The function of TPGS1 (tubulin polyglutamylase complex subunit 1, Ensembl gene identifier ENSG00000141933) is as follows. 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). .