The endoplasmic reticulum membrane-bending protein RETICULON facilitates chloroplast relocation movement in Marchantia polymorpha
The endoplasmic reticulum membrane-bending protein RETICULON facilitates chloroplast relocation movement in Marchantia polymorpha
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内质网膜弯曲蛋白RETICULON促进地钱叶绿体迁移运动
DOI：
10.1111/tpj.15787
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Kodama Yutaka
中科院分区：
文献类型：
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作者：
Ishikawa Kazuya;Konno Ryota;Hirano Satoyuki;Fujii Yuta;Fujiwara Masayuki;Fukao Yoichiro;Kodama Yutaka
植物细胞改变叶绿体的胞内位置以确保有效的光合作用，这是一个由蓝光受体光致蛋白控制的过程。叶绿体向弱光迁移（积累反应），并远离过量的光（回避反应）。叶绿体被内质网（ER）包围，内质网在整个细胞质中形成复杂的网络。为了确保叶绿体快速移位，内质网必须改变其结构与叶绿体移位运动，但鲜为人知的是关于其潜在的机制。在此，我们在地钱中寻找光促素的相互作用物，并鉴定了一个RETICULON（RTN）家族蛋白; RTN蛋白通过稳定真核细胞内质网膜的曲率在内质网小管的形成和内质网网络的维持中起着重要作用。地钱多形RTN 1（Marchantia polymorphaRTN 1，MpRTN 1）定位于内质网小管和内质网片的边缘，这与RTNs在其它植物和异养生物中的定位一致。Mprtn 1突变体显示ER小管直径增加，表明MpRTN 1在ER膜收缩中的作用。此外，Mprtn 1表现出延迟的叶绿体回避反应，但正常的叶绿体积累反应。内质网动态的活细胞成像显示，内质网重组受损Mprtn 1在叶绿体回避反应。这些结果表明，在叶绿体回避反应，MpRTN 1重组ER网络，并通过与phototropin的相互作用，促进叶绿体运动。我们的研究结果提供了证据表明，植物细胞通过以同步的方式控制多个细胞器的运动来响应波动的环境条件。
Plant cells alter the intracellular positions of chloroplasts to ensure efficient photosynthesis, a process controlled by the blue light receptor phototropin. Chloroplasts migrate toward weak light (accumulation response) and move away from excess light (avoidance response). Chloroplasts are encircled by the endoplasmic reticulum (ER), which forms a complex network throughout the cytoplasm. To ensure rapid chloroplast relocation, the ER must alter its structure in conjunction with chloroplast relocation movement, but little is known about the underlying mechanism. Here, we searched for interactors of phototropin in the liverwortMarchantia polymorphaand identified a RETICULON (RTN) family protein; RTN proteins play central roles in ER tubule formation and ER network maintenance by stabilizing the curvature of ER membranes in eukaryotic cells.Marchantia polymorphaRTN1 (MpRTN1) is localized to ER tubules and the rims of ER sheets, which is consistent with the localization of RTNs in other plants and heterotrophs. The Mprtn1mutant showed an increased ER tubule diameter, pointing to a role for MpRTN1 in ER membrane constriction. Furthermore, Mprtn1showed a delayed chloroplast avoidance response but a normal chloroplast accumulation response. The live cell imaging of ER dynamics revealed that ER restructuring was impaired in Mprtn1during the chloroplast avoidance response. These results suggest that during the chloroplast avoidance response, MpRTN1 restructures the ER network and facilitates chloroplast movement via an interaction with phototropin. Our findings provide evidence that plant cells respond to fluctuating environmental conditions by controlling the movements of multiple organelles in a synchronized manner.