Function
TTLL-4 is a monoglutamylase enzyme that modifies tubulin by adding a single glutamate residue to the gamma-carboxyl group of specific glutamate residues on target proteins. It plays a crucial role in the initiation step of the polyglutamylation reaction but is not involved in the elongation step. TTLL-4 preferentially modifies beta-tail tubulin over alpha-tubulin. This enzyme is implicated in the side-chain glutamylation of tubulin within sensory cilia. In conjunction with TTLL-5 and TTLL-11, TTLL-4 is essential for male mating.