Exam 2 Signaling Cascades

Question 1

what is the second messenger of epinephrine B2 adrenergic receptor signaling cascade and glucagon glucagon receptor signaling cascade?

Answer 1

cAMP

Question 2

what generates cAMP?

Answer 2

adenylyl cyclase

Question 3

what are the subunits of G proteins?

Answer 3

alpha, beta, gamma

Question 4

what kind of alpha subunit do Gs family proteins have?

Answer 4

stimulatory

Question 5

Gs family protein result

Answer 5

increase cAMP production

Question 6

why does the Gs family protein increase cAMP production?

Answer 6

it stimulates adenylyl cyclase which then generates cAMP

Question 7

what G-protein family pathway do epinephrine and glucagon work through?

Answer 7

Gs

Question 8

what kind of alpha subunits do Gi family proteins have?

Answer 8

inhibitory

Question 9

Gi family protein result

Answer 9

decrease cAMP production

Question 10

why does the Gi family protein decrease cAMP production?

Answer 10

it inhibits adenylyl cyclase or it activates phosphodiesterase

Question 11

what does the Gq family protein do?

Answer 11

activates phospholipase C

Question 12

what does the G12/13 family protein do?

Answer 12

activates Rho GTPase which is involved in cytoskeletal dynamics, organelle generation, etc.

Question 13

what catalyzes ATP to cyclic AMP?

Answer 13

adenylyl cyclase

Question 14

what catalyzes cyclic AMP to AMP?

Answer 14

phosphodiesterase

Question 15

what catalyzes phosphotidylinositol-4,5-biphosphate (PIP2) to diacylglycerol and inositol-1,4,5-triphosphate (IP3)

Answer 15

phospholipase C

Question 16

what catalyzes phosphotidylinositol-4,5-biphosphate (PIP2) to phosphotidylinositol-3,4,5-triphosphate (PIP3)

Answer 16

phosphoinositide-3-kinase (PI3K)

Question 17

what is the ratio of Protein Kinase A catalytic and regulatory subunits?

Answer 17

2 catalytic subunits : 2 regulatory subunits

Question 18

what do the Protein Kinase A regulatory subunits have?

Answer 18

two cAMP binding sites (4 cAMP bind to the 2 regulatory subunits)

Question 19

what occurs when two cAMP bind to the 2 regulatory subunits of Protein Kinase A?

Answer 19

the catalytic subunits are freed so they can phosphorylate targets

Question 20

what are the secondary messengers of the epinephrine alpha 1 adrenergic receptor signaling cascade?

Answer 20

diacylglycerol and inositol triphosphate (IP3)

Question 21

diacylglycerol in the epinephrine signal cascade

Answer 21

second messenger that activates Protein Kinase C

Question 22

inositol triphosphate (IP3) in epinephrine signal cascade

Answer 22

polar, doesn’t associated with membrane
activates Ca2+/CAM

Question 23

what are the primary kinases of the epinephrine signaling cascade?

Answer 23

Protein Kinase C and Ca2+/Calmodulin Protein Kinase (Ca2+/CAM)

Question 24

what G-protein-coupled receptor G-protein family does epinephrine to phospholipase Cbeta use?

Answer 24

Gq

Question 25

what does epinephrine activate?

Answer 25

phospholipase Cbeta

Question 26

what occurs after epinephrine activates phospholipase Cbeta and 2nd messengers are generated?

Answer 26

we activate kinases; goal is to metabolic targets

Question 27

what is the insulin receptor an example of?

Answer 27

a receptor tyrosine kinase

Question 28

what are the two major pathways in insulin receptor signaling (IRS-1)?

Answer 28

Ras (GDP/GTP Exchange) MAP Kinase Cascade and PI3K

Question 29

what occurs when insulin receptor signaling activates PI3K?

Answer 29

PI3K generates PIP3 and the effects are mediated my Protein Kinase B

Question 30

what kinase does PI3K activate?

Answer 30

protein kinase B

Question 31

what are the primary metabolic targets of Protein Kinase B?

Answer 31

- cardiomyocytes PFK2/FBPase-2 - glycogen synthase kinase (hepatocytes and skeletal myocytes) - PPP-1 regulatory subunit - phosphodiesterase 3beta isozyme (degrades cAMP) - FOXO-1

Question 32

what occurs when the insulin receptor signaling activates the Ras/MAPK Cascade?

Answer 32

MAPK, MAP2K, MAP3K mostly related to gene expression