Hematopoietic cell‐specific adapter proteins, SLP‐76 and BLNK, effectively activate NF‐AT as well as NF‐κB by Syk and Tec PTKs in non‐lymphoid cell lines

Abstract
To investigate the roles of various hematopoietic cell-specific adapter proteins in T cell receptor (TCR)-signaling leading to nuclear factor of activated T cell (NF-AT) and nuclear factor of κB (NF-κB) activation, we reconstituted TCR-signaling with CD8/ζ, various protein tyrosine kinases (PTKs), 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 family PTKs to activate NF-AT and NF-κB. We also show that Tec family PTKs enhanced endogenous phospholipase C (PLC)-γ1 phosphorylation induced by CD8/ζ and Syk in 293T cells. These results imply that PLC-γ1 may play a critical role in a hematopoietic cell-specific adapter protein-mediated NF-AT and NF-κB activation in a non-lymphoid cell.