Method of screening inhibitor of caspase activity by lipopolysaccharide

A method of screening for an inhibitor of caspase-4 activity, wherein the caspase-4 is activated by lipopolysaccharide (LPS), the method comprising:

• incubating a mixture comprising a caspase-4-derived polypeptide, lipopolysaccharide (LPS), and a test material, wherein the caspase-4-derived polypeptide comprises a caspase activation and recruitment domain (CARD) labeled with a fluorescent material, wherein the CARD has an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 1, 7 and 9, wherein a pH of the mixture is 5.5 to 9.5 and the incubation is conducted at 0° C. to 40° C.;
• measuring a fluorescence polarization (FP) value of the mixture:
• selecting the test material as an inhibitor of binding of CARD and LPS, when the measured FP value is lowered, as compared with that of a negative control not treated with the test material;
• and
• calculating, from the measured FP value, an inhibition rate of binding of CARD and LPS;
• wherein the CARD has a peptide tag at the N-terminus and having cysteine (Cys) inserted between the C-terminus of the peptide tag and the N-terminus of the CARD.