Intersectin, a Novel Adaptor Protein with Two Eps15 Homology and Five Src Homology 3 Domains

• Published in: The Journal of biological chemistry 1998-11, Vol.273 (47), p.31401-31407
• Main Authors: Yamabhai, Montarop, Hoffman, Noah G., Hardison, Nancy L., McPherson, Peter S., Castagnoli, Luisa, Cesareni, Gianni, Kay, Brian K.
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing; Adaptor Proteins, Vesicular Transport; Amino Acid Sequence; Animals; Binding, Competitive; Calcium-Binding Proteins - chemistry; Carrier Proteins - genetics; Carrier Proteins - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Dynamins; Endocytosis; Gene Library; GTP Phosphohydrolases - metabolism; HSC70 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Humans; Intracellular Signaling Peptides and Proteins; Ligands; Mice; Molecular Sequence Data; Nerve Tissue Proteins - metabolism; Oligopeptides; Oocytes; Peptide Library; Phosphoproteins - chemistry; Phosphoric Monoester Hydrolases - metabolism; Plant Proteins; Protein Binding; Proteins - genetics; Proteins - metabolism; Receptor-Interacting Protein Serine-Threonine Kinases; Selection, Genetic; Sequence Homology, Amino Acid; src Homology Domains; Xenopus laevis
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.47.31401

We screened a Xenopus laevis oocyte cDNA expression library with a Src homology 3 (SH3) class II peptide ligand and identified a 1270-amino acid-long protein containing two Eps15 homology (EH) domains, a central coiled-coil region, and five SH3 domains. We named this protein Intersectin, because it potentially brings together EH and SH3 domain-binding proteins into a macromolecular complex. The ligand preference of the EH domains were deduced to be asparajine-proline-phenylalanine (NPF) or cyclized NPF (CX1–2NPFXXC), depending on the type of phage-displayed combinatorial peptide library used. Screens of a mouse embryo cDNA library with the EH domains of Intersectin yielded clones for the Rev-associated binding/Rev-interacting protein (RAB/Rip) and two novel proteins, which we named Intersectin-binding proteins (Ibps) 1 and 2. All three proteins contain internal and C-terminal NPF peptide sequences, and Ibp1 and Ibp2 also contain putative clathrin-binding sites. Deletion of the C-terminal sequence, NPFL-COOH, from RAB/Rip eliminated EH domain binding, whereas fusion of the same peptide sequence to glutathione S-transferase generated strong binding to the EH domains of Intersectin. Several experiments support the conclusion that the free carboxylate group contributes to binding of the NPFL motif at the C terminus of RAB/Rip to the EH domains of Intersectin. Finally, affinity selection experiments with the SH3 domains of Intersectin identified two endocytic proteins, dynamin and synaptojanin, as potential interacting proteins. We propose that Intersectin is a component of the endocytic machinery.