Catalyzes the deglutamylation of polyglutamate side chains generated by post-translational polyglutamylation of proteins such as tubulins (Probable). Via the deglutamylation of tubulin, regulates the localization and velocity of kinesin motors and the structural integrity of microtubules in sensory cilia (PubMed:21982591, PubMed:29129530). In male CEM sensory neurons, regulates the cilia release of bioactive extracellular vesicles (PubMed:29129530). Also regulates microtubule dynamics in uterine muscle cells (PubMed:24780738). Binds 1 zinc ion per subunit. In hermaphrodites and males, expressed in amphid and IL2 ciliated sensory neurons (PubMed:20519502, PubMed:21982591). In males, expressed in CEM head neurons, RnB and HOB tail neurons, and in gubernacular erector and retractor muscles (PubMed:21982591). RNAi-mediated knockdown at the L1 or L4 larval stages causes a defect in egg-laying without affecting uterine and vulva muscle function. Belongs to the peptidase M14 family.