Fig. 1. HBx recruits Spindlin1 through a conserved N-terminal motif.
a HBx protein functional domains organization. The “A” region, Ser/Pro-rich region, H-box motif, and BH3-like motif are colored cyan, orange, blue and pink, respectively. HBx coordinates zinc via the conserved cysteine residues 61, 69,137 and histidine residues 139. b Surface plasmon resonance imaging profiling of Spindlin150–262 protein binding to different HBx peptides and H3K4me3 peptide. c Thermo-fluor shift melting curves of Spindlin150–262 with different HBx peptides. d ITC fitting curves of HBx2–21 peptide titrated to human Spindlin150–262 protein. e Co-immunoprecipitation (Co-IP) of Flag-Spindlin1 with HA-HBx using anti-Flag M2 agarose beads and anti-HA antibodies in HEK 293 T cells. Whole-cell lysates and immunoprecipitates were subjected to WB with the indicated antibodies. f Determination of the HBx2–21 region interacting with Spindlin1. HEK 293 T cells were co-transfected with Flag-Spindlin1 and HA-tagged WT HBx or mutant HBx containing alanine substitution spanning amino acids 2 to 21 (HA-HBx2–21M). Cellular extracts were immunoprecipitated with anti-Flag M2 beads and anti-HA antibodies and analyzed by the indicated antibodies using WB. (e–f) β-tubulin was measured and analyzed as an input control. Three biological repeats of each experiment were repeated independently with similar results. Source data are provided as a Source Data file.