Stimulus-dependent mobilization of protein kinase C.

Protein kinase C and its associated phorbol myristate acetate receptor moved from cytosol to membranes in human neutrophils stimulated with direct activators of the kinase, calcium ionophores, or chemotactic peptides. However, the peptides acted only in the presence of cytochalasin B and neither platelet-activating factor nor leukotriene B4 (+/- cyclochalasin B) induced this movement. Thus, protein kinase C appears variably involved in neutrophil responses: physiological agents may bypass or depend minimally upon the phosphorylating enzyme to elicit function.