Involvement of Src family protein tyrosine kinases in Ca(2+) sensitization of coronary artery contraction mediated by a sphingosylphosphorylcholine-Rho-kinase pathway.
We recently reported that sphingosylphosphorylcholine (SPC) is a novel messenger for Rho-kinase-mediated Ca(2+) sensitization of vascular smooth muscle (VSM) contraction. Subcellular localization and kinase activity of Src family protein kinases (SrcPTKs), except for c-Src, is controlled by a reversible S-palmitoylation, an event inhibited by eicosapentaenoic acid (EPA). We examined the possible involvement of SrcPTKs in SPC-induced Ca(2+) sensitization and effects of EPA. We used porcine coronary VSM and rat aortic VSM cells (VSMCs) in primary culture. An SrcPTKs inhibitor, PP1, and EPA inhibited SPC-induced contraction, concentration-dependently, without affecting [Ca(2+)](i) levels and the Ca(2+)-dependent contraction induced by high K(+) depolarization. A digitized immunocytochemical analysis in VSMCs revealed that SPC induced translocation of Fyn, but not of c-Src, from the cytosol to the cell membrane, an event abolished by EPA. Translocation of Rho-kinase from the cytosol to the cell membrane by SPC was also inhibited by EPA and PP1. The SPC-induced activation of SrcPTKs was blocked by EPA and PP1, but not by Y27632, an Rho-kinase inhibitor. Rho-kinase-dependent phosphorylation of myosin phosphatase induced by SPC was inhibited by EPA, PP1, and Y27632. Translocation and activation of SrcPTKs, including Fyn, play an important role in Ca(2+) sensitization of VSM contractions mediated by a SPC-Rho-kinase pathway.
Nakao
Fumiaki
F
Department of Cardiovascular Medicine, Yamaguchi University School of Medicine, Yamaguchi, Japan.
Kobayashi
Sei
S
Mogami
Kimiko
K
Mizukami
Yoichi
Y
Shirao
Satoshi
S
Miwa
Saori
S
Todoroki-Ikeda
Natsuko
N
Ito
Masaaki
M
Matsuzaki
Masunori
M
D000215:Acylation / Q000187:drug effects; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D003331:Coronary Vessels / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D007537:Isometric Contraction / Q000187:drug effects / Q000502:physiology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D010168:Palmitates / Q000494:pharmacology; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D015290:Second Messenger Systems / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D054460:rho-Associated Kinases; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D047908:Intracellular Signaling Peptides and Proteins; D010168:Palmitates; C005356:sphingosine phosphorylcholine; D010767:Phosphorylcholine; C022776:2-bromopalmitate; D019061:src-Family Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D013110:Sphingosine; D002118:Calcium