SNARE complexes of different composition jointly mediate membrane fusion in Arabidopsis cytokinesis.
SNARE complexes of different composition jointly mediate membrane fusion in Arabidopsis cytokinesis.
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DOI：
10.1091/mbc.e13-02-0074
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发表时间：
2013-05
影响因子：
3.3
通讯作者：
Jürgens G
中科院分区：
文献类型：
--
作者：
El Kasmi F;Krause C;Hiller U;Stierhof YD;Mayer U;Conner L;Kong L;Reichardt I;Sanderfoot AA;Jürgens G
分裂植物细胞的分隔膜是由传递至分裂平面的跨高尔基体网络衍生的膜囊泡同型融合而成。拟南芥的胞质分裂特异性突触蛋白形成两种不同类型的 SNARE 复合物，它们可以在胞质分裂过程中的膜融合中功能上相互替代。膜融合由可溶性 N-乙基马来酰亚胺敏感因子附着蛋白受体 (SNARE) 复合物介导。尽管真核胞质分裂中分离子细胞需要膜融合，但所涉及的 SNARE 复合物尚不清楚。在植物中，针对细胞分裂平面的膜囊泡相互融合，形成分隔膜，从细胞中心向外围延伸。在拟南芥中，胞质分裂特异性 Qa-SNARE KNOLLE 与另外两个 Q-SNARE、SNAP33 和新型植物特异性 SNARE 11 (NPSN11) 相互作用，后者在胞质分裂中的作用尚不清楚。在这里，我们通过免疫共沉淀表明 KNOLLE 形成了两种成分不同的 SNARE 复合物。一种复合物以三聚体质膜类型的 SNARE 复合物为模型，除了 KNOLLE 之外，还包括混杂的 Qb,c-SNARE SNAP33 和 R-SNARE 囊泡相关膜蛋白 (VAMP) 721,722，也参与先天免疫。相比之下，另一个含有 KNOLLE 的复合物是四聚体，包括 Qb-SNARE NPSN11、Qc-SNARE SYP71 和 VAMP721,722。通过突变（包括双突变体 npsn11 syp71）仅消除一种或另一种类型的 KNOLLE 复合体，会导致轻微或无胞质分裂缺陷。相比之下，两个双突变体snap33 npsn11和snap33 syp71消除了两种类型的KNOLLE复合物并表现出类似knolle的胞质分裂缺陷。因此，两种不同类型的 KNOLLE 复合物似乎共同介导拟南芥胞质分裂中的膜融合。
The partitioning membrane of dividing plant cells is made by homotypic fusion of trans-Golgi network–derived membrane vesicles delivered to the division plane. The cytokinesis-specific syntaxin of Arabidopsis forms two different types of SNARE complexes, which can functionally replace each other in membrane fusion during cytokinesis. 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.