Abstract The biogenesis and transport of lipoproteins are essential for systemic homeostasis and cardiometabolic health, yet how the secretory pathway acquires specialization to support high-capacity lipoprotein export remains unclear. Here, we report SEC16B as a tissue-selective modulator of the COPII machinery, critical for the efficient secretion of APOB-containing lipoproteins. Integrative bioinformatic analyses identify that SEC16B co-emerges with core genes involved in lipoprotein biogenesis. Functional studies, coupled with AI-driven prediction, reveal that SEC16B acts as a molecular brake to fine-tune COPII condensation for lipoprotein export. Mining of UK biobank data links SEC16B to metabolic traits in humans and suggests HNF4A-dependent regulation of SEC16B expression. Hepatic deletion of SEC16B in mice markedly reduces circulating APOB, triglycerides and cholesterol, while conferring robust protection against atherosclerosis and cardiac dysfunction and maintaining liver health. Collectively, these findings position SEC16B as a specialized modulator of lipoprotein export via the general secretory (SEC) pathway in the liver, suggesting potential therapeutic avenues for combating cardiometabolic diseases.
Wang et al. (Fri,) studied this question.