Disassembly of F-actin filaments in human endothelial cells cultured on type V collagen.
We examined the inhibitory activity of type V collagen on cell attachment and cell growth and the role of stress fibers and beta 1 integrin in cultured human endothelial cells. Human endothelial cells cultured on type V collagen attached temporarily to the substrate and formed stress fibers. However, the cells failed to proliferate and gradually detached from the substrate. After 24 h, the cells on type V collagen lacked discernible stress fibers (F-actin filaments) and exhibited dots in small aggregates of F-actin. In addition, the cells expressed little or no proteins as focal adhesions, including vinculin and beta 1 integrin. In contrast, the cells on fibronectin and type I collagen formed complete F-actin filaments, exhibited sufficient vinculin and beta 1 integrin, and grew logarithmically from 2 days. On the other hand, human smooth muscle cells formed complete F-actin filaments, revealed typical focal adhesions, and started to proliferate rapidly after 24 h on type V collagen as well as on fibronectin and type I collagen. Thus, the disassembly of F-actin filaments was observed as a specific phenomenon in human endothelial cells cultured on type V collagen. Moreover, the F-actin filaments disappeared from endothelial cells treated with cytochalasin D after 24 h and the cells detached from fibronectin and type I collagen with time, a result consistent with the observations on type V collagen. Accordingly, the disassembly of F-actin filaments in focal adhesions may result in the detachment of endothelial cells from type V collagen.
Yamamoto
K
K
Department of Cell Biology, Tokyo Metropolitan Institute of Gerontology, Japan.
Yamamoto
M
M
Noumura
T
T
D000199:Actins / Q000032:analysis*; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D016023:Integrins / Q000032:analysis; D007382:Intermediate Filaments / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000737:chemistry
D000199:Actins; D005353:Fibronectins; D016023:Integrins; D011956:Receptors, Cell Surface; C052131:extracellular matrix receptor; D003094:Collagen