The GAR motif of 53BP1 is arginine methylated by PRMT1 and is necessary for 53BP1 DNA binding activity.
The p53-binding protein 1 (53BP1) is rapidly recruited to sites of DNA double-strand breaks and forms characteristics nuclear foci, demonstrating its role in the early events of detection, signaling and repair of damaged DNA. 53BP1 contains a glycine arginine rich (GAR) motif of unknown function within its kinetochore-binding domain. Herein, we show that the GAR motif of 53BP1 is arginine methylated by protein arginine methyltransferase 1 (PRMT1), the same methyltransferase that methylates MRE11. 53BP1 contains asymmetric dimethylarginines (aDMA) within cells, as detected with methylarginine-specific antibodies. Amino acid substitution of the arginines within the GAR motif of 53BP1 abrogated binding to single and double-stranded DNA, demonstrating that the GAR motif is required for DNA binding activity of 53BP1. Fibroblast cells treated with methylase inhibitors failed to relocalize 53BP1 to sites of DNA damage and formed few gamma-H2AX foci, consistent with our previous data that MRE11 fails to relocalize to DNA damage sites in cells treated with methylase inhibitors. Our findings identify the GAR motif as a region required for 53BP1 DNA binding activity and as the site of methylation by PRMT1.
Boisvert
François-Michel
FM
Terry Fox Molecular Oncology, Bloomfield Center for Research on Aging, Lady Davis Institute for Medical Research, Department of Oncology, McGill University, Montréal, Québec, Canada.
Rhie
Alexandre
A
Richard
Stéphane
S
Doherty
Aidan J
AJ
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism*; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D005347:Fibroblasts / Q000166:cytology; D005998:Glycine / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry* / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D009154:Mutation; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D011484:Protein-Arginine N-Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000071857:Tumor Suppressor p53-Binding Protein 1
D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D012097:Repressor Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D004247:DNA; D001120:Arginine; C099988:PRMT1 protein, human; D011484:Protein-Arginine N-Methyltransferases; D005998:Glycine