Protein Tyrosine Phosphatase Receptor Type C Associated Protein (PTPRCAP)

PTPRCAP was identified as a transmembrane phosphoprotein specifically associated with tyrosine phosphatase PTPRC/CD45, a key regulator of T- and B-lymphocyte activation. The interaction with PTPRC may be required for the stable expression of this protein.

Schraven et al. (1994) described the cDNA and protein sequence of a 32-kD transmembrane phosphoprotein, which they called LPAP (lymphocyte phosphatase associated phosphoprotein), that noncovalently interacts with CD45 in human lymphocytes. The interaction of LPAP and CD45 is mediated by the transmembrane regions of both molecules and seems to be required for stable protein expression of LPAP. The mouse homolog is a 30-kD transmembrane protein.