Rapid T cell receptor-mediated SHP-1 S591 phosphorylation regulates SHP-1 cellular localization and phosphatase activity

J Leukoc Biol. 2007 Sep;82(3):742-51. doi: 10.1189/jlb.1206736. Epub 2007 Jun 15.


Since the tyrosine phosphatase SHP-1 plays a major role in regulating T cell signaling, we investigated regulation thereof by Ser/Thr phosphorylation. We found that T cell receptor (TCR) stimulation induced fast (<or=1 min) and transient phosphorylation of SHP-1 S591 in both Jurkat and human peripheral blood T-cells (PBT). Phosphorylation of S591 in T-cells could be mediated artificially by a constitutive active PKC-theta construct, but the dose dependence of inhibition by PKC inhibitors indicated that PKCs were not the relevant basophilic kinase in the physiological response. S591 phosphorylation inhibited phosphatase function since a S591D mutant had lower activity than the S591A mutant. Additional evidence that S591 phosphorylation alters SHP-1 function was provided by studies of Jurkat cells stably expressing SHP-1 wild type or mutants. In those cells, S591D mutation reduced the capacity of transfected SHP-1 to inhibit TCR-induced phosphorylation of PLC-gamma1. Interestingly, SHP-1 Y536 phosphorylation (previously shown to augment phosphatase activity) was also induced in PBT by TCR signal but at a much later time compared with S591 ( approximately 30 min). S591 phosphorylation also altered cellular distribution of SHP-1 because: 1) SHP-1 in lipid rafts and a sheared membrane fraction was hypophosphorylated; 2) In stably transfected Jurkat cell lines, S591D mutant protein had reduced presence in both lipid raft and the sheared membrane fraction; 3) S591 phosphorylation prevented nuclear localization of a C-terminal GFP tagged SHP-1 construct. Our studies also shed light on an additional mechanism regulating SHP-1 nuclear localization, namely conformational autoinhibition. These findings highlight elegant regulation of SHP-1 by sequential phosphorylation of serine then tyrosine.

Publication types

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

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Line
  • Cell Membrane / metabolism
  • Cell Nucleus / enzymology*
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Immunoprecipitation
  • Jurkat Cells / metabolism
  • Membrane Microdomains / enzymology
  • Membrane Microdomains / genetics
  • Mice
  • Mutation
  • Phospholipase C gamma / metabolism
  • Phosphorylation
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism
  • Protein Transport
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6 / genetics
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6 / metabolism*
  • Receptors, Antigen, T-Cell / metabolism*
  • Serine / metabolism
  • Signal Transduction
  • Tyrosine / metabolism


  • Receptors, Antigen, T-Cell
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Tyrosine
  • Serine
  • Protein Kinase C
  • Protein Tyrosine Phosphatase, Non-Receptor Type 6
  • Phospholipase C gamma