Role of EhRab7A in phagocytosis of type 1 fimbriated E. coli by Entamoeba histolytica.
Entamoeba histolytica, the causative agent of amoebic colitis and liver abscess in human, ingests the intestinal bacteria and variety of host cells. Phagocytosis of bacteria by the amebic trophozoite has been reported to be important for the virulence of the parasite. Here, we set out to characterize different stages of phagocytosis of type 1 E. coli and investigated the role of a set of amoebic Rab GTPases in the process. The localizations of the Rab GTPases during different stages of the phagocytosis were investigated using laser scanning confocal microscopy and their functional relevance were determined using fluorescence activated cell sorter based assay as well as colony forming unit assay. Our results demonstrate that EhRab7A is localized on the phagosomes and involved in both early and late stages of type 1 E. coli phagocytosis. We further showed that the E. coli or RBC containing phagosomes are distinct from the large endocytic vacuoles in the parasite which are exclusively used to transport human holotransferrin and low density lipoprotein. Remarkably, type 1 E. coli uptake was found to be insensitive to cytochalasin D treatment, suggesting that the initial stage of E. coli phagocytosis is independent of the formation of actin filaments.
Department of Biological Science, Indian Institute of Science Education and Research Bhopal Bypass Road, Bhauri, Bhopal, 462 066, Madhya Pradesh, India.
Kuldeep
K
Verma
Department of Parasitology, National Institute of Infectious Diseases, Tokyo, 162-8640, Japan.
Tomoyoshi
T
Nozaki
Department of Biological Science, Indian Institute of Science Education and Research Bhopal Bypass Road, Bhauri, Bhopal, 462 066, Madhya Pradesh, India.
Sunando
S
Datta
D000818:Animals; D004748:Entamoeba histolytica / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology; D004926:Escherichia coli / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence; D010587:Phagocytosis / Q000502:physiology; D010588:Phagosomes / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism*; D014168:Transferrin; D014617:Vacuoles / Q000378:metabolism; D014774:Virulence; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
D015800:Protozoan Proteins; D014168:Transferrin; D000090802:rab7 GTP-Binding Proteins; D020558:GTP Phosphohydrolases; C464925:Rab7 protein, Entamoeba histolytica; D020691:rab GTP-Binding Proteins