Yeast cell surface display of proteins and uses thereof

A method for selecting proteins for displayability on a yeast cell surface, comprising:

• transforming yeast cells with a vector which expresses a protein to be tested fused to a yeast cell wall protein, wherein mutagenesis is used to generate a variegated population of mutants of the protein to be tested;
• contacting said yeast cells with a label which binds to proteins that are displayed on the yeast cell surface and does not bind to proteins that are not displayed on the yeast cell surface;
• isolating said yeast cells with which said label is bound, wherein the presence of said label bound to a protein to be tested indicates said protein to be tested is displayable on the yeast cell surface, wherein said protein to be tested is scFv-KJ16 and said label is a T cell.

A method for selecting proteins with improved binding to a label comprising:

• transforming yeast cells with a vector expressing a protein to be tested fused to a yeast cell wall protein;
• contacting said yeast cells with a first label which binds to said protein to be tested;
• determining the level of said first label, wherein a higher level of said label indicates the protein to be tested has improved binding to the label than a protein to be tested that exhibits a lower level of said label.

A vector for performing the method for selecting proteins with improved binding to a label, said method comprising:

• transforming yeast cells with a vector expressing a protein to be tested fused to a yeast cell wall protein;
• contacting said yeast cells with a first label which binds to said protein to be tested;
• determining the level of said first label, wherein a higher level of said label indicates the protein to be tested has improved binding to the label than a protein to be tested that exhibits a lower level of said label said, vector comprising a gene coding for said cell wall protein fused to a gene for said protein of interest, wherein a flexible unstructured polypeptide linker is fused between the cell wall protein and the protein of interest.

A vector for performing the method for selecting proteins with improved binding to a label, said method comprising:

• transforming yeast cells with a vector expressing a protein to be tested fused to a yeast cell wall protein;
• contacting said yeast cells with a first label which binds to said protein to be tested;
• determining the level of said first label, wherein a higher level of said label indicates the protein to be tested has improved binding to the label than a protein to be tested that exhibits a lower level of said label, said vector comprising a gene coding for said cell wall protein fused to a gene for said protein of interest, further comprising a nucleic acid encoding an epitope tag polypeptide fused to said gene for said protein of interest, wherein said epitope tag polypeptide is selected from the group of HA (SEQ ID NO. 1), or c-myc (SEQ ID NO. 2), or a sequence selected from the group of DTYRYI (SEQ ID NO. 3), TDFYLK (SEQ ID NO. 4), EEEEYMPME (SEQ ID NO. 5), KPPTPPPEPET (SEQ ID NO. 6), HHHHHH (SEQ ID NO. 7), RYIRS (SEQ ID NO. 8), and DYKDDDDK (SEQ ID NO. 9).