Patent ID: 8173792

Claim:
A conditional protein stability system, comprising: a nucleic acid sequence encoding a fusion protein that includes a protein of interest fused in-frame to a single-polypeptide chain, ligand-dependent, stability-affecting protein that is derived from a naturally-occurring ligand binding protein and is a variant FKBP having an F36V amino acid substitution in addition to one or more amino acid substitutions selected from the group consisting of F15S, V24A, H25R, E60G, L106P, D100G, M66T, R71G, D100N, E102G, and K105I, and a ligand that binds to the stability-affecting protein to modulate its stability, wherein the ligand is Shield1, wherein upon introduction of the nucleic acid sequence to a cell, the fusion protein is expressed, and wherein the fusion protein is stabilized in the presence of the ligand.