Cell based assays for drug screening

A CRE-alkaline phosphatase reporter construct has been introduced into a mammalian cell line to investigate signal transduction pathways used by the calcitonin receptor. Calcitonin activated alkaline phosphatase production in the CRE-reporter cell line indicated coupling to the Gas protein and activation could be inhibited by antagonists. These cells allow functional screening and analysis of possible novel drugs. The genetic manipulation of the cAMP/CRE/CREB pathway for cGMP sensing using the CRE-alkaline phosphatase cell based assay shall be discussed. We show that by altering the amino acid sequences of the CREB within the substrate recognition region we may be able to alter the substrate specificity of CREB for phosphorylation by PKA and PKG.