UNC119 is a lipid-binding chaperone that functions as a solubilization factor for myristoylated proteins, with critical roles in multiple cellular processes. Mechanistically, UNC119 binds the myristoyl moiety of N-terminally myristoylated proteins and mediates their intracellular trafficking 1. In immune cells, UNC119 directly regulates T-cell receptor signaling by trafficking the Src family kinase LCK to the immunological synapse, with TCR activation occurring through the UNC119-LCK adaptor pathway 23. In sensory neurons and photoreceptors, UNC119 cooperates with intraflagellar transport proteins to traffic ciliary cargos, including the myristoylated G-protein GNAT1 4. Disease relevance includes primary immunodeficiency: UNC119 mutations impair LCK activation, causing diminished T cell responses, CD4 lymphopenia, and susceptibility to viral, bacterial, and fungal infections 3. Additionally, cone-rod dystrophy results from UNC119 dysfunction affecting photoreceptor protein trafficking 5. Clinically significant is UNC119's upregulation in hepatocellular carcinoma, where it promotes tumor growth and migration through Wnt/β-catenin and TGF-β/EMT signaling pathways 6. Anti-UNC119 treatment inhibits HCC proliferation and extends survival in preclinical models, suggesting therapeutic potential 6. In T acute lymphocytic leukemia, UNC119 inhibition reduces LCK localization and may represent a novel therapeutic approach 2.