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© The Rockefeller University Press,
0021-9525/1999//175 $5.00
The Journal of Cell Biology, Volume 147, Number 1,
, 1999 175-184
Original Article |
Plasma Membrane Microdomains Act as Concentration Platforms to Facilitate Intoxication by Aerolysin
Gisou.vandergoot{at}biochem.unige.ch
It has been proposed that the plasma membrane of many cell types contains cholesterol-sphingolipid–rich microdomains. Here, we analyze the role of these microdomains in promoting oligomerization of the bacterial pore-forming toxin aerolysin. Aeroly-sin binds to cells, via glycosyl phosphatidylinositol- anchored receptors, as a hydrophilic soluble protein that must polymerize into an amphipathic ring-like complex to form a pore. We first show that oligomerization can occur at >105-fold lower toxin concentration at the surface of living cells than in solution. Our observations indicate that it is not merely the number of receptors on the target cell that is important for toxin sensitivity, but their ability to associate transiently with detergent resistant microdomains. Oligomerization appears to be promoted by the fact that the toxin bound to its glycosyl phosphatidylinositol-anchored receptors, can be recruited into these microdomains, which act as concentration devices.
Key Words: aerolysin • cholesterol • microdomains • glycosyl phosphatidylinositol-anchored protein • oligomerization
© 1999 The Rockefeller University Press
Abbreviations used in this paper: β-MCD, β-methyl cyclodextrin; BHK, baby hamster kidney; DIGs, detergent insoluble glycosphingolipid complexes; GMEM, Glasgow minimal essential medium; GPI, glycosyl phosphatidylinositol; IM, incubation medium; PNS, postnuclear supernatant.
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