Cellular internalization of green fluorescent protein fused with herpes simplex virus protein VP22 via a lipid raft-mediated endocytic pathway independent of caveolae and Rho family GTPases but dependent on dynamin and Arf6

J Biol Chem. 2007 Sep 14;282(37):27503-27517. doi: 10.1074/jbc.M703810200. Epub 2007 Jul 20.

Abstract

VP22 is a structural protein of the herpes simplex virus and has been reported to possess unusual trafficking properties. Here we examined the mechanism of cellular uptake of VP22 using a fusion protein between the C-terminal half of VP22 and green fluorescent protein (GFP). Adsorption of VP22-GFP onto a cell surface required heparan sulfate proteoglycans and basic amino acids, in particular, Arg-164 of VP22. Inhibitor treatment, RNA interference, expression of dominant-negative mutant genes, and confocal microscopy all indicated that VP22-GFP enters cells through an endocytic pathway independent of clathrin and caveolae but dependent on dynamin and Arf6 activity. As with CD59 (a lipid raft marker), cell-surface VP22-GFP signals were resistant to Triton X-100 treatment but only partially overlapped cell-surface CD59 signals. Furthermore, unlike other lipid raft-mediated endocytic pathways, no Rho family GTPase was required for VP22-GFP internalization. Internalized VP22 initially entered early endosomes and then moved to lysosomes and possibly recycling endosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / physiology*
  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • Caveolae / physiology*
  • Chloroquine / pharmacology
  • Clathrin / physiology
  • Cricetinae
  • Cricetulus
  • Dynamins / physiology*
  • Endocytosis*
  • Endosomes / metabolism
  • Green Fluorescent Proteins / metabolism*
  • HeLa Cells
  • Humans
  • Membrane Microdomains / physiology*
  • Molecular Sequence Data
  • Recombinant Fusion Proteins / metabolism*
  • Viral Structural Proteins / metabolism*
  • rho GTP-Binding Proteins / physiology*

Substances

  • ADP-Ribosylation Factor 6
  • Clathrin
  • Recombinant Fusion Proteins
  • Viral Structural Proteins
  • herpes simplex virus type 1 protein VP22
  • Green Fluorescent Proteins
  • Chloroquine
  • ADP-Ribosylation Factors
  • ARF6 protein, human
  • rho GTP-Binding Proteins
  • Dynamins