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A protein factor extracted from murine brains confers physiological Ca 2+ sensitivity to exocytosis in sea urchin eggs
Author(s) -
Sasaki Hajime
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80620-v
Subject(s) - exocytosis , chaotropic agent , sea urchin , microbiology and biotechnology , biology , in vitro , biophysics , cortex (anatomy) , chemistry , calmodulin , biochemistry , membrane , enzyme , neuroscience
Exocytosis in sea urchin eggs can be reconstituted in vitro using the cell ghosts (the isolated cortices). When the isolated cortices were handled in the medium primarily composed of non‐chaotropic ions, exocytosis can be induced by a micromolar level of Ca 2+ . However, when the cortices are exposed to chaotropic anions such as Cl − , it is induced only at higher Ca 2+ concentrations of 10 −5 to 10 −4 M, due to the chaotropic anionic effect, by which a specific protein(s) is dissociated from the cortex. The dissociated protein can be added back to the cortex to restore the original Ca 2+ sensitivity [(1984) Dev. Biol . 101, 125–135]. A protein which has the similar effect on the isolated cortex was also found in the extract of murine brain. This protein was neither calmodulin, a G‐protein or a kinase. The data suggest the general regulatory mechanism of the Ca 2+ sensitivity of exocytosis by a protein factor widely distributed among cells.