Week+of+10-18-09

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I have continued reading the two papers (found here and here ), and have quickly learned the difference between high school and college papers. In addition, Dr. HG gave me another paper to read, found here.

The first paper I have looked at is the Mechanisms and Consequences of impaired lipid trafficking in Niemann-Pick type C1 deficient cells (this one). While it deals primarily with the NPC1 protein, it is still immensely useful. For example, it lays out a clear and concise definition of the disease, as well as other significant ideas:
 * Niemann-Pick type C:** a fatal and progressive neurodegenerative disease. It is caused in most cases by mutations to the NPC1 protein (although the NPC2 protein is easier to work with, so I will work with that one instead). The cause of the damage to neural tissues is due to the proteins being unable to properly regulate lipids, particularly cholesterol. Due to the blood-brain barrier, the brain produces its own cholesterols. It actually produces extra, which is converted and sent across the blood-brain barrier to the liver. Niemann-Pick disease appears to interfere with this process. The overabundance of cholesterol can lead to cell death.
 * NPC1 and NPC2:** transmembrane proteins that bind to cholesterols and help regulate movement. How exactly they do this is unknown. However, in NPC1 deficient cells, it is clear that there is an overabundance of unsterified cholesterol. Two models of interaction have been proposed. The first theorizes that NPC1 binds to cholesterols in the membranes of lysosmomes and endosomes, and then transfers the cholesterols to NPC2, which is soluble. The cholesterol would then be distributed to other cellular membranes. In the other model, NPC2 takes the cholesterols from the vesicle membranes and transfers it to NPC1, located in the lysosomes and endosomes. However, both of these models are incomplete without the help of additional proteins.