The endoplasmic reticulum, chloroplasts, and mitochondria are major plant organelles for protein synthesis, photosynthesis, metabolism, and energy production. Protein homeostasis in these organelles, maintained by a balance between protein synthesis and degradation, is essential for cell functions during plant growth, development, and stress resistance. Nucleus-encoded chloroplast- and mitochondrion-targeted proteins and ER-resident proteins are imported from the cytosol and undergo modification and maturation within their respective organelles. Protein folding is an error-prone process that is influenced by both developmental signals and environmental cues; a number of mechanisms have evolved to ensure efficient import and proper folding and maturation of proteins in plant organelles. Misfolded or damaged proteins with nonnative conformations are subject to degradation via complementary or competing pathways: intraorganelle proteases, the organelle-associated ubiquitin–proteasome system, and the selective autophagy of partial or entire organelles. When proteins in nonnative conformations accumulate, the organelle-specific unfolded protein response operates to restore protein homeostasis by reducing protein folding demand, increasing protein folding capacity, and enhancing components involved in proteasome-associated protein degradation and autophagy. This review summarizes recent progress on the understanding of protein quality control in the ER, chloroplasts, and mitochondria in plants, with a focus on common mechanisms shared by these organelles during protein homeostasis.

内质网，叶绿体和线粒体是蛋白质合成，光合作用，代谢和能量产生的主要植物细胞器。这些细胞器中的蛋白质稳态由蛋白质合成和降解之间的平衡维持，对于植物生长，发育和抗逆性期间的细胞功能至关重要。从细胞质中导入核编码的叶绿体和线粒体靶向蛋白以及内质网驻留蛋白，并在其各自的细胞器内进行修饰和成熟。蛋白质折叠是一个容易出错的过程，受发育信号和环境提示的影响。已经开发出许多机制来确保植物细胞器中蛋白质的有效导入以及蛋白质的正确折叠和成熟。具有非天然构象的错误折叠或损坏的蛋白质会通过互补或竞争途径降解：细胞器内蛋白酶，细胞器相关的泛素-蛋白酶体系统以及部分或整个细胞器的选择性自噬。当非天然构象的蛋白积累时，细胞器特异性的未折叠蛋白反应可通过减少蛋白折叠需求，增加蛋白折叠能力并增强蛋白酶体相关蛋白降解和自噬所涉及的成分来恢复蛋白稳态。这篇综述总结了植物对内质网，叶绿体和线粒体中蛋白质质量控​​制认识的最新进展，重点是这些细胞器在蛋白质稳态过程中共有的共同机制。