RPP14 encodes a protein subunit of human ribonuclease P (RNase P), a ribonucleoprotein complex responsible for tRNA processing 1. The protein localizes to the nucleolus, specifically within the dense fibrillar component, and requires other RNase P subunits for proper nucleolar targeting through a piggyback mechanism 2. Beyond its role in the RNase P complex that cleaves 5' leaders from precursor tRNAs, RPP14 exhibits distinct 3'-5' exoribonucleolytic activity that degrades the excised 5' leader sequences in a magnesium-dependent, processive manner 3. This exonuclease function requires interaction with OIP2 and may be part of exosome-related activities 4. Importantly, RPP14 knockdown broadly inhibits tRNA maturation, including splicing and 3' processing, indicating its central role in coordinating ordered tRNA biogenesis 3. The RPP14 gene has an unusual bicistronic structure, also encoding HsHTD2, a mitochondrial fatty acid synthesis enzyme, in a conserved vertebrate arrangement spanning 400 million years of evolution 5. This unique genetic organization links RNA processing with mitochondrial metabolism, suggesting coordinated regulation of these fundamental cellular processes 6.