The detergent extraction profile of PhIL1 suggests that it is associated with the cytoskeleton. Parasites were extracted under a variety of detergent and pH conditions, centrifuged at 15,000 × g, and analyzed by Western blotting using antibodies against PhIL1, IMC1, tubulin, and GAP45. The extraction profiles of PhIL1, IMC1, and tubulin are identical; each is efficiently extracted only when boiled in SDS. RIPA, radioimmunoprecipitation assay buffer; p, pellet; s, supernatant.