The Arabidopsis mitochondrial membrane‐bound ubiquitin protease UBP27 contributes to mitochondrial morphogenesis. (23rd May 2014)

• Record Type: Journal Article
• Authors: Pan, Ronghui; Kaur, Navneet; Hu, Jianping
• Is Part Of: Plant journal. Volume 78:Number 6(2014:Jun.)
• Page Start: 1047
• Page End: 1059
• Publication Date: 2014-05-23
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12532
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12532-abs-0001"> <title>Summary</title> <p>Mitochondria are essential organelles with dynamic morphology and function. Post‐translational modifications (PTMs), which include protein ubiquitination, are critically involved in animal and yeast mitochondrial dynamics. How PTMs contribute to plant mitochondrial dynamics is just beginning to be elucidated, and mitochondrial enzymes involved in ubiquitination have not been reported from plants. In this study, we identified an Arabidopsis mitochondrial localized ubiquitin protease, UBP27, through a screen that combined bioinformatics and fluorescent fusion protein targeting analysis. We characterized UBP27 with respect to its membrane topology and enzymatic activities, and analysed the mitochondrial morphological changes in <italic>UBP27</italic>T‐DNA insertion mutants and overexpression lines. We have shown that UBP27 is embedded in the mitochondrial outer membrane with an N<sub>in</sub>–C<sub>out</sub> orientation and possesses ubiquitin protease activities <italic>in vitro</italic>. UBP27 demonstrates similar sub‐cellular localization, domain structure, membrane topology and enzymatic activities with two mitochondrial deubiquitinases, yeast ScUBP16 and human HsUSP30, which indicated that these proteins are functional orthologues in eukaryotes. Although loss‐of‐function mutants of <italic>UBP27</italic> do not show obvious phenotypes in plant growth and mitochondrial morphology, <italic>UBP27</italic> overexpression can change mitochondrial morphology from rod to spherical shape and reduce the mitochondrial association of dynamin‐related protein 3 (DRP3) proteins, large GTPases that serve as the main mitochondrial fission factors. Thus, our study has uncovered a plant ubiquitin protease that plays a role in mitochondrial morphogenesis possibly through modulation of the function of organelle division proteins.</p> </abstract>