Plasmodium falciparum signal sequences: simply sequences or special signals?

The malaria parasite, Plasmodium falciparum, synthesises and exports severa l proteins inducing morphological and biochemical modifications of erythroc ytes during the erythrocytic cycle. The protein trafficking machinery of th e parasite is similar to that of other eukaryotic cells in several ways. Ho wever, some unusual features are also observed. The secretion of various po lypeptides was inhibited when P. falciparum-infected erythrocytes were incu bated with Brefeldin A. Immunoelectron microscopy studies revealed substant ial morphological changes in the endoplasmic reticulum following exposure o f parasitised erythrocytes to the drug. Immunofluorescence studies of Brefe ldin A-treated parasites suggest that polypeptide sorting to different intr acellular destinations begins at the endoplasmic reticulum. The parasite al so secretes polypeptides by a Brefeldin A-insensitive route that bypasses t he classical endoplasmic reticulum-Golgi complex pathway. (C) 2001 Australi an Society for Parasitology Inc. Published by Elsevier Science Ltd. All rig hts reserved.