title: SNARE complexes of different composition jointly mediate membrane fusion in Arabidopsis cytokinesis.
abstract: Membrane fusion is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Although membrane fusion is required for separating daughter cells in eukaryotic cytokinesis, the SNARE complexes involved are not known. In plants, membrane vesicles targeted to the cell division plane fuse with one another to form the partitioning membrane, progressing from the center to the periphery of the cell. In Arabidopsis, the cytokinesis-specific Qa-SNARE KNOLLE interacts with two other Q-SNAREs, SNAP33 and novel plant-specific SNARE 11 (NPSN11), whose roles in cytokinesis are not clear. Here we show by coimmunoprecipitation that KNOLLE forms two SNARE complexes that differ in composition. One complex is modeled on the trimeric plasma membrane type of SNARE complex and includes, in addition to KNOLLE, the promiscuous Qb,c-SNARE SNAP33 and the R-SNARE vesicle-associated membrane protein (VAMP) 721,722, also involved in innate immunity. In contrast, the other KNOLLE-containing complex is tetrameric and includes Qb-SNARE NPSN11, Qc-SNARE SYP71, and VAMP721,722. Elimination of only one or the other type of KNOLLE complex by mutation, including the double mutant npsn11 syp71, causes a mild or no cytokinesis defect. In contrast, the two double mutants snap33 npsn11 and snap33 syp71 eliminate both types of KNOLLE complexes and display knolle-like cytokinesis defects. Thus the two distinct types of KNOLLE complexes appear to jointly mediate membrane fusion in Arabidopsis cytokinesis.
authors.affiliation: Developmental Genetics, Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Farid
authors.initials: F
authors.lastname: El Kasmi
authors.forename: Cornelia
authors.initials: C
authors.lastname: Krause
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hiller
authors.forename: York-Dieter
authors.initials: YD
authors.lastname: Stierhof
authors.forename: Ulrike
authors.initials: U
authors.lastname: Mayer
authors.forename: Laura
authors.initials: L
authors.lastname: Conner
authors.forename: Lingtian
authors.initials: L
authors.lastname: Kong
authors.forename: Ilka
authors.initials: I
authors.lastname: Reichardt
authors.forename: Anton A
authors.initials: AA
authors.lastname: Sanderfoot
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis; D008561:Membrane Fusion; D025941:Protein Interaction Mapping; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D050766:Qb-SNARE Proteins / Q000235:genetics / Q000378:metabolism*; D050767:Qc-SNARE Proteins / Q000235:genetics / Q000378:metabolism*; D050683:R-SNARE Proteins / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C097724:KNOLLE protein, Arabidopsis; C464505:NPSN11 protein, Arabidopsis; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; C439366:SNAP33 protein, Arabidopsis; C570049:VAMP721 protein, Arabidopsis; C570050:VAMP722 protein, Arabidopsis