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Science. 2015 Oct 23;350(6259):450-4. doi: 10.1126/science.aac7444. Epub 2015 Oct 22.

Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts.

Author information

1
Plant Biology Laboratory, The Salk Institute, La Jolla, CA.
2
Waitt Advanced Biophotonics Center, The Salk Institute, La Jolla, CA.
3
Plant Biology Laboratory, The Salk Institute, La Jolla, CA. Division of Biological Sciences, University of California-San Diego, La Jolla, CA.
4
Plant Biology Laboratory, The Salk Institute, La Jolla, CA. Howard Hughes Medical Institute, The Salk Institute, La Jolla, CA.
5
Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.
6
Plant Biology Laboratory, The Salk Institute, La Jolla, CA. Howard Hughes Medical Institute, The Salk Institute, La Jolla, CA. chory@salk.edu.

Abstract

Energy production by chloroplasts and mitochondria causes constant oxidative damage. A functioning photosynthetic cell requires quality-control mechanisms to turn over and degrade chloroplasts damaged by reactive oxygen species (ROS). Here, we generated a conditionally lethal Arabidopsis mutant that accumulated excess protoporphyrin IX in the chloroplast and produced singlet oxygen. Damaged chloroplasts were subsequently ubiquitinated and selectively degraded. A genetic screen identified the plant U-box 4 (PUB4) E3 ubiquitin ligase as being necessary for this process. pub4-6 mutants had defects in stress adaptation and longevity. Thus, we have identified a signal that leads to the targeted removal of ROS-overproducing chloroplasts.

Comment in

PMID:
26494759
PMCID:
PMC4863637
DOI:
10.1126/science.aac7444
[Indexed for MEDLINE]
Free PMC Article

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