title: Novel insights into the mechanisms of CIN85 SH3 domains binding to Cbl proteins: solution-based investigations and in vivo implications.
abstract: CIN85 is a multifunctional protein that plays key roles in endocytic down-regulation of receptor tyrosine kinases, apoptosis, cell adhesion, and cytoskeleton rearrangement. Its three SH3 domains (CIN85A, CIN85B, and CIN85C) allow it to recruit multiple binding partners. To understand the manifold interactions of CIN85, we present a detailed high-resolution solution structural study of CIN85A and CIN85B binding to proline-arginine peptides derived from the cognate ligands Cbl and Cbl-b. We report the structure of CIN85B and provide evidence that both CIN85A and CIN85B, in isolation or when linked, form heterodimeric complexes with the peptides. We report unusual curved chemical shift changes for several residues of CIN85A when titrated with Cbl-b peptide, indicating the existence of more than one complex form. Here we demonstrate that CIN85A and CIN85B use different mechanisms for peptide binding.
authors.affiliation: Department of Biochemistry and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Abdessamad
authors.initials: A
authors.lastname: Ababou
authors.forename: Mark
authors.initials: M
authors.lastname: Pfuhl
authors.forename: John E
authors.initials: JE
authors.lastname: Ladbury
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D002151:Calorimetry; D017124:Conserved Sequence; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D050721:Proto-Oncogene Proteins c-cbl / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012996:Solutions; D013816:Thermodynamics; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D008024:Ligands; D046912:Multiprotein Complexes; D010446:Peptide Fragments; D011994:Recombinant Proteins; C433810:SH3KBP1 protein, human; D012996:Solutions; D050721:Proto-Oncogene Proteins c-cbl; C067419:CBL protein, human