Complex formation between PfPP5 and Pfhsp90. The following abbreviations have been used for the antibodies (labeled on top): C = non-immune serum; PP = anti-PP5; hs = anti-hsp90. The protein bands (Western blot) are indicated by hsp90 or PP5 (on the left), and the sizes of the protein standards are indicated (on the right) by their Mr values in thousands. Lane numbers are indicated on the bottom. About 0.5 mg of Pf cell pellet was lysed and subjected to immunoprecipitation (IP) with either a rabbit antibody against PP5 (lane 5) or a control non-immune serum (lanes 3) as described under Materials and Methods. The precipitate was analyzed in SDS-PAGE followed by Western blot using anti-PP5 (lane 2), anti-hsp90 (lanes 3–5), or non-immune serum. Total Pf cell extract (40 μg) was also directly subjected to SDS-PAGE and Western blot without immunoprecipitation (lanes 1, 2, 4).