Hematopoietic cell-specific adapter proteins, SLP-76 and BLNK, effectivelyactivate NF-AT as well as NF-kappa B by Syk and Tec PTKs in non-lymphoid cell lines

To investigate the roles of various hematopoietic cell-specific adapter pro teins in T cell receptor (TCR)-signaling leading to nuclear factor of activ ated T cell (NF-AT) and nuclear factor of KB (NF-kappaB) activation, we rec onstituted TCR-signaling with CD8/zeta, various protein tyrosine kinases (P TKs), and adapter proteins in a non-lymphoid cell line, 293T, We show that SLP-76 and BLNK, but not LAT, effectively co-operated with Syk and Tec fami ly PTKs to activate NF-AT and NF-kappaB. We also show that Tec family PTKs enhanced endogenous phospholipase C (PLC)-gamma1 phosphorylation induced by CD8/zeta and Syk in 293T cells. These results imply that PLC-yl may play a critical role in a hematopoietic cell-specific adapter protein-mediated NF -AT and NF-kappaB activation in a non-lymphoid cell. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rig hts reserved.