Disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating protein kinase C-alpha signaling.
Disruption of actin cytoskeleton with cytochalasin D has been known to induce chondrogenic differentiation of chick embryo limb bud mesenchymal cells. However, the mechanism(s) for the induction of chondrogenesis by cytochalasin D is not yet clearly known. In the present study, we examined possible involvement of protein kinase C (PKC) and extracellular signal-regulated protein kinase (Erk-1) in chondrogenesis of mesenchymal cells induced by disruption of actin cytoskeleton. Disruption of actin cytoskeleton with cytochalasin D or latrunculin B induced chondrogenesis of mesenchymal cells cultured at subconfluent cell density, as determined by type II collagen expression. Among the expressed PKC isoforms, cytochalasin D dramatically increased expression and activation of PKCalpha in a dose-dependent manner, and inhibition or downregulation of PKCalpha blocked cytochalasin D-induced chondrogenesis. Cytochalasin D also downregulated Erk-1 phosphorylation that is associated with chondrogenesis. Our results, therefore, suggest that disruption of actin cytoskeleton induces chondrogenesis of mesenchymal cells by activating PKCalpha and by inhibiting Erk-1 signaling.
Lim
Y B
YB
Department of Biology, Teacher's College, Taegu, 702-701, Korea.
Kang
S S
SS
Park
T K
TK
Lee
Y S
YS
Chun
J S
JS
Sonn
J K
JK
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology*; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D008648:Mesoderm / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D015398:Signal Transduction / Q000187:drug effects
D000199:Actins; D007527:Isoenzymes; D015638:Cytochalasin D; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases