G protein coupled receptor Flashcards
How many transmembrane domains do G protein coupled receptors?
They have 7 transmembrane domains
what is gtp?
guanosine triphosphate
what is the role of second messenger systems?
induce a cellular response
what is the structure of GPCR?
7 transmembrane spanning domains
coupled to a heterotrimer G protein complex
made of alpha beta and gamma subunits
How are GPCRs activated?
through the hydrolysis of GTP to GDP.
this provides energy for enzyme cascade
what is the role of adenylate cyclase?
it converts ATP into cyclic AMP
what is cyclic AMP?
second messenger in cells
what does cyclic AMP do?
It activates protein kinase A
leading to the phosphorylation of target proteins.
what do G alpha s receptors cause?
the stimulation of adenylate cyclase enzyme.
this converts ATP into cAMP.
cAMP then activates protein kinase A, leading to the phosphorylation of target cells
What do G alpha i receptors cause?
The inhibition of adenylate cyclase enzyme.
= reduced cAMP
= reduced action of protein kinase A
what is the role of phospholipase C when activated?
it breaks down PIP2 to IP3 and DAG
what is PIP2?
Membrane phospholipid
=Phosphatidyl inositol bisphosphate
what is PIP2 broken down into by the action of phospholipase C?
Into IP3 and DAG
what can IP3 cause?
the release of calcium from intracellular stores
what can DAG cause?
it activates protein kinase C
Where is the agonist binding domain of GPCRs?
N terminus
what terminal transduces intracellular effects in GPCRs?
C terminal
what do alpha GS receptors cause.
adenylate cyclase and cAMP
Increases adenylate cyclase
Increases cAMP
what do alpha Gi receptors cause.
adenylate cyclase and cAMP
Decreases adenylate cyclase
decreases cAMP
what do alpha Gq receptors cause.
phospholipase C and DAG
phospholipase c
IP3 = release of Ca
DAG = activates protein kinase C
