The function of Ensembl gene identifier ENSG00000135912 (TTLL4, tubulin tyrosine ligase like 4) is as follows. Monoglutamylase which modifies both tubulin and non-tubulin proteins, adding a single glutamate on the gamma-carboxyl group of specific glutamate residues of target proteins. Involved in the side- chain initiation step of the polyglutamylation reaction but not in the elongation step. Preferentially modifies beta-tail tubulin over the alpha-tubulin. Monoglutamylates nucleosome assembly proteins NAP1L1 and NAP1L4. Monoglutamylates nucleotidyltransferase CGAS, leading to inhibition of CGAS catalytic activity, thereby preventing antiviral defense function. Involved in KLF4 glutamylation which impedes its ubiquitination, thereby leading to somatic cell reprogramming, pluripotency maintenance and embryogenesis. .