Intracellular Signalling Flashcards
What does stimulation of the GPCR Gs do?
It stimulates the effector enzyme AC which increases levels of cAMP
What does stimulation of the GPCR Gq do?
It stimulates the effector enzyme PLC which increases levels of IP3 and DAG
What does stimulation of the GPCR Gi do?
It inhibits the effector enzyme AC and decreases levels of cAMP
Which adrenergic receptors stimulate Gs?
Beta 1 and 2
Which adrenergic receptors stimulate Gq?
Alpha 1
Which adrenergic receptors stimulate Gi?
Alpha 2
Which cholinergic receptor is an ion channel?
Nicotinic receptors
Which cholinergic receptor is a GPCR?
Muscarinic receptors
Which muscarinic receptors stimulate Gi?
M2 (cardiac)
Which muscarinic receptors stimulate Gq?
M3 (smooth muscle and glands)
What is the g-protein linked to each GPCR?
What are it’s individual parts?
When is it active and when is it inactive?
It is a X3 protein complex found intracellularly
Alpha, beta and gamma
It is inactive when all X3 of these are bound together and the alpha subunit is GDP bound
When active the alpha subunit is unbound from the rest of the molecule and is GTP bound (it is the GDP breaking off and GTP binding that triggers its dissociation from the rest of the molecule)
Where is the g-protein when it is inactive?
What happens when the GPCR is activated?
Away from the GPCR on the cell membrane (is not transmembrane (only associated with the membrane)
When the GPCR is activated it combines with the G-protein
What does cAMP activate in the second messenger pathway?
Protein kinase A
What are the X2 subunits of pKA?
What do these do to activate the kinase?
Which part is the kinase?
Regulatory and catalytic
They dissociate
The catalytic subunit is the kinase
