Filovirus Entry: A Novelty in the Viral Fusion World

Hunt, Catherine L.; Lennemann, Nicholas J.; Maury, Wendy

Interestingly, this processing may be insufficient for productive EBOV infection as studies have demonstrated that the smaller 17-19 kDa Cathepsin L and B-cleaved form cannot infect cells entirely lacking cathepsins [80] . Thus, it has been proposed that additional cathepsin-dependent GP 1 processing is required to generate the fusion-ready form of the glycoprotein [80] . The size and composition of this smaller form is not known. In contrast to these studies, a recent study demonstrated that a thermolysintrimmed GP 1 that is believed to generate a GP 1 that is similar to the Cathepsin L and B-cleaved form can be triggered to bind to liposomes at elevated temperatures under low pH and mildly reducing conditions [81] . This new study suggests that at least under these conditions this GP conformation is a fusion-ready form.