Rho-kinase dependent organization of stress fibers and focal adhesions in cultured fibroblasts.
The activation of Rho-kinase is known to modulate the organization of the actin-based cytoskeletal systems, including the formation of stress fibers and focal adhesions. Rho-kinase likely plays a more crucial and complex role in the organization of actin-based cytoskeletal systems than in that of myosin light chain kinase (MLCK). In order to understand the role of Rho-kinase in the organization of stress fibers and focal adhesions, we treated cultured fibroblasts with a Rho-kinase inhibitor and analyzed the stress fiber and focal adhesion organization under conventional fluorescence microscopy and replica electron microscopy. Some of the cells were transfected with GFP-labeled paxillin, actin or alpha-actinin, and the effects of the inhibitor were monitored in the living cells. The Rho-kinase inhibitor caused disassembly of the stress fibers and focal adhesions in the central portion of the cell within 1 h. However, the stress fibers and focal adhesions located in the cell periphery were not as severely affected by the Rho-kinase inhibitor. The time-lapse video recording revealed that when these cells were washed with a fresh medium in order to remove the Rho-kinase inhibitor, the stress fibers and focal adhesions located in the center of the cell gradually reorganized and, within 1.5-2 h, the cells completely recovered. This observation strongly suggests that the activation of Rho-kinase plays an important role in the organization of the central stress fibers and focal adhesions.
Katoh
Kazuo
K
Department of Anatomy, School of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-city, Tochigi 329-0498, Japan. katoichi@jichi.ac.jp
Kano
Yumiko
Y
Ookawara
Shigeo
S
D000185:Actinin / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism; D000577:Amides / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D022001:Focal Adhesions / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051379:Mice; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D041681:NIH 3T3 Cells; D051419:Paxillin / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D022502:Stress Fibers / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure; D014162:Transfection; D054460:rho-Associated Kinases
D000199:Actins; D000577:Amides; D047908:Intracellular Signaling Peptides and Proteins; D051419:Paxillin; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D011993:Recombinant Fusion Proteins; D000185:Actinin; C108830:Y 27632; D049452:Green Fluorescent Proteins; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases