Abstract
Homotypic fusion between early endosomes can be reconstituted in vitro. By using wortmannin and LY294002, inhibitors of phosphatidylinositol (Pl) 3-kinase, a requirement for this activity has been established in order for fusion to proceed efficiently. It has been shown that Pl 3-kinase activity is required downstream of rab5 activation, although a large excess of activated rab5 can overcome wortmannin inhibition. A series of experiments have also been performed which indicate a role for early endosomal autoantigen 1 (EEA1) in determining fusion efficiency. EEA1 dissociates from membranes following wortmannin treatment. It is proposed that the requirement of endosome fusion for Pl 3-kinase activity is to promote the association of EEA1 with endosomes.
Publication types
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Androstadienes / pharmacology
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Animals
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Carrier Proteins / physiology
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Endosomes / physiology*
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Enzyme Inhibitors / pharmacology
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GTP-Binding Proteins / physiology*
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Membrane Fusion*
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Membrane Proteins / physiology
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Models, Biological
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N-Ethylmaleimide-Sensitive Proteins
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Phosphatidylinositol 3-Kinases / physiology
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Signal Transduction
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Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
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Vesicular Transport Proteins*
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Wortmannin
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rab5 GTP-Binding Proteins
Substances
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Androstadienes
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Carrier Proteins
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Enzyme Inhibitors
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Membrane Proteins
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Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
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Vesicular Transport Proteins
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early endosome antigen 1
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Phosphatidylinositol 3-Kinases
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GTP-Binding Proteins
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N-Ethylmaleimide-Sensitive Proteins
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rab5 GTP-Binding Proteins
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Wortmannin