Thy-1 associated pp85--90 is a potential docking site for SH2 domain-containing signal transduction molecules

Cell Biol Int. 2001;25(1):33-42. doi: 10.1006/cbir.2000.0675.


Thy-1, a glycosylphosphatidylinositol (GPI)-anchored glycoprotein expressed at high levels on thymocytes, has been implicated in positive and negative signal transduction. We show that Thy-1 associates with a protein of 85--90 kDa, which is prominently phosphorylated in vitro as well as in vivo following the stimulation of thymocytes with pervanadate. pp85--90 is not identical to known proteins that are phosphorylated following T cell activation. The SH2 domains of fyn, csk, phosphatidylinositol 3'-kinase, rasGAP, vav and lck bind to pp85--90 with varying affinities. The SH2 domains of ZAP70, SHP-1 and PLC gamma 1 and the SH3 domains of lck, vav and HS1 did not bind to pp85--90. The molecular weight, iso-electric point, efficient phosphorylation by fyn and lck and preferential binding to the SH2 domain of fyn compared to that of lck indicate that Thy-1-associated pp85-90 may be identical to a recently cloned, fyn-associated transmembrane adaptor protein, PAG-85.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Electrophoresis, Gel, Two-Dimensional
  • Electrophoresis, Polyacrylamide Gel
  • Glutathione Transferase / metabolism
  • Hydrogen-Ion Concentration
  • Lymphocyte Activation
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins / chemistry
  • Proto-Oncogene Proteins c-fyn
  • Rats
  • Rats, Inbred Lew
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction*
  • T-Lymphocytes / metabolism
  • Thy-1 Antigens / chemistry*
  • Thy-1 Antigens / metabolism*
  • src Homology Domains


  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • Thy-1 Antigens
  • Glutathione Transferase
  • Fyn protein, rat
  • Proto-Oncogene Proteins c-fyn