Screening methods

A method of identifying a compound that modulates NCKX-mediated calcium ion (Ca2+) exchange across a cell membrane, the method comprising the steps of:

• (a) providing an adherent cell, the cell membrane of which comprises a NCKX polypeptide or a functionally equivalent variant thereof;
• (b) exposing the cell in suspension to a fluorescent calcium-sensitive dye, thereby causing intracellular uptake of the dye;
• (c) settling the cell onto a solid support without allowing the cell to adhere to the solid support;
• (d) exposing the cell to a test compound;
• (e) exposing the cell to calcium ions (Ca2+) and potassium ions (K+);
• and (e) measuring fluorescence from the intracellular calcium-sensitive dye after exposure of the cell to the test compound and the calcium and potassium ions, thereby to determine the rate and/or amount of calcium ion exchange across the cell membrane in the presence of the test compound, wherein steps (a) and (b) are performed prior to steps (c) to (f).