These results, together with those obtained with chemical inhibitors or neutralizing antibodies, strongly suggests that the cell fluorescence we detected basically relied on the completion of the virus fusion events with the release into the cytoplasm of the fluorescent molecules, a conclusion also supported by our results from the confocal microscope analysis.
Having all five calcium ions bound on the sensor does not guarantee vesicle release, since when a calcium ion detaches from the sensing mechanism before completion of fusion, the complex goes back to the not-fused state; an example of this is illustrated in the insert of Figure 9(c).
Mutant proteins were expressed and purified as described for SAP L31W until completion of cleavage of the fusion protein, when tag and target were separated by flowing once more through Ni-charged IMAC resin (GE Healthcare BioSciences, Sweden) before concentration and gel filtration on an S75 column into 50 mM MES pH 6.0, total ionic strength of 500 mM made up to this value using NaCl.
Upon completion of fusion the entire nuclear envelope had a lifetime of 2.5±0.15 ns and a FRET efficiency of 0.7.
In the simplest model, the universal SNARE-mediated fusion involves transport of the vesicle to the target membrane and 'priming' it for release, followed by calcium-mediated conformational change in the SNARE complex that leads to the completion of membrane fusion, and eventually to the release of granule contents [58].
In the simplest terms, SNARE-mediated fusion involves transport of the vesicle to the target membrane and 'priming' it for release, followed by calcium-mediated conformational change in the complex that leads to the completion of membrane fusion leading to release of granule contents (Fig 2).
Low pH is required to drive six-helix bundle formation leading to the completion of membrane fusion [22], [24], [27] [29].
Moreover, it is clear that luminal [Ca2+] and Ca2+-calmodulin are required for completion of the late endosome-lysosome fusion process and lysosome reformation associated with autophagy and, indeed, phagocytosis (84, 85).
Regardless of how periderm cells are removed from the midline seam, completion of palatal fusion is known to be critically dependent on TGFβ signalling acting via Smad-dependent and P38 MAPK-dependent pathways (17, 18, 30, 43).
