Human erythrocytes infected with the malarial parasite Plasmodium falciparum contain flattened membrane lamellae. It has been suggested that the lamellae may be involved in the sorting of malarial proteins to the cytoplasm and the cell membrane of the host erythrocyte. We have previously shown that the lamellae accumulate sphingolipids by virtue of their lipid composition in a manner similar to the trans-Golgi and the trans-Golgi network in mammalian cells. In this paper, we show by immunofluorescence microscopy that a monoclonal antibody to the lamellae labeled a perinuclear organelle that colocalized with WGA and the mannose-6-phosphate receptor in cultured mammalian cells. Immunoelectron microscopy experiments revealed that LWLI labels cisternae of the trans-face and the trans-Golgi network. Western blot analysis of subcellular fractions using LWLI detected a 170 kD protein which is associated with the luminal side of Golgi membranes of rat liver and is conserved in all cell lines studied. Our results indicate that (i) the 170 kD protein is a novel marker of the mammalian trans-Golgi and the trans-Golgi network and (ii) in addition to similarities in their morphological and lipid characteristics, the lamellae induced by P. falciparum in erythrocytes share proteinaceous determinants with the Golgi apparatus of mammalian cells.