The Synapse 1 Flashcards
What is the diameter and thickness of the postsynaptic density?
300-500nm diameter
50-60 nm thick
Functions of the PSD?
Scaffold and regulate receptors
PSD-95 is a protein within the PSD.
Describe its domains N-C terminus
N Terminus (which can dimerise with another psd95 N terminus) PDZ domains 1-2-3 SH3 domain (allows protein protein interactions) Guanylate kinase like domain (GUK) which has no enzymes activity
nNOS binds to what pdz domain of psd-95?
2
Presynaptic neuroligin bind to what?
Pdz 3 and Beta neurexin on presynaptic terminal
How many amino acids in length is a PDZ domain
About 100
What does the pdz domain bind to?
The C terminus of some protein which have the sequence
X-thr/ser-X-val-COOH
What sequence of amino acids is repeated in pdz domains and why is this important?
GLGF
creates hydrophobic pocket for hydrophobic C terminals
Why is arginine important in pdz domains?
Arginine at position 318 interacts with COO- via a water molecule
What technique was used to find where NMDAR bind to on psd95?
Yeast two hybrid
Who did the experiment to discover where NMDARs bind to in psd-95?
Kornau et al 1995
What was the bait in the yeast two hybrid experiment by kornau et al 1995?
C terminal of NMDAR
What was the prey in the yeast two experiment by kornau et al 1995?
Varying psd-95 constructs
What are the bait and prey attached to? Why is this important?
Bait - DNA binding domain
Prey - transcriptional activating domain
Come together is complementary bait and prey to allow transcription of something which allows yeast to survive
What NMDAR subunit binds to psd-95? And where in psd-95 does it bind?
GluN2B
Pdz 2
However 2A and 2B bind to pdz 1 and 2 by 2B has high affinity for pdz-2
What does GRIP an abbreviation for?
Glutamate Receptor Interacting Protein
What does PICK1 an abbreviation for?
Protein Interacting with C-kinase 1
What ionotropic glutamate receptor binds to GRIP and PICK1?
AMPARs
PICK1 binds with which subunits of AMPARs?
GluA2 and GluA3
What did Xi et al show in regards to PICK1 and GluA2 and 3 subunits?
They are colocalised via immunohistochemistry
What is the motif on AMPARs which allows them to interact with pdz domains?
SVKI C terminal (on GluA2 and GluA3)
Shares homologous with xT/SxV motif
What pdz domains of grip do AMPARs bind to?
Pdz 4 and 5
They also co immunoprecipitate
What phosphorylates GluA2 subunits to regulate scaffolding binding?
PKC
Where does PKC phosphorylate GluA2 subunits? What does this achieve?
S880
Promotes binding to PICK1 over GRIP
this is linked to internalisation and LTD
What does TARPS stand for? give an example
Transmembrane AMPA receptor regulatory protein
Stargazin
Stargazin is similar to what other protein?
Gamma subunit for voltage gated calcium channels
Stargazin interacts with what ionotropic glutamate receptor?
AMPA
site of interaction unknown
Functions of stargazin
Permits indirect associate of AMPARs with psd-95
AMPA surface delivery
Anchoring
Lateral translocation
What type of experiments show stargazin interacts with psd-95?
Co-immunoprecipitation
Immunohistochemistry shows punctate fluorescent blobs when coexpressed
What particular subunit has been studied for the role of stargazin in ampa surface delivery?
GluR1
Deleting the terminal 4 amino acids of stargazin reduces mEPSPs at post synaptic membrane as it cannot bind to psd-95
Therefore, although psd-95 is not important for number of AMPARs at membrane it is important for post synaptic membrane localisation
What does mGluR receptors scaffold to?
Homer
What group discovered the association of mGluR5 and Homer?
What technique was used?
Brakeman et al 1997
Yeast two hybrid and coimmunopreciptation with antihomer antibody then stain for mGluR5
What domain of homer binds to mGluR?
EVH1 domain bind to the c terminus if mGluR
EVH1 is in someways similar to pdz and contains GLGF repeats and an upstream arginine
What does an increase in synaptic activity do it homer
It increases its expression
What are the 2 domains of homer from C-N terminus?
C terminus - coiled coil + leucine zipper - EVH1 - N terminus
What is the function of the coiled coil and leucine zipper domain on homer?
Allows for homomeric and hetromeric interactions between homer isoforms
