This extensive (almost exhaustive) paper has been my free time reading for the last day and a half. I was aware that some grants had been funded looking at the phosphoproteomics of the malarial parasites and have been eagerly awaiting the results. I had no idea that something this good was in the pipeline.
Phosphopeptide enrichment was performed in a unique way: Peptides were separated by hydrophilic interaction liquid chromatography (HILIC) and the fractions were first enriched by IMAC, and the flowthrough was enriched by TiO2. I have always performed TiO2 first, then IMAC, but I see no reason why we wouldn't go the other direction with it. If anything, the propensity for IMAC to enrich acetylated peptides might mean that the TiO2 enrichment may be enhanced.
The output was ~1,200 individual phosphorylation sites, primarily from the parasite. The best part? They found tyrosine phosphorylation sites. The researchers were obviously as surprised as I was, as the primary take away from both Figures 3 and 4 were that they were true phosphotyrosine sites. This is a big deal because there are no predicted tyrosine kinases in the parasite. Yet these critical, fine-tuning phosphorylation events are occurring somehow.
The phosphoproteomics is not, however, the most impressive part of this very nice paper (although the timing was really good, considering we were about to start it ourselves!!). The best part is that they went through the organism and knocked out every gene that looked like a kinase in the parasite. By doing this they were able to determine what kinases were essential AND when. I will be referring to every table in this paper on a weekly basis, as our data is processed. I love when you see a paper in Nature or Science and have no doubt that it belongs there.
You can find this incredible work here.