title: Sphingosylphosphorylcholine induces stress fiber formation via activation of Fyn-RhoA-ROCK signaling pathway in fibroblasts.
abstract: Sphingosylphosphorylcholine (SPC), a bioactive sphingolipid, has recently been reported to modulate actin cytoskeleton rearrangement. We have previously demonstrated Fyn tyrosine kinase is involved in SPC-induced actin stress fiber formation in fibroblasts. However, Fyn-dependent signaling pathway remains to be elucidated. The present study demonstrates that RhoA-ROCK signaling downstream of Fyn controls stress fiber formation in SPC-treated fibroblasts. Here, we found that SPC-induced stress fiber formation was inhibited by C3 transferase, dominant negative RhoA or ROCK. SPC activated RhoA, which was blocked by pharmacological inhibition of Fyn activity or dominant negative Fyn. Constitutively active Fyn (ca-Fyn) stimulated stress fiber formation and localized with F-actin at the both ends of stress fibers, both of which were prevented by Fyn translocation inhibitor eicosapentaenoic acid (EPA). In contrast, inhibition of ROCK abolished only the formation of stress fibers, without affecting the localization of ca-Fyn. These results allow the identification of the molecular events downstream SPC in stress fiber formation for a better understanding of stress fiber formation involving Fyn.
authors.affiliation: Department of Molecular Physiology and Medical Bioregulation, Yamaguchi University Graduate School of Medicine, Minami-Kogushi, Ube, Japan.
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kishi
authors.forename: Hozumi
authors.initials: H
authors.lastname: Kawamichi
authors.forename: Katsuko
authors.initials: K
authors.lastname: Kajiya
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takada
authors.forename: Sei
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D036002:ADP Ribose Transferases / Q000494:pharmacology; D019943:Amino Acid Substitution; D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology; D004789:Enzyme Activation; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D022001:Focal Adhesions / Q000378:metabolism; D008246:Lysophospholipids / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000187:drug effects; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D022502:Stress Fibers / Q000187:drug effects / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein
chemical_list: D008246:Lysophospholipids; D011994:Recombinant Proteins; C005356:sphingosine phosphorylcholine; D010767:Phosphorylcholine; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D051417:Focal Adhesion Kinase 1; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; C496051:Ptk2 protein, mouse; D054460:rho-Associated Kinases; D001905:Botulinum Toxins; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D013110:Sphingosine; C032881:lysophosphatidic acid