Fig 1.

PI(4,5)P₂ compartmentalizes in lipid rafts and actin-rich pellet fractions. The DRM was isolated from Entamoeba histolytica trophozoites and subjected to sucrose gradient density fractionation. PI(4,5)P₂ was extracted from these fractions, and lipid dot blots were performed using antibodies specific to PI(4,5)P₂. (A) A representative blot is shown. Cells displayed PI(4,5)P₂ enrichment in lipid raft fractions (fractions 9 to 14) and in an actin-rich pellet fraction (fraction 20 P). (B) Semiquantitative scanning densitometry was used to analyze the distribution of PI(4,5)P₂ in membrane fractions, correcting for the difference in the starting volume of each membrane fraction. The total level of PI(4,5)P₂ in the DRM was calculated, and the percentage of PI(4,5)P₂ in each fraction (± SD; n = 3) is presented.