7. Conclusions
Cell division checkpoints and non-PEXEL protein export in Plasmodium falciparum-infected human RBCs are the two aspects that need to be pondered in apicomplexan cell biology. In this review, we have summarised the uncanny nature of a parasite ribosomal stalk protein P2 which appears to translocate to the infected RBC (iRBC) surface and seems to be involved in the regulation of parasite nuclear division at the initial stage. P2 being a non-PEXEL protein, requires prior oligomerization before trafficking to the iRBC surface which indicates that for non-PEXEL protein export, oligomerization might be one of the prerequisite steps in the cascade of molecular events of non-PEXEL protein trafficking in iRBCs.
Functional inhibition of P2 oligomers on the iRBC surface either by using monoclonal antibodies or by genetic knockdown resulted in the nuclear division arrest of the parasites which possibly suggests that the P2 oligomers might be involved as a checkpoint regulator or simply as a gatekeeper at the initial stage of nuclear division. Oligomeric P2 on the iRBC surface appears to form a channel protein complex either independently or in association with other parasite proteins to perform a regulatory role during parasite nuclear division. These serendipitous findings of the uncanny nature of P2 protein in malaria parasites offer to explore more about non-ribosomal indefensible functions of ribosomal proteins in apicomplexan parasites and certainly, the molecular role of P2 oligomers in the regulation of parasite nuclear division are being looked at towards a better fundamental understanding about cell division checkpoints and the possibility to inhibit the function of P2 oligomers using small molecules in iRBCs.