DOP1A (Dopey1) is a leucine zipper protein that functions as a dual-lipid-regulated cargo adaptor mediating protein trafficking between the Golgi apparatus and endosomes. Mechanistically, DOP1A assembles with Mon2 into a complex that localizes to the Golgi, endolysosome, and endoplasmic reticulum exit sites by binding phosphatidylinositol-4-phosphate and phosphatidic acid 1. The DOP1A-Mon2 complex recruits kinesin-1 motor proteins to facilitate centrifugally biased bidirectional transport of membrane carriers along microtubules 1. DOP1A dysfunction has emerging clinical relevance in both neurodevelopmental and neoplastic diseases. A homozygous DOP1A variant was identified in a consanguineous family with neurodevelopmental disorders, where the mutation disrupted protein-protein binding sites critical for Golgi-endosome trafficking, potentially affecting myelin-associated protein transport during development 2. In cancer contexts, DOP1A mutations stratified prognosis in stage IV gastric cancer patients 3, and alternative DOP1A splice variants (DOPEY1v2) were detected in peripheral blood and could discriminate breast cancer patients from healthy controls, with potential utility as diagnostic biomarkers 4. These findings suggest DOP1A plays essential roles in both normal neurobiological development and cancer pathogenesis.