What is polyglutamine?
Polyglutamine (Polyq) is a part of a protein that contains a long segment of glutamine amino acids, usually in the range of 10 to 40 glutamine residues. When a polyglutamine tract, sometimes called polyglutamine tail, is unusually long, it can lead to neurodegenerative disease in some individuals. The main diseases that result from this abnormality include Huntington's disease, Kennedy's disease, Haw River syndrome and various spinocerebellar ataxia.
The formation of an unusually long polyglutamin tract is often caused by genetic mutations. Many of these mutations are inherited; For example, Kennedy's disease is recessive, which means that the mutation of the disease for the disease is placed on the x-chromosome and that the individual must have to develop the disease. Other common neurodegenerative diseases caused by an increased length of polyq tract are autosomal dominant, which means the gene is present on the chromosome outside sex and the individual needs only one copy of the gene to develop nemOCI.
Genetic mutations often include excessive repetition of three-nucleotide sequences of cytidin-enenosine-guanosine (CAG). These triplets, known as CAG repetition, each code to add one rest of glutamine to the tail of polyglutamine. When there are too many repetitions, the tail is too long and creates problems for the protein molecule and finally for the body as a whole. The number of other CAG repetitions varies for any disease, and some individuals with a high number of CAG repetitions do not end up developing any forms of neurodegenerative disease, suggesting that there is a certain degree of chances or environmental factors that contribute to the development of the disease.
Long polyq tails can create several main problems in the body. First, they can disrupt the function or shape of the proteins on which Thej is strapped. Extra glutamine residues can often cause protein to have a badly, which prevents its ability normallywork in a cell. In addition, abnormal tails of polyglutamine can prevent these non -functional proteins to be fixed or destroyed by the internal defensive cells of the cell, which worsens their harmful effects.
Secondly, although cells of cells are able to repair proteins by cutting off excess polyglutamine units, units can often aggregate in protein tangled. These tangles can not only get in the way of normal cellular processes, but can also unintentionally capture other proteins and molecules, which further damages the cell. Each of the different neurodegenerative diseases results from a slightly different mechanism, but all include a certain level of abnormal tail length of polyglutamine that damages nerve cells.