E3L3: Cell Signaling 1

Question 1

Which of the following is NOT paired correctly with its function?

a. Gs – activates adenylyl cyclase
b. Gi – inhibits adenylyl cyclase
c. Gq – activates phospholipase C-beta

d. Gq – activates phospholipase C-alpha

Answer 1

d. Gq – activates phospholipase C-alpha

Question 2

Which of the following contain –Arg-Arg-X-Ser-Y (hydrophobic) sequences? Circle all that apply.

a. Regulatory subunit of PKA
b. CREBP
c. CREB-binding protein (CBP)
d. CFTR Chloride Channel
e. Cyclic AMP response protein (CRE)

Answer 2

b. CREBP
d. CFTR

Everything else is not a target of PKA.

TRICKY: CFTR channel can be phosphorylated by GRK, AND also PKA. See the discussion on Cholera toxin.

Question 3

Which of the following does NOT play an inhibitory role in GPCR signalling? Circle all that apply.

a. GPCR Kinase (GRK)
b. Arrestin

c. G-alpha-i (GTP) subunit
d. CREB

Answer 3

d. CREB

Question 4

Which of the following have kinase activity? Circle all that apply.

A. GRK
B. PKA.

C. Adenylyl Cyclase

D. Tyrosine Kinase Receptor

Question 5

Which of the following are transcription factors? Circle all that apply.

A. CREB

B. Cortisol Receptors

C. Vitamin D receptor

D. All of the above

Answer 5

D. All of the above

Note: don’t forget steroid hormone receptors have TF activity!

Question 6

Which of the following does NOT require the release of an inhibitory protein (or domain), for activation?

A. Cortisol receptor
B. PKA
C. CaM-Kinase II

D. CREB

Answer 6

D. CREB

Here’s a pic of CaM-Kinase II

Question 7

Which of the following G-protein subunits can possibly activate adenylyl cyclase?

A. Alpha-GTP subunit
B. Beta-Gama dimer
C. Alpha-GDP subunit
D. A and B

Answer 7

D. A and B

BOTH Alpha and Beta subunits can activate adenylyl cyclase!

Question 8

Which of the following is NOT a strategy for removing GPCR’s from the membrane?

A. Mono-ubiquitination
B. Arrestin-mediated exocytosis
C. GRK

D. All of the above are strategies

Answer 8

B. Arrestin-mediate exocytosis. Should be endocytosis.

Question 9

Which of the following is true regarding Cholera?

A. ADP-ribose group binds GDP-bound G-alpha-s subunit

B. ADP-ribose group binds GTP-bound G-alpha-s subunit

C. ADP-ribose group binds GDP-bound G-delta-s subunit
D. ADP-ribose group binds GTP-bound G-delta-s subunit

Answer 9

B. ADP-ribose group binds GTP-bound G-alpha-s subunit