B4GALT1

B4GALT1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2AE7, 2AEC, 2AES, 2AGD, 2AH9, 2FY7, 2FYA, 2FYB, 3EE5, 4EE3, 4EE4, 4EE5, 4EEA, 4EEG, 4EEM, 4EEO, 4L41
Identifiers
Aliases	B4GALT1, B4GAL-T1, CDG2D, GGTB2, GT1, GTB, beta4Gal-T1, beta-1,4-galactosyltransferase 1
External IDs	MGI: 95705 HomoloGene: 20378 GeneCards: B4GALT1
Gene ontology Molecular function • protein homodimerization activity • cytoskeletal protein binding • alpha-tubulin binding • transferase activity, transferring glycosyl groups • lactose synthase activity • transferase activity • beta-tubulin binding • UDP-galactosyltransferase activity • metal ion binding • manganese ion binding • N-acetyllactosamine synthase activity • galactosyltransferase activity • beta-N-acetylglucosaminylglycopeptide beta-1,4-galactosyltransferase activity Cellular component • Golgi cisterna membrane • Golgi membrane • desmosome • extracellular region • filopodium • extracellular space • brush border membrane • Golgi trans cisterna • glycocalyx • integral component of membrane • cell projection • cell surface • external side of plasma membrane • extracellular exosome • basolateral plasma membrane • plasma membrane • Golgi apparatus • membrane Biological process • regulation of acrosome reaction • glycoprotein biosynthetic process • epithelial cell development • penetration of zona pellucida • cell adhesion • lactose biosynthetic process • extracellular matrix organization • positive regulation of apoptotic process involved in mammary gland involution • positive regulation of epithelial cell proliferation involved in wound healing • angiogenesis involved in wound healing • leukocyte migration • wound healing • binding of sperm to zona pellucida • protein glycosylation • acute inflammatory response • branching morphogenesis of an epithelial tube • regulation of cellular component movement • negative regulation of cell proliferation • galactose metabolic process • development of secondary sexual characteristics • keratan sulfate biosynthetic process • mammary gland development • regulation of cell proliferation • positive regulation of apoptotic process • protein N-linked glycosylation • oligosaccharide biosynthetic process • carbohydrate metabolic process Sources:Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	2683	14595
Ensembl	ENSG00000086062	ENSMUSG00000028413
UniProt	P15291 Q86XA6	P15535
RefSeq (mRNA)	NM_001497	NM_022305
RefSeq (protein)	NP_001488.2	NP_071641.1
Location (UCSC)	Chr 9: 33.1 – 33.17 Mb	Chr 4: 40.8 – 40.85 Mb
PubMed search	[1]	[2]
Wikidata

Beta-1,4-galactosyltransferase 1 is an enzyme that in humans is encoded by the B4GALT1 gene.^[3][4]

This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have exclusive specificity for the donor substrate UDP-galactose; all transfer galactose in a beta1,4 linkage to similar acceptor sugars: GlcNAc, Glc, and Xyl. Each beta4GalT has a distinct function in the biosynthesis of different glycoconjugates and saccharide structures. As type II membrane proteins, they have an N-terminal hydrophobic signal sequence that directs the protein to the Golgi apparatus and which then remains uncleaved to function as a transmembrane anchor. By sequence similarity, the beta4GalTs form four groups: beta4GalT1 and beta4GalT2, beta4GalT3 and beta4GalT4, beta4GalT5 and beta4GalT6, and beta4GalT7. This gene is unique among the beta4GalT genes because it encodes an enzyme that participates both in glycoconjugate and lactose biosynthesis. For the first activity, the enzyme adds galactose to N-acetylglucosamine residues that are either monosaccharides or the nonreducing ends of glycoprotein carbohydrate chains. The second activity is restricted to lactating mammary tissues where the enzyme forms a heterodimer with alpha-lactalbumin to catalyze UDP-galactose + D-glucose <=> UDP + lactose. The two enzymatic forms result from alternate transcription initiation sites and post-translational processing. Two transcripts, which differ only at the 5' end, with approximate lengths of 4.1 kb and 3.9 kb encode the same protein. The longer transcript encodes the type II membrane-bound, trans-Golgi resident protein involved in glycoconjugate biosynthesis. The shorter transcript encodes a protein which is cleaved to form the soluble lactose synthase.^[4]

References

Further reading

External links

• GeneReviews/NCBI/NIH/UW entry on Congenital Disorders of Glycosylation Overview

PDB gallery
1nf5: Crystal Structure of Lactose Synthase, Complex with Glucose  1nhe: Crystal structure of Lactose synthase complex with UDP  1nkh: Crystal structure of Lactose synthase complex with UDP and Manganese  1nmm: beta-1,4-galactosyltransferase mutant Cys342Thr complex with alpha-lactalbumin and GlcNAc  1nqi: crystal structure of lactose synthase, a 1:1 complex between beta1,4-galactosyltransferase and alpha-lactalbumin in the presence of GlcNAc  1nwg: BETA-1,4-GALACTOSYLTRANSFERASE COMPLEX WITH ALPHA-LACTALBUMIN AND N-BUTANOYL-GLUCOAMINE  1o0r: Crystal structure of the catalytic domain of bovine beta1,4-galactosyltransferase complex with UDP-galactose  1o23: CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE  1oqm: A 1:1 complex between alpha-lactalbumin and beta1,4-galactosyltransferase in the presence of UDP-N-acetyl-galactosamine  2ae7: Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in Complex with Pentasaccharide  2aec: Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4GAL-T1) in Complex with GlcNAc-beta1,2-Man-alpha1,6-Man-beta-OR  2aes: Crystal Structure of Human M340H-Beta1,4-Galactosyltransferase-I (M340H-B4Gal-T1) in Complex with GlcNAc-beta1,2-Man-alpha1,3-Man-beta-OR  2agd: Crystal Structure of Human M340H-Beta-1,4-Galactosyltransferase-I(M340H-B4Gal-T1) in Complex with GlcNAc-beta1,4-Man-alpha1,3-Man-beta-OR  2ah9: Crystal Structure of Human M340H-Beta-1,4-Galactosyltransferase-I (M340H-B4Gal-T1) in Complex with Chitotriose  2fy7: Crystal structure of the catalytic domain of the human beta1,4-galactosyltransferase mutant M339H in apo form  2fya: Crystal structure of the catalytic domain of the human beta1, 4-galactosyltransferase mutant M339H complex with manganese  2fyb: Crystal structure of the catalytic domain of the human beta1,4-galactosyltransferase mutant M339H in complex with Mn and UDP-galactose in open conformation