Syntaxin specificity of cytokinesis in Arabidopsis.
Syntaxins interact with other SNAREs (soluble NSF-attachment protein receptors) to form structurally related complexes that mediate membrane fusion in diverse intracellular trafficking pathways. The original SNARE hypothesis postulated that each type of transport vesicle has its own distinct vesicle-SNARE that pairs up with a unique target-SNARE, or syntaxin, on the target membrane. However, recent evidence suggests that small G-proteins of the Rab family and their effectors mediate the initial contact between donor and acceptor membranes, providing complementary specificity to SNARE pairing at a later step towards membrane fusion. To assess the role of syntaxin specificity in membrane recognition requires a biological assay in which one syntaxin is replaced by other family members that do not normally function in that trafficking pathway. Here, we examine whether membrane fusion in Arabidopsis thaliana cytokinesis, which involves a plant-specific syntaxin, the cell-cycle-regulated KNOLLE (KN) protein, can be mediated by other syntaxins if expressed under the control of KN cis-regulatory sequences. Only a non-essential syntaxin was targeted to the plane of cell division and sufficiently related to KN to perform its function, thus revealing syntaxin specificity of cytokinesis.
Zentrum für Molekularbiologie der Pflanzen, Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 3, D-72076 Tübingen, Germany.
Isabel
I
Müller
Wenke
W
Wagner
Axel
A
Völker
Swen
S
Schellmann
Philippe
P
Nacry
Frank
F
Küttner
Zsuzsanna
Z
Schwarz-Sommer
Ulrike
U
Mayer
Gerd
G
Jürgens
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D050765:Qa-SNARE Proteins; D012333:RNA, Messenger / Q000032:analysis; D019076:Transgenes
D029681:Arabidopsis Proteins; C097724:KNOLLE protein, Arabidopsis; D008565:Membrane Proteins; D016271:Proto-Oncogene Proteins c-myc; D050765:Qa-SNARE Proteins; D012333:RNA, Messenger