Characteristics of splice variants of the skeletal muscle ryanodine receptor: implications for myotonic dystrophy

点击翻译按钮获取中文摘要

The project is to address some of the basic molecular changes that occur in skeletal muscle during development and in myotonic dystrophy. Myotonic dystrophy is a significant health issue since it is the most common adult muscular dystrophy, with an occurrence of ~1 in 7000. The results will provide much needed information about the membrane-associated molecular mechanisms that regulate muscle contraction and may provide a basis for drug design and treatment of myotonic dystrophy. Respiration and locomotion depend on the release of calcium ions from stores inside muscle cells. Ryanodine receptor calcium channels regulate calcium release from the stores. The essential nature of ryanodine receptors is underlined by death at or before birth when ryanodine receptor expression is defective. In addition genetic defects in the ryanodine receptor cause cardiac arrhythmias, malignant hyperthermia and central core disease. Ryanodine receptor function is compromised in heart failure and fatigue. The essential role of ryanodine receptors makes them a potential therapeutic target, but they are not used in this way because of our limited knowledge of the protein. Myotonic dystrophy is an autosomal dominant multi-system disorder, in which an expansion of non-coding DNA leads to changes in expression of several different proteins. Although the genetic basis of myotonic dystrophy is now reasonably well understood, the contribution of molecular changes in the affected proteins to the myopathy has not been investigated. Our group has recently discovered that the juvenile form of the ryanodine receptor protein is highly expressed in adults suffering from myotonic dystrophy. By discovering more about the properties of the juvenile isoform, we will understand more about the basic mechanisms of ryanodine receptor function in developing muscle and in myotonic dystrophy and be able to design drugs to specifically modify ryanodine receptor activity.