Neuroactive peptides are packaged as proproteins into dense core vesicles or secretory granules, where they are cleaved at dibasic residues by copackaged proprotein convertases. We show here that the Caenorhabditis elegans
egl-3 gene encodes a protein that is 57% identical to mouse proprotein convertase type 2 (PC2), and we provide evidence that this convertase regulates mechanosensory responses. Nose touch sensitivity (mediated by ASH sensory neurons) is defective in mutants lacking GLR-1 glutamate receptors (GluRs); however, mutations eliminating the
egl-3 PC2 restored nose touch sensitivity to
glr-1 GluR mutants. By contrast, body touch sensitivity (mediated by the touch cells) is greatly diminished in
egl-3 PC2 mutants. Taken together, these results suggest that
egl-3 PC2-processed peptides normally regulate the responsiveness of C. elegans to mechanical stimuli.