FIGURE 1: Model illustrating translational repression in malaria sporozoites.

(A) Translational repression by eIF2α phosphorylation and Puf2. Puf2 stabilizes and inhibits translation of a group of mRNAs by binding to their 3′ untranslated region. SAP1 stabilizes 38 uis mRNAs and non-uis mRNAs. EIF2α phosphorylation inhibits global protein synthesis.The stalled mRNAs are assembled into RNA granules.

(B) Regulation of eIF2α phosphorylation. Phosphorylation of eIF2α is controlled by the kinase UIS1 and the phosphatase UIS2. uis1 and uis2 transcripts are stabilized by SAP1, and the translation of uis2 is repressed by Puf2. UIS1 is dominant, and causes dormancy in Plasmodium sporozoites.