Ca2+ triggers massive exocytosis in Chinese hamster ovary cells.
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.
Coorssen
J R
JR
Abteilung Molekulare Zellforschung, Max-Planck-Institut fur Medizinische Forschung, Jahnstrasse 29, 69120 Heidelberg, Germany.
Schmitt
H
H
Almers
W
W
D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000502:physiology*; D006224:Cricetinae; D003412:Cricetulus; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010782:Photolysis
D016244:Guanosine 5'-O-(3-Thiotriphosphate); D008274:Magnesium; D002118:Calcium