Abstract: Methods and materials are disclosed for use in an enzyme fragment complementation assay using complementary fragments of ?-galactosidase to study the trafficking of proteins in a cell. Compounds that bind to a target peptide have been found to affect protein folding and therefore trafficking. ?-Galactosidase fragments, an enzyme donor (ED) and an enzyme acceptor (EA), are fused to a target peptide and to an intracellular compartment protein, wherein the compartment is involved in intracellular trafficking. Contacting the cell with a compound that binds to the target peptide results in enhanced movement of the protein through the cellular trafficking pathway comprised of the endoplasmic reticulum, Golgi apparatus, the plasma membrane, endosomes, etc. Using this approach, compounds that bind to a target peptide and alter its ability to traffic through the normal cellular pathway can be readily detected.

Abstract: Methods and materials are disclosed for use in an enzyme fragment complementation assay using complementary fragments of ?-galactosidase to study the trafficking of proteins in a cell. Compounds that bind to a target peptide have been found to affect protein folding and therefore trafficking. ?-Galactosidase fragments, an enzyme donor (ED) and an enzyme acceptor (EA), are fused to a target peptide and to an intracellular compartment protein, wherein the compartment is involved in intracellular trafficking. Contacting the cell with a compound that binds to the target peptide results in enhanced movement of the protein through the cellular trafficking pathway comprised of the endoplasmic reticulum, Golgi apparatus, the plasma membrane, endosomes, etc. Using this approach, compounds that bind to a target peptide and alter its ability to traffic through the normal cellular pathway can be readily detected.

Abstract: Methods and materials are disclosed for use in an enzyme fragment complementation assay using complementary fragments of ?-galactosidase to study the trafficking of proteins in a cell. Compounds that bind to a target peptide have been found to affect protein folding and therefore trafficking. ?-Galactosidase fragments, an enzyme donor (ED) and an enzyme acceptor (EA), are fused to a target peptide and to an intracellular compartment protein, wherein the compartment is involved in intracellular trafficking. Contacting the cell with a compound that binds to the target peptide results in enhanced movement of the protein through the cellular trafficking pathway comprised of the endoplasmic reticulum, Golgi apparatus, the plasma membrane, endosomes, etc. Using this approach, compounds that bind to a target peptide and alter its ability to traffic through the normal cellular pathway can be readily detected.

Abstract: Methods and materials are disclosed for use in an enzyme fragment complementation assay using complementary fragments of ?-galactosidase to study the trafficking of proteins in a cell. Compounds that bind to a target peptide have been found to affect protein folding and therefore trafficking. ?-Galactosidase fragments, an enzyme donor (ED) and an enzyme acceptor (EA), are fused to a target peptide and to an intracellular compartment protein, wherein the compartment is involved in intracellular trafficking. Contacting the cell with a compound that binds to the target peptide results in enhanced movement of the protein through the cellular trafficking pathway comprised of the endoplasmic reticulum, Golgi apparatus, the plasma membrane, endosomes, etc. Using this approach, compounds that bind to a target peptide and alter its ability to traffic through the normal cellular pathway can be readily detected.

Abstract: Sensitive assays for candidate compounds affecting GPCR activity are provided using a cell containing fusion proteins comprising a first fusion protein comprising (a) a target GPCR fused to a small fragment of ?-galactosidase through a linker comprising a phosphorylation site or (b) a GPCR or a protein of interest, where the GPCR and protein of interest form a complex and one of them is fused to the small fragment of ?-galactosidase; and a second fusion protein comprising arrestin fused to a large fragment of ?-galactosidase. In (a), the affinity of the small and large fragments is optimized based on the background to signal ratio and the absolute signal observed. The assay is performed using a ?-galactosidase substrate that provides a detectable optical signal.