title: Solution structure of the second SH3 domain of human CMS and a newly identified binding site at the C-terminus of c-Cbl.
abstract: CMS, cas ligand with multiple Src homology 3 (SH3) domains, belongs to a family of ubiquitously expressed adaptor proteins. Among the CMS binding proteins, c-Cbl has been mostly extensively studied. It was reported that the motif PKPFPR (residues 824-829) of c-Cbl can bind to the N-terminus SH3 domains of CMS. Here we report the solution structure of the second SH3 domain of CMS (CMS_SH3_B), furthermore, we have identified that a peptide from residues 701 to 714 of c-Cbl (Cbl-p), i.e. MTPSSRPLRPLDTS, can specially bind to CMS_SH3_B using NMR chemical shift perturbation, suggesting that the peptide is a new potential CMS binding site. Among the peptide, TPSSRPLR is the core binding motif and Arg709 plays a key role in the interaction. Cbl-p binding interface on CMS_SH3_B along a hydrophobic channel is composed of RT loop, n-Src loop and beta4 strand and divided into three pockets. This work indicates the solution structure of CMS_SH3_B bears the canonical beta-beta-beta-beta-alpha-beta fold and a new binding site in c-Cbl involved in its interaction with CMS, which probably contributes to the clustering of CMS. All the information provided here should be beneficial for the future functional study of CMS.
authors.affiliation: School of Life Science, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230027, Peoples Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Yao
authors.forename: Jiahai
authors.initials: J
authors.lastname: Zhang
authors.forename: Haiming
authors.initials: H
authors.lastname: Dai
authors.forename: Jianping
authors.initials: J
authors.lastname: Sun
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Jiao
authors.forename: Yajun
authors.initials: Y
authors.lastname: Tang
authors.forename: Jihui
authors.initials: J
authors.lastname: Wu
authors.forename: Yunyu
authors.initials: Y
authors.lastname: Shi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry*; D000595:Amino Acid Sequence; D001665:Binding Sites; D003598:Cytoskeletal Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D050721:Proto-Oncogene Proteins c-cbl / Q000737:chemistry*; D016415:Sequence Alignment; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C114545:CD2-associated protein; D003598:Cytoskeletal Proteins; D050721:Proto-Oncogene Proteins c-cbl; C067419:CBL protein, human