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Preparation of Synaptic Plasma Membrane and Postsynaptic Density Proteins Using a Discontinuous Sucrose Gradient
Published on: September 3, 2014
NCAM/spectrin complex disassembly results in PSD perforation and postsynaptic endocytic zone formation
Dmytro Puchkov1, Iryna Leshchyns'ka, Alexander G Nikonenko
1Zentrum für Molekulare Neurobiologie, Universitätskrankenhaus Hamburg-Eppendorf, 20246 Hamburg, Germany.
Neural cell adhesion molecule (NCAM) deficiency or disruption of its spectrin complex increases postsynaptic density perforations. This structural change is linked to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) internalization and may impact brain pathologies.
Area of Science:
- Neuroscience
- Cell Biology
- Synaptic Plasticity
Background:
- Mechanisms of postsynaptic density (PSD) perforation are unclear.
- Neural cell adhesion molecule (NCAM) plays a role in synaptic structure.
- The spectrin cytoskeleton's function in PSD integrity is not fully understood.
Purpose of the Study:
- To investigate the role of NCAM and its associated spectrin cytoskeleton in maintaining PSD structural integrity.
- To explore the functional implications of PSD perforation in synaptic function and membrane homeostasis.
- To determine the potential contribution of PSD perforation to neurological disorders.
Main Methods:
- Utilized NCAM-deficient (NCAM-/-) and wild-type (NCAM+/+) hippocampal neurons.
- Examined synaptic structures using electron microscopy.
- Investigated the disruption of the NCAM/spectrin complex.
- Assessed alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) internalization and endocytosis.
- Induced long-term potentiation (LTP) in neurons.
Main Results:
- NCAM-/- neurons exhibit a higher percentage of perforated PSDs.
- Disruption of the NCAM/spectrin complex increases PSD perforation in wild-type neurons.
- PSD perforations are associated with endocytic zones involved in AMPAR internalization.
- LTP induction leads to PSD perforation and subsequent AMPAR endocytosis, suggesting a role in membrane homeostasis.
- Enhanced AMPAR endocytosis occurs in NCAM-/- or spectrin-disrupted neurons under basal activity.
Conclusions:
- The NCAM-assembled spectrin cytoskeleton is crucial for maintaining PSD structural integrity.
- PSD perforation is a mechanism involved in AMPAR trafficking and membrane homeostasis during synaptic activation.
- Abnormal PSD perforation and enhanced endocytosis may contribute to brain pathologies linked to NCAM or spectrin dysfunction.
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