MGAT4B explained

Alpha-1,3-mannosyl-glycoprotein 4-beta-N-acetylglucosaminyltransferase B is an enzyme that in humans is encoded by the MGAT4B gene.^{[1] [2]}

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. Therefore, the protein is essential for the production of tri- and tetra-antennary sugar chains. The encoded protein may play a role in regulating the availability of serum glycoproteins, oncogenesis, and differentiation.^[2] Its affinities for donors of acceptors are lower than that of MGAT4A so it is suggested that it is not the main contributor in N-glycan biosynthesis.

Further reading

• Land A, Braakman I . Folding of the human immunodeficiency virus type 1 envelope glycoprotein in the endoplasmic reticulum. . Biochimie . 83 . 8 . 783–90 . 2001 . 11530211 . 10.1016/S0300-9084(01)01314-1 . 1874/5091 . 13576808 . free .
• Dedera DA, Gu RL, Ratner L . Role of asparagine-linked glycosylation in human immunodeficiency virus type 1 transmembrane envelope function. . Virology . 187 . 1 . 377–82 . 1992 . 1736542 . 10.1016/0042-6822(92)90331-I .
• Kalyanaraman VS, Rodriguez V, Veronese F, etal . Characterization of the secreted, native gp120 and gp160 of the human immunodeficiency virus type 1. . AIDS Res. Hum. Retroviruses . 6 . 3 . 371–80 . 1990 . 2187500 . 10.1089/aid.1990.6.371 .
• Pal R, Hoke GM, Sarngadharan MG . Role of oligosaccharides in the processing and maturation of envelope glycoproteins of human immunodeficiency virus type 1. . Proc. Natl. Acad. Sci. U.S.A. . 86 . 9 . 3384–8 . 1989 . 2541446 . 10.1073/pnas.86.9.3384 . 287137 . 1989PNAS...86.3384P . free .
• Dewar RL, Vasudevachari MB, Natarajan V, Salzman NP . Biosynthesis and processing of human immunodeficiency virus type 1 envelope glycoproteins: effects of monensin on glycosylation and transport. . J. Virol. . 63 . 6 . 2452–6 . 1989 . 2542563 . 10.1128/jvi.63.6.2452-2456.1989. 250699 .
• Kozarsky K, Penman M, Basiripour L, etal . Glycosylation and processing of the human immunodeficiency virus type 1 envelope protein. . J. Acquir. Immune Defic. Syndr. . 2 . 2 . 163–9 . 1989 . 2649653 .
• Robinson WE, Montefiori DC, Mitchell WM . Evidence that mannosyl residues are involved in human immunodeficiency virus type 1 (HIV-1) pathogenesis. . AIDS Res. Hum. Retroviruses . 3 . 3 . 265–82 . 1988 . 2829950 . 10.1089/aid.1987.3.265 .
• Blough HA, Pauwels R, De Clercq E, etal . Glycosylation inhibitors block the expression of LAV/HTLV-III (HIV) glycoproteins. . Biochem. Biophys. Res. Commun. . 141 . 1 . 33–8 . 1987 . 3099781 . 10.1016/S0006-291X(86)80330-8 .
• Montefiori DC, Robinson WE, Mitchell WM . Role of protein N-glycosylation in pathogenesis of human immunodeficiency virus type 1. . Proc. Natl. Acad. Sci. U.S.A. . 85 . 23 . 9248–52 . 1988 . 3264072 . 10.1073/pnas.85.23.9248 . 282716 . 1988PNAS...85.9248M . free .
• Fenouillet E, Jones I, Powell B, etal . Functional role of the glycan cluster of the human immunodeficiency virus type 1 transmembrane glycoprotein (gp41) ectodomain. . J. Virol. . 67 . 1 . 150–60 . 1993 . 8093218 . 10.1128/jvi.67.1.150-160.1993. 237347 .
• Maruyama K, Sugano S . Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides. . Gene . 138 . 1–2 . 171–4 . 1994 . 8125298 . 10.1016/0378-1119(94)90802-8 .
• Bolmstedt A, Sjölander S, Hansen JE, etal . Influence of N-linked glycans in V4-V5 region of human immunodeficiency virus type 1 glycoprotein gp160 on induction of a virus-neutralizing humoral response . J. Acquir. Immune Defic. Syndr. Hum. Retrovirol. . 12 . 3 . 213–20 . 1996 . 8673525 . 10.1097/00042560-199607000-00001. free .
• Papandreou MJ, Fenouillet E . Effect of various glycosidase treatments on the resistance of the HIV-1 envelope to degradation . FEBS Lett. . 406 . 1–2 . 191–5 . 1997 . 9109416 . 10.1016/S0014-5793(97)00273-1 . 17660 . free .
• Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, etal . Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library . Gene . 200 . 1–2 . 149–56 . 1997 . 9373149 . 10.1016/S0378-1119(97)00411-3 .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Clark HF, Gurney AL, Abaya E, etal . The secreted protein discovery initiative (SPDI), a large-scale effort to identify novel human secreted and transmembrane proteins: a bioinformatics assessment . Genome Res. . 13 . 10 . 2265–70 . 2003 . 12975309 . 10.1101/gr.1293003 . 403697 .
• Ota T, Suzuki Y, Nishikawa T, etal . Complete sequencing and characterization of 21,243 full-length human cDNAs . Nat. Genet. . 36 . 1 . 40–5 . 2004 . 14702039 . 10.1038/ng1285 . free .
• Brandenberger R, Wei H, Zhang S, etal . Transcriptome characterization elucidates signaling networks that control human ES cell growth and differentiation . Nat. Biotechnol. . 22 . 6 . 707–16 . 2005 . 15146197 . 10.1038/nbt971 . 27764390 .

Notes and References

1. Yoshida A, Minowa MT, Takamatsu S, Hara T, Ikenaga H, Takeuchi M . A novel second isoenzyme of the human UDP-N-acetylglucosamine:alpha1,3-D-mannoside beta1,4-N-acetylglucosaminyltransferase family: cDNA cloning, expression, and chromosomal assignment . Glycoconj J . 15 . 12 . 1115–23 . Jul 1999 . 10372966 . 10.1023/A:1006951519522 . 31297495 .
2. Web site: Entrez Gene: MGAT4B mannosyl (alpha-1,3-)-glycoprotein beta-1,4-N-acetylglucosaminyltransferase, isozyme B.