Protein kinase C regulates leukotriene B4 receptors in human neutrophils

Three protein kinase C (PKC) activators, viz. phorbol myristate acetate, mezerein, and rac-1-O-myristoyl-2-acetylglycerol, inhibited human neutrophil binding of [3H] leukotriene B4 (LTB4) by reducing the number of high-affinity receptors available to the arachidonic acid metabolite. The inhibitory effect occurred in whole cells and cytoplasts but not in isolated membranes; it appeared to involve the activation of PKC rather than direct competition for binding sites. PKC may govern cellular responsiveness by regulating the receptor-linked bioactions of endogenous mediators like LTB4.