Rigorous assays of membrane fusion show that a distinct tethering step is required for lumenal compartment mixing in a manner that extends beyond simply increasing the amount of total trans-SNARE complex.
A combination of advanced optical imaging and cryogenic electron microscopy has been used to explore membrane fusion in a synthetic system and provide new insights into neurotransmitter release.
The SNAP-25 linker acts as a functional component of SNARE complexes, initially facilitating SNARE interactions and later promoting fusion triggering and pore evolution by local membrane contacts.
Mechanically stimulating mitochondria causes them to divide via the recruitment of the mitochondrial fission machinery to the mechanically strained site, showing that intracellular organelles can be mechanoresponsive.
Chick optic fissure closure is a powerful new model system for epithelial fusion and has revealed Netrin-1 as a conserved and essential mediator of tissue fusion in multiple contexts.
A few SNARE complexes suffice to fuse membranes, but many more are needed to dilate the nascent fusion pore by molecular crowding for efficient neurotransmitter or hormone release during exocytosis.