Fig. 2. Summary of the putative substrates of PTPN22 in T cells.
Established substrates include Y420 and Y394 in activation loops of Src family kinases Fyn(18) and Lck(36] respectively, and the autoactivatory Y493 of Zap-70){Wu, 2006 #35). Putative PTPN22 substrates that undergo tyrosine phosphorylation upon TCR engagement include i) TCR-CD3ζ and CD3ε, ii) the guanine nucleotide exchange factor Vav, iii) the ATPase valosin containing protein (VCP)(11). Y75 of Src-kinase associated protein homolog (SKAP-HOM) is a recently-described T cell substrate for PTPN22(31).