Enables microtubule binding activity and tubulin-glutamic acid ligase activity. Acts upstream of or within several processes, including adult behavior; protein polyglutamylation; and sperm axoneme assembly. Predicted to be located in centrosome. Predicted to be integral component of membrane. Orthologous to human TPGS1 (tubulin polyglutamylase complex subunit 1). [provided by Alliance of Genome Resources, Apr 2022]