VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium; VIB Center for Medical Biotechnology, Albert Baertsoenkaai, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, Albert Baertsoenkaai, Ghent, Belgium
Ying Chen
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Mattias Vermeersch
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Liesbeth De Milde
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Valerie De Vleeschhauwer
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Annelore Natran
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Geert Persiau
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Dominique Eeckhout
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
VIB Center for Plant Systems Biology, Technologiepark, Zwijnaarde, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark, Zwijnaarde, Belgium
Protein ubiquitination is a very diverse post-translational modification leading to protein degradation or delocalization, or altering protein activity. In Arabidopsis thaliana, two E3 ligases, BIG BROTHER (BB) and DA2, activate the latent peptidases DA1, DAR1 and DAR2 by mono-ubiquitination at multiple sites. Subsequently, these activated peptidases destabilize various positive growth regulators. Here, we show that two ubiquitin-specific proteases, UBP12 and UBP13, deubiquitinate DA1, DAR1 and DAR2, hence reducing their peptidase activity. Overexpression of UBP12 or UBP13 strongly decreased leaf size and cell area, and resulted in lower ploidy levels. Mutants in which UBP12 and UBP13 were downregulated produced smaller leaves that contained fewer and smaller cells. Remarkably, neither UBP12 nor UBP13 were found to be cleavage substrates of the activated DA1. Our results therefore suggest that UBP12 and UBP13 work upstream of DA1, DAR1 and DAR2 to restrict their protease activity and hence fine-tune plant growth and development.
