Plasmodium Falciparum Biology - Proteome

Proteome

There are 5,268 predicted proteins in Plasmodium falciparum and roughly 60% share little or no similarity to proteins in other organisms and thus are without functional assignment. Of the predicted proteins, 31% contain at least one transmembrane domain and 17.3% have a signal peptide or signal anchor.

It is estimated that 10.4% of the proteome is targeted to the apicoplast and 4.7% to the mitochondria.

The parasite has different subsets of its proteome expressed during various stages of its developmental cycle. In one study, of the 2,415 proteins were identified in four stages(sporozoite, merozoite, trophozoite, gametocyte), representing 46% of the theoretical number of proteins. Only 6% of the proteins were found in all of the four stages. Of the proteins found, 51% were annotated as hypothetical proteins.

Merozoites contained high levels of cell recognition and invasion proteins. Trophozoites contained proteins implicated in erythrocyte remodeling and hemoglobin digestion. Gametocytes contained high amounts of gametocyte-specific transcription factors and cell cycle/DNA processing proteins. The gametocytes had low levels of polymorphic surface antigens. Sporozoites contained large amounts of proteins related to invasion, as well as members of the var and rif families.