When human hepatoma cells (HuH7) were incubated with fluorescently labeled C105Y for as little as 3 min, C105Y displays nuclear and cytoplasmic staining with enrichment of fluorescent signal in the nucleus and nucleolus. C105Y peptide is routed to the nucleolus very rapidly in an energy-dependent fashion, whereas membrane translocation and nuclear localization are energy-independent. When tested the involvement of known endocytosis pathways in uptake and trafficking of this peptide, C105Y peptide is internalized by a clathrin- and caveolin-independent pathway, although lipid raft-mediated endocytosis may play a role in peptide intracellular trafficking.