Arabidopsis R-SNAREs VAMP721 and VAMP722 are required for cell plate formation

作  者:Liang Zhang,Haiyan Zhang,Peng Liu,Huaiqing Hao,Jing Bo Jin, Jinxing Lin
影响因子:4.411
刊物名称:PLoS One
出版年份:Oct-2011
卷:6  期:10  页码:e26129

论文摘要:

Background: Cell plate formation during plant cytokinesis is facilitated by SNARE complex-mediated vesicle fusion at the
cell-division plane. However, our knowledge regarding R-SNARE components of membrane fusion machinery for cell plate
formation remains quite limited.
Methodology/Principal Findings: We report the in vivo function of Arabidopsis VAMP721 and VAMP722, two closely
sequence-related R-SNAREs, in cell plate formation. Double homozygous vamp721vamp722 mutant seedlings showed lethal
dwarf phenotypes and were characterized by rudimentary roots, cotyledons and hypocotyls. Furthermore, cell wall stubs
and incomplete cytokinesis were frequently observed in vamp721vamp722 seedlings. Confocal images revealed that green
fluorescent protein-tagged VAMP721 and VAMP722 were preferentially localized to the expanding cell plates in dividing
cells. Drug treatments and co-localization analyses demonstrated that punctuate organelles labeled with VAMP721 and
VAMP722 represented early endosomes overlapped with VHA-a1-labeled TGN, which were distinct from Golgi stacks and
prevacuolar compartments. In addition, protein traffic to the plasma membrane, but not to the vacuole, was severely
disrupted in vamp721vamp722 seedlings by subcellular localization of marker proteins.
Conclusion/Significance: These observations suggest that VAMP721 and VAMP722 are involved in secretory trafficking to
the plasma membrane via TGN/early endosomal compartment, which contributes substantially to cell plate formation
during plant cytokinesis.