The present invention relates to nucleotide sequences, particularly those of SEQ ID NO's 2, 7 and 9 that encode and may be used to express amino acid sequences that are useful in the identification and development of compounds for the prevention and treatment of metabolic diseases such as diabetes and obesity. The invention also relates to the amino acid sequences—such as proteins and/or polypeptides—that are encoded by, and that may be obtained by suitable expression of, the nucleotide sequences of the invention, particularly those set out in SEQ ID NO's 1, 6 and 8. The invention further relates to genetic constructs, host cells and organisms that have been transformed with the nucleotide sequences of the invention and that can express the amino acid sequences of the invention and methods and compositions which utilize the nucleotide and amino acid sequences of the invention.