Cytokinesis in Arabidopsis: Cytokinetic vesicles, cargo proteins and fusion machinery

在植物胞质分裂中，分隔膜通过将分泌囊泡靶向递送到细胞分裂平面以及囊泡彼此融合而产生，从而产生细胞板。 目前还不知道哪些蛋白质被转运以及它们在胞质分裂中起什么作用。 细胞动力学囊泡带有SNARE蛋白的所谓顺式复合物，其被酶促分解;随后，所谓的SM蛋白介导互补SNARE蛋白的反式复合物的形成，其促进相邻囊泡之间的融合。胞质分裂中顺式到反式SNARE复合物重组的调控机制尚不清楚。(1)提出的研究的一个主要目标是确定货物蛋白，这些蛋白在带有KNOLLE的膜囊泡上被递送到细胞分裂的平面，并有助于分隔膜的形成或成熟和/或形成横壁的合成或组装。根据待鉴定蛋白质的数量，我们将主要集中在我们的功能分析蛋白质，似乎特别参与胞质分裂。(2)另一个目的是确定AAA+ ATP酶和它的α-SNAP适配器参与cis-SNARE复合物解体之前，细胞板的形成，并阐明其在胞质分裂的行动。我们还将讨论是否捕获单体Qa-SNARE诺勒SM蛋白KEULE涉及直接的物理相互作用与拆卸机械。(3)第三个目的是通过鉴定特异性决定因素来分析Qa-SNARE和SM蛋白质在胞质分裂中的相互作用，所述特异性决定因素将SM蛋白质KEULE与其parabolic SEC 1B在与诺勒的相互作用中区分开，并且通过定义SM相互作用所需的相关诺勒序列基序。我们还将确定与诺勒相比，KEULE和SEC 1B是否以相同或不同的方式与SYP 132相互作用。

In plant cytokinesis, the partitioning membrane originates through target delivery of secretory vesicles to the cell division plane and the fusion of vesicles with one another, generating the cell plate. It is not known what proteins are transported and what role they play in cytokinesis. The cytokinetic vesicles bear so-called cis-complexes of SNARE proteins, which are enzymatically disassembled; subsequently, so-called SM proteins mediate the formation of trans-complexes of complementary SNARE proteins that facilitate the fusion between adjacent vesicles. Regulatory mechanisms underlying the reorganisation of cis to trans-SNARE complexes in cytokinesis are not known.(1) A major objective of the proposed research is to identify cargo proteins that are delivered on KNOLLE-bearing membrane vesicles to the plane of cell division and contribute to the formation or maturation of the partitioning membrane and/or the synthesis or assembly of the forming cross wall. Depending on the number of proteins to be identified, we will primarily focus our functional analysis on proteins that appear specifically involved in cytokinesis.(2) Another objective is to identify the AAA+ ATPase and its alpha-SNAP adaptor involved in cis-SNARE complex disassembly prior to cell plate formation and to characterise their action in cytokinesis. We will also address whether the capture of monomeric Qa-SNARE KNOLLE by SM protein KEULE involves direct physical interaction with the disassembling machinery.(3) A third objective is to analyse the interaction between Qa-SNAREs and SM proteins in cytokinesis by identifying specificity determinants that distinguish SM protein KEULE from its paralogue SEC1B in interaction with KNOLLE and by defining relevant KNOLLE sequence motifs required for SM interaction. We will also determine whether KEULE and SEC1B interact with SYP132 in the same or a different manner compared to KNOLLE.