Effects of T350 phospho- on gene repression activity of EZH2

The Polycomb group (PcG) protein enhancer of zeste homolog 2 (EZH2) plays an essential role in histone methylation-mediated epigenetic gene silencing. We demonstrate that under physiological conditions, cyclin-dependent kinase 1 (CDK1) and 2 (CDK2) bind to and phosphorylate EZH2 at threonine 350 (T350) in an evolutionally conserved motif. T350 phosphorylation is required for EZH2 function in silencing of genes that promote differentiation and inhibit proliferation and migration. Blockage of T350 phosphorylation by generating a T350A mutation largely diminishes the global effect of EZH2 on gene silencing. Seven experiments have been designed. LNCaP cells were transfected with si-Control, si-EZH2, si-EZH2 plus RNAi resistant EZH2 plasmid, or si-EZH2 plus RNAi resistant T350A mutated EZH2 plsamid for 60 hours, or treated with DMSO, 5 uM TSA, or 10 uM Roscovitine for 24 hours. Two replicates per experiment.