Maintaining the integrity of organelles despite the cellular disturbances that arise during stress is essential for life. To ensure organelle proteostasis (protein homeostasis), plants have evolved multitiered quality control mechanisms that work together to repair or recycle the damaged organelles. Despite recent advances, our understanding of plant organelle quality control mechanisms is far from complete. Especially, the crosstalk between different quality control pathways remains elusive. Here, we highlight recent advances on organelle quality control, focusing on the targeted protein degradation pathways that maintain the homeostasis of the endoplasmic reticulum (ER), chloroplast, and mitochondria. We discuss how plant cells decide to employ different degradation pathways and propose tools that could be used to discover the missing components in organelle quality control.
Keywords: CDC48; Model substrates; Organelle quality control; Proteasome; Selective autophagy; Unfolded protein response; Viral replication.
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