Glycan Engineering and Production of 'Humanized' Glycoprotein in Yeast Cells

Abstract

Protein therapeutics, such as antibodies and cytokines, is the largest class of new drug candidates being developed by pharmaceutical companies. Although most of these glycoproteins are produced in mammalian cells, there is concern that their large-scale production could be affected by an inadequate supply of bovine serum. There is also the risk of viral infection spreading through the use of contaminated protein therapeutics. Consequently, protein expression systems in yeast have been established because protein manufacturing costs are cheaper than in mammalian cells, and yeast systems are virus-free. However, yeasts cannot generate human-type glycans, and thus cannot produce therapeutic glycoproteins for human use. There has therefore been considerable interest in glycan remodeling, from yeast-type to human-type. 'Humanized' glycoproteins can now be generated in yeast by disrupting yeast-specific glycosyltransferases and introducing genes responsible for sugar-nucleotide synthesis, its transported from the cytosol to Golgi lumen, as well as their transfer and hydrolysis. A compound that inhibits yeast O-mannosyltransferase suppresses yeast-specific O-mannosyl modification, and can produce mucin-type glycoproteins. These systems are just being developed to the stage where the production in glycoengineered yeast of biopharmaceutical glycoproteins such as cytokines, antibodies for therapeutics, and enzymes for replacement therapy for lysosomal diseases are being evaluated for clinical applications. Yeast glycoprotein expression systems are expected to become the dominant approach for the production of human glycoproteins in the near future.

Inhibition of HPA-1a alloantibody-mediated platelet destruction by a deglycosylated anti–HPA-1a monoclonal antibody in mice: toward targeted treatment of fetal-alloimmune thrombocytopenia

“…This will require a humanized form of the mAb SZ21 (or another HPA-1a-specific antibody), a technology well established for other therapeutic antibodies. 33,34 For human use, however, there are important issues that cannot be assessed in our study and need to be taken into consideration. It is known that the b-subunit of the aVb3 integrin on endothelium and placenta bears the HPA-1a epitope(s).…”

Synthesis of Threefold Glycosylated Proteins using Click Chemistry and Genetically Encoded Unnatural Amino Acids

“…Eukaryotic proteins and in particular cell-surface proteins are frequently glycosylated, [1][2] which has fueled the interest of chemist to develop new methods for the synthesis of glycosylated proteins. [3][4][5][6][7][8][9][10][11][12][13][14][15] Protein glycosylation is essential for the proper function of the respective proteins and in the case of glycosylated protein therapeutics, such as erythropoietin, the activity of the protein strongly depends on glycosylation patterns.…”

Genetically modified microorganisms as producers of biologically active compounds

“…В последние годы предпринимаются попытки получения штаммов дрож-жей, которые способны синтезировать олигосахари-ды, свойственные гликопротеинам млекопитающих. Для этого часть генов дрожжей, контролирующих гли-козилирование белков, замещают генами других орга-низмов (Chiba, Akeboshi, 2009).…”