PT  - JOURNAL ARTICLE
AU  - Jakob Petereit
AU  - Owen Duncan
AU  - Monika W Murcha
AU  - Ricarda Fenske
AU  - Emilia Cincu
AU  - Jonathan Cahn
AU  - Adriana Pružinská
AU  - Aneta Ivanova
AU  - Laxmikanth Kollipara
AU  - Stefanie Wortelkamp
AU  - Albert Sickmann
AU  - Jiwon Lee
AU  - Ryan Lister
AU  - A Harvey Millar
AU  - Shaobai Huang
TI  - Coordination and assembly of protein complexes encoded across mitochondrial and nuclear genomes is assisted by CLPP2 in <em>Arabidopsis thaliana</em>
AID  - 10.1101/2020.01.22.907055
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.01.22.907055
4099  - http://biorxiv.org/content/early/2020/01/23/2020.01.22.907055.short
4100  - http://biorxiv.org/content/early/2020/01/23/2020.01.22.907055.full
AB  - Protein homeostasis in eukaryotic organelles and their progenitor prokaryotes is regulated by a series of proteases including the caseinolytic protease (CLPP). CLPP has essential roles in chloroplast biogenesis and maintenance, but the significance of the plant mitochondrial CLPP remains unknown and factors that aid coordination of nuclear and mitochondrial encoded subunits for complex assembly in mitochondria await discovery. We generated knock-out lines of the single gene for the mitochondrial CLP protease subunit, CLPP2, in Arabidopsis thaliana. Mutants had higher abundance of transcripts from mitochondrial genes encoding OXPHOS protein complexes, while transcripts for nuclear genes encoding other subunits of the same complexes showed no change in abundance. In contrast, the protein abundance of specific nuclear-encoded subunits in OXPHOS complexes I and V increased in CLPP2 knockouts, without accumulation of mitochondrial-encoded counterparts in the same complex. Protein complexes mainly or entirely encoded in the nucleus were unaffected. Analysis of protein import, assembly and function of Complex I revealed that while function was retained, protein homeostasis was disrupted through decreased assembly, leading to accumulation of soluble subcomplexes of nuclear-encoded subunits. Therefore, CLPP2 contributes to the mitochondrial protein degradation network through supporting coordination and assembly of protein complexes encoded across mitochondrial and nuclear genomes.One sentence summary CLPP contributes to the mitochondrial protein degradation network through supporting coordination and assembly of protein complexes encoded across mitochondrial and nuclear genomes.