Cryo-EM structure of the FVa–APC complex. The model illustrates the domain organization of FVa (A1-A2-A3-C1-C2) and APC (Gla-EGF1-EGF2–protease domain [PD]). The complex is shown in cartoon representation and overlaid onto the corresponding electron density map. Individual domains are distinctly colored: yellow (A1), green (A2), cyan (A3), brown (C1), and purple (C2) for FVa; red (PD) and blue (Gla, EGF1, EGF2) for APC. The structure reveals that the interaction between FVa and APC is exclusively mediated by the A2 domain of FVa and the protease domain of APC. APC adopts a curved conformation, driven by the misalignment of its Gla domain to the protein’s main axis. See Figure 1A in the article by Mohammed et al that begins on page 3166.