Linked Life Data

15347665

Source:http://linkedlifedata.com/resource/pubmed/id/15347665

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2004-11-15
pubmed:databankReference
pubmed:abstractText
In mammals, Rab5 and Rab7 play a specific and coordinated role in a sequential process during phagosome maturation. Here, we report that Rab5 and Rab7 in the enteric protozoan parasite Entamoeba histolytica, EhRab5 and EhRab7A, are involved in steps that are distinct from those known for mammals. EhRab5 and EhRab7A were localized to independent small vesicular structures at steady state. Priming with red blood cells induced the formation of large vacuoles associated with both EhRab5 and EhRab7A ("prephagosomal vacuoles (PPV)") in the amoeba within an incubation period of 5-10 min. PPV emerged de novo physically and distinct from phagosomes. PPV were gradually acidified and matured by fusion with lysosomes containing a digestive hydrolase, cysteine proteinase, and a membrane-permeabilizing peptide amoebapore. After EhRab5 dissociated from PPV, 5-10 min later, the EhRab7A-PPV fused with phagosomes, and EhRab7A finally dissociated from the phagosomes. Immunoelectron and light micrographs showed that PPV contained small vesicle-like structures containing fluid-phase markers and amoebapores, which were not evenly distributed within PPV, suggesting that the mechanism was similar to multivesicular body formation in PPV generation. In contrast to Rab5 from other organisms, EhRab5 was involved exclusively in phagocytosis, but not in endocytosis. Overexpression of wild-type EhRab5 enhanced phagocytosis and the transport of amoebapore to phagosomes. Conversely, expression of an EhRab5Q67L GTP form mutant impaired the formation of PPV and phagocytosis. Altogether, we propose that the amoebic Rab5 plays an important role in the formation of unique vacuoles, which is essential for engulfment of erythrocytes and important for packaging of lysosomal hydrolases, prior to the targeting to phagosomes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
49497-507
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15347665-Amino Acid Sequence, pubmed-meshheading:15347665-Animals, pubmed-meshheading:15347665-Animals, Genetically Modified, pubmed-meshheading:15347665-Cysteine Endopeptidases, pubmed-meshheading:15347665-DNA, Complementary, pubmed-meshheading:15347665-Entamoeba histolytica, pubmed-meshheading:15347665-Epitopes, pubmed-meshheading:15347665-Fluorescent Antibody Technique, Indirect, pubmed-meshheading:15347665-GTP Phosphohydrolases, pubmed-meshheading:15347665-Humans, pubmed-meshheading:15347665-Lysosomes, pubmed-meshheading:15347665-Microscopy, Immunoelectron, pubmed-meshheading:15347665-Models, Biological, pubmed-meshheading:15347665-Molecular Sequence Data, pubmed-meshheading:15347665-Phagocytosis, pubmed-meshheading:15347665-Plasmids, pubmed-meshheading:15347665-Protozoan Proteins, pubmed-meshheading:15347665-Saccharomyces cerevisiae, pubmed-meshheading:15347665-Time Factors, pubmed-meshheading:15347665-rab5 GTP-Binding Proteins
pubmed:year
2004
pubmed:articleTitle
Rab5-associated vacuoles play a unique role in phagocytosis of the enteric protozoan parasite Entamoeba histolytica.
pubmed:affiliation
Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't