TTLL12 (tubulin tyrosine ligase like 12) is a multifunctional protein that primarily serves as a negative regulator of tubulin post-translational modifications and antiviral signaling pathways. The protein negatively regulates tubulin detyrosination and polyglutamylation modifications 1. In antiviral immunity, TTLL12 acts as a negative regulator of the RIG-I pathway by directly interacting with VISA/MAVS, TBK1, and IKKε, thereby inhibiting virus-induced type I interferon expression and promoting viral replication 1. During SARS-CoV-2 infection, vitamin D reduces TTLL12 expression through vitamin D receptor-mediated DNA methylation, which enhances interferon responses and reduces viral replication 2. In cancer, TTLL12 is upregulated across multiple cancer types and promotes tumor progression by modulating myeloid-derived suppressor cells through CCL9 chemokine secretion, leading to immunosuppression and resistance to anti-PD-1 therapy 3. The protein is also associated with poor prognosis in gastric cancer patients when overexpressed 4. TTLL12 expression varies during human oocyte meiosis, with differential expression patterns between in-vivo and in-vitro matured oocytes, suggesting a role in developmental competence 5. These findings establish TTLL12 as a key regulator linking tubulin modifications, immune responses, and cancer progression.