UNC119B is a myristoyl-binding chaperone that facilitates trafficking of N-terminally myristoylated proteins to specific cellular compartments 1. It functions as a lipid-binding adapter with an immunoglobulin-like fold that masks hydrophobic myristoyl moieties, enabling transport through the hydrophilic cytosol 1. UNC119B demonstrates selective cargo binding, with affinity variations up to 427-fold for different myristoylated substrates 2. A key biological role involves localizing myristoylated NPHP3 to primary cilia; UNC119B knockdown prevents this ciliary trafficking 1. The protein is released from cargo through interaction with small GTPases ARL2 and ARL3 in a GTP-dependent manner 3. Beyond cilia biology, UNC119B negatively regulates glucose homeostasis by inhibiting Rac1 activation, thereby impairing GLUT4 translocation in response to insulin 4. UNC119B overexpression correlates with poor prognosis in hepatocellular carcinoma, contributing to immunotherapy resistance and chemotherapy resistance 5. Additionally, UNC119B serves as a protein interactor that allosterically activates PSKH1 kinase 6. Genetic compensation mechanisms upregulate UNC119B in CEP290-deficient models to partially rescue ciliary defects 7.