Pore formation by Vibrio cholerae cytolysin requires cholesterol in both monolayers of the target membrane.
Vibrio cholerae cytolysin (VCC) forms oligomeric transmembrane pores in cholesterol-rich membranes. To better understand this process, we used planar bilayer membranes. In symmetric membranes, the rate of the channel formation by VCC has a superlinear dependency on the cholesterol membrane fraction. Thus, more than one cholesterol molecule can facilitate VCC-pore formation. In asymmetric membranes, the rate of pore formation is limited by the leaflet with the lower cholesterol content. Methyl-beta-cyclodextrin, which removes cholesterol from membranes, rapidly inhibits VCC pore formation, even when it is added to the side opposite that of VCC addition. The results suggest that cholesterol in both membrane leaflets aid VCC-pore formation and that either leaflet can function as a kinetic bottleneck with respect to the rate of pore-formation.
Krasilnikov
Oleg V
OV
Laboratory of Membrane Biophysics, Department of Biophysics and Radiobiology, Federal University of Pernambuco, Av. prof. Moraes Rego, S/N, 50670-901 Recife, PE, Brazil. kras@ufpe.br
Merzlyak
Petr G
PG
Lima
Vera L M
VL
Zitzer
Alexander O
AO
Valeva
Angela
A
Yuldasheva
Liliya N
LN
D000818:Animals; D002417:Cattle; D002784:Cholesterol / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008562:Membrane Glycoproteins / Q000737:chemistry*; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins / Q000737:chemistry*; D014734:Vibrio cholerae / Q000378:metabolism*; D047392:beta-Cyclodextrins / Q000737:chemistry
D008051:Lipid Bilayers; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D047392:beta-Cyclodextrins; D054353:Perforin; D002784:Cholesterol