2_MechanismsOfHormoneAction

Question 1

What are the various signaling pathways for hormone receptors?

Answer 1

1) enzymatic, 2) channel gating, 3) vesicular trafficking, 4) cell motility, 5) transcription

Question 2

Where are steroid receptors generally found?

Answer 2

cytosol

Question 3

Where are thyroid hormone receptors generally found?

Answer 3

nucleus

Question 4

How are hormone receptors regulated?

Answer 4

by type, by sensitivity, and by abundance

Question 5

What G proteins are in Family I?

Answer 5

G-alpha-S; G-alpha-olf

Question 6

What G proteins are in Family II?

Answer 6

G-alpha-I; G-alpha-O; G-beta-gamma-O; G-alpha-T

Question 7

What G proteins are in Family III?

Answer 7

G-alpha-q

Question 8

What is the function of G-alpha-S?

Answer 8

activates adeylyl cyclase and activates Ca++

Question 9

What is the function of G-alpha-olf?

Answer 9

activates adenylyl cyclase

Question 10

What is the function of G-alpha-I?

Answer 10

inhibits adenylyl cyclase

Question 11

What is the function of G-alpha-O?

Answer 11

activates phospholipase C-beta

Question 12

What is the function of G-beta-gamma-O?

Answer 12

activates K+, activates phospholipase C-beta, inactivates Ca++

Question 13

What is the function of G-alpha-T?

Answer 13

activates cGMP phosphodiesterase in rods

Question 14

What is the function of G-alpha-Q?

Answer 14

activates phospholipase C-beta

Question 15

Describe the structure of a GPCR.

Answer 15

7-transmembrane segments; extracellular N-terminus; trimeric G-proteins (alpha/beta/gamma)

Question 16

Describe the structure of G-alpha?

Answer 16

varies – 28 proteins from 16 genes

Question 17

Describe the structure of G-beta-gamma.

Answer 17

5-beta and 12-gamma members regarded as 1 unit

Question 18

Describe the structure of an enzyme-linked hormone receptor.

Answer 18

Signaling complex as a molecular scaffold that is pre-assembled in lipid racts

Question 19

What are the discussed types of enzyme-linked receptors?

Answer 19

RTK & RATK

Question 20

How do RTKs & RATKs function?

Answer 20

as dimers

Question 21

What are the 3 essential receptor components for a steroid receptor?

Answer 21

transcription-regulation domain; DNA-binding domain; steroid-binding domain

Question 22

What is a hormone-response element?

Answer 22

DNA sequence specific for an intracellular receptor

Question 23

How do steroid receptors make a transcription facotr?

Answer 23

dimerization

Question 24

How are nuclear receptors different from steroid receptors in structure?

Answer 24

additional extension in DNA-binding domain

Question 25

How do nuclear receptors produce a transcription factor?

Answer 25

as monomers, as homodimers, or as heterodimers with RXR

Question 26

How are nuclear receptors regulated?

Answer 26

by abundance & sensitivity through: 1) spatiotemporal expression, 2) phosphorylation, 3) protein-protein interaction, 4) ubuiquitination, 5) acetylation

Question 27

How are cell-surface receptors regulated?

Answer 27

1) sequestration, 2) lysosomal down-regulation, 3) inactivation, 4) signaling protein inactivation, 5) production of inhibitory protein

Question 28

What pathway does Leptin function through?

Answer 28

Jak/STAT