Regulation of oscillations in filamentous actin content in polymorphonuclear leukocytes stimulated with leukotriene B(4) and platelet-activating factor.
Stimulation of neutrophils with LTB(4) or PAF results in the production of a rapidly oscillating actin polymerization/depolymerization response. Treatment of neutrophils with inhibitors of PKC prior to stimulation with ligand resulted in a masking of the F-actin oscillations. Because myosin has been shown to be a substrate for neutrophil PKC, this protein was investigated as a potential downstream mediator of F-actin oscillations. Stimulation of neutrophils with LTB(4) resulted in myosin light chain being serine phosphorylated in a PKC-dependent manner. This phosphorylation was shown to occur in a manner that is kinetically distinct from the myosin phosphorylation induced by FMLP, a potent activator of actin polymerization that alone does not induce F-actin oscillations. Additionally, disruption of intracellular actin-myosin interactions resulted in inhibition of LTB(4)- as well as PAF-induced F-actin oscillations. These data suggest that PKC and downstream phosphorylation of myosin as well as actin-myosin interaction may play roles in mediating the production of neutrophil F-actin oscillations.
Rengan
R
R
Departments of Surgery and Biological Chemistry, University of Michigan Medical School and V. A. Medical Center, Ann Arbor, 48105-2399, Michigan, USA.
Omann
G M
GM
D000199:Actins / Q000378:metabolism*; D002451:Cell Compartmentation; D018260:Gelsolin / Q000378:metabolism; D006801:Humans; D007975:Leukotriene B4 / Q000494:pharmacology*; D018994:Myosin Light Chains / Q000378:metabolism; D009218:Myosins / Q000037:antagonists & inhibitors; D009504:Neutrophils / Q000187:drug effects*; D010507:Periodicity; D010766:Phosphorylation; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011485:Protein Binding; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D012694:Serine / Q000378:metabolism
D000199:Actins; D018260:Gelsolin; D018994:Myosin Light Chains; D010972:Platelet Activating Factor; D007975:Leukotriene B4; D012694:Serine; D011493:Protein Kinase C; D009218:Myosins