NSF/αSNAP2-mediated cis-SNARE complex disassembly precedes membrane fusion generating the cell plate during Arabidopsis cytokinesis

Eukaryotic membrane fusion requires trans -SNARE complexes bridging the gap between adjacent membranes ([Jahn and Scheller, 2006][1]). Fusion between a transport vesicle and its target membrane transforms the trans -into a cis -SNARE complex. The latter interacts with the hexameric AAA+-ATPase NSF and its co-factor αSNAP, forming a 20S complex ([Zhou et al., 2015][2]; [Zhao and Brunner, 2016][3]). ATPase activity disassembles the SNARE complex into Qa-SNARE, which folds back onto itself, and its partners ([Huang et al., 2019][4]; [Kim et al., 2021][5]). Fusion of identical membranes has a different sequence of events ([Baker and Hughson, 2016][6]). The fusion partners each have cis -SNARE complexes to be broken up by NSF and αSNAP. The Qa-SNARE monomers are then stabilized by interaction with Sec1-type regulators (SM proteins) to form trans -SNARE complexes, as shown for the yeast vacuole ([Baker et al., 2015][7]). Membrane fusion in Arabidopsis cytokinesis is formally akin to vacuolar fusion ([Müller and Jürgens, 2016][8]). Membrane vesicles fuse with one another to form the partitioning membrane known as cell plate. C is -SNARE complexes of cytokinesis-specific Qa-SNARE KNOLLE and its SNARE partners are assembled at the ER and delivered by traffic via Golgi/TGN to the cell division plane (Karnahl and Park et al., 2017). SM protein KEULE is required for the formation of trans -SNARE complexes between adjacent membrane vesicles ([Park et al., 2012][9]). Here, we identify the missing NSF-type AAA+-ATPase and its adaptor αSNAP2 required for disassembly of KNOLLE cis -SNARE complexes. In addition, we show that NSF is also required for other trafficking pathways and interacts with the respective Q-SNAREs. In conclusion, the SNARE complex disassembly machinery is conserved in plants and plays a unique essential role in cytokinesis. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-15 [2]: #ref-44 [3]: #ref-42 [4]: #ref-14 [5]: #ref-18 [6]: #ref-1 [7]: #ref-2 [8]: #ref-23 [9]: #ref-27