title: Chondrogenesis induced by actin cytoskeleton disruption is regulated via protein kinase C-dependent p38 mitogen-activated protein kinase signaling.
abstract: Disruption of the actin cytoskeleton in subconfluent mesenchymal cells induces chondrogenic differentiation via protein kinase C (PKC) alpha signaling. In this study, we investigated the role of p38 mitogen-activated protein (MAP) kinase in the chondrogenic differentiation of mesenchymal cells that is induced by depolymerization of the actin cytoskeleton. Treatment of mesenchymal cells derived from chick embryonic limb buds with cytochalasin D (CD) disrupted the actin cytoskeleton with concomitant chondrogenic differentiation. The chondrogenesis was accompanied by an increase in p38 MAP kinase activity and inhibition of p38 MAP kinase with SB203580 blocked chondrogenesis. Together these results suggest an essential role for p38 MAP kinase in chondrogenesis. In addition, inhibition of p38 MAP kinase did not alter CD-induced increased expression and activity of PKC alpha, whereas down-regulation of PKC by prolonged exposure of cells to phorbol ester inhibited CD-induced p38 MAP kinase activation. Our results therefore suggest that PKC is involved in the regulation of chondrogenesis induced by disruption of the actin cytoskeleton via a p38 MAP kinase signaling pathway.
authors.affiliation: Department of Biology, Teachers' College, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Young-Bin
authors.initials: YB
authors.lastname: Lim
authors.forename: Shin-Sung
authors.initials: SS
authors.lastname: Kang
authors.forename: Won Gun
authors.initials: WG
authors.lastname: An
authors.forename: Young-Sup
authors.initials: YS
authors.lastname: Lee
authors.forename: Jang-Soo
authors.initials: JS
authors.lastname: Chun
authors.forename: Jong Kyung
authors.initials: JK
authors.lastname: Sonn
mesh_terms: D000199:Actins / Q000502:physiology*; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology*; D015638:Cytochalasin D; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008648:Mesoderm; D020928:Mitogen-Activated Protein Kinases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000199:Actins; D004791:Enzyme Inhibitors; D015638:Cytochalasin D; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases