Flashcards in Chronic receptor modulation Deck (20):
What are Micro RNAs (miRNAs)
19-24 nucleotides long
Enables sequence-specific inhibition.
They are highly stable and transported between cells by microvesicles)
Loss of gating by removal of activation signal (ligand or voltage)
(signal gone; response stops)
Loss of gating after activation signal is removed.
(response continues even when signal has gone)
Explain desensitisation in the context of the 5-HT receptors in guinea pigs
Response is lost after prolonged exposure to 5-HT. This is not because of endocytosis of the receptor.
5-HT is moved into cells and is slowly released. This prevents desensitisation recovery (though cannot cause desensitisation on its own) - Resensitisation is blocked by low levels of 5-HT
What is palonosetron and how does it work
It inhibits 5-HT3 receptors (pseudo-permanent antagonist). Has high affinity for the receptors. Used in radiotherapy and chemotherapy-induced emesis.
Receptors can recover, but by replacement of receptors with new [unbound] receptors.
How does the GABAa receptor undergo endocytosis
Clathrin and AP (adaptor protein) 2 complex mediates endocytosis. This is to regulate the number of receptors available at the cell surface.
Where are GABAa receptors usually delivered to/removed from
What does LTP stand for
Long Term Potentiation
What are the causes of early phase LTP
Phosphorylation and trafficking
Give some examples of RNA modification
GluR2 editing (of the gene RNA)
What are pharmacological chaperones
Secreted transmembranal proteins. Found in ER, Goigi, Lysosomes, Surface.
Give some examples of pharmacological chaperones found in the ER
Protein disulphide isomerases (PDI)
Give some examples of co-translational process in the ER
Disulphide bond formation
Protein folding and oligomerisation
What do glycosylated proteins have to do to get out of the ER
One step - requires glucose removal. Policed by calnexin (pharma chaperone)
Why is disulphide bond formation important
Important for forming tertiary structure
Chaperone = Protein disulphide isomerases (PDI)
What role do Calnexin and BiP have in RNA modifications
Act on immature proteins.
Specifically on Monoglucosylated sugars (calnexin) and Hydrophobic domains (BiP).
Fixes up the protein just before it leaves the ER to go into the cytoplasm.
What is KDEL
Present in ER and Golgi. Includes BiP, Calnexin and PDI
What are assembly signals
Intracellular signals that drive subunit-subunit interactions. (in receptors). Highly conserved
Give some examples of chemical chaperones
Low temperature? (slows processes down so higher success rate)