Growth factors induce differential phosphorylation profiles of the Hrs-STAM complex: a common node in signalling networks with signal-specific properties

Biochem J. 2005 Aug 1;389(Pt 3):629-36. doi: 10.1042/BJ20050067.

Abstract

Hrs (hepatocyte growth factor-regulated tyrosine kinase substrate) and STAM (signal-transducing adaptor molecule) form a heterodimeric complex that associates with endosomal membranes and is tyrosine-phosphorylated in response to a variety of growth factors including EGF (epidermal growth factor), HGF (hepatocyte growth factor) and PDGF (platelet-derived growth factor). Phosphorylation of the Hrs-STAM complex requires receptor endocytosis. We show that an intact UIM (ubiquitin interaction motif) within Hrs is a conserved requirement for Hrs phosphorylation downstream of both EGF and HGF stimulations. Consistent with this, expression of a dominant-negative form of the E3 ubiquitin ligase, c-Cbl, inhibits EGF- and HGF-dependent Hrs phosphorylation. Despite this conservation, kinase inhibitor profiles using PP1 (4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) and SU6656 indicate that distinct non-receptor tyrosine kinases couple EGF, HGF and PDGF stimulation with the tyrosine phosphorylation of the Hrs-STAM complex. Crucially, analysis with phospho-specific antibodies indicates that these kinases generate a signal-specific, combinatorial phosphorylation profile of the Hrs-STAM complex, with the potential of diversifying tyrosine kinase receptor signalling through a common element.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Line, Tumor
  • Endosomal Sorting Complexes Required for Transport
  • ErbB Receptors / physiology
  • Growth Substances / physiology*
  • Humans
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Proto-Oncogene Proteins c-met / physiology
  • Receptors, Platelet-Derived Growth Factor / physiology
  • Signal Transduction / physiology*

Substances

  • Adaptor Proteins, Signal Transducing
  • Endosomal Sorting Complexes Required for Transport
  • Growth Substances
  • Phosphoproteins
  • STAM protein, human
  • hepatocyte growth factor-regulated tyrosine kinase substrate
  • ErbB Receptors
  • Proto-Oncogene Proteins c-met
  • Receptors, Platelet-Derived Growth Factor