CASQ2

The protein encoded by this gene specifies the cardiac muscle family member of the calsequestrin family. Calsequestrin is localized to the sarcoplasmic reticulum in cardiac and slow skeletal muscle cells. The protein is a calcium binding protein that stores calcium for muscle function. Mutations in this gene cause stress-induced polymorphic ventricular tachycardia, also referred to as catecholaminergic polymorphic ventricular tachycardia 2 (CPVT2), a disease characterized by bidirectional ventricular tachycardia that may lead to cardiac arrest. [provided by RefSeq, Jul 2008]

Full Name

Calsequestrin 2

Function

Calsequestrin is a high-capacity, moderate affinity, calcium-binding protein and thus acts as an internal calcium store in muscle. Calcium ions are bound by clusters of acidic residues at the protein surface, especially at the interface between subunits. Can bind around 60 Ca2+ ions. Regulates the release of lumenal Ca2+ via the calcium release channel RYR2; this plays an important role in triggering muscle contraction. Plays a role in excitation-contraction coupling in the heart and in regulating the rate of heart beats.

Biological Process

Cardiac muscle contraction Source: BHF-UCL
Cellular response to caffeine Source: BHF-UCL
Detection of calcium ion Source: BHF-UCL
Ion transmembrane transport Source: Reactome
Negative regulation of potassium ion transmembrane transporter activity Source: BHF-UCL
Negative regulation of potassium ion transport Source: BHF-UCL
Negative regulation of ryanodine-sensitive calcium-release channel activity Source: BHF-UCL
Protein polymerization Source: UniProtKB
Purkinje myocyte to ventricular cardiac muscle cell signaling Source: BHF-UCL
Regulation of cardiac conduction Source: Reactome
Regulation of cardiac muscle contraction by regulation of the release of sequestered calcium ion Source: BHF-UCL
Regulation of cell communication by electrical coupling Source: BHF-UCL
Regulation of heart rate Source: UniProtKB
Regulation of membrane repolarization Source: BHF-UCL
Regulation of release of sequestered calcium ion into cytosol Source: GO_Central
Regulation of release of sequestered calcium ion into cytosol by sarcoplasmic reticulum Source: BHF-UCL
Sequestering of calcium ion Source: BHF-UCL
Striated muscle contraction Source: ProtInc

Cellular Location

Sarcoplasmic reticulum lumen. This isoform of calsequestrin occurs in the sarcoplasmic reticulum's terminal cisternae luminal spaces of cardiac and slow skeletal muscle cells.

Involvement in disease

Ventricular tachycardia, catecholaminergic polymorphic, 2 (CPVT2): An arrhythmogenic disorder characterized by stress-induced, bidirectional ventricular tachycardia that may degenerate into cardiac arrest and cause sudden death. Patients present with recurrent syncope, seizures, or sudden death after physical activity or emotional stress. CPVT2 inheritance is autosomal recessive.

PTM

Phosphorylation in the C-terminus, probably by CK2, moderately increases calcium buffering capacity.
N-glycosylated.