Fig. 4: The PCRCR complex is processed by PMX and formed in micronemes or a microneme subset.

Immunoblots on proteins found in different compartments of the merozoite: microneme, rhoptry neck, rhoptry body and exoneme. Processing Inhibition Assays were set up with either 3D7, PMX-HA and PMIX-HA parasites. The derivation of PMIX-HA, and PMX-HA¹¹ parasites has been described. All assays included C1. Supernatant (S or supe) and merozoite (M or mero) fractions are shown. Below each blot is a diagram of the expected products under Control and C1 conditions. a Immunoblot of the rhoptry neck protein, PfRh5. b Immunoblot of the microneme protein, PTRAMP. c Immunoblot of the microneme protein, PfRipr. d, e Immunoblots of the microneme proteins, PfCSS and PfCyRPA. f Immunoblot of the exoneme and microneme protease, PMX. g Immunoblot of the rhoptry body protein, PMIX. h, i Immunoblots of the microneme proteins, AMA1 and EBA140. j Immunoblot of the rhoptry neck protein, PfRh2. All proteins were separated under reducing conditions, except the PfRipr proteins. The approximate location of the mAb or pAb used for the immunoblots is shown in the schematic for each protein, together with the calculated size of the unprocessed or processed product in kDa. The asterisk (*) indicates a cross-reaction of some Abs with albumin in supernatant fractions. k WM4 blocks exoneme and microneme discharge. The merozoite fractions from a Processing inhibition assay on PMX-HA parasites treated with either C1 or the PMX inhibitor, WM4, were saponin-lysed. Proteins from equal volumes of the saponin supernatant (S) and saponin pellet (P) were separated by SDS-PAGE and probed with either HA or Rh5 mAbs. The illustrations of C1 and WM4-treated merozoites are identical, since the data shows that WM4 just like C1, blocks exoneme and microneme discharge. The blue boxes delineate the proteins detected in the saponin pellets (i.e., remaining within the merozoites) under both treatments. Source data are provided as a source data file.