The endocytic protein intersectin is a major binding partner for the Ras exchange factor mSos1 in rat brain

Xin Kang Tong, Natasha K. Hussain, Elaine De Heuvel, Alexei Kurakin, Elia Abi-Jaoude, Christopher C. Quinn, Michael F. Olson, Richard Marais, Danny Baranes, Brian K. Kay, Peter S. McPherson

Research output: Contribution to journalArticlepeer-review

Abstract

We recently identified intersectin, a protein containing two EH and five SH3 domains, as a component of the endocytic machinery. The N-terminal SH3 domain (SH3A), unlike other SH3 domains from intersectin or various endocytic proteins, specifically inhibits intermediate events leading to the formation of clathrin-coated pits. We have now identified a brain-enriched, 170 kDa protein (p170) that interacts specifically with SH3A. Screening of combinatorial peptides reveals the optimal ligand for SH3A as Pp(V/I)PPR, and the 170 kDa mammalian son-of-sevenless (mSos1) protein, a guanine-nucleotide exchange factor for Ras, contains two copies of the matching sequence, PPVPPR. Immunodepletion studies confirm that p170 is mSos1. Intersectin and mSos1 are co-enriched in nerve terminals and are co-immunoprecipitated from brain extracts. SH3A competes with the SH3 domains of Grb2 in binding to mSos1, and the intersectin-mSos1 complex can be separated from Grb2 by sucrose gradient centrifugation. Overexpression of the SH3 domains of intersectin blocks epidermal growth factor-mediated Ras activation. These results suggest that intersectin functions in cell signaling in addition to its role in endocytosis and may link these cellular processes.

Original languageEnglish (US)
Pages (from-to)1263-1271
Number of pages9
JournalEMBO Journal
Volume19
Issue number6
DOIs
StatePublished - Mar 15 2000

Keywords

  • Clathrin
  • EH domain
  • Endocytosis
  • Ras
  • SH3 domain

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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