There is much evidence to indicate that cholesterol forms lateral membranemicrodomains (rafts), and to suggest their important role in cellular signaling. However, no probe has been produced to analyze cholesterol behavior, especially cholesterol movement in rafts, in real time. To obtain a potent tool for analyzing cholesterol dynamics in rafts, we prepared and characterized several truncated fragments of h-toxin (perfringolysin O), a cholesterol-binding cytolysin, whose chemicallymodified formhas been recently shown to bind selectively to rafts. .
