Mitochondrial pleomorphy in plant cells is driven by contiguous ER dynamics.
Mitochondrial pleomorphy in plant cells is driven by contiguous ER dynamics.
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DOI：
10.3389/fpls.2015.00783
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发表时间：
2015
影响因子：
5.6
通讯作者：
Mathur J
中科院分区：
文献类型：
--
作者：
Jaipargas EA;Barton KA;Mathur N;Mathur J
线粒体是一种多形的双膜细胞器，参与所有真核生物的细胞能量学。动物和酵母细胞中的线粒体是典型的管状网状结构，长度为几微米，但在绿色植物中，它们主要被观察到为0.2-1.5 μm的斑点。虽然通过几种保守蛋白质的协调活性进行的裂变和融合塑造了线粒体，但内质网（ER）最近已被鉴定为酵母和哺乳动物细胞中此过程中的额外参与者。在植物细胞中的Escheria-ER关系仍然在很大程度上未被表征。在这里，通过对整个线粒体多形性的实时成像，我们揭示了植物中主要是点状线粒体形式的潜在基础。我们证明，线粒体形态的变化，在响应光和胞浆糖水平在ER介导的方式。然而，大的ER多边形和低动力学在黑暗条件下有利于线粒体融合和延伸，小的ER多边形导致增加的裂变和主要是小线粒体。缺氧还降低ER动力学并增加线粒体融合以产生巨大线粒体。通过观察正常植物和分裂受损的拟南芥nmt 1 -2和drp 3a突变体中的线粒体延长，我们还建立了薄的扩展称为matrixules和珠串线粒体表型是直接后果的线粒体-ER相互作用。
Mitochondria are pleomorphic, double membrane-bound organelles involved in cellular energetics in all eukaryotes. Mitochondria in animal and yeast cells are typically tubular-reticulate structures and several micro-meters long but in green plants they are predominantly observed as 0.2–1.5 μm punctae. While fission and fusion, through the coordinated activity of several conserved proteins, shapes mitochondria, the endoplasmic reticulum (ER) has recently been identified as an additional player in this process in yeast and mammalian cells. The mitochondria-ER relationship in plant cells remains largely uncharacterized. Here, through live-imaging of the entire range of mitochondria pleomorphy we uncover the underlying basis for the predominantly punctate mitochondrial form in plants. We demonstrate that mitochondrial morphology changes in response to light and cytosolic sugar levels in an ER mediated manner. Whereas, large ER polygons and low dynamics under dark conditions favor mitochondrial fusion and elongation, small ER polygons result in increased fission and predominantly small mitochondria. Hypoxia also reduces ER dynamics and increases mitochondrial fusion to produce giant mitochondria. By observing elongated mitochondria in normal plants and fission-impaired Arabidopsis nmt1-2 and drp3a mutants we also establish that thin extensions called matrixules and a beads-on-a-string mitochondrial phenotype are direct consequences of mitochondria-ER interactions.