BIOCHEMICAL STUDIES OF PROTEIN ARGININE AND LYSINE METHYLTRANSFERASES

Abstract

PRMT5 CAN CATALYZE THE SYMMETRIC DIMETHYLATION OF ARGININE RESIDUES ON A WIDE VARIETY OF SUBSTRATES AND REGULATES MULTIPLE CELLULAR PROCESSES. TO IDENTIFY NEW HIGH-CONFIDENCE METHYLATED SITES FOR PRMT5, WE FIRST UTILIZED HEAVY METHYL SILAC IN COMBINATION WITH LC-MS/MS ON WT OR PRMT5 KNOCKOUT NEURAL STEM/PROGENITOR CELLS. WE ALSO PROFILED PRMT5 PUTATIVE TARGETS BY PERFORMING METHYLATION ON A HUMAN PROTEIN MICROARRAY-BASED PLATFORM. AMONG THESE TARGETS, CNBP WAS SELECTED TO FURTHER STUDY THE SUBSTRATE SPECIFICITY OF PRMT5. PRDM FAMILY IS CHARACTERIZED BY AN N-TERMINAL PR DOMAIN AND A VARIABLE NUMBER OF C-TERMINAL ZINC FINGERS. WE FOCUS ON THE BIOCHEMICAL CHARACTERIZATION OF PRDM9 AND PRDM15. WE SHOWED THAT THE CATALYTIC ACTIVITY OF PRDM9 IS FAR MORE EXTENSIVE THAN PREVIOUSLY DESCRIBED. IN ADDITION, PRDM9 ALSO CAN METHYLATE ADDITIONAL NON-HISTONE SUBSTRATES. PRDM15 PR DOMAIN IS CATALYTICALLY INACTIVE. THE CRYSTAL STRUCTURE OF PRDM15 PR DOMAIN SUGGESTS THAT THIS PR DOMAIN CANNOT ACCOMM