Identification and characterization of the interaction between heat-shock protein 90 and phospholipase C-gamma 1

Abstract

Phosphoinositide-specific phospholipase C-gamma 1 (PLC-gamma 1) is a pivotal mediator in the signal transduction cascades induced by many growth factors. Using a yeast two-hybrid system, heat-shock protein 90 (Hsp90) was identified as a PLC-gamma 1-binding protein, A co-immunoprecipitation experiment, using anti-PLC-gamma 1 antibody, demonstrated an in vivo interaction between Hsp90 and PLC-gamma 1 in the NIH-3T3 cells. The interaction in NIH-3T3 was unaffected by the PDGF treatment, inducing phosphorylation and activation of PLC- gamma 1. Direct interaction between Hsp90 and PLC-gamma 1 was confirmed by in vitro binding experiments using purified Hsp90 and PLC-gamma 1. Furthermore, Hsp90 increased the PIP2-hydrolyzing activity of PLC-gamma 1 up to 2-fold at 0.1 mu M in vitro, Taken together, me show for the first time, the interaction of PLC-gamma 1 with Hsp90, both in vivo and in vitro. We suggest that Hsp90 may play a role in PLC-gamma 1-mediated signal transduction.