Publication Information
Rytz et al., 2018
Abstract
Plant Cell. 2018 May;30(5):1077-1099. doi: 10.1105/tpc.17.00993. Epub 2018 Mar
27.
SUMOylome Profiling Reveals a Diverse Array of Nuclear Targets Modified by the
SUMO Ligase SIZ1 during Heat Stress.
Rytz TC(1)(2), Miller MJ(2), McLoughlin F(1), Augustine RC(1), Marshall RS(1),
Juan YT(3), Charng YY(3), Scalf M(4), Smith LM(4), Vierstra RD(5)(2).
Author information:
(1)Department of Biology, Washington University in St. Louis, St. Louis,
Missouri 63130.
(2)Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706.
(3)Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115,
Taiwan.
(4)Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706.
(5)Department of Biology, Washington University in St. Louis, St. Louis,
Missouri 63130 rdvierstra@wustl.edu.
The posttranslational addition of small ubiquitin-like modifier (SUMO) is an
essential protein modification in plants that provides protection against
numerous environmental challenges. Ligation is accomplished by a small set of
SUMO ligases, with the SAP-MIZ domain-containing SIZ1 and METHYL
METHANESULFONATE-SENSITIVE21 (MMS21) ligases having critical roles in stress
protection and DNA endoreduplication/repair, respectively. To help identify
their corresponding targets in Arabidopsis thaliana, we used siz1 and mms21
mutants for proteomic analyses of SUMOylated proteins enriched via an engineered
SUMO1 isoform suitable for mass spectrometric studies. Through multiple data
sets from seedlings grown at normal temperatures or exposed to heat stress, we
identified over 1000 SUMO targets, most of which are nuclear localized. Whereas
no targets could be assigned to MMS21, suggesting that it modifies only a few
low abundance proteins, numerous targets could be assigned to SIZ1, including
major transcription factors, coactivators/repressors, and chromatin modifiers
connected to abiotic and biotic stress defense, some of which associate into
multisubunit regulatory complexes. SIZ1 itself is also a target, but studies
with mutants protected from SUMOylation failed to uncover a regulatory role. The
catalog of SIZ1 substrates indicates that SUMOylation by this ligase provides
stress protection by modifying a large array of key nuclear regulators.
© 2018 American Society of Plant Biologists. All rights reserved.
DOI: 10.1105/tpc.17.00993
PMCID: PMC6002191
PMID: 29588388 [Indexed for MEDLINE]
