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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6720
pubmed:dateCreated
1999-3-11
pubmed:abstractText
Intracellular membrane docking and fusion requires the interplay between soluble factors and SNAREs. The SNARE hypothesis postulates that pairing between a vesicular v-SNARE and a target membrane z-SNARE is the primary molecular interaction underlying the specificity of vesicle targeting as well as lipid bilayer fusion. This proposal is supported by recent studies using a minimal artificial system. However, several observations demonstrate that SNAREs function at multiple transport steps and can pair promiscuously, questioning the role of SNAREs in conveying vesicle targeting. Moreover, other proteins have been shown to be important in membrane docking or tethering. Therefore, if the minimal machinery is defined as the set of proteins sufficient to reproduce in vitro the fidelity of vesicle targeting, docking and fusion as in vivo, then SNAREs are not sufficient to specify vesicle targeting. Endosome fusion also requires cytosolic factors and is regulated by the small GTPase Rab5. Here we show that Rab5-interacting soluble proteins can completely substitute for cytosol in an in vivo endosome-fusion assay, and that the Rab5 effector EEA1 is the only factor necessary to confer minimal fusion activity. Rab5 and other associated proteins seem to act upstream of EEA1, implying that Rab5 effectors comprise both regulatory molecules and mechanical components of the membrane transport machinery. We further show that EEA1 mediates endosome docking and, together with SNAREs, leads to membrane fusion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
397
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
621-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10050856-Adenosine Triphosphate, pubmed-meshheading:10050856-Animals, pubmed-meshheading:10050856-Cattle, pubmed-meshheading:10050856-Chromatography, Affinity, pubmed-meshheading:10050856-Chromatography, Agarose, pubmed-meshheading:10050856-Cytosol, pubmed-meshheading:10050856-Endosomes, pubmed-meshheading:10050856-GTP-Binding Proteins, pubmed-meshheading:10050856-HeLa Cells, pubmed-meshheading:10050856-Humans, pubmed-meshheading:10050856-Intracellular Membranes, pubmed-meshheading:10050856-Membrane Fusion, pubmed-meshheading:10050856-Membrane Proteins, pubmed-meshheading:10050856-Protein Binding, pubmed-meshheading:10050856-Recombinant Fusion Proteins, pubmed-meshheading:10050856-SNARE Proteins, pubmed-meshheading:10050856-Vesicular Transport Proteins, pubmed-meshheading:10050856-rab5 GTP-Binding Proteins
pubmed:year
1999
pubmed:articleTitle
The Rab5 effector EEA1 is a core component of endosome docking.
pubmed:affiliation
European Molecular Biology Laboratory, Heidelberg, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't