PLASMODIUM-FALCIPARUM - PROTEIN LOCALIZATION ALONG A NOVEL, LIPID-RICH TUBOVESICULAR MEMBRANE NETWORK IN INFECTED ERYTHROCYTES

Erythrocytes infected with Plasmodium falciparum contain a novel netwo rk of tubovesicular membranes which can be prominently labeled by fluo rescent sphingolipids and have been implicated in trafficking pathways in infected red cells. We have developed a method to simultaneously i mage lipids of the tubovesicular membrane network and exported parasit e proteins by high-resolution confocal microscopy. Our results indicat e that Exp1 (a 23-kDa protein marker of the parasitophorous vacuolar m embrane and intraerythrocytic loops) concentrates in membrane domains on the periphery of the parasite and in the tubovesicular membrane net work. In contrast, a 45-kDa protein localized to the Maurer's clefts i s distributed in punctate domains along lipid labeled tubovesicular me mbranes, frequently along the periphery of the network juxtaposed to t he red cell membrane. These results strongly suggest that the lipid-ri ch tubovesicular membranes are a complex network containing domains of parasite proteins. (C) 1994 Academic Press, Inc.