Assays for sensory modulators using a sensory cell specific g-protein alpha subunit

Abstract

The invention identifies nucleic acid and amino acid sequences of a sensory cell specific G-protein alpha subunit that are specifically expressed in sensory cells, e.g., taste cells, antibodies to such G-protein alpha subunits, methods of detecting such nucleic acids and subunits, and methods of screening for modulators of a sensory cell specific G-protein alpha subunit.

1 . A method for identifying a compound that modulates signal transduction in taste cells, the method comprising the steps of:
 (i) contacting the compound with a taste cell that expresses a G-protein alpha subunit polypeptide, wherein the G-protein alpha subunit polypeptide comprises the sequence of SEQ ID NO:2, and a taste cell specific G-protein coupled receptor (GPCR); and   (ii) determining a functional effect of the compound upon the G-protein alpha subunit polypeptide, thereby identifying a compound that modulates signal transduction in taste cells.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the functional effect is a chemical effect. 
     
     
         5 . The method of  claim 1 , wherein the functional effect is a physical effect. 
     
     
         6 - 8 . (canceled) 
     
     
         9 . The method of  claim 1 , wherein the G-protein alpha subunit polypeptide is expressed in a cell or a cell membrane. 
     
     
         10 . The method of  claim 9 , wherein the functional effect is measured by determining changes in the electrical activity of cells expressing the G-protein alpha subunit polypeptide. 
     
     
         11 . The method of  claim 10 , wherein the changes in electrical activity are measured by an assay selected from the group consisting of a voltage clamp assay, a patch clamp assay, a radiolabeled ion flux assay, or a fluorescence assay using voltage sensitive dyes. 
     
     
         12 . The method of  claim 9 , wherein the functional effect is determined by measuring changes in the level of phosphorylation of sensory cell specific proteins. 
     
     
         13 . The method of  claim 9 , wherein the functional effect is determined by measuring changes in transcription levels of sensory cell specific genes. 
     
     
         14 . The method of  claim 9 , wherein the functional effect is determined by measuring changes in intracellular cyclic AMP (cAMP), cyclic GMP (cGMP), inositol triphosphate (IP 3 ), diacyl glycerol (DAG), or Ca 2+ . 
     
     
         15 . The method of  claim 14 , wherein the changes in intracellular cAMP or cGMP are measured using immunoassays. 
     
     
         16 . The method of  claim 9 , wherein the cell or cell membrane is attached to a solid substrate. 
     
     
         17 . The method of  claim 9 , wherein the cell is a eukaryotic cell. 
     
     
         18 . The method of  claim 17 , wherein the cell is a human cell. 
     
     
         19 . The method of  claim 18 , wherein the cell is an HEK 293 cell. 
     
     
         20 . The method of  claim 9 , wherein the G-protein alpha subunit polypeptide is co-expressed with G-protein coupled receptor (GPCR)-B3 or GPCR-B4. 
     
     
         21 . The method of  claim 1 , wherein the G-protein alpha subunit polypeptide is linked to a solid phase. 
     
     
         22 . The method of  claim 21 , wherein the G-protein alpha subunit polypeptide is covalently linked to the solid phase. 
     
     
         23 - 24 . (canceled)