Selective Autophagy Regulates Chloroplast Protein Import and Promotes Plant Stress Tolerance

Overview

Journal EMBO J

Specialties Biotechnology
Molecular Biology

Date 2023 May 30

PMID 37248861

Authors

Chen Wan

Hui Zhang

Hongying Cheng

Robert G Sowden

Wenjuan Cai

R Paul Jarvis

Qihua Ling

Affiliations

Soon will be listed here.

Abstract

Chloroplasts are plant organelles responsible for photosynthesis and environmental sensing. Most chloroplast proteins are imported from the cytosol through the translocon at the outer envelope membrane of chloroplasts (TOC). Previous work has shown that TOC components are regulated by the ubiquitin-proteasome system (UPS) to control the chloroplast proteome, which is crucial for the organelle's function and plant development. Here, we demonstrate that the TOC apparatus is also subject to K63-linked polyubiquitination and regulation by selective autophagy, potentially promoting plant stress tolerance. We identify NBR1 as a selective autophagy adaptor targeting TOC components, and mediating their relocation into vacuoles for autophagic degradation. Such selective autophagy is shown to control TOC protein levels and chloroplast protein import and to influence photosynthetic activity as well as tolerance to UV-B irradiation and heat stress in Arabidopsis plants. These findings uncover the vital role of selective autophagy in the proteolytic regulation of specific chloroplast proteins, and how dynamic control of chloroplast protein import is critically important for plants to cope with challenging environments.

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