INTACT CELL ASSAY FOR PROTEIN TYROSINE PHOSPHATASES

摘要

The invention relates to an intact cell assay for direct quantitation of protein tyrosine phosphatase (PTP) activity using the baculovirus expression system. A PTP expressed in transformed host insect cells is processed and localized in their predicted subcellular compartments. Assays are performed on the PTP expressing host cells challenged with a substrate such as, p- nitrophenyl phosphate. This substrate is hydrolysed to p-nitrophenol by expressed phosphatase activity. Emergence of p-nitrophenol is determined spectrophotometrically and is a measure of PTP activity. Further, the assay and transformed host cells of this invention are particularly useful in a screening method for selecting potential inhibitors to PTPs. Basically, transformed host cells are pre-incubated with or without inhibitors and the assay conducted as described. This invention relates to an intact cell assay with a direct readout of PTP activity that is useful in a cell-based screeni ng method for selecting inhibitors of PTPs.