Receptors and Cell Signaling

Question 1

How does viagra work?

Answer 1

Inhibits cGMP PDE so there is a ton of cGMP in the cell –> smooth muscle relaxation and vasodilation

Question 2

What type of GPCR does light have?

Answer 2

Gt

Question 3

What type of GPCR has been implicated in a wide range of cancers?

Answer 3

RAS

30-50% of lung and colon, 90% of pancreatic cancers assoc w/ mutations in RAS

Question 4

What does binding of a ligand to an RTK cause?

Answer 4

dimerization

Question 5

What type of GPCR does acetylcholine have?

Answer 5

Gq

Question 6

What does Pertussis do in the body?

Answer 6

Prevents alpha subunit on G protein working in Gi path –> no inhibition of AC and overproduction of cAMP –> loss of fluids and excessive mucous in airway epithelium

Question 7

What residues are phosphorylated in an RTK?

Answer 7

tyrosine

Question 8

What does caffeine do?

What type of GPCR does this correspond to?

Answer 8

inhibits cAMP PDE –> more cAMP in the cell –> increased heart rate
Gs

Question 9

What type of GPCR does histamine have?

Answer 9

Gs

Question 10

What does breast cancer drug herceptin target?

Answer 10

HER2 - an EGF-binding RTK

Question 11

What does cholera do in the body?

Answer 11

modifies alpha subunit of G protein in Gs path –> decreases GTPase activity –> AC continuously stimulated and cAMP overproduced –> Cl- channels open in intestine –> dehydration and diarrhea

Question 12

What type of GPCR does dopamine have?

Answer 12

Gi

Question 13

What does nitric oxide do?

When do you not want to prescribe nitrates?

Answer 13

activates guanylate cyclase in smooth muscle –> creation of cGMP –> smooth muscle relaxation and vasodilation
don’t want to take nitrates w/ viagra because you could have too much cGMP and vasodilation that BP drops too low