GBP2 and breast cancer: To determine GBP2 dependence on Drp1 to regulate cell invasion of breast cancer cells, we treated cells with Mdivi-1, a Drp1-specific inhibitor that allows for unopposed fusion.25 As shown in Supplementary Figure 4e, Mdivi-1 treatment destroyed GBP2-Drp1 binding and inhibited invasion of cells with or without IFN-γ-induced GBP2 expression (Supplementary Figure 4f).