This entry includes THEMIS1/2/3 from animals. THEMIS1 and THEMIS2 are restricted to B and myeloid cells, and the more distantly related THEMIS3 is expressed in the large and small intestine. THEMIS is involved in the early TCR (T-cell antigen receptor) signal transduction and thymocyte selection []. It is recruited to LAT through GRB2 association and LAT phosphotyrosine GRB2 binding sites []. THEMIS contains CABIT modules that bind directly to the SHP-1 PTP (protein tyrosine phosphatase) domain and inhibit SHP-1 PTP activity by promoting or stabilizing oxidation of the catalytic cysteine [].