CellSig13 - 22 Flashcards Preview

Y2S2 - Cell Signalling > CellSig13 - 22 > Flashcards

Flashcards in CellSig13 - 22 Deck (23):
1

Identify 2 types of intracellular receptors

Gases, nuclear receptors

2

Two gaseous ligands

NO, CO

3

Four nuclear receptor ligands

Steroid hormones, thyroid hormones, retinoids, vitamin D

4

Characterise NO

Very reactive gaseous free radical

5

What catalyses the production of NO?

NOS - NO synthase through two monooxygenase reactions

6

Outline structure of NOS

Reductase domain that binds NADPH, FMN, FAD; haem binding domain

7

What are the three types of NOS?

e, n and iNOS

8

What is important to note about eNOS and nNOS?

They are constitutively expressed - cNOS

9

What is different about iNOS?

Its expression is inducible

10

Characterise cNOS

Activity induced by Ca2/calmodulin

11

Characterise eNOS

Endothelial (NOS3)

12

Characterise nNOS

Neural (NOS1)

13

Characterise iNOS

Inducible (NOS2) - activity constitutively active, expression inducible

14

What are the main differences between cNOS and iNOS?

cNOS: calmodulin dependent, picomoles released, short-lasting release; iNOS: opposite, nanomoles released, long lasting

15

What is the NOS target?

Guanylyl cyclase

16

What was NOS originally known as and why?

EDRF - released by endothelia, relaxes smooth muscle

17

How does NO act in the immune system?

Kills bacteria and parasites and induces cell death

18

What drugs affect NO signalling?

Nitroglycerin - metabolised to NO, treats angina; viagra - inhibitor of type V phosphodiesterase, increases NO, prolonging increases in cGMP levels

19

Signalling molecules that bind with nuclear receptors

Cortisol, estradiol, testosterone, vitamin D3, thyroxine, retinoic acid

20

Outline the topography of nuclear receptors

Inhibitory proteins hold them in inactive states, ligand removes inhibitors, receptors interact with co-activators and transcription is controlled

21

What does RXR stand for?

Retinoid X receptor

22

What do all heterodimer nuclear receptors have in common?

Share a partner in RXR

23

What do all homodimer nuclear receptors have in common?

RE - response element