Abstract

The intraerythrocytic development of Plasmodium falciparum diverges from the paradigm of the eukaryotic cell cycle. During schizogony the parasite undergoes multiple rounds of DNA replication and nuclear division without cytokinesis. It is expected that, similar to the eukaryotic cell cycle, the fluctuation and the reversible phosphorylation of key proteins will be important for regulation of the unique cell cycle of P. falciparum. We applied a high-throughput proteomics approach to identify the proteome and phosphoproteome of the parasite. We have used the isobaric tag for relative and absolute quantitation (iTRAQ) method for global analysis of the parasite proteome and phosphoproteome. The analysis revealed 2,797 proteins, 1,337 phosphoproteins, and 6,293 phosphorylation sites, constructing the most comprehensive analysis of the intraerythrocytic stages to date. This will provide a better understanding of the regulation of the complex cell cycle and may identify novel potential therapeutic targets. Interestingly, expression and phosphorylation levels change independently of one another. Although P. falciparum lacks traditional tyrosine kinases, we identified numerous phosphorylated tyrosine residues. Furthermore, we identified unique asparagine-containing phosphorylation motifs. This study provides insight inot the biology of individual proteins as well as the development of P. falciparum in the intraerythrocytic stages, which represents a promising approach in the pursuit for new anti-malarials.