Redefining how flaviviruses build infectious virions

Flaviviruses including dengue (DENV) and Zika (ZIKV) pose escalating global health threats, yet how infectious virions form within host cells remains poorly understood. While the canonical model depicts sequential assembly along the secretory pathway, our recent discoveries challenge this linear model, revealing that flaviviruses generate specialised "morphogenesis hubs"‒distinct ER/ERGIC-derived compartments enriched in GTPases, membrane-shaping proteins, and lipid-transfer machinery that recruit cholesteryl-ester-enriched lipid droplets (CE-LDs). We propose that these hubs couple lipid metabolism with virion assembly and are the predominant sites of infectious particle formation. This proposal employs spatial proteomics (LOPIT-DC), cryo-electron tomography, live-imaging, and targeted lipidomics across physiologically relevant iPSC-derived cells to: (1) resolve the molecular composition and assembly dynamics of morphogenesis hubs; (2) dissect how remodelled lipid droplets supply envelope lipids to morphogenesis hubs, driving virion infectivity; and (3) define viral adaptations in structural proteins (prM/E, capsid) and 3'UTR motifs that optimise hub exploitation, enhancing epidemic fitness. By reframing infectious virion formation as hub-centric morphogenesis, this work will expose druggable virus-host interfaces with broad-spectrum antiviral potential while illuminating fundamental mechanisms of inter-organelle lipid transport and virus-induced compartment biogenesis. Beyond flaviviruses, this framework provides a roadmap for dissecting virion biogenesis across diverse membrane-remodelling viruses including coronaviruses and alphaviruses.