Membrane Receptors

Question 1

Four main types of receptors

Answer 1

Ligand gated ion channels (Ionotropic receptors)
G protein coupled receptors
Kinase linked receptors
Nuclear receptors

Question 2

What are G protein coupled receptors GPCRs

Answer 2

• Largest family of membrane receptors (~800)
• 7TM domain
• Mediate effects of many hormones and neurotransmitters
• Major targets of pharmacological intervention (~40% drugs on market)

Question 3

What are the G protein subunits

Answer 3

Alpha
Beta
Gamma

Question 4

How GPCRs inmate change

Answer 4

Signalling molecule binds to GPCRS and causes conformational change
Alpha subunit exchanges GDP for GTP
Alpha dissociates from beta and gamma
Alpha subunit regulates target proteins

GTP hydrolysed into GDP and ready to initiate another reaction

Question 5

Different effects of G protein

Answer 5

Activate second messenger ATP to cAMP regulated by alpha subunit
Ion channels regulated by beta and gamma subunits

Question 6

Effect of G alpha s unit

Answer 6

↑adenylyl cyclase

Question 7

Effect of Gαi/o

Answer 7

↓ adenylyl cyclase

Question 8

What is adenylyl cyclase activated by

Answer 8

Effector enzyme activated by Gαs