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 (PubMed:9314557). Plays a role in maintaining nuclear shape, maybe as a component of the LINC complex and through interaction with microtubules (PubMed:29878215). Interacts (via coiled-coil domain) with ITPR3 (PubMed:20071408). Interacts with SUN1 and SUN2 (PubMed:29878215). Interacts with microtubules (PubMed:29878215). Colocalized with ITPR3 on the endoplasmic reticulum membrane. Spleen and thymus. Expressed at high levels in pre B-cells, mature B-cells and pre T-cells. Expressed at low levels in mature T-cells and plasma B-cells. Expressed in circumvallate (CV), foliate (FL) and fungiform (FF) taste papillae cells of the tongue epithelium. The removal of the C-terminal lumenal domain occurs by proteolytic processing. Belongs to the IRAG2 family.