How Flu Viruses Enter Our Cells: A New View of Viral Uptake
Recent research has revealed that cells don’t passively succumb to flu viruses; instead, thay actively participate in the virus’s entry, almost “capturing” it. As Professor Yamauchi puts it, “The infection of our body cells is like a dance that the virus and cell perform with each other.” This understanding comes from a new microscopy technique detailed in a study published in the journal PNAS.
traditionally, it was thought the body’s cells were simply hijacked during viral infection. Though, the dynamic interplay between virus and cell occurs as viruses exploit a natural cellular process used to transport essential substances – hormones, cholesterol, and iron - into the cells.
Like these vital substances, influenza viruses must first attach to molecules on the cell surface. this process resembles surfing: the virus scans the surface, attaching to molecules untill it finds an ideal entry point – a location with a high concentration of receptor molecules that allow for efficient absorption.
Once the cell’s receptors detect a virus attached to its membrane, it begins to form a depression or pocket at that location. This structure is built and stabilized by clathrin proteins. Gradually, this invagination grows, enveloping the virus and forming a bubble-like vesicle. The cell then transports this vesicle inside, where the vesicle coat dissolves, releasing the virus.
Previous methods for studying this process, like electron microscopy, required destroying the cells, providing only snapshots in time. Fluorescence microscopy, while non-destructive, offered limited spatial resolution.
the breakthrough comes with a combined approach: atomic force and fluorescence microscopy, dubbed “vivid atomic force microscopy” - “vivid” standing for “Virus View.” This technology allows researchers to observe the virus’s entry into the cell in unprecedented detail, revealing the dynamic nature of the process.
The research team demonstrated that the cell actively promotes viral uptake at multiple stages. It actively recruits clathrin proteins to the site of viral attachment and causes the cell surface to undulate, creating bulges that actively capture the virus. These wave-like membrane movements intensify as the virus is drawn into the cell.
This new method has significant implications for antiviral drug progress, offering a way to test potential drugs in real-time within cell cultures. The researchers also believe the technique can be applied to study the behavior of other viruses and even vaccines.
[A related video explaining the process can be found here: https://www.youtube-nocookie.com/embed/zySUz2kbbnA?wmode=transparent&jqoemcache=0ECWn]
