| First Author | Sørensen JB | Year | 2003 |
| Journal | J Gen Physiol | Volume | 122 |
| Issue | 3 | Pages | 265-76 |
| PubMed ID | 12939392 | Mgi Jnum | J:105824 |
| Mgi Id | MGI:3616733 | Doi | 10.1085/jgp.200308855 |
| Citation | Sorensen JB, et al. (2003) Examining synaptotagmin 1 function in dense core vesicle exocytosis under direct control of Ca2+. J Gen Physiol 122(3):265-76 |
| abstractText | We tested the long-standing hypothesis that synaptotagmin 1 is the Ca2+ sensor for fast neurosecretion by analyzing the intracellular Ca2+ dependence of large dense-core vesicle exocytosis in a mouse strain carrying a mutated synaptotagmin C2A domain. The mutation (R233Q) causes a twofold increase in the KD of Ca2+-dependent phospholipid binding to the double C2A-C2B domain of synaptotagmin. Using photolysis of caged calcium and capacitance measurements we found that secretion from mutant cells had lower secretory rates, longer secretory delays, and a higher intracellular Ca2+-threshold for secretion due to a twofold increase in the apparent KD of the Ca2+ sensor for fast exocytosis. Single amperometric fusion events were unchanged. We conclude that Ca2+-dependent phospholipid binding to synaptotagmin 1 mirrors the intracellular Ca2+ dependence of exocytosis. |
