This gene encodes a molecular chaperone which binds specifically to free alpha-globin and is involved in hemoglobin assembly. The encoded protein binds to monomeric alpha-globin until it has been transferred to beta-globin to form a heterodimer, which in turn binds to another heterodimer to form the stable tetrameric hemoglobin. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015].