Prions Essay

Prions are the causative agents of a few rapidly progressive neurodegenerative diseases known as transmissible spongiform encephalopathies, or prion diseases. These are infectious isoforms of a host-encoded cellular protein known as the prion protein. Prion diseases affect humans and animals and are uniformly fatal in nature. [1]

Structure of prions

Prions are small infectious particles composed of abnormally folded protein that causes progressive neurodegenerative conditions. [2] Prions-the term was coined in 1982 by Stanley B. Prusiner, who was among the others to postulate their existence. A prion particle is composed of one or more amyloid fibers or oligomers, which are further composed of prion proteins. [2] Research shows that prions are resistant to the action of heat, radiation and chemical action.[3]

In 1995, investigators Byron Caughey of the National Institute of Allergy and Infectious Diseases and Peter Lansbury of Brigham and Women’s Hospital found out an analogy of Vonnegut’s ice-nine and structure of prions. [2] The infectious particles that spreads the prion disease: scrapie consisted of highly stable crystals of a normally innocuous material found in the brains of sheep. [2] Crystalline clumps of this misfolded version of the protein coaxes other molecules of the same protein to fold into the aberrant conformation. The process continues until virtually all of that protein in a cell or tissue has been converted to prions. [2,3] Prion proteins have the capability to recruit other proteins of the same sequence as they grow into a neatly organized lattice structure. When a new monomer arrives, it links to the fibril and assumes the exact shape of its neighbor. Fibrils can ultimately cluster together to for...

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...rticular protein, called MAVS, which is key to our innate ability to fight certain viral infections, acquires a self-perpetuating fibrillar form in cells that have become infected with virus and amplifies the cellular alarm signal. [7] This ultimately induces the production of interferons that recruit macrophages to combat the infection. [7]

Prions: still a mystery

Associated with numerous neurological diseases, prions or misfolded proteins may also play decisive roles in normal cellular functioning. [2] Much research has been conducted on prion biology, but many questions still remained unanswered such as how PrPC is converted to PrPSc; how prions move from host to host; how they bring out disease symptoms; normal physiological functions of PrP. [6] Future studies on prion protein will open the avenues for treatment of other neurodegenerative disorders as well.