The B lymphocyte antigen receptor is a multimeric complex that includes the antigen-specific component，surface immunoglobulin (Ig). Surface Ig non-covalently associates with two other proteins，Ig-alpha and Ig-beta，which are necessary for expression and function of the B-cell antigen receptor. This gene encodes the Ig-alpha protein of the B-cell antigen component. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq，Jul 2008].