Metallocarboxypeptidase that mediates deglutamylation of target proteins. Catalyzes the deglutamylation of polyglutamate side chains generated by post-translational polyglutamylation in proteins such as tubulins. Also removes gene-encoded polyglutamates from the carboxy-terminus of target proteins such as MYLK. Does not show detyrosinase or deglycylase activities from the carboxy-terminus of tubulin. Metallocarboxypeptidase that mediates deglutamylation of tubulin and non-tubulin target proteins. Catalyzes the removal of polyglutamate side chains present on the gamma-carboxyl group of glutamate residues within the C-terminal tail of tubulin protein. Specifically cleaves tubulin long-side-chains, while it is not able to remove the branching point glutamate. Also catalyzes the removal of polyglutamate residues from the carboxy-terminus of non-tubulin proteins. (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. Colocalizes with gamma-tubulin in the centrioles and with glutamylated tubulin in the basal bodies of ciliated cells. Belongs to the peptidase M14 family. Was initially shown to catalyze the removal of carboxy-terminus tyrosine from alpha-tubulin (By similarity). However, later studies did not identified any detyrosinase or deglycylase activities from the carboxy-terminus of tubulin (By similarity). Was originally thought to have detyrosinating activity from C-terminal positions on tubulin.