May act as a viral regulatory protein involved in the modulation of mitogenic signaling pathways. May be involved in virion morphogenesis and viral pathogenesis. Expedites the processing and secretion of AMBP from the hepatocyte (By similarity). Homodimer. Interacts with host SRC, HCK, FYN, PIK3R3 and GRB2 (via SH3 domain); binding does not activate the kinases. Interacts with host AMBP/bikunin and AMBP/alpha-1-microglobulin peptides. Interacts with host HPX/hemopexin. The phosphorylated form interacts with the unglycosylated capsid protein (By similarity). The N-terminal region seems to associate with the cytoskeleton probably via one of its hydrophobic regions. Not glycosylated. Belongs to the hepevirus ORF3 protein family.