title: A protein factor extracted from murine brains confers physiological Ca2+ sensitivity to exocytosis in sea urchin eggs.
abstract: 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 Ca2+. However, when the cortices are exposed to chaotropic anions such as Cl-, it is induced only at higher Ca2+ 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 Ca2+ 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 Ca2+ sensitivity of exocytosis by a protein factor widely distributed among cells.
authors.affiliation: Bio-Science Laboratory Inc., Yamagata, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002118:Calcium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005089:Exocytosis / Q000187:drug effects*; D006168:Guinea Pigs; D051379:Mice; D010063:Ovum / Q000187:drug effects*; D012377:Rodentia; D012617:Sea Urchins
chemical_list: D002118:Calcium