general structure and activation of GPCR

how many subunits in g protein

18 alpha, 5 beta, 12 gamma

what subunit is GDP coupled to

alpha subunit

how many transmembrane domains does GPCR have

7

where are the terminals located for the GPCR

• n terminus outside of the cell

• c terminus sits inside of the cell

where is the agonist binding site found

• along the top of the transmemwhebrane domains

• close to the membrane

where is the g protein binding site found

inner face of the membrane

which family is GPCR part of

family A

which subtypes of muscarinic acetylcholine receptors bind to which g proteins

M1, M3, M5 - Gq odd number

M2, M4 - Gi even number

activation of the GPCR

• signal from outside of the cell interacts with GPCR

• receptor activated

• enables interaction w g protein

• creates change in the g protein

• GDP exchanged for GTP

• alpha subunit coupled with GTP interacts with target protein

• secondary messenger molecule

turning off GPCR

• agonist leaves g coupled receptor

• receptor switches off

• alpha subunit hydrolyses GTP → GDp + Pi

• g protein associates again