Bozdech Z, VanWye J, Haldar K, Schurr E
McGill Centre for the Study of Host Resistance, Department of Experimental Medicine, McGill University, Montreal, Quebec, Canada.
Mol Biochem Parasitol. 1998 Nov 30;97(1-2):81-95. doi: 10.1016/s0166-6851(98)00135-2.
PFGCN20 is a member of the ATP-binding cassette family of proteins that is closely related to the yeast translational regulator Gcn20p. We have generated a polyclonal antibody against the N-terminal region of PFGCN20 and studied the cellular localization of PFGCN20 throughout the erythrocytic life cycle of Plasmodium falciparum. PFGCN20 was found to be present at all stages and a pronounced export of PFGCN20 into the erythrocyte was observed in the trophozoite and schizont stages. In the indirect immunofluorescence assay, PFGCN20 was found to display significant colocalization with antigens detected by the monoclonal antibody 41E11. In contrast, there was only a minimal overlap of PFGCN20 localization with EMP2 and HRP2. Immunoelectron microscopy demonstrated a pronounced accumulation of PFGCN20 in the lumen of the parasitophorous vacuole and deconvolution fluorescence microscopy showed membrane association with selective regions of a tubovesicular network in the red cell. We also observed a concentration of PFGCN20 in electron-dense plaques just underneath the parasite's plasma membrane and an association of PFGCN20 with cytoplasmic vesicular structures within the parasite. The observed export of PFGCN20 and its association with the tubovesicular network in host red cells, may be indicative of the fact that PFGCN20 functions as ATP-binding subunit of an unknown multimeric ABC-transporter. The cytoplasmic localization of PFGCN20 in the parasite, however, suggests that the involvement of PFGCN20 in translational regulation or other cytoplasmic biological functions cannot be ruled out.
PFGCN20是ATP结合盒蛋白家族的成员，与酵母翻译调节因子Gcn20p密切相关。我们制备了一种针对PFGCN20 N端区域的多克隆抗体，并研究了PFGCN20在恶性疟原虫整个红细胞生命周期中的细胞定位。发现PFGCN20在所有阶段均存在，并且在滋养体和裂殖体阶段观察到PFGCN20明显输出到红细胞中。在间接免疫荧光测定中，发现PFGCN20与单克隆抗体41E11检测到的抗原显示出明显的共定位。相比之下，PFGCN20的定位与EMP2和HRP2仅有最小程度的重叠。免疫电子显微镜显示PFGCN20在寄生泡腔内明显积聚，去卷积荧光显微镜显示与红细胞中肾小管状网络的选择性区域存在膜关联。我们还观察到PFGCN20在寄生虫质膜正下方的电子致密斑块中聚集，并且PFGCN20与寄生虫内的细胞质囊泡结构有关联。观察到的PFGCN20的输出及其与宿主红细胞中肾小管状网络的关联，可能表明PFGCN20作为未知多聚体ABC转运蛋白的ATP结合亚基发挥作用。然而，PFGCN20在寄生虫中的细胞质定位表明，不能排除PFGCN20参与翻译调控或其他细胞质生物学功能的可能性。
