Component of ribonuclease P, a protein complex that generates mature tRNA molecules by cleaving their 5'-ends. Endonucleolytic cleavage of RNA, removing 5'-extranucleotides from tRNA precursor. Binds 1 zinc ion per subunit. Component of nuclear RNase P. RNase P consists of an RNA moiety and at least 9 protein subunits including POP1, POP3, POP4, POP5, POP6, POP7, POP8, RPP1 and RPR2, many of which are shared with the RNase MPR complex. Present with 2070 molecules/cell in log phase SD medium. Belongs to the eukaryotic/archaeal RNase P protein component 4 family.