Fig. 2: SIRT1 deacetylates SAMHD1 at K354 in response to DSBs.

a Schematic of SAMHD1 protein depicting key domains and lysine residues tested in b and c for acetylation are shown. NLS nuclear localization signal, SAM sterile alpha-motif protein interaction domain, HD histidine-aspartate catalytic domain, CtIP CtIP-interacting domain, Vpx Viral Vpx-binding domain. SAMHD1 sequence alignment across species showing evolutionary conservation of lysine residues tested for acetylation is also shown. b, c SAMHD1-GFP WT or non-acetylable lysine to arginine (KR) mutants were overexpressed in 293 T cells and protein lysates from cells (±10 Gy IR) were IP’ed with anti-GFP (in b) or acetylated lysine (Lys-Ac; in c) antibodies. Input and IP’ed products were separated by SDS-PAGE and blotted with indicated antibodies. d, e Validation of custom site-specific anti-acetyl SAMHD1 K354 antibody. d Protein lysates from 293 T cells silenced for SAMHD1 using two different siRNAs (1 and UTR) or a NT control were western blotted with antibodies that recognize SAMHD1 or SAMHD1 specifically acetylated at lysine 354 (Ac-SAMHD1 K354). e Protein lysates from 293T and 293T cells over-expressing SAMHD1-GFP WT or SAMHD1-GFP K354R (KR) were probed with indicated antibodies. f 293T and 293T cells silenced for SIRT1 or SAMHD1 were exposed to IR (10 Gy for 4 h) and processed for western blot with indicated antibodies. Source data are provided as a Source Data file.