GPCRs

Question 1

What is signal amplification

Answer 1

Increase in the number of effectors, secondary messagars, protein kinases and proteins phosphorylated
This would then allow the stronger more intense response

Question 2

What are the agonists and antagonists related to G proteins

Answer 2

agonist would be Gs (stimulatory)
Antagonists would be Gi (inhibitory)

Question 3

What pathways would the Gq undergo

Answer 3

There effectors would be phospholipase C,
stimulates ip3 or DAG
this could then have the effect on the Ca2+ channels

Question 4

What receptors would be Gq

Answer 4

Alpha 1
Muscarnic 3 and sometimes 1

Question 5

What does heterotrimeric mean

Answer 5

Contains 3 subunits (alpha, beta and gamma)

Question 6

What would happen when the GPCR is activated

Answer 6

The GDP binds originally
The Ligand binds
GDP now released and GTP binds
Conformational change in the shape of the receptor
Alpha unit can be released and would have GTP unbind
The GDP can then bind back to the alpha receptor and the ligand can unbind
alpha unit would bind back to the beta and gamma (when the inactive GDP)

Question 7

How many extracellular, cytosolic and transcellular components would there be on the GPCR

Answer 7

4 extracellular
4 cytosolic
7 transcellular

Question 8

How can you terminate a signal

Answer 8

Unbinding of the ligand
GTPase enzyme that would break down active GTP to inactive GDP