Flagging fusion: Phosphatidylserine signaling in cell-cell fusion.

Jarred M Whitlock, Leonid V Chernomordik

The Journal of biological chemistry 2021 Jan-Jun

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Formations of myofibers, osteoclasts, syncytiotrophoblasts, and fertilized zygotes share a common step, cell-cell fusion. Recent years have brought about considerable progress in identifying some of the proteins involved in these and other cell-fusion processes. However, even for the best-characterized cell fusions, we still do not know the mechanisms that regulate the timing of cell-fusion events. Are they fully controlled by the expression of fusogenic proteins or do they also depend on some triggering signal that activates these proteins? The latter scenario would be analogous to the mechanisms that control the timing of exocytosis initiated by Ca2+ influx and virus-cell fusion initiated by low pH- or receptor interaction. Diverse cell fusions are accompanied by the nonapoptotic exposure of phosphatidylserine at the surface of fusing cells. Here we review data on the dependence of membrane remodeling in cell fusion on phosphatidylserine and phosphatidylserine-recognizing proteins and discuss the hypothesis that cell surface phosphatidylserine serves as a conserved "fuse me" signal regulating the time and place of cell-fusion processes. Published by Elsevier Inc.

Citation

Jarred M Whitlock, Leonid V Chernomordik. Flagging fusion: Phosphatidylserine signaling in cell-cell fusion. The Journal of biological chemistry. 2021 Jan-Jun;296:100411