question: Which are the different proteins/isoforms encoded but the ASPH (aspartate beta-hydroxylase) gene in humans?
answer: Alternative splicing of the locus AbetaH-J-J (asparetyl-beta-hydroxylase) generates three functionally distinct proteins: an enzyme, AbetaH (aspartyl-beta-hydroxylase), a structural protein of the sarcoplasmic reticulum membrane (junctin), and an integral membrane calcium binding protein (junctate). Aspartyl (asparaginyl)-beta-hydroxylase (AAH), has also two related transcripts, Humbug and Junctin, which lack catalytic domains.  The smallest BAH-related transcript (2,789 base pairs) uses an alternative 3' terminal exon, resulting in a protein lacking a catalytic domain. Evolutionary conservation of this noncatalytic isoform of BAH (humbug) is demonstrated in mouse, man, and Drosophila. A human junctin isoform (isoform 1, 225 aa) was also identified and characterized. The isoform 1 has a 15 aa insertion at the amino acid residue 55 of the human junctin.