Raam

RYR2

The RYR2 gene encodes the ryanodine receptor 2, a crucial protein in cardiac muscle cells responsible for the release of calcium ions from the sarcoplasmic reticulum into the cytoplasm. This process is essential for cardiac muscle contraction and overall heart function. Mutations in the RYR2 gene are associated with various cardiac disorders, including catecholaminergic polymorphic ventricular tachycardia (CPVT) and arrhythmogenic right ventricular dysplasia (ARVD).

Structure

The RYR2 protein is a large homotetrameric complex that forms a calcium release channel in the sarcoplasmic reticulum membrane. Each subunit of the RYR2 protein is composed of approximately 4,967 amino acids, making it one of the largest ion channel proteins. The structure of RYR2 includes several domains, such as the N-terminal domain, the central domain, and the C-terminal domain, which contains the transmembrane segments that form the channel pore.

Function

RYR2 plays a pivotal role in cardiac excitation-contraction coupling. Upon electrical stimulation of the heart, calcium ions enter the cardiac muscle cell through voltage-gated calcium channels. This influx of calcium triggers the opening of RYR2 channels, leading to a massive release of calcium from the sarcoplasmic reticulum into the cytoplasm. The increase in cytoplasmic calcium concentration initiates the interaction between actin and myosin filaments, resulting in muscle contraction.

Clinical Significance

Mutations in the RYR2 gene can lead to abnormal calcium release, which is implicated in several cardiac disorders:

• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): A condition characterized by stress-induced arrhythmias, which can lead to syncope or sudden cardiac death. CPVT is often caused by autosomal dominant mutations in the RYR2 gene.

• Arrhythmogenic Right Ventricular Dysplasia (ARVD): A disorder that affects the heart muscle, leading to arrhythmias and an increased risk of sudden cardiac death. Some cases of ARVD have been linked to mutations in the RYR2 gene.

Research and Therapeutic Approaches

Research into RYR2 focuses on understanding the molecular mechanisms of calcium release and the pathophysiology of RYR2-related disorders. Therapeutic approaches aim to stabilize the RYR2 channel and prevent abnormal calcium release. Beta-blockers and calcium channel blockers are commonly used to manage symptoms in patients with RYR2 mutations.

Also see

• Calcium signaling
• Cardiac muscle contraction
• Ion channel
• Catecholaminergic polymorphic ventricular tachycardia
• Arrhythmogenic right ventricular dysplasia

Cardiovascular disease A-Z

Most common cardiac diseases

• Cardiac arrhythmia‎
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A

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• Cardiovascular disease in Australia
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B

• Brown atrophy of the heart

C

• Ebb Cade
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D

• Duke Treadmill Score
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E

• Eisenmenger's syndrome
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H

• Heart attack
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I

• Idiopathic giant-cell myocarditis
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K

• Keshan disease

L

• Loeffler endocarditis

M

• Mydicar
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N

• Nonbacterial thrombotic endocarditis

O

• OLR1
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P

• Papillary fibroelastoma
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R

• Right axis deviation
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S

• Saturated fat and cardiovascular disease
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T

• Traumatic cardiac arrest

V

• Ventricular aneurysm
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W

• Waon therapy