The cytoplasmic tails of P. falciparum adhesins are phosphorylated in vitro.
(A) The cytoplasmic tail sequences of the EBL and PfRh protein families are shown. Putative phosphorylation sites for kinases as predicted by NetPhosK are shown with the predicted kinase above the residue and represent the prediction score of the algorithm above 0.5. Residues that have a predicted CK2 site are labelled with the corresponding amino acid number. (B) In vitro kinase assays of EBL and PfRh cytoplasmic tails with merozoite lysates. Autoradiograph of in vitro kinase assays 32P with EBL and PfRh cytoplasmic tail sequences fused to GST. Merozoite lysates were used as a source of kinase activity and the coomasie brilliant blue stained gel of the individual fusion proteins is shown in the right panel. All proteins show labelling with radioactive phosphate except GST alone and the PfRh1 cytoplasmic tail. Molecular weight markers in kDa are shown on the left of the gel. (C) In vitro kinase assays of EBL cytoplasmic tails with a small panel of P. falciparum recombinant kinases. The first lane has only the recombinant cytoplasmic tail whereas subsequent lanes have both recombinant tail and kinase as labelled. Some of the EBL and PfRh tails are phosphorylated by PfCK2 but not by any other kinases in the panel. Migration of each recombinant protein is highlighted with an asterisk.
