DAP3 (Death-Associated Protein 3) is a mitochondrial ribosomal protein encoded by the *MRPS29* gene, playing dual roles in cellular homeostasis and apoptosis regulation. Initially identified as a pro-apoptotic factor, DAP3 is involved in the intrinsic apoptosis pathway, interacting with mediators like FADD (FAS-associated death domain protein) to promote caspase activation. Structurally, it contains a death domain motif, characteristic of proteins involved in apoptosis signaling. Beyond apoptosis, DAP3 is essential for mitochondrial ribosome assembly and translation, contributing to oxidative phosphorylation and cellular energy production. Dysregulation of DAP3 has been implicated in cancer, neurodegenerative diseases, and mitochondrial disorders. For instance, reduced DAP3 expression correlates with tumor progression in certain cancers, while mutations may impair mitochondrial function. Antibodies targeting DAP3 are vital tools in studying these mechanisms. They enable detection of DAP3 expression via Western blotting, immunohistochemistry, or immunofluorescence, aiding research on apoptosis pathways, mitochondrial dysfunction, and disease biomarkers. Commercial DAP3 antibodies are typically raised against specific epitopes, requiring validation for specificity in diverse experimental models. Ongoing studies continue to explore DAP3's role in cellular stress responses and its therapeutic potential in diseases linked to mitochondrial defects or apoptotic resistance.