Synapse Formation, Maturation, Elimination, and Maintenance

4/24/01


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Table of Contents

Synapse Formation, Maturation, Elimination, and Maintenance

Overview

Model Systems

NMJ

Hippocampal cells in culture labelled for GluR and GABAR

Steps to CNS synapse formation

Hippocampal Growth Cone PN15

3D of the previous growth cone

Hippocampal Dendritic Filopodia at PN6

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Dynamics of Dendritic Protrusions

Lifetime of Dendritic Protrusions

Summary Fate of Dendritic Protrusions

Ultrastructure of two dendritic filopodia synapsing on 1 axon (pn6)

Synapses between axonal and dendritic filopodia (pn4)

Long dendritic filopodium with “nascent” synapse (pn4) along its middle

Branched filopodium - 5 synapses (pn6)

Role of Filopodia in Synaptogenesis

Synapse Maturation

Order

Transported presynaptic components

Movement of GFP - VAMP Vesicle clusters

Contents of Mobile GFP-VAMP clusters

Functional assay of nonmotile GFP-VAMP vesicle clusters

Pre-set synaptic sites on axons?

Once established, synapses no longer require Sec6

Model how Sec6 organizes “pre” - synaptogenesis

Start here on Wednesday Assembly of Cell Adhesion Molecules during synapse Formation

Example - N-Cadherins colocalize with GAD (GABA) in young but not older hippocampal cultures

Suggests that N-Cadherins needed early but not later to organize the GABAergic synapses

Assembly of Postsynaptic Receptors during Glutamatergic Synapse Formation

Example Postsynaptic Assembly

Sequence of Postsynaptic Assembly

Spine maturation regulated by drebrin

Syndecan-2 enhances spine maturation

Summary - CNS Synapse Maturation

Synapse Elimination a Normal Process of Maturation

Synapse Elimination at the NMJ

Effects of Synapse Elimination - NMJ

Effects of Synapse Elimination - NMJ

NMJ Synapse Elimination Signals

Synapse Elimination and Refinement in the CNS

Examples CNS Synapse Elimination

Author: Kristen Harris