G Protein Coupled Receptors Flashcards
Where are g-protein coupled receptors located?
Membrane
Enzyme responsible for cAMP formation?
Adenylyl cyclase
What is cAMP?
Nucleotide synthesised within cell from ATP byaction of adenylyl cyclase
What do protein kinases do?
Regulate the function of many different cellular proteins by controlling protein phosphorylation
Two key second messenger pathways controlled by receptors via G proteins
Adenylyl cyclase and phospholipase c
Purpose of G protein coupled receptor
Detect extracellular signal and transduce a cellular response
Structure of GPCR
- Has 7 transmembrane domain
- coupled to G protein heterotrimeric G protein complex
- agonist binding side
How is G protein activated
Signal molecule binds to G protein- coupled receptor
a subunit exchanges GDP for GDP
a subunit dissociates from b +y subunits which trigger cellular response
GTP is hydrolysed and signal molecule comes off receptor
a subunit comes back together with receptor and b+y subunits
Galphai and galphas have differential effects on this enzyme
Adenylate cyclase
Enzyme activated by galphaq
Phospholipase C
Enzyme activated by cAMP
Protein kinase A
What is broken drown into IP3 and DAG?
PIP2
cAMP is what type of messenger?
Key secondary messenger
What does cAMP go on to do?
Activate protein kinase A, phosphorylation of target proteins,
PIP2 is?
A membrane phospholipid