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The A rabidopsis mitochondrial membrane‐bound ubiquitin protease UBP 27 contributes to mitochondrial morphogenesis
Author(s) -
Pan Ronghui,
Kaur Navneet,
Hu Jianping
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12532
Subject(s) - microbiology and biotechnology , mitochondrial fission , mitochondrial fusion , biology , mitochondrion , ubiquitin , dnaja3 , translocase of the inner membrane , mitochondrial carrier , organelle , inner mitochondrial membrane , mitochondrial membrane transport protein , bacterial outer membrane , biochemistry , mitochondrial dna , gene , escherichia coli
Summary Mitochondria are essential organelles with dynamic morphology and function. Post‐translational modifications ( PTM s), which include protein ubiquitination, are critically involved in animal and yeast mitochondrial dynamics. How PTM s 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 A rabidopsis mitochondrial localized ubiquitin protease, UBP 27, through a screen that combined bioinformatics and fluorescent fusion protein targeting analysis. We characterized UBP 27 with respect to its membrane topology and enzymatic activities, and analysed the mitochondrial morphological changes in UBP 27 T ‐ DNA insertion mutants and overexpression lines. We have shown that UBP 27 is embedded in the mitochondrial outer membrane with an N in – C out orientation and possesses ubiquitin protease activities in vitro . UBP 27 demonstrates similar sub‐cellular localization, domain structure, membrane topology and enzymatic activities with two mitochondrial deubiquitinases, yeast S c UBP 16 and human H s USP 30, which indicated that these proteins are functional orthologues in eukaryotes. Although loss‐of‐function mutants of UBP 27 do not show obvious phenotypes in plant growth and mitochondrial morphology, UBP 27 overexpression can change mitochondrial morphology from rod to spherical shape and reduce the mitochondrial association of dynamin‐related protein 3 ( DRP 3) proteins, large GTP ases 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.