Plasmodium Hsp40 and human Hsp70: A potential cochaperone-chaperone complex.

Out of the total forty four members of Plasmodium falciparum Hsp40 protein family, nineteen of them possess a PEXEL motif, and are predicted to be exported into the cytosol of an infected RBC. It is speculated that the human Hsp70 (hHsp70), which resides into the cytosol of the host erythrocyte, along with the exported PfHsp40s assists in the folding of parasitic proteins, thus playing a crucial role in the establishment of virulence. However, till date no experimental evidence supports this hypothesis. Our work establishes that the PEXEL motifs containing Type II PfDNAJ proteins specifically interact with hHsp70 (HSPA1A). It suggests that there exists a specific factor in PfDNAJ that determines the choice of cognate Hsp70. This opens up an interesting avenue of malaria research.