Hemagglutinin-induced fusion of HAb2 and PLC cells: dynamics of fusion pore conductance.
Infection of cells with influenza virus is mediated by the virus envelope protein hemagglutinin (HA) which induces fusion of viral and target membranes. Earlier we showed using fluorescent microscopy that HAb2 cells expressing HA on their plasma membranes fused with PLC cells when pH of the external medium was decreased to -5. In the present work we used double whole-cell recording to monitor the intercellular conductance in HAb2/PLC cell pairs during fusion. In approximately 40% of cell pairs the pH drop induced the intercellular conductance, which we interpret as the formation of a fusion pore. The following stages of the conductance growth were distinguished: initial fluctuations near zero (flicker), a subsequent slow increase up to 1-4 nS and a final rapid increase up to 10-100 nS (complete fusion). The first detectable intercellular conductance change (opening of a fusion pore) was accompanied by an increase in the conductances of both HAb2 and PLC cell membrane. This observation suggests that the early pore complex should be leaky. The dynamics of the intercellular conductance appeared to depend upon the voltage difference between the fusing HAb2 and PLC cells: voltages higher than 40 mV facilitated the conductance growth.
Belozersky Institute of Physical and Chemical Biology, Lomonosov Moscow State University, Russia.
Dunina-Barkovskaya AYA
A V
AV
Samsonov
V S
VS
Pivovarov
V A
VA
Frolov
D002459:Cell Fusion; D002462:Cell Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D006389:Hemagglutinins, Viral / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology*; D008954:Models, Biological; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D006389:Hemagglutinins, Viral; D007473:Ion Channels