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KMID : 0578319950050020114
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Molecules and Cells
1995 Volume.5 No. 2 p.114 ~ p.118
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The Action of Protein Kinase C in regulating the Cpreading of HeLa Cells on a Collagen Substratum
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Chun, Jang-Soo
Kang, Shin-Sung/Sacobson, Bruce S.
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Abstract
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The Spreading of HeLa cells on a collagen substratum requires production of arachidonic acid by phopholipase A₂as a consequence of cell surface collagen receptor clustering. Arachidonic acid is subsequently metabolized via lipoxygenase, and a lipoxygenase metabolite(s) in turn induces production of diacylglycerol. Production of arachidonic acid and diacylglycerol induces activation of protein kinase C (PKC) in which membrane-bound PKC activity is transiently increased upon attachment and prior to cell spreading. This study was carried out to examine further the role of PKC in the regulation of HeLa cell spreading on a collagen substratum. It was found that inhibition of PKC with a specific inhibitor blocks HeLa cell spreading, while activation of PKC with 12-O-tetradecanoyl phorbol-13-acetate (TPA) enhances the rate and the extent of cell spreading. In addition, PKC activation with TPA enhances cell spreading in various conditions that reduce the number of cells spread, such as at a gelatin concentration below threshold concentration, in the presence of Arg-Gly-Asp peptide, and at reduced temperatures. PKC activation with TPA also overcomes the inhibition of cell spreading induced by blocking of either arachidonic acid release or lipoxygenase metabolite(s) formation. Inhibition of PKC with calphostin C blocks TPA effects and other PKC activators such as mezerein also enhance cell spreading, indicating that the effect of TPA is via activation of PKC. Data suggest that formation of a lipoxygenase metabolite(s) from released arachidonic acid induces production of diacylglycerol which activates PKC, and the activated PKC then initiates the cell spreading mechanism.
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KEYWORD
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