6: Pathways of Cell Signaling

Question 1

Growth factor receptor kinases

Answer 1

extracellular growth factor binds to receptor causing a conformation change and stimulation of kinase activity, the phosphate groups on the kinase attracts other proteins

Question 2

What is an example of a growth factor receptor kinase?

Answer 2

insulin

Question 3

Ras-activating protein

Answer 3

helps exchange GDP for GTP, making Ras active

Question 4

Ras

Answer 4

monomer becomes active when bound to GTP, activating more signaling pathways

Question 5

MAP

Answer 5

mitogen activated protein

Question 6

What enzymes does Ras activate?

Answer 6

1. MAP-kinase-kinase-kinase
2. MAP kinase-kinase
3. MAP kinase

Question 7

What does MAP-kinase signal?

Answer 7

prepare for mitosis

Question 8

Epidermal growth factor (EGF) receptor

Answer 8

example of tyrosine-kinase receptor; EGF binds to an extracellular ligand domain, activating many pathways

Question 9

What do steroidal anti-inflammatory drugs block?

Answer 9

intracellular recpetor

Question 10

What hormones work via an intracellular receptor?

Answer 10

cortisol, sex hormone, thyroid hormone

Question 11

TGF-beta

Answer 11

transforming growth factor-beta

Question 12

SMADs

Answer 12

recruited to a receptor that has been activated by TGF-beta and heads to the nucleus to activate a gene promoter

Question 13

CREB

Answer 13

cAMP response element binding protein

Question 14

What does CREB do?

Answer 14

it is a target of protein kinase that activated gene expression

Question 15

What phosphorylates CREB?

Answer 15

active protein-kinase A

Question 16

3 ways to terminate receptor signaling

Answer 16

1. receptor inactivation
2. receptor internalization
3. receptor degredation

Question 17

Receptor inactivation

Answer 17

b arrestin binds to the receptor and inactivates it

Question 18

Receptor internalization

Answer 18

an endosome removes the receptor from the surface and is stored until needed later

Question 19

Receptor degredation

Answer 19

a lysosome internalizes and destroys the receptor

Question 20

2 pathways used in acinar cells in pancreas

Answer 20

1. cAMP and PKA
2. Ca2+ release

Question 21

What cells in the pancreas make insulin?

Answer 21

beta

Question 22

What does the pancreas confuse xylitol with in dogs?

Answer 22

glucose