Metallocarboxypeptidase that catalyzes the removing of polyglutamate side chains that are present on the gamma-carboxyl group of glutamate residues of tubulin in sensory cilia (PubMed:17244817, PubMed:20519502). Probably via the deglutamylation of tubulin, promotes microtubule stability required for axon regrowth after injury (PubMed:23000142). Also regulates microtubule dynamics in uterine muscle cells (PubMed:24780738). (L-glutamyl)(n+1)-gamma-L-glutamyl-L-glutamyl-[protein] + H2O = (L-glutamyl)(n)-gamma-L-glutamyl-L-glutamyl-[protein] + L-glutamate Binds 1 zinc ion per subunit. Expressed in labial and amphid neurons. RNAi-mediated knockdown at the L1 or L4 larval stages or in the egg-laying apparatus causes a reduction in egg-laying due to a defect in the egg-laying apparatus muscles. Belongs to the peptidase M14 family.