Schematic outline of phospholipid biosynthesis pathways in Plasmodium falciparum and yeast. P. falciparum pathways are depicted with black arrows and yeast pathways are depicted in gray. The gene encoding this activity has not been identified in Plasmodium and no homologs of plant SD enzymes exist in Plasmodium parasites. EK, ethanolamine kinase; ECT, ethanolamine phosphate cytidylyltransferase; EPT, ethanolamine phosphotransferase; CK, choline kinase; CCT, choline phosphate cytidylyltransferase; CPT, choline phosphotransferase; PSD, phosphatidylserine decarboxylase; PSS, phosphatidylserine synthase; PEM1/2, phophatidylethanolamine methyltransferases (1 and 2); PfPMT, phosphoethanolamine methyltransferase; PS, phosphatidylserine; PE, phosphatidylethanolamine; PC, phosphatidylcholine; PSD, PS decarboxylase; SD, serine decarboxylase.