G proteins and their receptors and effectors

Question 1

G Protein: Gs

Receptors for: β-Adrenergic, amines, glucagon, histamine,
serotonin, and many other hormones

Effector / Signaling Pathway:

Answer 1

↑Adenylyl cyclase
→ ↑cAMP

Question 2

G Protein: Gi1, Gi2, Gi3

Receptors for: α - Adrenergic, amines, acetylcholine, (muscarinic), opioids, serotonin

Effector / Signaling Pathway:

Answer 2

↓Adenylyl cyclase
→ ↓cAMP

Open cardiac K+ channels → heart rate

Question 3

G Protein: Golf

Receptors for: Odorants (olfactory epithelium)

Effector / Signaling Pathway:

Answer 3

↑Adenylyl cyclase
→ ↑cAMP

Question 4

G Protein: Go

Receptors for: Neurotransmitters in brain (not yet specifically identified)

Effector / Signaling Pathway:

Answer 4

Not yet clear

Question 5

G Protein: Gq

Receptors for: Acetylcholin (muscarinic), bombesin, serotonin (5-HTiC), and many others

Effector / Signaling Pathway:

Answer 5

↑Phospholipase C
→ ↑IP3 diacylglycerol, cytoplasmic Ca2+

Question 6

G Protein: Gt1, Gt2

Receptors for: Photons (rhodopsin and color opsins in
retinal rod and cone cells)

Effector / Signaling Pathway:

Answer 6

↑cGMP phosphodiesterase
→ ↓cGMP (phototransduction)