Terminal hydroxylation of eIF5A hypusination influences mitochondrial protein expression and cellular metabolism in fission yeast

Hypusination of eIF5A is an essential, oxygen-dependent post-translational modification catalyzed sequentially by DHPS and deoxyhypusine hydroxylase (DOHH). Although previous SILAC-based studies in budding yeast established that DOHH acts as an oxygen sensor regulating mitochondrial translation, whether this mechanism represents a generalized eukaryotic paradigm or a species-specific adaptation remains unknown. Here, we investigated the proteome-wide impact of disrupting the terminal hydroxylation of eIF5A using a DOHH-deficient mutant ( mmd1 Δ) in the evolutionarily distant fission yeast Schizosaccharomyces pombe . Utilizing an ORFeome-scale proteomic approach under a uniform expression framework, we demonstrate that DOHH loss does not uniformly reduce protein abundance but preferentially alters the abundance of mitochondrial proteins, specifically oxidative phosphorylation (OXPHOS) components. Reflecting these proteomic shifts, mmd1 Δ cells exhibited impaired respiration and a compensatory metabolic shift toward fermentation. Crucially, oxygen limitation reduced hypusinated eIF5A levels and recapitulated the mmd1 Δ phenotype in fission yeast. By demonstrating that this post-translational circuit operates identically across highly divergent yeast models, our results establish the evolutionary conservation of the DOHH-eIF5A axis, firmly validating it as a universal mechanism coupling environmental oxygen availability to mitochondrial translation.