The function of POP4 (POP4 ribonuclease P/MRP subunit, ENSG00000105171) is as follows. Component of ribonuclease P, a ribonucleoprotein complex that generates mature tRNA molecules by cleaving their 5'-ends. {ECO:0000269|PubMed:10024167, ECO:0000269|PubMed:10352175, ECO:0000269|PubMed:30454648}.