24.01.2013
• Subjects: Amino Acid Sequence; Binding Sites; Enzyme Activation; Integrin beta3 - chemistry; Integrin beta3 - metabolism; Models, Molecular; Molecular Sequence Data; Peptides - chemistry; Peptides - metabolism; Protein Binding; Protein Conformation; Proto-Oncogene Proteins pp60(c-src) - chemistry; Proto-Oncogene Proteins pp60(c-src) - genetics; Proto-Oncogene Proteins pp60(c-src) - metabolism; Sequence Alignment; src Homology Domains
• ISSN: 0006-4971; 1528-0020; 1528-0020
• DOI: 10.1182/blood-2012-07-440644

The integrin β3-mediated c-Src priming and activation, via the SH3 domain, is consistently associated with diseases, such as the formation of thrombosis and the migration of tumor cells. Conventionally, activation of c-Src is often induced by the binding of proline-rich sequences to its SH3 domain. Instead, integrin β3 uses R760GT762 for priming and activation. Because of the lack of structural information, it is not clear where RGT will bind to SH3, and under what mechanism this interaction can prime/activate c-Src. In this study, we present a 2.0-Å x-ray crystal structure in which SH3 is complexed with the RGT peptide. The binding site lies in the “N”-Src loop of the SH3 domain. Structure-based site-directed mutagenesis showed that perturbation on the “N”-Src loop disrupts the interaction between the SH3 domain and the RGT peptide. Furthermore, the simulated c-Src:β3 complex based on the crystal structure of SH3:RGT suggests that the binding of the RGT peptide might disrupt the intramolecular interaction between the SH3 and linker domains, leading to the disengagement of Trp260:“C”-helix and further activation of c-Src. •Crystal structure of SH3:RGT complex reveals how integrin β3 primes/activates c-Src kinase.