title: A novel peptide-SH3 interaction.
abstract: SH3 domains constitute a family of protein-protein interaction modules that bind to peptides displaying an X-proline-X-X-proline (XPXXP) consensus. We report that the SH3 domain of Eps8, a substrate of receptor and non-receptor tyrosine kinases, displays a novel and unique binding preference. By a combination of approaches including (i) screening of phage-displayed random peptide libraries, (ii) mapping of the binding regions on three physiological interactors of Eps8, (iii) alanine scanning of binding peptides and (iv) in vitro cross-linking, we demonstrate that a proline-X-X-aspartate-tyrosine (PXXDY) consensus is indispensable for binding to the SH3 domain of Eps8. Screening of the Expressed Sequence Tags database allowed the identification of three Eps8-related genes, whose SH3s also display unusual binding preferences and constitute a phylogenetically distinct subfamily within the SH3 family. Thus, Eps8 identifies a novel family of SH3-containing proteins that do not bind to canonical XPXXP-containing peptides, and that establish distinct interactions in the signaling network.
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Via Ripamonti 435, 20141 Milan.
authors.forename: A M
authors.initials: AM
authors.lastname: Mongioví
authors.forename: P R
authors.initials: PR
authors.lastname: Romano
authors.forename: S
authors.initials: S
authors.lastname: Panni
authors.forename: M
authors.initials: M
authors.lastname: Mendoza
authors.forename: W T
authors.initials: WT
authors.lastname: Wong
authors.forename: A
authors.initials: A
authors.lastname: Musacchio
authors.forename: G
authors.initials: G
authors.lastname: Cesareni
authors.forename: P P
authors.initials: PP
authors.lastname: Di Fiore
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D016384:Consensus Sequence; D003598:Cytoskeletal Proteins; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; C489989:EPS8 protein, human; C083430:Eps8 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D011506:Proteins; D011993:Recombinant Fusion Proteins