ARPP19 Protein

ARPP19, cAMP-regulated phosphoprotein 19, is specifically phosphorylated at Ser-62 during mitosis by MASTL, also known as the Greatwall kinase. The phos-phorylation of ARPP19 leads to inactivation of PP2A through its interaction with PR55-delta, which is essential in maintaining the activity of CDK1/cyclin B1 and promoting mitotic G2/M transition (1). Significant reduction of ARPP-19 was observed in brains of Alzheimer’s disease and Down syndrome (2). ARPP-19 was also found to contribute to tumor growth in hepatocellular carcinoma and papillary carcinoma (3).