Journal Article

FZJ-2020-02150

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The mouse heart mitochondria N terminome provides insights into ClpXP-mediated proteolysis

Hofsetz, E. ; Demir, F.FZJ* ; Szczepanowska, K. ; Kukat, A. ; Kizhakkedathu, J. ; Trifunovic, A. (Corresponding author) ; Huesgen, P. F. (Corresponding author)FZJ*

2020
The American Society for Biochemistry and Molecular Biology Bethesda, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/25792  doi:10.1074/mcp.RA120.002082

Abstract: The mammalian mitochondrial proteome consists of more than 1100 annotated proteins and their proteostasis is regulated by only a few ATP-dependent protease complexes. Technical advances in protein mass spectrometry allowed for detailed description of the mitoproteome from different species and tissues and their changes under specific conditions. However, protease-substrate relations within mitochondria are still poorly understood. Here, we combined Terminal Amine Isotope Labeling of Substrates (TAILS) N termini profiling of heart mitochondria proteomes isolated from wild type and Clpp−/− mice with a classical substrate-trapping screen using FLAG-tagged proteolytically active and inactive CLPP variants to identify new ClpXP substrates in mammalian mitochondria. Using TAILS, we identified N termini of more than 200 mitochondrial proteins. Expected N termini confirmed sequence determinants for mitochondrial targeting signal (MTS) cleavage and subsequent N-terminal processing after import, but the majority were protease-generated neo-N termini mapping to positions within the proteins. Quantitative comparison revealed widespread changes in protein processing patterns, including both strong increases or decreases in the abundance of specific neo-N termini, as well as an overall increase in the abundance of protease-generated neo-N termini in CLPP-deficient mitochondria that indicated altered mitochondrial proteostasis. Based on the combination of altered processing patterns, protein accumulation and stabilization in CLPP-deficient mice and interaction with CLPP, we identified OAT, HSPA9 and POLDIP2 and as novel bona fide ClpXP substrates. Finally, we propose that ClpXP participates in the cooperative degradation of UQCRC1. Together, our data provide the first landscape of the heart mitochondria N terminome and give further insights into regulatory and assisted proteolysis mediated by ClpXP.

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Contributing Institute(s):

1. Analytik (ZEA-3)

Research Program(s):

1. 553 - Physical Basis of Diseases (POF3-553) (POF3-553)

Appears in the scientific report 2020

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Database coverage:
; ; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; NCBI Molecular Biology Database ; PubMed Central ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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