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). Interacts with odr-4. Recruited to the endoplasmic reticulum upon interaction with odr-4. Expressed in head and tail neurons (PubMed:24603482). Expressed in the amphid head neurons ADL, ASI, ASH, ASJ, ASG, ADF, ASK, AWA, AWB, AWC, and in two tail neurons, the phasmid tail neurons PHA and PHB (PubMed:23449979). Aberrant localization of odr-10, str-2, str-112 and str-113. Reduced response to odorants mediated by AWA and AWC olfactory neurons. Increased aggregation and response to O2 levels when knocked down with npr-1. Belongs to the peptidase C78 family.