Sanchez, B.-J. | Search bioRxiv

bioRxiv2026

Infection Tunes the Dynamics of Adenoviral E1A Disordered Regions

Intrinsically Disordered Proteins and protein regions (IDPs) are abundant in many viral proteomes and play diverse roles in the viral infectious cycles. The adenovirus Early Protein 1A (E1A) is one such viral IDP. E1A acts as a molecular hub that regulates viral infection by mediating interactions between viral and multiple host proteins. Like other IDPs, E1A exists in a flexible ensemble of conformations. Despite a demonstrated link between ensemble structure and function in E1A, no real-time measurement of its ensemble has been performed. Here, we use live cell FRET microscopy to measure the local ensemble structure of E1A in human cells, both in healthy cells and in cells infected with adenovirus. We found specific disordered regions undergo significant changes to their ensemble in infected cells. Furthermore, infection also alters the propensity of these regions to partition between the cytoplasm and nucleus, a hallmark of E1A function during infection. Our results showcase that the structural ensembles of viral IDPs are responsive to infection, and suggest that these may play a role in regulating infection progression. SignificanceIntegral to many viral proteomes are intrinsically disordered proteins and protein regions (IDPs), which target and rewire cellular pathways to ensure infection progression. During this process, the physical and chemical composition of the cell changes dramatically: metabolism is rewired, viral proteins are produced en masse, and as a result, the chemical composition of the host proteome is significantly altered. IDPs are known to be structurally sensitive to even mild changes in their environment, and their structural changes can result in a change to function. Here, using live cell FRET microscopy, we show that the structure and spatial localization of an adenovirus IDP, E1A, is altered in cells infected by the virus. Beyond a possible functional role for structural sensitivity in viral IDP function, our findings suggest that host IDPs may also be structurally altered by infection, with downstream functional consequences.

biophysics↗

bioRxiv2024

HAdV-5 infection dysregulates cysteine, purine, and unsaturated fatty acid metabolism in fibroblasts

Viral infections can cause cellular dysregulation of metabolic reactions. Viruses alter host metabolism to meet their replication needs. The impact of viruses on specific metabolic pathways is not well understood, even for a well-studied virus-like human adenovirus. Adenoviral infection is known to affect cellular glycolysis and respiration, however, global effects on cellular metabolic pathways in response to adenoviral infection are lacking, particularly in normally quiescent structural cells, such as fibroblasts. Further, few studies have employed an untargeted approach with an emphasis on viral dosage and duration of infection. To address this, we employed untargeted metabolomics to quantify the dynamic metabolic shifts in fibroblasts infected with human adenovirus serotype 5 (HAdV-5) at three dosages (0.5, 1.0, and 2.0 multiplicity of infection [MOI]) and across four time points (6, 12, 24, and 36 h post-infection [HPI]). The greatest differences in individual metabolites were observed at 6- and 12-hours post-infection. In addition to its effects on glycolysis and respiration, adenoviral infection downregulated cysteine and unsaturated fatty acid metabolism, while upregulated purine metabolism. These results reveal the specific metabolic pathways that are perturbed by adenoviral infection and the associated dynamic shifts in metabolism, suggesting that viral infections alter energetics via profound changes in protein, lipid, and nucleic acid metabolism. The results revealed previously unconsidered metabolic pathways disrupted by HAdV-5 that can alter cells, even in non-excitable structural cells, such as fibroblasts. ImportanceHuman adenoviruses overtake the DNA replication machinery of the infected host, rewiring mitotic events and leading to effects on cellular respiration and glycolysis. Fibroblast lineages are normally quiescent cells that display a repertoire of responses to certain agonists. While metabolism often begins with glucose breakdown in the form of aerobic glycolysis, additional pathways are important for the overall functioning of the cell. Data on shifts in the metabolism of fibroblast cells in response to human adenoviral infection are lacking. We used an untargeted metabolomic approach to better understand the dynamic metabolic changes in human kidney cells in response to three viral dosages across four time points post infection. Profound shifts were observed for the cysteine, purine, and unsaturated fatty acid metabolites. This analysis provides a global perspective and highlights previously underappreciated aspects of how human adenoviruses alter host metabolism.

microbiology↗