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The involvement of the small GTP-binding protein Rab5a in neuronal endocytosis.
- Source :
-
Neuron [Neuron] 1994 Jul; Vol. 13 (1), pp. 11-22. - Publication Year :
- 1994
-
Abstract
- Rab5a is a small GTPase that regulates fusion of endocytic vesicles to early endosomes. We investigated whether Rab5a is involved in early endocytic traffic in both the axonal and the somatodendritic domains of polarized neurons. Using immunofluorescence, endogenous Rab5a was detected in axons and dendrites. Its localization in axons strongly overlapped that of the synaptic vesicle protein synaptophysin. Indeed, Rab5a co-immunoisolated with synaptophysin-containing vesicles, and antibodies against Rab5a labeled synaptic vesicle-like structures in nerve terminals. The functional association of Rab5a with dendritic and axonal early endosomes was assayed by electron microscopy after overexpression of wild-type and mutant Rab5a in cultured hippocampal neurons. This induced the formation of abnormal endosomes in both the somatodendritic and the axonal domains. These results show a role for Rab5a in axonal and dendritic endocytosis, and the presence of Rab5a on synaptic vesicles indicates that the axonal endosomes participate in the biogenesis of these vesicles.
- Subjects :
- Animals
Axons chemistry
Axons physiology
Brain ultrastructure
Cells, Cultured
Dendrites chemistry
Dendrites physiology
Fluorescent Antibody Technique
GTP-Binding Proteins analysis
Microscopy, Electron
Neurons ultrastructure
Rats
Subcellular Fractions chemistry
Synaptic Vesicles chemistry
Synaptophysin analysis
Synaptosomes chemistry
rab5 GTP-Binding Proteins
Endocytosis
GTP-Binding Proteins physiology
Hippocampus cytology
Neurons physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0896-6273
- Volume :
- 13
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Neuron
- Publication Type :
- Academic Journal
- Accession number :
- 8043272
- Full Text :
- https://doi.org/10.1016/0896-6273(94)90456-1