Tbio B4GALT1 Beta-1,4-galactosyltransferase 1

Protein Summary

Description

The Golgi complex form catalyzes the production of lactose in the lactating mammary gland and could also be responsible for the synthesis of complex-type N-linked oligosaccharides in many glycoproteins as well as the carbohydrate moieties of glycolipids. The cell surface form functions as a recognition molecule during a variety of cell to cell and cell to matrix interactions, as those occurring during development and egg fertilization, by binding to specific oligosaccharide ligands on opposing cells or in the extracellular matrix. 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. [provided by RefSeq, Jul 2008]

Uniprot Accession IDs

• P15291
• B2R710
• D3DRL2
• Q12909
• Q12910
• Q12911
• Q14456
• Q14509
• Q14523
• Beta-1,4-GalTase 1

Gene Name

• B4GALT1

Ensembl ID

• ENST00000379731
• ENSP00000369055
• ENSG00000086062

Symbol

• GGTB2
• GT1
• GTB
• CDG2D
• GGTB2
• B4GAL-T1
• beta4Gal-T1

Knowledge Table

Most Knowledge About	Knowledge Value (0 to 1 scale)
transcription factor perturbation	1
biological process	0.95
PubMedID	0.91
transcription factor binding site profile	0.91
disease perturbation	0.9

Protein Classes

PANTHER Classes

Protein / Transferase / Glycosyltransferase / Beta-1,4-galactosyltransferase 1

DTO Classes

Protein / Enzyme / Transferase / Glycosyltransferase / Beta-1,4-galactosyltransferase 1

IDG Development Level Summary

Tdark

These are targets about which virtually nothing is known. They do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 166.53   (req: < 5)

Gene RIFs: 50   (req: <= 3)

Antibodies: 167   (req: <= 50)

Tbio

These targets do not have known drug or small molecule activities
- AND - satisfy two or more of the following criteria:

Pubmed score: 166.53   (req: >= 5)

Gene RIFs: 50   (req: > 3)

Antibodies: 167   (req: > 50)

- OR - satisfy the following criterion:

Gene Ontology Terms: 29

Tchem

Target has at least one ChEMBL compound with an activity cutoff of < 30 nM - AND - satisfies the preceding conditions

Active Ligand: 0

Tclin

Target has at least one approved drug - AND - satisfies the preceding conditions

Active Drug: 0