HIP1 and HIP1r Stabilize Receptor Tyrosine Kinases and Bind 3-Phosphoinositides Via Epsin N-terminal Homology Domains

Teresa S. Hyun, Dinesh S. Rao, Djenann Saint-Dic, L. Evan Michael, Priti D. Kumar, Sarah V. Bradley, Ikuko F. Mizukami, Katherine I. Oravecz-Wilson, Theodora S. Ross

Research output: Contribution to journalArticle

55 Scopus citations


Huntingtin-interacting protein 1-related (HIP1r) is the only known mammalian relative of huntingtin-interacting protein 1 (HIP1), a protein that transforms fibroblasts via undefined mechanisms. Here we demonstrate that both HIP1r and HIP1 bind inositol lipids via their epsin N-terminal homology (ENTH) domains. In contrast to other ENTH domain-containing proteins, lipid binding is preferential to the 3-phosphate-containing inositol lipids, phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,5-bisphosphate. Furthermore, the HIP1r ENTH 'domain, like that of HIP1, is necessary for lipid binding, and expression of an ENTH domain-deletion mutant, HIP1r/ΔE, induces apoptosis. Consistent with the ability of HIP1r and HIP1 to affect cell survival, full-length HIP1 and HIP1r stabilize pools of growth factor receptors by prolonging their half-life following ligand-induced endocytosis. Although HIP1r and HIP1 display only a partially overlapping pattern of protein interactions, these data suggest that both proteins share a functional homology by binding 3-phosphorylated inositol lipids and stabilizing receptor tyrosine kinases in a fashion that may contribute to their ability to alter cell growth and survival.

Original languageEnglish (US)
Pages (from-to)14294-14306
Number of pages13
JournalJournal of Biological Chemistry
Issue number14
StatePublished - Apr 2 2004


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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