Just a TRIM

The other day in biology our teacher decided to show us a video about the immune system and how our cells protect themselves from the threat of a viral infection. One particular part of the video mentioned the protein TRIM 21, I was curious and decided to do some research on what it really was.

When a virus enters the body it is attacked by our immune system, antibodies attach themselves to the virus and usually this paralyses it and makes it easy prey for our white blood cells. However some viruses do manage to escape and then move on the enter the cells. It was thought that once a virus had reached this stage and penetrated the cell, it was infected and the only possible way of preventing the spread of the infection was to destroy itself.

adenovirus being degraded by a proteasome

It was recently discovered that there is one more line of defense inside the cell against the intruder. Antibodies that have attached themselves to the virus stay attached when it enters the cell. Tripartite motif (TRIM 21) is a naturally occurring protein inside the cell which identifies substances marked with antibodies and tags it with ubiquitin. This essentially marks it ready for degradation by the proteasome. The proteasome is an organelle designed to degradate unneeded or damaged proteins and it acts as a big recycler, breaking them down so that they might be used in the construction of new proteins. Once a virus has been marked, the proteasome breaks it down just as it would a protein.

But how can we use this information in producing new therapies to fight viruses? Many are calling it the breakthrough that will could us cure the common cold, surely this can be done by giving us more TRIM 21. This may be done by encouraging the immune system to create more TRIM 21 so that it can be more effective in destroying viruses. Derek Lowe suggests that another solution such as encouraging the production of more antibodies would be the best way. It makes sense, seeing as it's not due to a lack of TRIM 21 that viruses manage to infect cells; it's because sometimes a virus escapes being tagged by antibodies, evading notice and slipping through the defense systems.

I reccomend that you watch this video, a clip from BBC's The Hidden Life of the Cell

Bibliography:
http://www.independent.co.uk/news/science/a-cure-for-the-common-cold-may-finally-be-achieved-as-a-result-of-a-remarkable-discovery-in-a-cambridge-laboratory-2122607.html
http://pipeline.corante.com/archives/2010/11/03/trim21_a_cure_for_the_common_cold_maybe_not_.php