Method and apparatus for analysis of protein-protein interaction

1. A method for measuring activation of a signaling pathway in a cell or a tissue, comprising steps (1), (2), (3), (4), and (5), or steps (1), (2), (3), (4-1), (4-2), and (5):

(1) preparing a substrate having a first protein immobilized thereto by adding a test sample containing the first protein to the substrate;

(2) adding and reacting the prepared first protein-immobilized substrate with a maker-conjugated second protein;

(3) measuring a signal from the reactant obtained in step (2);

(4) measuring a signal value per unit amount of the first protein in the test sample added in step (1) based on the signal measured in step (3);

(4-1) obtaining a signal value per unit amount of the test sample added in step (1) based on the signal measured in step (3);

(4-2) obtaining a signal value per unit amount of the first protein contained in the test sample based on the signal value per unit amount of the test sample as measured in step (4-1);

(5) comparing a result obtained in step (4) or (4-2) with that obtained in a reference sample,

wherein the test sample is the cell, the tissue, lysate, homogenate, or extract of the cell or the tissue, or a body fluid comprising the cell or the tissue, which are all isolated from a mammalian subject,

the reference sample comprises a normal cell, a cell having a known activation level of a signaling pathway in which the first protein is involved, or a cell isolated from a subject having a known activation level of a signaling pathway in which the first protein is involved, and

the first protein is involved in the signaling pathway, and the second protein interacts with the first protein,

wherein the signal value per unit amount of the first protein of step (4) or (4-2) is a quantitative value of a signal or signal intensity obtained by dividing the signal value measured in step (3) or (4-1) by weight or concentration of the first protein in the test sample added in step (1).

2. The method of claim 1 , wherein the marker is at least one selected from the group consisting of a small-molecule compound, a protein, a peptide, and a nucleic acid, all of which generate a signal that can be measured through detection of an enzymatic reaction, fluorescence, luminescence, or radiation.

3. The method of claim 1 , wherein the marker in the step (2) is at least one selected from the group consisting of a small-molecule compound, a protein, a peptide, and a nucleic acid, all of which generate fluorescence; and the step (3) of measuring a signal is carried out using a total internal fluorescence microscope, a fluorescence camera, or a combination thereof.

4. The method of claim 3 , wherein the fluorescence camera is set to have an exposure time of about 0.001 sec to about 1 sec per frame.

5. The method of claim 1 , wherein the first protein and the second protein are each independently at least one selected from proteins involved in the signaling pathway in the cell or tissue, and the second protein is a protein that is located downstream of the first protein in the signaling pathway.

6. The method of claim 5 , wherein the first protein is a cell membrane protein.

7. The method of claim 6 , wherein the first protein is at least one selected from the group consisting of receptor tyrosine kinases, toll-like receptors, G-protein-coupled receptors (GPCR), transferrin receptors, low-density lipoprotein (LDL) receptors, ROS1; BCR-Abl1 fusion proteins; non-receptor kinases; GTPases; hormone receptors; anti-apoptotic proteins; and immune checkpoint proteins.

8. The method of claim 1 , wherein:

the first protein and the second protein are each independently of two or more kinds of proteins involved in the signaling pathway in the cell or tissue, the second protein being located downstream of the first protein in the signaling pathway, and

the value, obtained in step (4) or (4-2), per unit amount of the first protein contained in the test sample is a sum of the values respectively obtained for each of the two or more kinds of the first protein and each of the two or more kinds of the second protein.

9. A method for screening a first protein as a target of a therapy suitable for application to a subject, comprising steps (1), (2), (3), (4), and (5), or steps (1), (2), (3), (4-1), (4-2) and (5):(1) preparing a substrate having a first protein immobilized thereto by adding a test sample containing the first protein to the substrate;

(2) adding and reacting the prepared first protein-immobilized substrate with a maker-conjugated second protein;

(3) measuring a signal from the reactant obtained in step (2);

(4) measuring a signal value per unit amount of the protein in the test sample added in step (1) based on the signal measured in step (3), or

(4-1) obtaining a signal value per unit amount of the test sample added in step (1) based on the signal measured in step (3); and

(4-2) obtaining a signal value per unit amount of the first protein contained in the test sample based on the signal value per unit amount of the test sample as measured in step (4-1),

wherein the steps (1), (2), (3), and (4), or steps (1), (2), (3), (4-1), and (4-2) are carried out for each of two or more different first proteins; and

(5) comparing the results obtained in steps (4) or (4-2) for the two or more different first proteins,

wherein the test sample is a cell, a tissue, a cell or tissue lysate, homogenate, or extract, or a body fluid, which are all isolated from the subject, and the first protein is involved in the signaling pathway, and the second protein interacts with the first protein,

wherein the signal value per unit amount of the first protein of step (4) or (4-2) is a quantitative value of a signal or signal intensity obtained by dividing the signal value measured in step (3) or (4-1) by weight or concentration of the first protein in the test sample added in step (1).