Myotonin-protein kinase

Myotonin-protein kinase (DMPK) is a protein kinase that is encoded by the DMPK gene in humans. This protein is involved in the regulation of muscle contraction and is associated with the neuromuscular disorder known as myotonic dystrophy.

Structure

The DMPK protein is a member of the serine/threonine protein kinase family. It contains a kinase domain that is responsible for its enzymatic activity. The protein is primarily expressed in skeletal muscle, heart, and brain tissues.

Function

DMPK plays a crucial role in the maintenance of muscle structure and function. It is involved in the regulation of calcium homeostasis, which is essential for proper muscle contraction. The protein also participates in the signaling pathways that control muscle cell differentiation and survival.

Genetic Basis

The DMPK gene is located on chromosome 19 and contains a region of CTG repeats. In healthy individuals, the number of CTG repeats is typically between 5 and 37. However, in individuals with myotonic dystrophy, the number of repeats is significantly increased, often exceeding 50.

Myotonic Dystrophy

Myotonic dystrophy is a genetic disorder characterized by progressive muscle wasting and weakness. It is caused by the expansion of CTG repeats in the DMPK gene, leading to the production of an abnormal RNA transcript. This abnormal RNA sequesters important RNA-binding proteins, disrupting normal cellular function and leading to the symptoms of the disease.

Clinical Significance

The expansion of CTG repeats in the DMPK gene is the primary cause of myotonic dystrophy type 1 (DM1). The severity of the disease is correlated with the number of repeats, with larger expansions leading to more severe symptoms. Genetic testing for CTG repeat expansion is used to diagnose the condition.

Related pages

• Myotonic dystrophy
• Protein kinase
• Genetic disorder
• Muscle contraction

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  DMPK CTG Repeat