GALNT9
Domain
There are two conserved domains in the glycosyltransferase region: the N-terminal domain (domain A, also called GT1 motif), which is probably involved in manganese coordination and substrate binding and the C-terminal domain (domain B, also called Gal/GalNAc-T motif), which is probably involved in catalytic reaction and UDP-Gal binding.
The ricin B-type lectin domain binds to GalNAc and contributes to the glycopeptide specificity.
Function
Catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor. Does not glycosylate apomucin or SDC3.
Pathway
Protein modification; protein glycosylation.
Sequence Similarities
Belongs to the glycosyltransferase 2 family. GalNAc-T subfamily.
Tissue Specificity
Specifically expressed in brain. Not expressed in heart, placenta, lung, liver, skeletal muscle, kidney, pancreas, spleen, thymus, prostate, testis, ovary, small intestine, colon and leukocyte. In brain, it is expressed in cerebellum, frontal lobe, temporal lobe, putamen and spinal cord, weakly expressed in cerebral cortex. Not expressed in medulla and occipital pole.
Cellular localization
- Golgi apparatus membrane
- Single-pass type II membrane protein
Alternative names
Polypeptide N-acetylgalactosaminyltransferase 9, Polypeptide GalNAc transferase 9, Protein-UDP acetylgalactosaminyltransferase 9, UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 9, GalNAc-T9, pp-GaNTase 9, GALNT9