A microscopy-based screen identifies cellular kinases modulating mitochondrial translation

ABSTRACT: Mitochondrial DNA encodes thirteen subunits of the oxidative phosphorylation (OXPHOS) system, which are synthesized inside the organelle and essential for cellular energy supply. How mitochondrial gene expression is regulated and integrated into cellular physiology is little understood. Here, we performed a high-throughput screen combining fluorescent-labelling of mitochondrial translation products with siRNA-mediated knockdown, to identify cellular kinases regulating translation. As proof of principle, the screen identified known kinases that affect mitochondrial translation, and it also revealed several kinases not yet linked to this process. Among the latter, we focused on the primarily cytosolic kinase FN3K, which localizes partially to mitochondria, to support translation. Mass spectrometric (MS) bottom-up analysis of peptide samples after FN3K-flag immunoisolation in isolated mitochondria (transfected with FN3K-flag plasmid) enabled the identification of several proteins of the mitochondrial ribosome to be interacting with FN3K. Further experiments showed that FN3K likely modulates the assembly of mitochondrial ribosomes, thereby affecting translation. Overall, our work provides a reliable approach to identify new protein functions for mitochondrial gene expression, in a high throughput manner.

INSTRUMENT(S): timsTOF Pro 2

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Hela Cell

SUBMITTER: Carina Hansohn  

LAB HEAD: Henning Urlaub

PROVIDER: PXD053045 | Pride | 2025-01-02

REPOSITORIES: Pride