Proximity biotinylation proteomics in stimulated endothelial cells generates a snapshot of the proteins that take part in WPB exocytosis and VWF string release. Candidate plus-end directed motor proteins for anterograde transport of WPBs over microtubules that are identified in this study are kinesins KIF5B and KIF11. Following WPB fusion, p21-activated kinase PAK2 initiates the formation of septin rings consisting of heteroduplexes of SEPT2, SEPT6, SEPT7, and SEPT9, leading to the formation of contractile actomyosin rings that squeeze VWF out of the postfusion WPB.