The invention provides an isolated nucleic acid molecule having substantially the same nucleotide sequence as SEQ ID NO:1. Also provided is an isolated oligonucleotide having at least 15 contiguous nucleotides of a nucleotide sequence referenced as SEQ ID NO:11. An isolated polypeptide having substantially the same amino acid sequence as SEQ ID NO:2 is further provided as well as an antibody, or antigen binding fragment thereof, which specifically binds to an ATX polypeptide and has an amino acid sequence as referenced in SEQ ID NO:2. A method for identifying an ATX-modulatory compound is additionally provided. The method consists of measuring the level of an ATX polypeptide in the presence of a test compound, wherein a difference in the level of said ATX polypeptide in the presence of said test compound compared to in the absence of said test compound indicating that said test compound is an ATX-modulatory compound, and wherein said ATX-modulatory compound is not caffeine or wortmannin.