Figure 4.

EGFR-mediated sorting of HBV preS1 to the late endosome was important for the productive HBV infection. A, left, HepG2-NTCP cells transfected with si-EGFR and transduced with EGFR (EGFR^re-WT) or that carried mutations of Lys (amino acids 692, 713, 843, 905, and 946) to Arg (EGFR^re-5R) were observed by confocal microscopy as shown in Fig. 3. Arrows, preS1-EGFR speckles localized in the late endosome (left panels). Right, HBV infection was evaluated with intracellular HBc (right panels, red) and core-associated HBV DNA (right graph). Protein expressions of EGFR or its variant (EGFR) and actin as an internal control (actin) are also shown. B–E, similar analysis was performed using HepG2-NTCP cells (B and D) and primary human hepatocytes (C and E) transfected with or without siRNA against STAM (B and C) or LAPTM4B (D and E), known trafficking adaptors that facilitate and suppress EGFR sorting to the late endosome, respectively. Scale bars, 10 μm (left panels of A, B, and D) and 100 μm (right panels of A, B, and D). Error bars, S.D. Data are representative of at least n = 3 independent experiments. *, p < 0.05; **, p < 0.01.