MGAT4B

MGAT4B, also known as Mannosyl (Alpha-1,3-)-Glycoprotein Beta-1,4-N-Acetylglucosaminyltransferase, Isozyme B, is a human gene that encodes an enzyme belonging to the glycosyltransferase family. Specifically, it's a member of the N-acetylglucosaminyltransferase IV (GnT-IV) family.

The protein produced by the MGAT4B gene catalyzes the transfer of N-acetylglucosamine (GlcNAc) in a beta-1,4 linkage to the alpha-1,3-mannose residue of N-linked oligosaccharides. This is an important step in the biosynthesis of complex N-glycans, which are crucial for proper protein folding, stability, trafficking, and function. The glycosylation pattern of proteins can significantly affect their biological activity and interactions with other molecules.

The MGAT4B enzyme is localized to the Golgi apparatus, the cellular organelle responsible for processing and sorting proteins. It functions alongside other glycosyltransferases to create the diverse array of glycan structures found on glycoproteins.

MGAT4B is believed to play a role in various biological processes, including cell adhesion, cell signaling, and immune responses. Research suggests its involvement in the glycosylation of proteins involved in these processes.

Variations in the MGAT4B gene have been studied in relation to various diseases. Dysregulation of glycosylation pathways, including alterations in MGAT4B activity, can be associated with cancer progression, autoimmune disorders, and other conditions. However, further research is needed to fully elucidate the specific roles of MGAT4B in these diseases.

The enzyme encoded by MGAT4B is structurally related to another isozyme, MGAT4A. While they share similar functions, they may have distinct substrate specificities and tissue expression patterns, contributing to the overall complexity of N-glycan biosynthesis.