The function of RYR2 (ryanodine receptor 2, ENSG00000198626) is as follows. Cytosolic calcium-activated calcium channel that mediates the release of Ca(2+) from the sarcoplasmic reticulum into the cytosol 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+) cytosolic 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. {ECO:0000269|PubMed:10830164, ECO:0000269|PubMed:17984046, ECO:0000269|PubMed:20056922, ECO:0000269|PubMed:27733687, ECO:0000269|PubMed:33536282}.