College of Plant Protection, China Agricultural University, Beijing 100193, China; State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
College of Plant Protection, China Agricultural University, Beijing 100193, China.
Cell Rep. 2023 Dec 26;42(12):113480. doi: 10.1016/j.celrep.2023.113480. Epub 2023 Nov 28.
The endoplasmic reticulum (ER) is the largest intracellular endomembrane system; it shows dynamic changes upon environmental stress. To maintain ER morphology and homeostasis under stress, the excessive ER membrane and the associated unwanted proteins can be removed via ER-phagy. Although a few ER-phagy receptors have been reported in mammals and yeast, their functional counterparts in plants remain largely unexplored. Here, we report that the HVA22 family protein OsHLP1 is an uncharacterized ER-phagy receptor in rice (Oryza sativa L.). OsHLP1 interacts with OsATG8b and recruits ER subdomains and the cargo protein OsNTL6, a negative immune regulator, to autophagosomes upon infection with the fungus Magnaporthe oryzae, which substantially activates disease resistance in rice. AtHVA22J, an Arabidopsis thaliana OsHLP1 ortholog, induced similar ER-phagy in plants. Altogether, we unraveled a conservative protein family that may act as ER-phagy receptors in higher plants, and in particular, we highlighted their roles in rice immune responses.
内质网（ER）是最大的细胞内内膜系统；它在环境压力下表现出动态变化。为了在压力下维持 ER 的形态和动态平衡，可以通过 ER 自噬去除过多的 ER 膜和相关的不需要的蛋白质。尽管哺乳动物和酵母中已经报道了一些 ER 自噬受体，但它们在植物中的功能对应物在很大程度上仍未被探索。在这里，我们报告说 HVA22 家族蛋白 OsHLP1 是水稻（Oryza sativa L.）中一种未被描述的 ER 自噬受体。OsHLP1 与 OsATG8b 相互作用，并在感染真菌稻瘟病菌时招募 ER 亚区和货物蛋白 OsNTL6（一种负免疫调节剂）到自噬体中，这大大激活了水稻的抗病性。拟南芥 AtHVA22J 是 OsHLP1 的拟南芥同源物，在植物中诱导了类似的 ER 自噬。总之，我们揭示了一个保守的蛋白质家族，它可能在高等植物中作为 ER 自噬受体发挥作用，特别是我们强调了它们在水稻免疫反应中的作用。
