Based on the results obtained in the inducible transgenic GFAP-CreER-Notch1-cKO and GFAPCreER-ETBR-cKO mice, LeComte et al. (2015) determined that the Notch1–STAT3–ETBR axis connects a signaling network that promotes reactive astrocyte proliferation after brain ischemia. Here, NOTCH1 is linked to brain ischemia.