PNMA5 (PNMA family member 5) is a retrotransposon-derived mammalian gene located on chromosome X that functions as a pro-apoptotic protein with distinct functional domains. The protein localizes to the nucleus through a C-terminal nuclear localization signal (amino acids 391KRRR), while its N-terminal domain mediates protein-protein interactions, particularly with MOAP-1 (PNMA4) 1. PNMA5 undergoes -1 programmed ribosomal frameshifting to generate alternative protein isoforms, a mechanism conserved across mammals and subject to positive selection in primates 2. Functionally, PNMA5 promotes apoptotic signaling in cancer cells; co-expression with MOAP-1 significantly enhances chemosensitivity to Etoposide treatment in MCF-7 breast cancer cells 1. Conversely, PNMA5 exhibits pro-metastatic properties in several cancer contexts. USP22-mediated deubiquitination of PNMA5 promotes prostate cancer cell proliferation, migration, and invasion 3. In non-small cell lung cancer bone metastasis, the miR-877-3p/PNMA5 regulatory axis controls ferroptosis and epithelial-mesenchymal transition 4. PNMA5 expression is dysregulated in multiple cancers including early-onset gastric cancer and colon cancer metastasis, serving as a prognostic biomarker [PMID:40539460; 56]. Additionally, PNMA5 correlates with inflammatory responses in periodontitis under hyperglycemic conditions 6, and represents a potential prognostic marker in glioblastoma 7.