Prions:

Posted by Judy Arbique Jun 12, 2007

The whole principle of prions has remained pretty much a mystery to me. I just can’t picture an infectious protein! Perhaps I’m stuck in the paradigm of an outdated definition of infectious pathogens. Infections, in my training and lab experience, have included organisms that I’ve seen or experienced and read about extensively. How can an agent be infectious if it does not fit one of our traditional classifications of parasite, bacteria, virus or fungus? I have “half a mind” (key phrase) to suggest that we reclassify the realm of prions to science fiction!

Unfortunately, my initial response was similar to that of many people when faced with something they don’t understand.

It took awhile before I accepted the idea of a virus as a potential agent of infection. And, I didn’t really believe until I saw my first electron micrograph photo. Even though I believed in viruses at that point, I was far from understanding viruses or viral infectious and reproductive processes.

I have not seen a prion. To date, I have been confused by reading journal articles about prions. So I understand very little about them at this point.

Proteins are essential to cellular processes – to life. Prions are out-of-control proteins.

Proteins are chains of amino acids that fold over on each other: prions misfold and unfold in unexpected ways, and encourage other proteins to follow suit. Some of the misformed proteins (prions) form long strands of amyloid: amyloid clumps have been found in the brains of animals who have died as a result of prion infection. Presumably, the difference between natural “good” prions and unnatural “bad” prions is related to the over stimulation of amyloid production.

Mad cow disease, its equivalent in sheep, scrapie, and its human equivalent, Cruetzfeldt-Jakob disease are likely the only exposure most of us have had to prions, but apparently, there’s a flip-side: researchers have discovered non-pathogenic prions that play beneficial roles in biology. Some prions may even be essential to learning and memory.

Source:

Scientists identify prion’s infectious secret.