RPP25 (ribonuclease P/MRP subunit p25) is a critical protein component of two essential ribonucleoprotein complexes: ribonuclease P (RNase P) and ribonuclease MRP (RNase MRP) 1. In RNase P, RPP25 participates in generating mature tRNA molecules by cleaving their 5' leader sequences 1. As an MRP component, RPP25 contributes to cleavage of pre-rRNA sequences 2. Mechanistically, RPP25 functions as an RNA-binding protein within these complexes 1. Critically, RPP25 forms a stable heterodimer with Rpp20, a prerequisite for robust RNA recognition 3. This heterodimer binds the P3 domain of RNase MRP RNA with nanomolar affinity, whereas individual subunits show negligible binding 3. The Rpp20-Rpp25 heterodimer regulates RNA-binding activity, subcellular localization to nucleoli, and coordinated protein expression 4. Disease relevance includes developmental disorders, as RMRP mutations affecting the RPP25-binding interface are associated with inherited developmental disorders 2. Additionally, RPP25 expression is decreased in autism spectrum disorder brain tissue 5, and elevated RPP25 promotes cervical cancer cell proliferation and migration 6. In cardiovascular disease, RPP25 represents a tissue-specific therapeutic target identified through coronary artery transcriptomics 7, suggesting potential relevance to atherosclerosis mechanisms.