Poliovirus binding to its receptor in lipid bilayers results in particle-specific, temperature-sensitive channels.

Abstract

Poliovirus (PV) infection starts with binding to its receptor (PVR), followed by a receptor-aided, temperature-sensitive conformational change of the infectious particle (sedimenting at 160S) to a particle which sediments at 135S. Reported in this communication is the successful incorporation into lipid bilayers of two forms of the receptor: the full-length human receptor and a modified clone in which the extracellular domains of the receptor were fused to a glycosylphosphatidylinositol tail. Addition of virus (160S) to receptor-containing bilayers leads to channel formation, whereas no channels were observed when the receptor-modified viral particle (135S) was added. Increasing the temperature from 21 to 31 degrees C led to a 10-fold increase in the magnitude of the single channel conductance, which can be interpreted as a conformational change in the channel structure. A mutant PV with an amino acid change in VP4 (one of the coat proteins) which is defective in genome uncoating failed to produce channels, suggesting that VP4 might be involved in the channel architecture. These studies provide the first electrophysiological characterization of the interactions between poliovirus and its receptor incorporated into a lipid bilayer membrane. Furthermore, they form the foundation for future studies aiming at defining the molecular architecture of the virus-receptor complex.