The scientists will report in the Nov. 3 issue of Nature a comparison of newly discovered protein-interactions in Plasmodium falciparum with protein interactions reported earlier in four other well studied model organisms -- yeast, a nematode worm, the fruit fly, and a bacterium that causes digestive-tract ulcers in humans. The authors of the study, Trey Ideker, a professor of bioengineering at UCSD's Jacobs School of Engineering, and two graduate students, Silpa Suthram and Taylor Sittler, said the malaria parasite's protein interactions "set it apart from other species."
"We've known since the Plasmodium genome was sequenced three years ago that 40 percent of its 5,300 proteins are significantly similar, or homologous, to proteins in other eukaryotes, but until now we didn't know that the malaria parasite assembles those proteins so uniquely," said Ideker. "Since our earlier research showed that yeast, worm, and fly have hundreds of both conserved proteins and protein interactions, we didn't initially believe our own analysis, which showed that there are only three Plasmodium protein interactions in common with yeast and none in common with the other species studied." The World Health Organization warns that malaria is a growing threat to health worldwide, particularly in poor countries. No malaria vaccine has been developed, and once powerful antimalarial drugs are less and less effective because Plasmodium falciparum has developed resistance to those drugs. Even mosquitoes that transmit malaria are developing resistance to the most commonly used insecticides.