Cvrčková Fatima, Oulehlová Denisa, Žárský Viktor
Department of Experimental Plant Biology, Faculty of Sciences, Charles University, Viničná 5, 128 43 Prague 2, Czech Republic.
Int J Mol Sci. 2014 Dec 23;16(1):1-18. doi: 10.3390/ijms16010001.
The cytoskeleton plays a central part in spatial organization of the plant cytoplasm, including the endomebrane system. However, the mechanisms involved are so far only partially understood. Formins (FH2 proteins), a family of evolutionarily conserved proteins sharing the FH2 domain whose dimer can nucleate actin, mediate the co-ordination between actin and microtubule cytoskeletons in multiple eukaryotic lineages including plants. Moreover, some plant formins contain transmembrane domains and participate in anchoring cytoskeletal structures to the plasmalemma, and possibly to other membranes. Direct or indirect membrane association is well documented even for some fungal and metazoan formins lacking membrane insertion motifs, and FH2 proteins have been shown to associate with endomembranes and modulate their dynamics in both fungi and metazoans. Here we summarize the available evidence suggesting that formins participate in membrane trafficking and endomembrane, especially ER, organization also in plants. We propose that, despite some methodological pitfalls inherent to in vivo studies based on (over)expression of truncated and/or tagged proteins, formins are beginning to emerge as candidates for the so far somewhat elusive link between the plant cytoskeleton and the endomembrane system.
细胞骨架在包括内膜系统在内的植物细胞质的空间组织中起着核心作用。然而，目前所涉及的机制仅得到部分理解。formin（FH2蛋白）是一类进化上保守的蛋白家族，共享FH2结构域，其二聚体可使肌动蛋白成核，在包括植物在内的多个真核生物谱系中介导肌动蛋白和微管细胞骨架之间的协调。此外，一些植物formin含有跨膜结构域，并参与将细胞骨架结构锚定到质膜，甚至可能锚定到其他膜上。即使对于一些缺乏膜插入基序的真菌和后生动物formin，直接或间接的膜结合也有充分记录，并且FH2蛋白已被证明在真菌和后生动物中与内膜结合并调节其动态。在这里，我们总结现有证据表明formin在植物中也参与膜运输和内膜，尤其是内质网的组织。我们提出，尽管基于截短和/或标记蛋白（过）表达的体内研究存在一些固有的方法缺陷，但formin正开始成为迄今为止植物细胞骨架与内膜系统之间某种难以捉摸的联系的候选者。
