Subunit of the tubulin polyglutamylase complex (TPGC). The complex mediates cilia and flagella polyglutamylation which is essential for their biogenesis and motility (Probable). May act in the targeting of the tubulin polyglutamylase complex. Required for the development of the spermatid flagellum (By similarity). Part of the neuronal tubulin polyglutamylase complex which contains TPGS1, TPGS2, TTLL1, LRRC49 and NICN1 (Probable). Interacts with PCM1, CSTPP1 and LRRC49 (PubMed:34782749). Associated with microtubules from neurites, centrosomes, basal bodies and axonemes.