Midterm 3 Synaptogenesis Part 1

Overview

Prinicpal mechanisms underlying synaptogenesis

Transynaptic adhesion complexes

Adhesive TACS

Inductive TACS

What is the difference between sufficient and necessary?

For instance

Necessary: The disease will not occur without the presence of the factor

Example Mycobacterium TB for TB

Sufficient: The preesence of the factor always results in disease

Rabies virus for rabies

When are glutamatergic synapses made? How many are made?

What are the 2 primary models that have been proposed for synaptogenesis?

When unpaired axonal and dendritic transynaptic adhesion complex proteins come into contact they are the seed for?

What do trans-synaptic adhesion complexes consist of? What do they do?

How are they connected?

What are the classes of trans-synaptic adhesion complexes

What is the significance of filopodia?

Filopodia are the precursors to dendritic spines

Once they grab onto an axon and synaptic maturation takes place then they start looking like mature dendritic spines

What do cadherins do? (DONT LOOK AT IMAGE

There are basically 2 factors; adhesive and inductive factors.

The job of an adhesive factor like cadherin is to stablize the axon and dendritic point of contact like glue

FORGET about protocadherins

Describe Ephrins. What does contact do?

What is the significance of EPhrin/Eph receptor interactions What does Eph receptor expression in fibroblasts do?

They are sufficient to make synapses

The receptors are post synaptic

There are 9 FAA receptors

USUALLY

FA receptors bind to F1A ligands

FB to FB

Dont know what to write for this

What is the significance of different combinations of Ephrins/Eph receptors forming?

•Different combinations of Ephrin/Eph receptor complexes likely ensure the appropriate circuits are formed.

•

•Specific combinations  may also confer specific synaptic properties that are best suited for information processing at that specific location.

As the hippocampus is developing, you want to ensure that axons are connected in a particular way

There are unique ephrin receptors to ensure the appropriate circuits are formed.

When do different combinations of ephrins form?

Ephrin B3 is later replaced in ephrin B2,

Later in life that a combination that helped you connect the axons to a dendrite is not conferring the synaptic properties that you necessarily want to have, so you start producing a different ephrin/ephrin receptor

What are neurexins/neuroligins purpose? What do neuroligins grab onto?

They are inductive

Great diversity of types even within alpha and beta. OVER 2000

Neuroligins grab onto PSD-95 to aid accumulation of receptors and other synaptic proteins

AMPA and TARP bind into PDZ 1 and 2 and Neuroligin into PDZ 3

What are neuroligins sufficient for? WHat about neurexins?

What does overexpressing Neuroligin 1 do?

What are neurexins and neuroligins necessary for?

• 
  

• Different neurexins are expressed in different regions of the brain

Different combinations of Neurexins/Neuroligins form in different places in the brain.

What are neuroligins necessary for aand what are they sufficient for? Give some examples

Last couple of slides are a bit autistic