Nemaline myopathy is a condition characterised by weakness of the skeletal muscl

Question

Nemaline myopathy is a condition characterised by weakness of the skeletal muscles, and is often accompanied by respiratory paralysis. The severity of the disease varies; some patients die early in childhood due to respiratory paralysis, while others are relatively unaffected but have difficulty walking or standing. Some forms of nemaline myopathy are caused by a mutation in the gene encoding tropomyosin. In a paragraph, explain why patients with mutations in the tropomyosin gene could cause patients to experience these symptoms. Include at least one specific example of a molecular interaction between tropomyosin and another protein that could be disrupted by the tropomyosin mutation

Explanation / Answer

Nemaline myopathy is caused by defective genes involved in proteins interacting with sarcomere. There are several genes involved to cause this disease. The severity of the disease lies with the number of genes and the genes involved. These cytoskeletal proteins give stability to cell structure and are involved in contraction of muscles. The TNNT1 protein - Tropomyosin protein type I is responsible for thin filament regulatory complex which yields calcium sensitivity to striated muscle actin-myosin ATPase complex.

The mutation in -tropomyosin decreases the sensitivity of muscle contraction in response to Ca2+ that leads to a condition called hypotonia.

-tropomyosin mutation inhibits the thin filaments length and activation by affecting troponin protein and also denies the proper formation of myosin cross-bridges, thus resulting in defective muscle contraction.

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