STIMULATION OF A HISTONE-H4 PROTEIN-KINASE IN TRITON X-100 LYSATES OF RABBIT PERITONEAL NEUTROPHILS PRETREATED WITH CHEMOTACTIC FACTORS - EFFECT OF LEUKOTRIENE-B4 AND CYTOCHALASIN-B

The effects of leukotriene B4 on the stimulation of a histone H4 kinase activity in rabbit peritoneal neutrophils have been studied. LTB4 activated the kinase within 10 sec with the increasingly activity decaying to near basal level after 20 sec of stimulation. The effect was not inhibited by removal of extracellular calcium or loading the cells with quin-2/AM. Pretreatment of the cells with cytochalasin B greatly enhanced and prolonged the activation of the kinase. Pretreatment of the cells with LTB4 or fMet-Leu-Phe inhibited the effect of the later addition of LTB4. Since similar characteristics of LTB4 and cytochalasin B have also been observed in LTB4-stimulated responses such as secretion and superoxide generation, the results suggest a potential role of H4 kinase in LTB4-stimulated responses.