Figure 9.

Model of AFF-1-mediated repair via extracellular vesicle-cell fusion. PVD (red) is in close proximity to the epithelial seam cells (blue). AFF-1 (black pins) is expressed in seam cells and additional tissues, but not in the PVD. Upon injury, AFF-1-containing extracellular vesicles (EVs) are highly released from the seam cells. Some of these EVs reach the PVD and promote fusion of severed dendrites. EFF-1 (green pins) is expressed in the PVD but it does not act to fuse severed dendrites on its own. Instead, it may collaborate with AFF-1-EVs. We propose that menorah–menorah fusion is mediated by AFF-1-EVs that merge with the structurally compatible EFF-1 expressed in the PVD. EFF-1-coated pseudotyped viruses can fuse with cells expressing AFF-1 on their surface and vice versa (Avinoam et al. 2011).