ABSTRACT
Many extracellular signaling molecules including hormones, growth factors, neurotransmitters and immunoglobulins elicit intracellular responses by activating phosphatidylinositol-specific phospholipase C (PI-PLC) upon binding to their cell surface receptors. Activated PLC catalyses the hydrolysis of Phosphotidylinositol 4,5- bisphosphate (PIP2) to generate DAG and IP3 , which act as signaling molecules that control various cellular processes. Exploring the mechanism of regulation of PLC activity may lead to understanding various signaling events that regulate cell growth and differentiation. One of the dramatic effects of profilin is inhibition of PIP2 hydrolysis by PLC- γ in eukaryotic cells. In the present study, the effect of profilin on Phosphotidylinositol specific phospholipase C (PIPLC) purified from Bacillus thuringiensis (Bt) was examined. Assay of PI-PLC activity indicated that Bovine profilin activated the hydrolysis of phosphotidylinositol (PI) by BtPI-PLC in a concentration dependent manner under in vitro conditions. A 250 % increase in activity was noted in the presence of profilin but not in presence of phosphoprofilin. In the presence of profilin more proteins are observed in the soluble fraction. In conclusion it can be stated that that profilin activates bacterial PLC activity towards PI hydrolysis.