Phospholipase C-gamma 1 binds to actin-cytoskeleton via its C-terminal SH2 domain in vitro

Association of phospholipase C (PLC)-gamma 1 with the cytoskeleton has been postulated to be one of the crucial steps for PLC-gamma 1 activation arid translocation to the plasma membrane. In this report, direct binding assays were carried out to study which fragment of PLC-gamma 1 Src-homology region has been able to bind io the actin-cytoskeleton. Using GST fusion proteins containing various deletions of the PLC-gamma 1 Src homology region, it was found that PLC-gamma 1 binds to the actin-cytoskeleton directly via its C-terminal SH2 domain but nut the SH3 domain in vitro. However, the binding of the C-terminal SH2 domain of PLC-gamma 1 to actin did not interfere with the SH2 domain's ability to associate with phosphotyrosine, which suggested that actin and phosphotyrosine residues may bind to different sequences in the C-terminal SH2 domain of PLC-gamma 1. (C) 1996 Academic Press, Inc.