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Cells’ early warning system for viruses works like bank sensor alarm

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Protein sounds alarm on viruses/EMBL,Cusack

In “Cells Have Early-Warning System for Intruders” (ScienceDaily, Oct. 14, 2011), we learn:

When a thief breaks into a bank vault, sensors are activated and the alarm is raised. Cells have their own early-warning system for intruders, and scientists at the European Molecular Biology Laboratory (EMBL) in Grenoble, France, have discovered how a particular protein sounds that alarm when it detects invading viruses. The study, published October 14 in Cell, is a key development in our understanding of the innate immune response, shedding light on how cells rapidly respond to a wide range of viruses including influenza, rabies and hepatitis.

In response to a viral infection, RIG-I recognises viral genetic material — specifically, viral RNA — and primes the cell to produce the key anti-viral molecule, interferon. Interferon is secreted and picked up by surrounding cells, causing them to turn on hundreds of genes that act to combat the infection. To understand how RIG-I senses only viral RNA, and not the cell’s own RNA, and sounds the alarm, the scientists used intense X-ray beams generated at the European Synchrotron Radiation Facility (ESRF) to determine the three-dimensional atomic structure of RIG-I in the presence and absence of viral RNA, in a technique called X-ray crystallography. They found that in the absence of a viral infection, the receptor is ‘sleeping with one eye open’: the part of RIG-I that senses viral RNA is exposed, whilst the domains responsible for signalling are hidden, out of reach of the signalling machinery. When RIG-I detects viral RNA, it changes shape, ‘waking up’ the signalling domains, which become accessible to trigger interferon production. Although the EMBL scientists used RIG-I from the mallard duck, this receptor’s behaviour is identical to that of its human counterpart.

Which all just got naturally selected, right?

One Reply to “Cells’ early warning system for viruses works like bank sensor alarm

  1. 1
    Upright BiPed says:

    biosemiosis, materially manifested, transient information

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