title: Pore formation by Vibrio cholerae cytolysin requires cholesterol in both monolayers of the target membrane.
abstract: 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.
authors.affiliation: 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
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Krasilnikov
authors.forename: Petr G
authors.initials: PG
authors.lastname: Merzlyak
authors.forename: Vera L M
authors.initials: VL
authors.lastname: Lima
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Zitzer
authors.forename: Angela
authors.initials: A
authors.lastname: Valeva
authors.forename: Liliya N
authors.initials: LN
authors.lastname: Yuldasheva
mesh_terms: 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
chemical_list: D008051:Lipid Bilayers; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D047392:beta-Cyclodextrins; D054353:Perforin; D002784:Cholesterol