Methods of evaluating phosphatase inhibitors

A method for detecting a compound which inhibits dephosphorylation of a cAMP responsive element binding protein (CREB), wherein the method comprises

• contacting a protein with (A) CREB and a protein kinase that phosphorylates CREB to phosphorylate CREB, or (B) a phosphorylated CREB in the presence or absence of a test compound, measuring the phosphorylation level of CREB;
• wherein a higher level of phosphorylation in the presence of the test compound compared to the absence of the compound is indicative that the compound inhibits dephosphorylation of CREB, and:
• wherein (1) the protein comprises the amino acid sequence of SEQ ID NO:
• 4, (2) the protein is encoded by a polynucleotide that hybridizes under stringent conditions with the full length complement of SEQ ID NO:
• 3, wherein the stringent conditions comprise a washing step in 0.1×SCC and 0.1% SDS at 65° C., and wherein the protein has CREB dephosphorylation activity;
• or (3) the protein comprises an amino acid sequence with at least 95% homology to the amino acid sequence of SEQ ID NO:
• 4, wherein the protein has CREB dephosphorylation activity.