TY - JOUR
T1 - Patch clamp studies of single cell-fusion events mediated by a viral fusion protein
AU - Spruce, A. E.
AU - Iwata, A.
AU - White, J. M.
AU - Almers, W.
PY - 1989
Y1 - 1989
N2 - TO enter cells, viruses must fuse their envelope with a host cell membrane. Fusion is mediated by specific, membrane-spanning fusion proteins1,2, of which the influenza virus haemagglutinins (HA) are the best characterized. Several HAs have been sequenced, and the crystal structure of the major part of one HA is known3. The conditions for fusion and some of the rearrangements in the HA that accompany fusion1-3 are well understood, but it remains unclear how HA causes bilayers to fuse. We have observed, in real time, unitary cell-fusion events caused by HA. Fibroblasts expressing HA were induced to fuse with red blood cells by a rapid drop in pH4. Fusion was monitored by fluorescence microscopy, and by measuring the membrane conductance and capacitance of the fibroblast. The earliest event observed was the sudden opening of an aqueous pore connecting the cytoplasms of the fusing cells. Initially, the pore conductance often fluctuated between zero and ∼600 pS, as if the pore were opening and closing repeatedly. Later, it increased over tens of seconds, as if the pore dilated. We suggest that, as in exocytosis5, HA-mediated membrane fusion begins with the formation of a narrow pore. Based on the conductance, we estimate the initial diameter of the pore to be no more than twice that of a gap junction channel6.
AB - TO enter cells, viruses must fuse their envelope with a host cell membrane. Fusion is mediated by specific, membrane-spanning fusion proteins1,2, of which the influenza virus haemagglutinins (HA) are the best characterized. Several HAs have been sequenced, and the crystal structure of the major part of one HA is known3. The conditions for fusion and some of the rearrangements in the HA that accompany fusion1-3 are well understood, but it remains unclear how HA causes bilayers to fuse. We have observed, in real time, unitary cell-fusion events caused by HA. Fibroblasts expressing HA were induced to fuse with red blood cells by a rapid drop in pH4. Fusion was monitored by fluorescence microscopy, and by measuring the membrane conductance and capacitance of the fibroblast. The earliest event observed was the sudden opening of an aqueous pore connecting the cytoplasms of the fusing cells. Initially, the pore conductance often fluctuated between zero and ∼600 pS, as if the pore were opening and closing repeatedly. Later, it increased over tens of seconds, as if the pore dilated. We suggest that, as in exocytosis5, HA-mediated membrane fusion begins with the formation of a narrow pore. Based on the conductance, we estimate the initial diameter of the pore to be no more than twice that of a gap junction channel6.
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U2 - 10.1038/342555a0
DO - 10.1038/342555a0
M3 - Article
C2 - 2586627
AN - SCOPUS:0024331657
SN - 0028-0836
VL - 342
SP - 555
EP - 558
JO - Nature
JF - Nature
IS - 6249
ER -