Loss of T-cell protein tyrosine phosphatase induces recycling of the platelet-derived growth factor (PDGF) beta-receptor but not the PDGF alpha-receptor

Mol Biol Cell. 2006 Nov;17(11):4846-55. doi: 10.1091/mbc.e06-04-0306. Epub 2006 Sep 13.

Abstract

We have previously shown that the T-cell protein tyrosine phosphatase (TC-PTP) dephosphorylates the platelet-derived growth factor (PDGF) beta-receptor. Here, we show that the increased PDGF beta-receptor phosphorylation in TC-PTP knockout (ko) mouse embryonic fibroblasts (MEFs) occurs primarily on the cell surface. The increased phosphorylation is accompanied by a TC-PTP-dependent, monensin-sensitive delay in clearance of cell surface PDGF beta-receptors and delayed receptor degradation, suggesting PDGF beta-receptor recycling. Recycled receptors could also be directly detected on the cell surface of TC-PTP ko MEFs. The effect of TC-PTP depletion was specific for the PDGF beta-receptor, because PDGF alpha-receptor homodimers were cleared from the cell surface at the same rate in TC-PTP ko MEFs as in wild-type MEFs. Interestingly, PDGF alphabeta-receptor heterodimers were recycling. Analysis by confocal microscopy revealed that, in TC-PTP ko MEFs, activated PDGF beta-receptors colocalized with Rab4a, a marker for rapid recycling. In accordance with this, transient expression of a dominant-negative Rab4a construct increased the rate of clearance of cell surface receptors on TC-PTP ko MEFs. Thus, loss of TC-PTP specifically redirects the PDGF beta-receptor toward rapid recycling, which is the first evidence of differential trafficking of PDGF receptor family members.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytoplasmic Vesicles / metabolism
  • Dimerization
  • Fibroblasts / cytology
  • Ligands
  • Mice
  • Mice, Knockout
  • Phosphorylation
  • Protein Processing, Post-Translational
  • Protein Transport
  • Protein Tyrosine Phosphatase, Non-Receptor Type 2
  • Protein Tyrosine Phosphatases / deficiency*
  • Protein Tyrosine Phosphatases / metabolism*
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism*
  • Receptor, Platelet-Derived Growth Factor beta / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • rab4 GTP-Binding Proteins / metabolism

Substances

  • Ligands
  • Recombinant Fusion Proteins
  • Receptor, Platelet-Derived Growth Factor alpha
  • Receptor, Platelet-Derived Growth Factor beta
  • Protein Tyrosine Phosphatase, Non-Receptor Type 2
  • Protein Tyrosine Phosphatases
  • Ptpn2 protein, mouse
  • rab4 GTP-Binding Proteins