FIG. 5.

L phosphorylation induced by extracellular stimuli correlates with ERK activation. (A) Time course of preparation and cell culture of hepatocytes from a DHBV-infected duck. Total proteins from hepatocyte lysates (lanes 2 to 11) were separated by SDS–10% PAGE, and L protein was detected by Western blotting. In lane 6, 1.3 times more lysate was applied to compensate for a reduction of DHBV proteins reproducibly observed at around day 6 postplating. Cold treatment (lanes 10 and 11) was performed for 12 h starting at 6 h postplating. Two microliters of a DHBV-positive serum, containing approximately 5 × 10¹⁰ subviral particles, was applied as a reference (lane 1). susp. hep., suspended hepatocytes. (B) Effects of various stimuli on PDHs from a second DHBV-infected duck. Hepatocyte lysates were separated by SDS–10% PAGE, and L protein (upper panel) and active ERK1/2 (lower panel) were detected by Western blotting.