Patent ID: 7247706

Claim:
An isolated polypeptide comprising the amino acid sequence set forth in SEQ ID NO: 14, wherein: (1) either the proline residue at position 230 has been replaced with an amino acid residue selected from the group consisting of glycine, alanine, isoleucine, leucine, and valine, or the serine residue present at position 241 has been replaced with an amino acid residue selected from the group consisting of threonine, methionine, asparagine, glutamine, and tyrosine; or (2) both the proline residue at position 230 has been replaced with an amino acid residue selected from the group consisting of glycine, alanine, isoleucine, leucine, and valine, and the serine residue present at position 241 has been replaced with an amino acid residue selected from the group consisting of threonine, methionine, asparagine, glutamine, and tyrosine, and wherein said polypeptide, when produced in a recombinant SH-EP1 cell that contains an encoding DNA sequence for said polypeptide, evidences increased intracellular calcium accumulation in the presence of nicotine as agonist.