Plays a role in the delivery of peptides to major histocompatibility complex (MHC) class I molecules; this occurs in a transporter associated with antigen processing (TAP)-independent manner. May play a role in taste signal transduction via ITPR3. May play a role during fertilization in pronucleus congression and fusion. Plays a role in maintaining nuclear shape, maybe as a component of the LINC complex and through interaction with microtubules. Plays a role in the regulation of cellular excitability by regulating the hyperpolarization-activated cyclic nucleotide-gated HCN4 channel activity (By similarity). . This is the function of IRAG2 (inositol 1,4,5-triphosphate receptor associated 2, ENSG00000118308).