Patent ID: 7413536

Claim:
A method of screening for a carrier-mediated transport protein and/or a substrate thereto, comprising: (a) providing a library comprising different complexes, each complex comprising a compound and a separate reporter, the compound varying between different complexes; (b) providing one or more cells, each cell expressing a carrier-mediated transport protein; (c) contacting the one or more cells with a plurality of complexes from the library simultaneously; and (d) selectively detecting a signal from a reporter internalized within one or more of the cells as compared to signal from reporter outside the cell to indicate that a complex whose reporter generated the signal comprises a compound that is a substrate for a carrier-mediated transport protein; provided that if the reporter comprises a fluorophore, the complex comprises a compound, a fluorophore and a quencher, and the fluorophore is linked to the quencher by a linker susceptible to cleavage within the cell, whereby the quencher quenches fluorescence from the fluorophore outside the cell and is cleaved from the fluorophore within the cell after the complex is internalized within the cell, whereby the reporter preferentially generates the signal once internalized within the cell.