Reticulon proteins modulate autophagy of the endoplasmic reticulum in maize endosperm
Reticulon proteins modulate autophagy of the endoplasmic reticulum in maize endosperm
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DOI：
10.7554/elife.51918
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发表时间：
2020-02-03
期刊：
影响因子：
7.7
通讯作者：
Otegui, Marisa S.
中科院分区：
文献类型：
--
作者：
Zhang, Xiaoguo;Ding, Xinxin;Otegui, Marisa S.
网织红蛋白（Rtn）形成内质网（ER）的管状结构域，在某些情况下是选择性ER周转的自噬受体。我们已经发现，玉米Rtn1和Rtn2控制内质网的稳态和自噬通量胚乳糊粉层细胞，在那里的ER积累的脂滴和合成的存储蛋白的积累在萌发过程中代谢。玉米Rtn1和Rtn2在胚乳中表达，定位于ER，并以剂量依赖性方式重塑ER结构。Rtn1和Rtn2与Atg8a相互作用使用四个Atg8相互作用基序（AIM）位于C-末端，胞质环，跨膜段内。Rtn2和Atg8之间的结合在ER应激时升高。玉米rtn2突变体显示增加的自噬和ER应激反应伴侣的上调。我们认为玉米Rtn1和Rtn2作为自噬介导的ER周转的受体，因此对于ER稳态和抑制ER应激至关重要。
Reticulon (Rtn) proteins shape tubular domains of the endoplasmic reticulum (ER), and in some cases are autophagy receptors for selective ER turnover. We have found that maize Rtn1 and Rtn2 control ER homeostasis and autophagic flux in endosperm aleurone cells, where the ER accumulates lipid droplets and synthesizes storage protein accretions metabolized during germination. Maize Rtn1 and Rtn2 are expressed in the endosperm, localize to the ER, and remodel ER architecture in a dose-dependent manner. Rtn1 and Rtn2 interact with Atg8a using four Atg8-interacting motifs (AIMs) located at the C-terminus, cytoplasmic loop, and within the transmembrane segments. Binding between Rtn2 and Atg8 is elevated upon ER stress. Maize rtn2 mutants display increased autophagy and up-regulation of an ER stress-responsive chaperone. We propose that maize Rtn1 and Rtn2 act as receptors for autophagy-mediated ER turnover, and thus are critical for ER homeostasis and suppression of ER stress.