T-Cell, Immune Regulator 1 (TCIRG1)

TIRC7 protein is predicted to have an N-terminal cytoplasmic domain, a 7-transmembrane domain structure, and an extracellular C domain. There are multiple putative phosphorylation sites for protein kinases C and A as well as N-linked glycosylation sites. Northern blot analysis revealed that alloantigen stimulation resulted in a 20-fold upregulation of the expected 2.5- as well as a 4.0-kb transcript of TCIRG1. TCIRG1 expression could be blocked by cyclosporine A, suggesting that its expression occurs via the calcineurin signaling pathway. Northern blot analysis also revealed that TIRC7 is almost exclusively expressed in immune system tissues but not in various B-cell lines. Western blot analysis detected TIRC7 predominantly in membrane extracts of human lymphocytes as a single protein of 75 kD.