Thiol protease which recognizes and hydrolyzes the peptide bond at the C-terminal Gly of ufm-1, a ubiquitin-like modifier protein bound to a number of target proteins (PubMed:29251776, PubMed:24603482). Required, with oct-4, for the localization of a subset of 7 transmembrane domain odorant receptors, including odr-10, to the cilia of olfactory neurons AWA and AWC (PubMed:9590179). Operates in aggregation behavior, and responses to oxygen levels (PubMed:12410303). {Experimental EvidencePubMed:12410303, Experimental EvidencePubMed:24603482, Experimental EvidencePubMed:29251776, Experimental EvidencePubMed:9590179}.