disease:A chromosomal aberration involving IGHA1 is found in multiple myeloma (MM) cell lines. Translocation t(1;14)(q21;q32) that forms a FCRL4-IGHA1 fusion protein.,function:Ig alpha is the major immunoglobulin class in body secretions. It may serve both to defend against local infection and to prevent access of foreign antigens to the general immunologic system.,PTM:3-Hydroxykynurenine, an oxidized tryptophan metabolite that is common in biological fluids, reacts with alpha-1-microglobulin to form heterogeneous polycyclic chromophores including hydroxanthommatin. The chromophore reacts with accessible cysteines forming non-reducible thioether cross-links with Ig alpha-1 chain C region Cys-352.,similarity:Contains 3 Ig-like (immunoglobulin-like) domains.,subunit:Monomeric or polymeric.,