Methods for isolating ligands of the human bitter taste receptor TAS2R49

A method for isolating an antagonist of hTAS2R49 bitter taste receptor activity, wherein the bitter taste receptor is encoded by a polynucleotide selected from the group consisting of:

• (a) polynucleotides that encode at least a mature form of the polypeptide having the amino acid sequence as shown in SEQ ID NO:
• 2;
• (b) polynucleotides that have a coding nucleotide sequence as shown in SEQ ID NO:
• 1 encoding at least the mature form of the polypeptide;
• (c) polynucleotides that encode a fragment or variant of a polypeptide encoded by a polynucleotide of any one of (a) to (b), wherein in said variant no more than 30 amino acid residues are conservatively substituted compared to a polypeptide encoded by a polynucleotide of any one of (a) to (b) or in said variant no more than 30 amino acids are deleted compared to a polypeptide encoded by a polynucleotide of any one of (a) to (b), and said fragment or variant has hTAS2R49 bitter taste receptor activity;
• (d) polynucleotides that are orthologs of the polynucleotide sequences shown in SEQ ID NO:
• 1 encoding at least the mature form of the corresponding bitter taste receptor;
• (e) polynucleotides that encode a polypeptide having hTAS2R49 bitter taste receptor activity, and where said polypeptide is at least 90% identical to a polypeptide as shown in SEQ ID NO:
• 2;
• and
• (f) polynucleotides the complementary strand of which hybridizes under highly stringent conditions to a polynucleotide as defined in any one of (a) to (e) and which encode a polypeptide having hTAS2R49 bitter taste receptor activity;
• comprising the steps:
• (1) contacting a bitter taste receptor encoded by said polynucleotide or a cultured host cell genetically engineered with said polynucleotide or with a vector containing said polynucleotide to express said bitter taste receptor with a potential antagonist or a pharmaceutically acceptable salt thereof;
• and
• (2) determining whether the potential antagonist inhibits the bitter taste receptor activity;
• wherein prior to, concomitantly and/or after step (1) said bitter taste receptor or said cultured host cell is contacted with an agonist of bitter taste receptor hTAS2R49, said agonist being selected from the group consisting of
• (I) cromolyn (formula I)
• or an agonist of bitter taste receptor hTAS2R49 structurally related to cromolyn;
• and
• (II) diphenidol (formula II)
• or an agonist of bitter taste receptor hTAS2R49 structurally related to diphenidol.