Tyrosine phosphorylation of RAS by ABL allosterically enhances effector binding

FASEB J. 2015 Sep;29(9):3750-61. doi: 10.1096/fj.15-271510. Epub 2015 May 21.

Abstract

RAS proteins are signal transduction gatekeepers that mediate cell growth, survival, and differentiation through interactions with multiple effector proteins. The RAS effector RAS- and RAB-interacting protein 1 (RIN1) activates its own downstream effectors, the small GTPase RAB5 and the tyrosine kinase Abelson tyrosine-protein kinase (ABL), to modulate endocytosis and cytoskeleton remodeling. To identify ABL substrates downstream of RAS-to-RIN1 signaling, we examined human HEK293T cells overexpressing components of this pathway. Proteomic analysis revealed several novel phosphotyrosine peptides, including Harvey rat sarcoma oncogene (HRAS)-pTyr(137). Here we report that ABL phosphorylates tyrosine 137 of H-, K-, and NRAS. Increased RIN1 levels enhanced HRAS-Tyr(137) phosphorylation by nearly 5-fold, suggesting that RAS-stimulated RIN1 can drive ABL-mediated RAS modification in a feedback circuit. Tyr(137) is well conserved among RAS orthologs and is part of a transprotein H-bond network. Crystal structures of HRAS(Y137F) and HRAS(Y137E) revealed conformation changes radiating from the mutated residue. Although consistent with Tyr(137) participation in allosteric control of HRAS function, the mutations did not alter intrinsic GTP hydrolysis rates in vitro. HRAS-Tyr(137) phosphorylation enhanced HRAS signaling capacity in cells, however, as reflected by a 4-fold increase in the association of phosphorylated HRAS(G12V) with its effector protein RAF proto-oncogene serine/threonine protein kinase 1 (RAF1). These data suggest that RAS phosphorylation at Tyr(137) allosterically alters protein conformation and effector binding, providing a mechanism for effector-initiated modulation of RAS signaling.

Keywords: GTPase; RAF1; RIN1; signal transduction.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Substitution
  • Animals
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Mutation, Missense
  • Oncogene Proteins v-abl / chemistry
  • Oncogene Proteins v-abl / genetics
  • Oncogene Proteins v-abl / metabolism*
  • Phosphorylation / genetics
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins p21(ras) / chemistry
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Rats
  • Signal Transduction / physiology*
  • Tyrosine / chemistry
  • Tyrosine / genetics
  • Tyrosine / metabolism
  • rab5 GTP-Binding Proteins / chemistry
  • rab5 GTP-Binding Proteins / genetics
  • rab5 GTP-Binding Proteins / metabolism
  • raf Kinases / chemistry
  • raf Kinases / genetics
  • raf Kinases / metabolism

Substances

  • Intracellular Signaling Peptides and Proteins
  • MAS1 protein, human
  • Oncogene Proteins v-abl
  • Proto-Oncogene Mas
  • RIN1 protein, human
  • Tyrosine
  • raf Kinases
  • RAB5C protein, human
  • Proto-Oncogene Proteins p21(ras)
  • rab5 GTP-Binding Proteins

Associated data

  • PDB/4XVQ
  • PDB/4XVR