A novel 145 kd brain cytosolic protein reconstitutes Ca2+-regulated secretion in permeable neuroendocrine cells
The regulated secretory pathway is activated by elevated cytoplasmic Ca2+; however, the components mediating Ca2+ regulation have not been identified. In semi-intact neuroendocrine cells, Ca2+-activated secretion is ATP- and cytosol protein-dependent. We have identified a novel brain protein, p145,...
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Veröffentlicht in: | Cell 1992-09, Vol.70 (5), p.765-775 |
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Sprache: | eng |
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Zusammenfassung: | The regulated secretory pathway is activated by elevated cytoplasmic Ca2+; however, the components mediating Ca2+ regulation have not been identified. In semi-intact neuroendocrine cells, Ca2+-activated secretion is ATP- and cytosol protein-dependent. We have identified a novel brain protein, p145, as a cytosolic factor that reconstitutes Ca2+-activated secretion in two neuroendocrine cell types. The protein is a dimer of 145 kd subunits, exhibits Ca2+-dependent interaction with a hydrophobic matrix, and binds phospholipid vesicles, suggesting a membrane-associated function. A p145-specific antibody inhibits the reconstitution of Ca2+-activated secretion by cytosol, indicating an essential role for p145. The restricted expression of p145 in tissues exhibiting a regulated secretory pathway suggests a key role for this protein in the transduction of Ca2+ signals into vectorial membrane fusion events. |
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ISSN: | 0092-8674 1097-4172 |
DOI: | 10.1016/0092-8674(92)90310-9 |