Fast Hormonal Signal Transduction Processes (2)

Question 1

What is the structure of PKA?

Answer 1

R2C2 heterotetramer - 2 regulatory subunits, 2 catalytic subunits

Question 2

What type of kinase is PKA?

Answer 2

Serine/threonine kinase

Question 3

How many molecules of cAMP bind to each regulatory subunit to cause dissociation from the catalytic subunits?

Answer 3

2 - 4 per PKA

Question 4

Which enzyme breaks down cAMP to AMP?

Answer 4

Cyclic nucleotide phosphodiesterase

Question 5

What is beta-ARK?

Answer 5

GPCR kinase

Question 6

What does beta-ARK bind to?

Answer 6

Beta-gamma subunit of G-protein

Question 7

What is the effect of beta-ARK?

Answer 7

Phosphorylates receptor C-terminus - creates binding site for beta-arrestin

Question 8

What is the effect of beta-arrestin?

Answer 8

Blocks intracellular loops of receptor - cell cannot respond to receptor stimulation

Question 9

What is the effect of PLC?

Answer 9

Breaks down PIP2 - forms hydrophobic DAG and hydrophilic IP3

Question 10

What type of kinase is PKC?

Answer 10

Serine/threonine kinase

Question 11

What type of kinase is the EGF receptor?

Answer 11

Receptor tyrosine kinase

Question 12

What is the effect of EGF receptor?

Answer 12

Activates transcription factors - causes cell growth - long-term effect

Question 13

What is Grb-2?

Answer 13

Adaptor protein

Question 14

What is Sos?

Answer 14

GEF

Question 15

What is Ras?

Answer 15

Monomeric G-protein

Question 16

What increases the GTPase activity of Ras?

Answer 16

GTPase activating proteins (GAPs)

Question 17

What type of kinase is the insulin receptor?

Answer 17

Receptor tyrosine kinase

Question 18

How do PKB and PDK1 bind to PIP3?

Answer 18

Pleckstrin homology domains

Question 19

What are the effects of the insulin receptor?

Answer 19

Short-term - GLUT4 translocation

Long-term - via Grb-2 binding to IRS-1 - activates MAPK pathway