Signal Transduction in Metabolism

Question 0

What enzyme does IRS-1-P activate?

Answer 0

PI3K (PIP2–>PIP3)

Question 1

What 2 messengers promote movement of GLUT4 transporters into the plasma membrane?

Answer 1

IRS-1-P

Cbl-P

Question 2

What 3 things does PI3K do in metabolism?

Answer 2

Activate Akt which stimulates GLUT4 into plasma membrane

Activate protein phosphatase 1

Inactivate glycogen synthase kinase (GSK3), increasing glycogen activity

Question 3

What serves as a docking protein after insulin binds it’s receptor?

Answer 3

IRS-1-P

Question 4

Describe the insulin receptor

Answer 4

α2β2 tetramer held together by disulfide bonds and can autophosphorylate (tyrosine kinase activity)

Question 5

3 roles of insulin in fuel metabolism

Answer 5

1) increase ser/thr phosphatase activity
2) control gene expression
3) move GLUT4 into plasma membrane

Question 6

How do caffeine and theophylline act as stimulants?

Answer 6

Competitive inhibitors of cAMP phosphodiesterase (so more cAMP)

Question 7

First thing cholera toxin does

Answer 7

Covalently modifies Gα via ADP-ribosylation (inactivates GTPase activity)

Question 8

When does αGDP become αGTP?

Answer 8

When the hormone binds the receptor

Question 9

Glucagon activates what pathway?

Answer 9

Adenylate cyclase

Question 10

β-adrenergic receptors are a part of which pathway?

Answer 10

Adenylate cyclase

Question 11

α-adrenergic receptors are a part of which pathway?

Answer 11

Inositol phosphate

Question 12

What are the 3 1st messenger hormones of fuel metabolism and what tissues are they located in?

Answer 12

1) insulin - liver, muscle, adipose
2) glucagon - liver, adipose
3) epinephrine - liver, muscle, adipose