dictyNews
Electronic Edition
Volume 39, number 5
February 22, 2013

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=========
Abstracts
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Membrane and actin reorganization
in electropulse-induced cell fusion

GŸnther Gerisch1*, Mary Ecke1, Ralph Neujahr1,2, Jana Prassler1, 
Andreas Stengl1, MaxHoffmann3, Ulrich S. Schwarz3, and 
Eberhard Neumann4.

1Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; 
2Present address: CarlZeiss Microscopy GmbH, 81371 MŸnchen, Germany, 
3 Heidelberg University, Bioquant andInstitute for Theoretical Physics, 69120 
Heidelberg, Germany, and 
4University of Bielefeld, Biophysical Chemistry, 33501 Bielefeld, Germany

Corresponding author: gerisch@biochem.mpg.de


J. Cell Science, in press

When cells of Dictyostelium discoideum are exposed to electric pulses they 
are induced to fuse, yielding motile polykaryotic cells. By combining electron 
microscopy and direct recording of fluorescent cells, we have studied the 
emergence of fusion pores in the membranes and the localization of actin to 
the cell cortex. In response to electric pulsing, the plasma membranes of two 
contiguous cells are turned into tangles of highly bent and interdigitated 
membranes. Live imaging of cells double-labeled for membranes and 
filamentous actin revealed that actin is induced to polymerize in the fusion 
zone to temporally bridge the gaps in the vesiculating membrane. The diffusion 
of green fluorescent protein (GFP) from one fusion partner to the other was 
scored using spinning disc confocal microscopy. Fusion pores that allowed 
intercellular exchange of GFP were formed after a delay, which may last up 
to 24 seconds after exposure of the cells to the electric field. These data 
indicate that the membranes persist in a fusogenic state before pores of 
about 3 nm diameter are formed.
 
 
Submitted by GŸnther Gerisch [gerisch@biochem.mpg.de]
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[End dictyNews, volume 39, number 5]