TTLL4 and Autoimmunity: The monoglutamylation exerted by tubulin tyrosine ligase-like 4 (TTLL4) impairs the synthase activity of cGAS, and the polyglutamylation catalysed by TTLL6 impedes the DNA-binding affinity of cGAS.83 cGAS also undergoes acetylation at K384, K394 or K414, which are vital modifications to keep cGAS inactive, without DNA challenge or viral infection, and aspirin prevents self-DNA-induced autoimmunity by efficiently acetylating cGAS.84 In addition to suppressing the activity of cGAS, certain PTMs maintain the protein levels at a proper range.