Integration of single and multicellular wound responses.
Single cells and multicellular tissues rapidly heal wounds. These processes are considered distinct, but one mode of healing--Rho GTPase-dependent formation and closure of a purse string of actin filaments (F-actin) and myosin-2 around wounds--occurs in single cells and in epithelia. Here, we show that wounding of one cell in Xenopus embryos elicits Rho GTPase activation around the wound and at the nearest cell-cell junctions in the neighbor cells. F-actin and myosin-2 accumulate at the junctions and around the wound itself, and as the resultant actomyosin array closes over the wound site, junctional F-actin and myosin-2 become mechanically integrated with the actin and myosin-2 around the wound, forming a hybrid purse string. When cells are ablated rather than wounded, Rho GTPase activation and F-actin accumulation occur at cell-cell junctions surrounding the ablated cell, and the purse string closes the hole in the epithelium. Elevation of intracellular free calcium, an essential upstream signal for the single-cell wound response, also occurs at the cell-cell contacts and in neighbor cells. Thus, the single and multicellular purse string wound responses represent points on a signaling and mechanical continuum that are integrated by cell-cell junctions.
Clark
Andrew G
AG
Department of Zoology, University of Wisconsin-Madison, Madison, WI 53706, USA.
Miller
Ann L
AL
Vaughan
Emily
E
Yu
Hoi-Ying E
HY
Penkert
Rhiannon
R
Bement
William M
WM
D000199:Actins / Q000502:physiology*; D000818:Animals; D001757:Blastomeres; D020013:Calcium Signaling; D004625:Embryo, Nonmammalian / Q000293:injuries / Q000378:metabolism; D004789:Enzyme Activation; D007365:Intercellular Junctions / Q000502:physiology*; D024462:Myosin Type II / Q000502:physiology*; D014945:Wound Healing / Q000235:genetics / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology; D020741:rho GTP-Binding Proteins / Q000502:physiology*
D000199:Actins; D024462:Myosin Type II; D020741:rho GTP-Binding Proteins