Functional diversity between Rho-kinase- and MLCK-mediated cytoskeletal actions in a myofibroblast-like hepatic stellate cell line.
Using a rat myofibroblast-like hepatic stellate cell line, we studied the actomyosin-based cytoskeletal actions mediated by Rho-kinase and/or myosin light chain kinase (MLCK). Calmodulin/MLCK inhibitors W-7 and ML-7 attenuated cell migration dose-relatedly at concentrations from 10(-6) to 10(-4)M and collagen gel-contraction by the cells at 10(-4)M, respectively. Rho-kinase inhibitors Y-27632 and HA1077 attenuated the gel-contraction at concentrations from 10(-6) to 10(-4) M, respectively. These Rho-kinase inhibitors attenuated cell migration at 10(-7)M but enhanced the migration at 10(-4)M, respectively. They altered cell morphology showing prominent peripheral actin bundles and sparse central stress fibers, in comparison with the calmodulin/MLCK inhibitors. Both ML-7 and Y-27632 attenuated phosphorylation of myosin regulatory light chain and cell attachment to extracellular substrate. ML-7 attenuated the activation of GTP-binding protein Rac, while Y-27632 did not. These findings suggest that the actomyosin-based cytoskeletal actions can be functionally diverse depending on the Rho-kinase-mediated pathway and the MLCK-mediated pathway.
Department of Gastroenterology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan. yanase-lim@h.u-tokyo.ac.jp
Mikio
M
Yanase
Hitoshi
H
Ikeda
Itsuro
I
Ogata
Atsushi
A
Matsui
Eisei
E
Noiri
Tomoaki
T
Tomiya
Masahiro
M
Arai
Yukiko
Y
Inoue
Kazuaki
K
Tejima
Kayo
K
Nagashima
Takako
T
Nishikawa
Masao
M
Shibata
Mitsuo
M
Ikebe
Marcos
M
Rojkind
Kenji
K
Fujiwara
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D003094:Collagen; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000201:enzymology* / Q000502:physiology* / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000166:cytology* / Q000201:enzymology; D032342:Muscle Cells / Q000166:cytology; D018994:Myosin Light Chains / Q000378:metabolism; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors / Q000502:physiology*; D009281:Naphthalenes / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D051381:Rats; D013449:Sulfonamides / Q000494:pharmacology; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases
D001381:Azepines; D002147:Calmodulin; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains; D009281:Naphthalenes; D013449:Sulfonamides; C070571:ML 7; C017967:W 7; D003094:Collagen; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D020744:rac GTP-Binding Proteins