RTL10 is a domesticated retrotransposon-derived gene on chromosome 22 that functions as a pro-apoptotic regulator through BH3 domain-dependent mechanisms 1. RTL10 belongs to the SIRH/RTL family of genes domesticated from Metaviridae retrotransposons, though it shows widespread loss of protein-coding capacity despite retention in several mammalian lineages 1. The protein operates within the intrinsic apoptosis pathway by interacting with Bcl-2 family members to modulate mitochondrial outer membrane permeabilization (MOMP), a critical checkpoint in programmed cell death 2. RTL10's pro-apoptotic function depends on its BH3 domain, which facilitates protein-protein interactions characteristic of BH3-only proteins that trigger apoptosis in response to cellular stressors 3. Like other BH3-domain containing proteins, RTL10 likely regulates mitochondrial membrane potential and contributes to the balance between pro- and anti-apoptotic Bcl-2 family members 4. The therapeutic potential of targeting BH3-dependent apoptotic pathways, demonstrated by successful BH3-mimetics in cancer treatment 56, suggests RTL10 may have relevance in conditions characterized by apoptosis resistance, though direct clinical applications require further investigation.