The process by which a vesicle fuses to a membrane within a cell is moderated by a group of proteins called the SNARE complex. When one SNARE protein on the surface of a vesicle meets the three other SNARE proteins on the target membrane it triggers the vesicle fusion process. Two other proteins, β-SNAP and NSF, then disassemble the SNARE complex to prepare for another round of fusion. Using zebrafish with a nonfunctional β-SNAP protein as a model organism, the researchers found that when the SNARE complex failed to disassemble, one of the SNARE proteins on the target membrane, BNip1, activated the apoptosis of the photoreceptor cell. When β-SNAP is functional properly, however, it prevents BNip1 from initiating programed cell death. In this way, the dual function of BNip1 as a member of the SNARE complex and a protein that can initiate photoreceptor apoptosis provides the link between these two processes.
Credit: Nishiwaki et al
