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Uncovering multiple axonal targeting pathways in hippocampal neurons
Dolora Wisco1, Eric D Anderson, Michael C Chang
1Brookdale Department of Molecular, Cell, and Developmental Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.
The Journal of Cell Biology
|October 1, 2003
Summary
Neuronal polarity relies on membrane protein sorting. This study reveals a novel dendrite-to-axon transcytotic pathway for NgCAM axonal targeting in hippocampal neurons, alongside a direct route for specific mutants.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Neuronal polarity is crucial for brain function.
- Differential sorting of membrane proteins dictates neuronal structure.
- Axonal targeting of proteins like NgCAM is essential for neuronal development.
Purpose of the Study:
- To investigate the subcellular targeting pathways of NgCAM in hippocampal neurons.
- To elucidate the role of endocytosis and transcytosis in axonal protein localization.
- To identify distinct routes for membrane protein transport to the axon.
Main Methods:
- Kinetic analysis of NgCAM transport.
- Investigating the effect of endocytosis down-regulation on NgCAM localization.
- Utilizing NgCAM mutants with specific tail motif alterations (YRSL).
Main Results:
- NgCAM transiently appears on the somatodendritic membrane before axonal accumulation.
- Axonal localization of NgCAM depends on endocytosis.
- A dendrite-to-axon transcytotic pathway is proposed for NgCAM.
- NgCAM mutants bypass transcytosis, utilizing a direct axonal route.
Conclusions:
- Multiple distinct pathways contribute to axonal accumulation of membrane proteins in hippocampal neurons.
- Endocytosis-dependent transcytosis is a key route for NgCAM.
- Cytoplasmic tail motifs regulate pathway selection for axonal targeting.