Asymmetric dimethylation of ribosomal S6 kinase 2 regulates its cellular localisation and pro-survival function

Ribosomal S6 kinases (S6Ks) are critical regulators of cell growth, homeostasis, and survival, with dysregulation of these kinases found to be associated with various malignancies. While S6K1 has been extensively studied, S6K2 has been neglected despite its clear involvement in cancer progression. Protein arginine methylation is a widespread post-translational modification regulating many biological processes in mammalian cells. Here, we report that p54-S6K2 is asymmetrically dimethylated at Arg-475 and Arg-477, two residues conserved amongst mammalian S6K2s and several AT-hook-containing proteins. We demonstrate that this methylation event results from the association of S6K2 with the methyltransferases PRMT1, PRMT3, and PRMT6 in vitro and in vivo and leads to nuclear the localisation of S6K2 that is essential to the pro-survival effects of this kinase to starvation-induced cell death. Taken together, our findings highlight a novel post-translational modification regulating the function of p54-S6K2 that may be particularly relevant to cancer progression where general Arg-methylation is often elevated

Search of protein kinase CK2 inhibitors based on purine-2,6-diones derivatives

This work is aimed to the search of protein kinase CK2 inhibitors among the purine-2,6-dione derivatives by molecular docking and biochemical tests. It was found that the most active compound 8-[2-[(3-methoxyphenyl)methylidene]hydrazine-1-yl]-3-methyl-7-(3-phenoxypropyl)-2,3,6,7-tetrahydro-1H-purine-2,6-dione inhibited protein kinase CK2 with IC50 value of 8.5 µM in vitro in kinase assay. Biochemical tests and computer simulation results allowed determining the binding mode of the most active compound and structure-activity relationships