MGAT4B

This gene encodes a key glycosyltransferase that regulates the formation of tri- and multiantennary branching structures in the Golgi apparatus. The encoded protein, in addition to the related isoenzyme A, catalyzes the transfer of N-acetylglucosamine (GlcNAc) from UDP-GlcNAc in a beta-1,4 linkage to the Man-alpha-1,3-Man-beta-1,4-GlcNAc arm of R-Man-alpha-1,6(GlcNAc-beta-1,2-Man-alpha-1,3)Man-beta-1,4-GlcNAc-beta-1,4-GlcNAc-beta-1-Asn. The encoded protein may play a role in regulating the availability of serum glycoproteins, oncogenesis, and differentiation. [provided by RefSeq]

Full Name

mannosyl (alpha-1,3-)-glycoprotein beta-1,4-N-acetylglucosaminyltransferase, isozyme B

Function

Glycosyltransferase that catalyze the transfer of GlcNAc from UDP-GlcNAc to the GlcNAcbeta1-2Manalpha1-3 arm of the core structure of N-linked glycans through a beta1-4 linkage and participates in the production of tri- and tetra-antennary N-linked sugar chains (PubMed:17006639, PubMed:10372966).

Prefers complex-type N-glycans over hybrid-types (PubMed:17006639).

Has lower affinities for donors or acceptors than MGAT4A, suggesting that, under physiological conditions, it is not the main contributor in N-glycan biosynthesis (PubMed:17006639).

Biological Process

N-glycan processing Source: ProtInc
Positive regulation of protein glycosylation in Golgi Source: UniProtKB
Protein N-linked glycosylation Source: GO_Central
Viral protein processing Source: Reactome

Cellular Location

Golgi apparatus
Golgi apparatus membrane
Note: A processed soluble form also exists.

Topology

Cytoplasmic: 1-7
Helical: 8-28
Lumenal: 29-548

PTM

N-glycosylated.