Noonan syndrome-associated SHP-2/Ptpn11 mutants enhance SIRPalpha and PZR tyrosyl phosphorylation and promote adhesion-mediated ERK activation

J Biol Chem. 2008 May 30;283(22):15328-38. doi: 10.1074/jbc.M801382200. Epub 2008 Mar 31.

Abstract

Noonan syndrome (NS) is an autosomal dominant disorder that is associated with multiple developmental abnormalities. Activated mutations of the protein-tyrosine phosphatase, SHP-2/PTPN11, have been reported in approximately 50% of NS cases. Despite being activated, NS-associated SHP-2 mutants require plasma membrane proximity to evoke disease-associated signaling. Here we show that NS-associated SHP-2 mutants induce hypertyrosyl phosphorylation of the transmembrane glycoproteins, SIRPalpha (signal-regulatory protein alpha) and PZR (protein zero-related), resulting in their increased association with NS-associated SHP-2 mutants. NS-associated SHP-2 mutants enhanced SIRPalpha and PZR tyrosyl phosphorylation either by impairing SIRPalpha dephosphorylation or by promoting PZR tyrosyl phosphorylation. Importantly, during embryogenesis in a mouse model of NS, SIRPalpha and PZR were hypertyrosyl-phosphorylated and bound increased levels of the NS-associated SHP-2 mutant. SIRPalpha and PZR have been implicated in extracellular matrix-dependent signaling. Mouse embryonic fibroblasts derived from a mouse model of NS displayed enhanced ERK activation in response to fibronectin plating. Knockdown of SIRPalpha and PZR in these cells attenuated the enhanced activation of ERK following fibronectin plating. Thus, SIRPalpha and PZR serve as scaffolds that facilitate plasma membrane recruitment and signaling of NS-associated SHP-2 mutants.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Membrane / genetics
  • Cell Membrane / metabolism*
  • Disease Models, Animal
  • Embryo, Mammalian / enzymology
  • Embryonic Development / genetics
  • Enzyme Activation / genetics
  • Extracellular Signal-Regulated MAP Kinases / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fibroblasts / enzymology
  • Fibronectins
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Mutation*
  • Noonan Syndrome / enzymology*
  • Noonan Syndrome / genetics
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Phosphorylation
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11 / genetics
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11 / metabolism*
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / metabolism*
  • Signal Transduction* / genetics

Substances

  • Fibronectins
  • Intracellular Signaling Peptides and Proteins
  • MPZL1 protein, mouse
  • Phosphoproteins
  • Ptpns1 protein, mouse
  • Receptors, Immunologic
  • Extracellular Signal-Regulated MAP Kinases
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Ptpn11 protein, mouse