Publication Information
Kim et al., 2013
No external accession available
Abstract
Plant Cell. 2013 May;25(5):1523-40. doi: 10.1105/tpc.112.108613. Epub 2013 May
10.
Advanced proteomic analyses yield a deep catalog of ubiquitylation targets in
Arabidopsis.
Kim DY(1), Scalf M, Smith LM, Vierstra RD.
Author information:
(1)Department of Genetics, University of Wisconsin, Madison, Wisconsin 53706,
USA.
The posttranslational addition of ubiquitin (Ub) profoundly controls the
half-life, interactions, and/or trafficking of numerous intracellular proteins.
Using stringent two-step affinity methods to purify Ub-protein conjugates
followed by high-sensitivity mass spectrometry, we identified almost 950
ubiquitylation substrates in whole Arabidopsis thaliana seedlings. The list
includes key factors regulating a wide range of biological processes, including
metabolism, cellular transport, signal transduction, transcription, RNA biology,
translation, and proteolysis. The ubiquitylation state of more than half of the
targets increased after treating seedlings with the proteasome inhibitor MG132
(carbobenzoxy-Leu-Leu-Leu-al), strongly suggesting that Ub addition commits many
to degradation by the 26S proteasome. Ub-attachment sites were resolved for a
number of targets, including six of the seven Lys residues on Ub itself with a
Lys-48>Lys-63>Lys-11>>>Lys-33/Lys-29/Lys-6 preference. However, little sequence
consensus was detected among conjugation sites, indicating that the local
environment has little influence on global ubiquitylation. Intriguingly, the
level of Lys-11-linked Ub polymers increased substantially upon MG132 treatment,
revealing that they might be important signals for proteasomal breakdown. Taken
together, this proteomic analysis illustrates the breadth of plant processes
affected by ubiquitylation and provides a deep data set of individual targets
from which to explore the roles of Ub in various physiological and developmental
pathways.
DOI: 10.1105/tpc.112.108613
PMCID: PMC3694690
PMID: 23667124 [Indexed for MEDLINE]
