Actin-Propelled Invasive Membrane Protrusions Promote Fusogenic Protein Engagement During Cell-Cell Fusion

Abstract

To Fuse or Not to Fuse? Cell-cell fusion is poorly understood, although we know that in the nematode, Caenorhabditis elegans , it involves cell-surface fusogens and in the fly, Drosophila , the actin cytoskeleton plays a role. Shilagardi et al. (p. 359 ) reconstituted a high-efficiency, inducible cell-fusion culture system, in which they found that the C. elegans fusogen, Eff-1, induced a low level of cell-cell fusion that was enhanced by coexpression with a cell adhesion molecule, Sticks and stones (Sns), required for myoblast fusion in Drosophila. Sns-enhanced cell-cell fusion was mediated by dynamic actin polymerization that generated invasive membrane protrusions at sites of fusion.