Ryanodine receptors

Ryanodine receptors
Properties of human protein
Mass / length primary structure	4,900-5,000 amino acids
Identifier
Gene names	RYR1  ; RYR2 ; RYR3
Transporter classification
TCDB	1.A.3.1
designation	Ryanodine-InsP 3 calcium channel family
Occurrence
Parent taxon	Euteleostomi

Ryanodine receptors are a family of calcium ion channels , the activation of which causes the release of calcium ions from the sarcoplasmic reticulum into the cytosol . So they play a role in triggering muscle contractions. Ryanodine receptors get their name from the terpenoid ryanodine , which was originally obtained from the plant Ryania speciosa ( Salicaceae ). Ryanodine selectively binds to and blocks ryanodine receptors.

Subtypes

There are three subtypes of ryanodine receptors:

• RYR1 is mainly expressed in skeletal muscle , but is also found in Purkinje cells of the cerebellum. In the striated muscles, RYR1 is in direct connection with the dihydropyridine receptors in the membrane of the transverse tubules. In the event of a change in conformation of the L-type calcium channels triggered by the action potential of the muscle, the RYR1 channels also open. In this way, calcium ions are initially released from the sarcoplasmic reticulum into the cytosol of the muscle cell. RYR1 thus plays a key role in electromechanical coupling . Mutations of the RYR1 gene are observed in central core myopathy and multicore myopathy . They represent an essential disposition for the development of malignant hyperthermia and can be inhibited by dantrolene , which is also the treatment of the same disease.
• RYR2 is expressed in the heart muscles . Mutations of this receptor subtype lead to catecholaminergic polymorphic ventricular tachycardia , an autosomal dominant inherited form of ventricular tachycardia , which is associated with noticeable widening of the QRS complex in the ECG and which can lead to syncope and sudden cardiac death .
• RYR3 is expressed in skeletal muscles during fetal development and the neonatal period, but remains largely confined to the brain in adults . Here this subtype may be involved in learning processes.

Web links

• Schematic representation of the calcium interactions at the ryanodine receptor [1]

literature

Individual evidence

1. ↑ Unitprot entries: RYR1_HUMAN ; RYR2_HUMAN ; RYR3_HUMAN
2. ↑ Zucchi & Ronca-Testoni: The sarcoplasmic reticulum Ca2 + channel / ryanodine receptor: Modulation by endogenous effectors, drugs and disease states. Pharmacol Rev . 1997; 49 (1): 1-51. PMID 9085308 (review article) PDF
3. ↑ Jiang et al .: RyR2 mutations linked to ventricular tachycardia and sudden death reduce the threshold for store-overload-induced Ca2 + release (SOICR). PNAS . 2004; 101 (35): 13062-7. PMID 15322274
4. ↑ Balschun et al .: Deletion of the ryanodine receptor type 3 (RyR3) impairs forms of synaptic plasticity and spatial learning. EMBO J 1999; 18: 5264-5273. PMID 10508160