Hypusination of the translation factor eIF5A regulates mitochondrial tRNA processing to promote prostate cancer aggressiveness

Protein synthesis plays a central role in cancer development and progression. eukaryotic initiation factor 5 A (eIF5A), a translation factor activated by hypusination, is implicated in tumorigenesis, however, its mode of action is still unclear. We find that hypusinated eIF5A (eIF5A^hyp) promotes metastasis and tumor growth in prostate cancer (PCa) by supporting mitochondrial metabolism and translation. eIF5A^hyp controls the subcellular localization of Mitochondrial Ribonuclease P Protein 3 (MRPP3) mRNA encoding a protein essential for mitochondrial tRNA (mt-tRNA) maturation. We show that eIF5A^hyp regulates the nuclear export of MRPP3 mRNA, its expression, thereby promoting mt-tRNA maturation. Our findings establish that MRPP3 enhances mitochondrial metabolism and supports PCa metastasis. Importantly, its expression restores mitochondrial translation and tumor growth inhibited by the downregulation of eIF5A^hyp. Together, we uncover a critical role for eIF5A^hyp in mitochondrial protein synthesis and highlight its broader implications in coordinating the expression of nuclear and mitochondrial genomes, linking hypusination to cancer progression.