How membrane fusion and fission occur in live cells
Merging and division of cell membranes, known as fusion and fission, are vital to numerous processes in eukaryotic cells, like those of humans, animals, and plants. However, the ways that membranes’ two thin layers, known individually as ‘leaflets’, remodel themselves to control fusion and fission remains unclear due to difficulties of studying the two processes in live cells.
IRP researchers led by Ling-Gang Wu, Ph.D., labelled each of the cell membrane’s two leaflets with fluorescent proteins for the first time in live cells, allowing for detailed visualization of membrane layers in action. Their technique revealed that fusion and fission of the cell membrane is dynamically controlled by sequential merging or separation of each membrane leaflet with its counterpart, through an intermediate step called hemi-fusion/fission in which only one of the two membrane layers is fused.
This finding provides the missing evidence in three decades of cellular membrane studies, revealing that the hemi-fused intermediate structure can dynamically transition to fusion and fission in live cells. Because membrane fusion and fission are essential to proper cell division, transportation of materials into and out of cells, fertilization, viral entry, and many other cellular processes, understanding the steps involved and how they are mediated may benefit biomedical investigations into numerous disease processes.
Zhao WD, Hamid E, Shin W, Wen PJ, Krystofiak ES, Villarreal SA, Chiang HC, Kachar B, & Wu LG. (2016). Hemi-fused structure mediates and controls fusion and fission in live cells. Nature. Jun 23;534(7608):548-552.