Patent ID: 7169567

Claim:
A method of screening for an agonist or an antagonist of PTH receptor activity comprising: (a) contacting cells with a test compound wherein said cells express a rΔNt polypeptide, wherein said cells comprise a polynucleotide having a nucleotide sequence selected from the group consisting of: (i) a nucleotide sequence from position 1 to position 1320 in SEQ ID NO:1; (ii) a nucleotide sequence from position 4 to position 1320 in SEQ ID NO:1; (iii) a nucleotide sequence from position 67 to position 1320 in SEQ ID NO:1; (iv) a nucleotide sequence encoding the rΔNt polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. PTA-1136; and (v) a nucleotide sequence encoding the mature rΔNt polypeptide having the amino acid sequence encoded by the cDNA clone contained in ATCC Deposit No. PTA-1136; wherein said polypeptide comprises a deletion of the extracellular amino-terminal ligand binding domain of a PTH-1 receptor and wherein said polypeptide increases intracellular cAMP levels when activated by PTH or PTH-related peptide and wherein said extracellular amino-terminal ligand binding domain has an amino acid sequence from residue 26 to residue 181 in wild-type PTH receptor; (b) measuring cAMP accumulation in said cells; and (c) determining whether said test compound is an agonist or an antagonist of PTH receptor activity; wherein an agonist is identified as a compound that increases cAMP accumulation and an antagonist prevents cAMP accumulation.