Activation of coagulation factor X (FX) is arguably the most important step in the formation of blood clots. When tissues are damaged by external injury, FX activation is initiated by the formation of a complex between FVIIa and tissue factor, which binds and activates FX after anchoring into negatively charged cellular membranes. This key step involves the formation of a tripartite complex on the membrane, which was earlier modeled by Resource researchers and published in Blood Advances. In collaboration with the Ohi lab and Morrissey lab at the University of Michigan, the previous model is now largely confirmed by the first cryo-EM structure of the complex on the membrane, a study reported as a cover story in Blood.