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Calcium drives fusion of SNARE‐apposed bilayers
Author(s) -
Jeremic Aleksandar,
Kelly Marie,
Cho Jin Ah,
Cho SangJoon,
Horber J.K.Heinrich,
Jena Bhanu P.
Publication year - 2004
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2003.11.004
Subject(s) - lipid bilayer fusion , calcium , vesicle , snap25 , snare complex , fusion , vesicle fusion , microbiology and biotechnology , biophysics , chemistry , liposome , biology , synaptic vesicle , membrane , biochemistry , linguistics , philosophy , organic chemistry
N ‐ethylmalemide‐sensitive factor attachment protein receptor (SNARE) has been proposed to play a critical role in the membrane fusion process. The SNARE complex was suggested to be the minimal fusion machinery. However, there is mounting evidence for a major role of calcium in membrane fusion. Hence, the role of calcium in SNARE‐induced membrane fusion was the focus of this study. It revealed that recombinant v‐SNARE and t‐SNARE, reconstituted into separate liposomes, interact to bring lipid vesicles into close proximity, enabling calcium to drive fusion of opposing bilayers. Exposure to calcium triggered vesicle fusion at both, high potency and efficacy. The half‐time for calcium‐induced fusion of SNARE‐reconstituted vesicles was determined to be ∼10 s, which is two orders of magnitude faster than in its absence. Calcium acts downstream of SNAREs, since the presence of SNAREs in bilayers increases the potency of calcium‐induced vesicle fusion, without significantly influencing its efficacy. Hence, this study suggests that in the physiological state in cells, both SNAREs and calcium operate as the minimal fusion machinery.