MSU-Department of Energy-Plant Research Laboratory, Michigan State University, 612 Wilson Road, East Lansing, MI 48824-1312, USA.
Plant J. 2013 Jul;75(2):339-49. doi: 10.1111/tpj.12227. Epub 2013 Jun 12.
Movement of secretory organelles is a fascinating yet largely mysterious feature of eukaryotic cells. Microtubule-based endomembrane and organelle motility utilizing the motor proteins dynein and kinesin is commonplace in animal cells. In contrast, it has been long accepted that intracellular motility in plant cells is predominantly driven by myosin motors dragging organelles and endomembrane-bounded cargo along actin filament bundles. Consistent with this, defects in the acto-myosin cytoskeleton compromise plant growth and development. Recent findings, however, challenge the actin-centric view of the motility of critical secretory organelles and distribution of associated protein machinery. In this review, we provide an overview of the current knowledge on actin-mediated organelle movement within the secretory pathway of plant cells, and report on recent and exciting findings that support a critical role of microtubules in plant cell development, in fine-tuning the positioning of Golgi stacks, as well as their involvement in cellulose synthesis and auxin polar transport. These emerging aspects of the biology of microtubules highlight adaptations of an ancestral machinery that plants have specifically evolved to support the functioning of the acto-myosin cytoskeleton, and mark new trends in our global appreciation of the complexity of organelle movement within the plant secretory pathway.
细胞内细胞器的运动是真核细胞中一个迷人但在很大程度上还不为人知的特征。利用动力蛋白 dynein 和驱动蛋白 kinesin 的基于微管的内膜和细胞器运动在动物细胞中很常见。相比之下，长期以来人们一直认为，植物细胞中的细胞内运动主要是由肌球蛋白马达拖动细胞器和内膜结合的货物沿着肌动蛋白丝束进行的。与此一致的是，肌动球蛋白细胞骨架的缺陷会损害植物的生长和发育。然而，最近的发现挑战了肌动蛋白在关键分泌细胞器的运动和相关蛋白机器分布中的中心观点。在这篇综述中，我们概述了目前关于植物细胞分泌途径中肌动蛋白介导的细胞器运动的知识，并报告了最近令人兴奋的发现，这些发现支持微管在植物细胞发育中的关键作用，微调了高尔基体堆叠的定位，以及它们在纤维素合成和生长素极性运输中的参与。这些微管生物学的新兴方面强调了植物特有的适应性，即对祖先机制的适应，以支持肌动球蛋白细胞骨架的功能，并标志着我们对植物分泌途径中细胞器运动复杂性的全球认识的新趋势。
