Synaptotagmin Isoforms Couple Distinct Ranges of Ca2+, Ba2+, and Sr2+ Concentration to SNARE-mediated Membrane Fusion
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چکیده
منابع مشابه
Reconstitution of Ca2+-regulated membrane fusion by synaptotagmin and SNAREs.
We investigated the effect of synaptotagmin I on membrane fusion mediated by neuronal SNARE proteins, SNAP-25, syntaxin, and synaptobrevin, which were reconstituted into vesicles. In the presence of Ca2+, the cytoplasmic domain of synaptotagmin I (syt) strongly stimulated membrane fusion when synaptobrevin densities were similar to those found in native synaptic vesicles. The Ca2+ dependence of...
متن کاملSr2+ Binding to the Ca2+ Binding Site of the Synaptotagmin 1 C2B Domain Triggers Fast Exocytosis without Stimulating SNARE Interactions
Sr(2+) triggers neurotransmitter release similar to Ca(2+), but less efficiently. We now show that in synaptotagmin 1 knockout mice, the fast component of both Ca(2+)- and Sr(2+)-induced release is selectively impaired, suggesting that both cations partly act by binding to synaptotagmin 1. Both the C(2)A and the C(2)B domain of synaptotagmin 1 bind Ca(2+) in phospholipid complexes, but only the...
متن کاملVariable cooperativity in SNARE-mediated membrane fusion.
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex drives the majority of intracellular and exocytic membrane fusion events. Whether and how SNAREs cooperate to mediate fusion has been a subject of intense study, with estimates ranging from a single SNARE complex to 15. Here we show that there is no universally conserved number of SNARE complexes involved ...
متن کاملSynaptotagmin-Mediated Bending of the Target Membrane Is a Critical Step in Ca2+-Regulated Fusion
Decades ago it was proposed that exocytosis involves invagination of the target membrane, resulting in a highly localized site of contact between the bilayers destined to fuse. The vesicle protein synaptotagmin-I (syt) bends membranes in response to Ca(2+), but whether this drives localized invagination of the target membrane to accelerate fusion has not been determined. Previous studies relied...
متن کاملSynaptotagmin-1 utilizes membrane bending and SNARE binding to drive fusion pore expansion.
In regulated vesicle exocytosis, SNARE protein complexes drive membrane fusion to connect the vesicle lumen with the extracellular space. The triggering of fusion pore formation by Ca(2+) is mediated by specific isoforms of synaptotagmin (Syt), which employ both SNARE complex and membrane binding. Ca(2+) also promotes fusion pore expansion and Syts have been implicated in this process but the m...
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ژورنال
عنوان ژورنال: Molecular Biology of the Cell
سال: 2005
ISSN: 1059-1524,1939-4586
DOI: 10.1091/mbc.e05-04-0277