Multiple roles of PP2A binding motif in hepatitis B virus core linker and PP2A in regulating core phosphorylation state and viral replication
Fig 2
Effects of HBc linker mutations on CTD state of phosphorylation.
A. Schematic of HBc domain structure and mAb epitope locations. The NTD and CTD are depicted as pink and blue boxes, with the linker peptide in between as a thin line. Epitopes recognized by the HBc-specific mAbs: 1D8 for NTD (ca. 70–80), independent of CTD state of phosphorylation; A701 for unphosphorylated S162/T160; and 25–7 for unphosphorylated S178. B. HepG2 cells were transfected with indicated HBc expression constructs and were harvested seven days post-transfection. Cytoplasmic lysates from the transfected cells were resolved by SDS-PAGE (top) or NAGE (bottom) and detected by western blot analysis, using the NTD-specific mAb 1D8 (for total HBc proteins) and two non-phosphorylated CTD-specific mAbs, A701 and 25–7. C. The CTD dephosphorylation signals from total HBc (quantified following SDS-PAGE; black bars) or capsids (quantified following NAGE; gray bars) were normalized to total HBc or capsid signal (A701/1D8, top; 25-7/1D8, bottom). The normalized A701 or 25–7 signals of the linker mutants are shown relative to that of the WT HBc, which was set to 1.00. *, P<0.05; **, P<0.01;***, P<0.001.