Further studies that used a retinal ischemia–reperfusion model revealed that ProTα protects retinal cells via ecto-F1 ATPase coupled with the Gi-coupled P2Y12 receptor and Toll-like receptor 4 (TLR4)/MD2 coupled with a Toll–IL-1 receptor domain-containing adaptor inducing IFN-β (TRIF). Here, TLR4 is linked to retinal ischemia.