Abstract
Phospholipase C is a key enzyme for transmembrane signalling, since it generates phosphoinositide-derived intracellular messengers. The enzyme localization was studied by indirect immunofluorescent technique, using a rabbit monospecific antibody directed to the purified bacterial phospholipase C. This antibody, which is inhibitory in vitro and on phospholipase C of intact cells, cross-reacted with the enzyme from a variety of cell types (skeletal and smooth muscle cells, nerve cells, fibroblasts, leukocytes, erythrocytes) and species (frog, guineapig, rat, man). The reaction was specific, as demonstrated by using the F(ab')2 fragment of the antibody molecule. Since the membrane-bound phospholipase C can be revealed by immunofluorescence on the surface of isolated, intact cells, it is concluded that the membrane-associated phospholipase C is a transmembrane protein.
