Two distinct modes of myosin assembly and dynamics during epithelial wound closure.
Actomyosin contraction powers the sealing of epithelial sheets during embryogenesis and wound closure; however, the mechanisms are poorly understood. After laser ablation wounding of Madin-Darby canine kidney cell monolayers, we observed distinct steps in wound closure from time-lapse images of myosin distribution during resealing. Immediately upon wounding, actin and myosin II regulatory light chain accumulated at two locations: (1) in a ring adjacent to the tight junction that circumscribed the wound and (2) in fibers at the base of the cell in membranes extending over the wound site. Rho-kinase activity was required for assembly of the myosin ring, and myosin II activity was required for contraction but not for basal membrane extension. As it contracted, the myosin ring moved toward the basal membrane with ZO-1 and Rho-kinase. Thus, we suggest that tight junctions serve as attachment points for the actomyosin ring during wound closure and that Rho-kinase is required for localization and activation of the contractile ring.
Tamada
Masako
M
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Perez
Tomas D
TD
Nelson
W James
WJ
Sheetz
Michael P
MP
D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D016764:Cell Polarity; D048430:Cell Shape; D002645:Chickens; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology* / Q000201:enzymology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D018994:Myosin Light Chains / Q000737:chemistry* / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D020836:Protein Structure, Quaternary; D019108:Tight Junctions / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology*; D054460:rho-Associated Kinases
D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains; D000205:Actomyosin; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases