The function of IRAG1 (inositol 1,4,5-triphosphate receptor associated 1, Ensembl gene identifier ENSG00000072952) is as follows. Plays a role as NO/PRKG1-dependent regulator of IP3-induced calcium release; its phosphorylation by PRKG1 inhibits bradykinin and IP3-induced calcium release from intracellular stores. Recruits PRKG1 to the endoplasmic reticulum and may mediate the assembly of PRKG1 and ITPR1 in a macrocomplex. Involved in PRKG1 signaling cascade leading to inhibition of platelet activation and aggregation. Also mediates NO- dependent inhibition of calcium signaling in gastrointestinal smooth muscle contributing to NO-dependent relaxation (PubMed:14729908). Plays a role in the regulation of cellular excitability by regulating the hyperpolarization-activated cyclic nucleotide-gated HCN4 channel activity (By similarity). {ECO:0000250|UniProtKB:Q9WUX5, ECO:0000269|PubMed:14729908}.