Calcium channel that mediates the release of Ca(2+) from the sarcoplasmic reticulum into the cytoplasm in muscle and thereby plays a role in triggering muscle contraction. May regulate Ca(2+) release by other calcium channels. Calcium channel that mediates Ca(2+)-induced Ca(2+) release from the endoplasmic reticulum in non-muscle cells. Plays a role in cellular calcium signaling. Contributes to cellular calcium ion homeostasis. Isoform 2 lacks a predicted transmembrane segment and does not form functional calcium channels by itself; however, it can form tetramers with isoforms that contain the full complement of transmembrane segments and modulate their activity. Homotetramer. Isoform 2 can form tetramers with isoform 1. Heterotetramer with RYR2. Interacts with FKBP1A. Interacts with CALM. Interacts with SELENON (By similarity). The number of predicted transmembrane domains varies between orthologs, but both N-terminus and C-terminus seem to be cytoplasmic. Detected in hippocampus, cerebellum, striatum, frontal brain cortex and parietal brain cortex. Detected in skeletal muscle, diaphragm muscle and myometrium (at protein level). Detected in egg cells. Detected in heart, diaphragm, stomach, spleen, ovary, testis germ cells, brain and cerebellum. Detected in cerebral artery smooth muscle cells. The calcium release channel activity resides in the C-terminal region while the remaining part of the protein resides in the cytoplasm. No apparent phenotype. Mice are born at the expected Mendelian rate and are fertile. They appear normal, except for increased locomotor activity and decreased social contact duration in social interaction tests. Channel activity is modulated by the alkaloid ryanodine that binds to the open calcium-release channel with high affinity. At low concentrations, ryanodine maintains the channel in an open conformation. High ryanodine concentrations inhibit channel activity. Channel activity is regulated by calmodulin (CALM). The calcium release is activated by elevated cytoplasmic calcium levels in the micromolar range, by caffeine and adenine nucleotides, such as AMP and ATP. Inhibited by Mg(2+) and ruthenium red. Lacks a predicted transmembrane segment and is not expected to form functional calcium channels. Belongs to the ryanodine receptor (TC 1.A.3.1) family. RYR3 subfamily.