12 research outputs found
Assessment of Caspase Activities in Intact Apoptotic Thymocytes Using Cell-Permeable Fluorogenic Caspase Substrates
Intramolecular Resonance Dipole−Dipole Interactions in a Profluorescent Protease Substrate
Structural Characteristics of Fluorophores That Form Intramolecular H-Type Dimers in a Protease Substrate â€
Intracellular protease activation in apoptosis and cell-mediated cytotoxicity characterized by cell-permeable fluorogenic protease substrates
IFITM-2 and IFITM-3 but Not IFITM-1 Restrict Rift Valley Fever Virus
We show that interferon-induced transmembrane protein 1 (IFITM-1), IFITM-2, and IFITM-3 exhibit a broad spectrum of antiviral activity against several members of the Bunyaviridae family, including Rift Valley fever virus (RVFV), La Crosse virus, Andes virus, and Hantaan virus, all of which can cause severe disease in humans and animals. We found that RVFV was restricted by IFITM-2 and -3 but not by IFITM-1, whereas the remaining viruses were equally restricted by all IFITMs. Indeed, at low doses of alpha interferon (IFNα), IFITM-2 and -3 mediated more than half of the antiviral activity of IFNα against RVFV. IFITM-2 and -3 restricted RVFV infection mostly by preventing virus membrane fusion with endosomes, while they had no effect on virion attachment to cells, endocytosis, or viral replication kinetics. We found that large fractions of IFITM-2 and IFITM-3 occupy vesicular compartments that are distinct from the vesicles coated by IFITM-1. In addition, although overexpression of all IFITMs expanded vesicular and acidified compartments within cells, there were marked phenotypic differences among the vesicular compartments occupied by IFITMs. Collectively, our data provide new insights into the possible mechanisms by which the IFITM family members restrict distinct viruses