This is one of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance. Required for correct processing of both the 5' and 3' ends of 5S rRNA precursor, which is does in conjunction with ribonuclease M5 (RNase M5, rnmV). Possibly folds the 5S rRNA precursor into the correct conformation, thus acting as a chaperone. Part of the 50S ribosomal subunit (PubMed:30126986). Part of the 5S rRNA/L5/L18/L25 subcomplex (Probable). Contacts the 23S rRNA and 5S rRNA (Probable). Required for catalysis of RNase M5 (PubMed:6432797). Belongs to the universal ribosomal protein uL18 family.