receptor protein tyrosine phosphatase RO protein tyrosine phosphatase U2 D28 receptor-type tyrosine-protein phosphatase O glomerular epithelial protein 1 PTPase U2 GLEPP1 PTPU2 protein tyrosine phosphatase, non-receptor type 15 R-PTP-O PTPROt PTPBK PTPoc Ptpn15 PTPphi