The degradation of signal peptides by cell surface proteases is one of the main factors regulating the development and behavior of organisms. Neprilysins (NEP), transmembrane proteins belonging to the family of zinc-metalloproteases, are known to play keyroles in these processes. In mammals, the knockout of neprilysins could lead to cellular disorganisation inducing diseases like prostata cancer and cardiovascular diseases. Although the proteome from C. elegans is intensively studied, very little is known about the function of neprilysins in the nematode. Sequence analysis of ZK20.6 (NEP-1), the C. elegans protein with highest similarity to mammalien neprilysins, showed, that the 753 aa protein includes all neprilysin typical characteristics like a short intracellular domain, one transmembrane domain and a long extracellular active domain. By fusion of
nep-1 promoter fragments to the GFP reporter, we determined the expression pattern of
nep-1 to be limited to the pharyngeal cells of the worm. Knockout of
nep-1 lead to an uncoordinated (unc) movement of the worms resulting in a 75 % reduced locomotion when compared to wild type worms. While changes in the pharyngeal pumping rate were not detectabel by eye, high sensitive electrophysiological recording of the pharyngeal activity showed a higher sensitivity of
nep-1 pharynxes to the neuropeptide AF1 (FLP-8 in C. elegans), which is a first hint, that AF1 is a NEP-1 substrate in C. elegans. Until now it is unclear, if the reduced AF1 cleavage in the head region of the worm is the release for the unc-phenotype, but further electrophysiological and biochemical analysis of the
nep-1 animals and of the recombinant protein will help to characterize a possible coherence.