Enables tubulin-glutamic acid ligase activity. Acts upstream of or within several processes, including cerebellar Purkinje cell differentiation; mucociliary clearance; and protein polyglutamylation. Located in ciliary basal body. Used to study primary ciliary dyskinesia. Orthologous to human TTLL1 (tubulin tyrosine ligase like 1). [provided by Alliance of Genome Resources, Apr 2022]