Arming yeast cells are budding yeast cells covered with proteins, the gene sequences for which have been determined. Proteins are displayed on the surface of budding yeast cells genetically as fusion proteins with the C-terminal half of α-agglutinin. This yeast is called arming yeast. α-agglutinin is the most outer surface protein and is fixed to the cell walls by addition of β-1,6-glucan, which is the main component of cell walls, to a GPI anchor, which is an anchor to connect β-1,6-glucan with the cell. As a result, the displayed proteins are the most outer surface proteins.
The biological process is as follows. Firstly, the vectors, which have the genes of proteins with the C-terminal half of α-agglutinins, are added to yeast cells. Second, the nucleus makes the proteins with the C-terminal half of the α-agglutinins. Next, secretory vesicles with the proteins are carried to the cell membrane and exocytosis occurs. Then the GPI anchor is fixed to the cell membrane and is released. Finally, the α-agglutinins are connected to the cell wall and the displayed proteins face out.
In previous research, proteins were studied with destructive methods and the purification of the proteins was necessary. By using arming yeast cells, the displayed proteins on the cells can be measured directly.