Ca2+ triggers massive exocytosis in Chinese hamster ovary cells. |
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Authors: | J R Coorssen H Schmitt and W Almers |
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Institution: | Abteilung Molekulare Zellforschung, Max-Planck-Institut fur Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany. |
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Abstract: | We have tracked the cell surface area of CHO cells by measuring the membrane capacitance, Cm. An increase in cytosolic Ca2+], Ca2+]i, increased the cell surface area by 20-30%. At micromolar Ca2+]i the increase occurred in minutes, while at 20 microM or higher Ca2+]i it occurred in seconds and was transient. GTPgammaS caused a 3% increase even at 0.1 microM Ca2+]i. We conclude that CHO cells, previously thought capable only of constitutive exocytosis, can perform Ca2+-triggered exocytosis that is both massive and rapid. Ca2+-triggered exocytosis was also observed in 3T3 fibroblasts. Our findings add evidence to the view that Ca induces exocytosis in cells other than known secretory cells. |
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