L9 - GPCRs Flashcards Preview

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Flashcards in L9 - GPCRs Deck (50)
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1

Which is the largest receptor family

GPCRs

2

Structural features of GPCRs

7 transmembrane spanning domains

3

Alpha helix 3 in GPCRs

always orientated towards centre of structure

4

Function of alpha helix 3 in GPCRs

contributes to binding site

5

What connects TM domains

Intracellular and extracellular loops

6

N terminus location GPCRs

Points out of the cell - extracellular

7

C terminus function in GPCRs

regulation of receptor function

8

What do receptor families share

one or more homologous domains

9

States of GPCRs

resting and active

10

Which regions open up the GPCR

TM5 and TM6

11

TM3 function in GPCR

central location, crucial for transduction of ligand binding

12

What domains does TM3 send the transduction to

TM5 and TM6

13

What else can contribute to ligand binding

Extracellular N terminus

14

PAR receptor

GPCR for thrombin

15

What activates PAR receptors

proteinases

16

PAR receptor function

blood clotting and wound healing

17

Thrombin

protease (enzyme)

18

Thrombin function

cleaves amino terminus of receptor

19

Effect of cleaving amino terminus of PAR receptor

activates receptor

20

What two receptors are involved in blood clotting

thrombin receptor and ADP

21

Blood thinners interfere with which receptors

thrombin receptor and ADP

22

Which patients require blood thinners

patients at risk of stroke or clotting

23

ADP receptor type

purinergic

24

Allosteric modulator

molecules that act away from ligand binding site

25

Impact of allosteric modulator

may impact receptor function

26

Describe the resting GPCR

three inactive components

27

How is the resting GPCR activated

ligand binding and exchange of GDP for GTP

28

End result of active GPCR

three separate active components

29

inactive alpha subunit Gprotein characteristics

alpha subunit has high affinity for GDP

30

GEF

guanine exchange factor

31

GEF function

causes GDP to fall off and GTP to come on

32

RGS

regulators of G protein signalling

33

How is receptor signalling system adapted

feedback

34

Olfactory receptors activation

transduced through same trimeric G protein

35

What do RGS proteins stimulate

GTPase activity

36

What is duration of signalled by activated trimeric G protein regulated by

rate of GDP hydrolysis by Ga

37

What do G proteins control production of

second messengers, and ion channels

38

What are effectors of trimeric G proteins

enzymes

39

What do G proteins effectors (enzymes) control levels of

second messengers

40

What is local concentration fo 2nd messengers determined by

rate of production, rate of diffusion and rate of removal

41

What regulates cAMP production

adenylyl cyclase

42

What removes cAMP

phosphodiesterase

43

What does activated adenylyl cyclase catalyse

ATP into cAMP

44

How many isoforms of adenylate cyclase are there

10

45

What activates adenylate cyclase

Gas

46

What inhibits adenylyl cyclase

Gai

47

What does B2 adreno-receptor regulate

metabolism in liver and skeletal muscle

48

What does stimulation of cAMP and adenylate cyclase activate

PKA

49

PKA function in metabolism

sets up signalling cascade that phosphorylates enzymes controlling glycogen metabolism

50

What is the effect of a stimulus on cell function determined by

receptor and signalling molecules expressed in that cell