Journal: The Journal of Biological Chemistry
Article Title: The SETD2 L1609P mutation found in leukemia disrupts methyltransferase activity and reduces histone H3K36 trimethylation
doi: 10.1016/j.jbc.2026.111259
Figure Lengend Snippet: The L1609P mutation decreases methyltransferase activity and intrinsic protein stability of SETD2 catalytic core in vitro . A , upper panel : schematic representation of the SETD2 domains. The SETD2 L1609P mutation is located in the SET domain within the SETD2 catalytic core (composed of the AWS, SET, and post-SET domains). Lower left panel : Structural representation of the SETD2 active site (PDB entry: 5JJY ) with a zoomed-in view of the substrate (H3K36M peptide) and cofactor (SAH) binding sites. Lower right panel : Sequence alignment of residues 1603 to 1619 of the SET domain of human SETD2 with the equivalent sequences of human G9A, EZH2, NSD1, NSD2, SETD8, MLL1, MLL2, SETD8, ASH1 (sequence retrieved from the UniProt database). Conserved residues are highlighted in blue . The secondary structure of the SETD2 residues (deduced from PDB entry: 5JJY ) is shown above the alignment. The SETD2 residue L1609 and the equivalent residues in the other SET domain-containing enzymes are highlighted in orange . B , in vitro methylation of recombinant histone H3, core histones (purified from HEK293T SETD2-KO cells) or recombinant nucleosomes. SETD2-dependent H3K36me3 methylation was detected using an anti-H3K36me3 antibody. Ponceau Red staining of histones is shown. The purified catalytic core of SETD2 WT and SETD2 L1609P mutant used in the assays were detected using an anti-6xHis-tag antibody. C , SETD2 mono-methylation, dimethylation, or trimethylation activities were determined by UFLC assays using H3K36 fluorescent peptides as previously described ( , ). Bar graphs and error bars represent the mean and SD of three independent experiments. D , automethylation of SETD2 and methylation of α-tubulin detected by autoradiography using 3 H-SAM. Coomassie Blue staining was used as loading control. E , determination of the intrinsic protein stability of SETD2 WT or SETD2 L1609P by thermal shift assay (TSA). Left panel : T m values were determined by the minimum of the first derivative of the fluorescence emission as a function of temperature (dFluo/dT). Right panel : Bar graphs and error bars represent the mean and SD of nine experiments. SETD2, SET-domain containing protein 2; UFLC, ultrafast liquid chromatography.
Article Snippet: A pet28a-MHL plasmid containing the cDNA coding for the human SETD2 catalytic domain (Addgene #25348, residues 1433–1711) was used in order to produce 6xHis-tagged WT SETD2 in BL21 HI-control (DE3) E . coli .
Techniques: Mutagenesis, Activity Assay, In Vitro, Binding Assay, Sequencing, Residue, Methylation, Recombinant, Purification, Staining, Autoradiography, Control, Thermal Shift Assay, Fluorescence, Liquid Chromatography