Figure 2

The p120 form of PfA-M1 is present in the PV space. Identical amounts of synchronized trophozoite stages were treated with streptolysin O (SLO) (lanes 1, 2, 3) or 0.1% saponin (SAPO) (lanes 4, 5, 3) as described in the Methods section. Lane 1 corresponds to SLO supernatant (SNT) i.e. the cytoplasm of iRBC while lane 4 corresponds to SAPO supernatant, i.e. the cytoplasm of iRBC plus PV content. Remaining pellets containing intact parasites devoid of host cytosol (SLO treatment) or devoid of host cytosol plus PV content (SAPO treatment) were washed twice in PBS, further lysed in ice-cold water in presence of protease inhibitors and separated by centrifugation into soluble fractions (SF, lanes 2 and 5, for the SLO and SAPO treatments, respectively) and membrane fractions (MF, lanes 3 and 6, for the SLO and SAPO treatments, respectively). Processed samples were separated by SDS-PAGE and blotted with antibodies corresponding to PfA-M1 (A. anti-MAP1 antibodies [6]) and several control markers: anti-PfPV1 antibodies (B), used as PV markers [22], anti-PfBip (C) [21] and anti-PfAldolase (D) antibodies [15] used as parasite reticulum endoplasmic and cytoplasm markers, respectively. The molecular masses kDa are shown on the left.