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Title: Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts

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 in this study, 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. As a result, we have identified a signal that leads to the targeted removal of ROS-overproducing chloroplasts.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [2] ;  [1]
  1. The Salk Inst., La Jolla, CA (United States)
  2. The Salk Inst., La Jolla, CA (United States); Washington Univ. School of Medicine, St. Louis, MO (United States)
  3. The Salk Inst., La Jolla, CA (United States); Univ. of California-San Diego, La Jolla, CA (United States)
  4. The Salk Inst., La Jolla, CA (United States); Shepherd Univ., Shepherdstown, WV (United States)
  5. Max Planck Institute for Developmental Biology, Tubingen (Germany); Univ. of California, Los Angeles, CA (United States)
  6. Max Planck Institute for Developmental Biology, Tubingen (Germany)
Publication Date:
Grant/Contract Number:
FG02-04ER15540; CA014195; NS072031
Type:
Accepted Manuscript
Journal Name:
Science
Additional Journal Information:
Journal Volume: 350; Journal Issue: 6259; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Research Org:
The Salk Inst., La Jolla, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Institutes of Health (NIH); German Research Foundation (DFG)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1345047