Publication Information
Zhang et al., 2018
Abstract
New Phytol. 2018 May;218(3):1106-1126. doi: 10.1111/nph.14909. Epub 2017 Nov 23.
N-terminomics reveals control of Arabidopsis seed storage proteins and proteases
by the Arg/N-end rule pathway.
Zhang H(1)(2), Gannon L(1), Hassall KL(3), Deery MJ(2), Gibbs DJ(4), Holdsworth
MJ(5), van der Hoorn RAL(6), Lilley KS(2), Theodoulou FL(1).
Author information:
(1)Plant Sciences Department, Rothamsted Research, Harpenden, AL5 2JQ, UK.
(2)Cambridge Centre for Proteomics, Department of Biochemistry and Cambridge
Systems Biology Centre, University of Cambridge, Cambridge, CB2 1QR, UK.
(3)Computational and Analytical Sciences Department, Rothamsted Research,
Harpenden, AL5 2JQ, UK.
(4)School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK.
(5)School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK.
(6)Plant Chemetics Laboratory, Department of Plant Sciences, University of
Oxford, Oxford, OX1 3RB, UK.
Comment in
New Phytol. 2018 May;218(3):879-881.
The N-end rule pathway of targeted protein degradation is an important regulator
of diverse processes in plants but detailed knowledge regarding its influence on
the proteome is lacking. To investigate the impact of the Arg/N-end rule pathway
on the proteome of etiolated seedlings, we used terminal amine isotopic
labelling of substrates with tandem mass tags (TMT-TAILS) for relative
quantification of N-terminal peptides in prt6, an Arabidopsis thaliana N-end
rule mutant lacking the E3 ligase PROTEOLYSIS6 (PRT6). TMT-TAILS identified over
4000 unique N-terminal peptides representing c. 2000 protein groups. Forty-five
protein groups exhibited significantly increased N-terminal peptide abundance in
prt6 seedlings, including cruciferins, major seed storage proteins, which were
regulated by Group VII Ethylene Response Factor (ERFVII) transcription factors,
known substrates of PRT6. Mobilisation of endosperm α-cruciferin was delayed in
prt6 seedlings. N-termini of several proteases were downregulated in prt6,
including RD21A. RD21A transcript, protein and activity levels were
downregulated in a largely ERFVII-dependent manner. By contrast, cathepsin B3
protein and activity were upregulated by ERFVIIs independent of transcript. We
propose that the PRT6 branch of the pathway regulates protease activities in a
complex manner and optimises storage reserve mobilisation in the transition from
seed to seedling via control of ERFVII action.
© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.
DOI: 10.1111/nph.14909
PMCID: PMC5947142
PMID: 29168982 [Indexed for MEDLINE]
