Résumé
Partially purified plasma membranes prepared from
myo-[
3H]inositol-prelabeled WRK1 cells exhibit a phosphatidylinositol 4,5-bisphosphate (PIP
2) phospholipase C activity sensitive to NaF. NaF increased the production of IP
2 and IP
3 in a time- and concentration-dependent manner. The maximal increase in IP
2 and IP
3 production rates represented 400 ± 18 and 360 ± 40% of the basal production rate, respectively. Half-maximum stimulation was reached with 2–4 mM NaF. The observed effect was specific for F
−. Aluminium potentiated fluoride-induced IP
3 and IP
2, accumulation in a concentration-dependent manner. The effect of fluoride on the PIP
2 phospholipase C from WRK1 cell membranes appears to be similar to the well-documented effect of F
− on the well-characterized N
s. N
i and transducin GTP-binding proteins. This observation constitutes an additional argument to suggest that a GTP-binding protein is involved in the process of receptor-mediated activation of PIP
2 phospholipase C.