Component of ribonuclease P, a ribonucleoprotein complex that generates mature tRNA molecules by cleaving their 5′-ends (PubMed:10444065, PubMed:30454648, PubMed:9037013, PubMed:9630247). Also a component of the MRP ribonuclease complex, which cleaves pre-rRNA sequences (PubMed:28115465).