Calcium channel that mediates the release of Ca(2+) from the sarcoplasmic reticulum into the cytoplasm and thereby plays a key role in triggering cardiac muscle contraction. Aberrant channel activation can lead to cardiac arrhythmia. In cardiac myocytes, calcium release is triggered by increased Ca(2+) levels due to activation of the L-type calcium channel CACNA1C. The calcium channel activity is modulated by formation of heterotetramers with RYR3. Required for cellular calcium ion homeostasis. Required for embryonic heart development.
PKA-mediated hyperphosphorylation of a conserved serine, Ser-2843 in skeletal RyR and Ser-2809 in cardiac RyR, results in an aberrant SR function during heart failure. hyperphosphorylated RyRs are leaky and therefore lead to a reduced SR Ca2+ load and impaired contractile function in heart failure