ETRAMPs are located in the PVM with their C termini facing the RBC cytosol. (A–C) Distribution of ETRAMP4 around the parasite periphery in fixed cells. Top two panels of A depict ETRAMP4 staining (FITC) and nuclear staining (DAPI) of a schizont stage parasite; spots of more intense staining are indicated by small arrows. Bottom two panels of A show ETRAMP4 (FITC) and nuclear staining (DAPI) of a late trophozoite stage parasite. The single patch of strong staining is indicated by a large arrow. (B) Extensions from the parasite body are labeled by anti-ETRAMP4 serum, indicating localization in blebbing vesicles or the TVM. The top panel shows ETRAMP4 (FITC) detected in a young trophozoite; below the nucleus is shown (DAPI). The extension is indicated by an arrow. (C) Costaining with a rabbit anti-aldolase serum verifies that the periphery of the parasite is decorated by ETRAMP4 antiserum; the four panels represent the same section depicting a young trophozoite. From top to bottom, ETRAMP4 (FITC), aldolase (Cy3), nucleus (DAPI), and aldolase and ETRAMP4 merged. Bars, 5 mm.
Spielmann T, Fergusen DJ, Beck HP. etramps, a new Plasmodium falciparum gene family coding for developmentally regulated and highly charged membrane proteins located at the parasite-host cell interface. Mol Biol Cell. 2003 14:1529-44.