Viruses appear to be mischievous little creatures. They float around harmlessly until- BAM! You’re suddenly infected by one. However, viruses are actually very vulnerable. Our bodies are designed in such a way that at every step of the infectious cycle, there’s always an obstacle that the virus has to overcome. Now, if I wrote about every method a virus uses to break these obstacles, I’d end up writing a book. So I’ll talk about a tiny chunk of the process: translation.
Firstly, what is translation?
In simple terms, it’s the process by which mRNA (aka messenger RNA) produces proteins encoded in its genome. A thread of mRNA is strung through a cell’s ribosome and, with the help of tRNAs, it becomes a protein.
How does a virus inhibit cellular translation?
The eIF-4E protein is mandatory for cellular translation to work.You can see it in pink below:
The virus’ main task is to ensure the eIF-4E cannot bind to the red protein (eIF-4G) because if those two bind, cellular translation initiates. So it uses its handy little asset: 4E-bp1.
The 4E-bp1 protein, shown in blue, is first dephosphorylated. This is evident in the diagram, since the protein loses the orange circle it was attached to. Once it’s dephosphorylated, eIF-4E can bind to 4E-bp1. eIF-4E cannot come out of 4E-bp1, hence it cannot attach itself to eIF-4G. Due to this, cellular translation cannot happen.
Once the virus has successfully inhibited cellular translation, it can modulate the process so that it can make its own viral proteins and further replicate!
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Cover image credits: GIPHY
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