Lecture 10: Synapse Formation

What are the stages of synaptogenesis

1. Growth cone contacts a target cell

2. Growth cone undergoes physical transformation

3. Target cell undergoes physical changes as well

4. Synaptic maturation and differentiation

N/L-type activates with great…

depolarizations

Presynaptic Terminal → Releases ______________

Vesicles

Synaptic Cleft → Filled with _______________

Neurotransmitters

Postsynaptic Density → Contains ______________

enriched in membrane associated proteins & cytoskeletal components

Many excitatory synapses form on what?

Dendrites

Inhibitory synapses are found on what?

Cell body or near it

Growth cones release neurotransmitters during

Path finding

Optical measurement of vesicle release

dye the shites

Do synapses form rapidly

Yes

Chemoattractants hyperpolarize or depolarize the growth cone?

Depolarize

Chemorepellents hyperpolarize or depolarize the growth cone?

Hyperpolarize

Cadherins

Calcium dependent homophilic adhesion molecules W

What do Cadherins do?

Connect actin cytoskeleton via alpha/beta catenin

Nectin

Ig-like adhesion molecule interacting with actin via afadin

What are FasII, SynCAM

Cell adhesion molecules

Pontine growth cones stop when contacting what?

Granule cells

Loss of NLGN causes what?

Dramatic loss of synaptic transmission

SYG-1/2 are necessary for formation of what?

Synapse

HSN neurons synapse onto what interneurons?

VC4/5

HSN axons interact with what cells acting as a guidepost?

Epithelial

SYD1/2 recruits active zone proteins to regulate what?

Presynaptic assembly

ECM signals induce what

AChR clustering

Post synaptic density

A complex nature of intracellular protein scaffold that interacts with and anchors neurotransmitter receptors

Gephyrin is necessary for what receptor clustering?

Glycine

Neuroligin signaling influences what receptor clustering?

GABA

Ach receptor clustering is _____ dependent

Contact

Agrin KO prevents what?

AChR clustering

Agrin-MuSK signaling promotes what?

AchR clustering and upregulation

With only Ach as a signal, what happens to receptors?

They disperse

Proteome down regulation step 1

Synaptic acitivty causes increased translation of arc

Proteome down regulation step 2

Arc promotes AMPA receptor internalization

Proteome down regulation step 3

E3-Ligase Ube3a marks Arc for degradation