Membrane tethering by the host ER-resident GTPase Atlastin-2 is critical for flavivirus replication

ABSTRACT: Flaviviruses (genus Orthoflavivirus) are arthropod-borne viruses which cause approximately 400 million annual global infections in humans. As obligate intracellular pathogens, flaviviruses must co-opt cellular machinery to facilitate their infection and spread. Notably, all flaviviruses replicate in association with the host endoplasmic reticulum (ER); genome replication, sequestered within virus-induced ER invaginations called viral replication organelles (vROs), is coupled to viral assembly, which occurs on ER membranes juxtaposed to sites of vRO formation. Owing to the ER’s incredible topological complexity, ER remodeling proteins exert considerable influence in the regulation of flavivirus infections. We previously reported that the cellular ER remodeling protein Atlastin-2 (ATL2), normally responsible for fusing homotypic ER tubules, is critical for the replication of multiple flaviviruses, including dengue virus (DENV) and Zika virus (ZIKV). However, a mechanistic explanation for the function of ATL2 during infection was unclear. In this work, we report on the conserved role that ATL2 plays in facilitating the spatial organization of flavivirus replication. Immunofluorescence and electron microscopy indicated that ATL2 knockdown resulted in significant vRO spatial dysregulation in both DENV- and ZIKV-infected cells, with an accompanying decrease in virus production and increase in the activation of cellular innate immune responses as vRO formation was disrupted. Correlative light and electron microscopy demonstrated that ATL2 concentrated in areas of vRO formation during flavivirus infection. ATL2 mutational analysis showed that tethering-competent but fusion-defective ATL2 was sufficient to rescue DENV and ZIKV replication in ATL2-knockout cells. Finally, a synthetic peptide that inhibited ATL2 activity significantly reduced DENV replication in cell culture and in human primary cells. Taken together, these results show that ATL2 plays a critical and conserved role in flavivirus infection, with its membrane tethering activity functioning to organize membranes for vRO biogenesis. Importantly, this function can be targeted to inhibit viral replication.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture, Fibroblast

DISEASE(S): Lung Adenocarcinoma

SUBMITTER: Pietro Scaturro  

LAB HEAD: Pietro Scaturro

PROVIDER: PXD068694 | Pride | 2026-08-18

REPOSITORIES: Pride