L9 - GPCRs

Question 1

Which is the largest receptor family

Answer 1

GPCRs

Question 2

Structural features of GPCRs

Answer 2

7 transmembrane spanning domains

Question 3

Alpha helix 3 in GPCRs

Answer 3

always orientated towards centre of structure

Question 4

Function of alpha helix 3 in GPCRs

Answer 4

contributes to binding site

Question 5

What connects TM domains

Answer 5

Intracellular and extracellular loops

Question 6

N terminus location GPCRs

Answer 6

Points out of the cell - extracellular

Question 7

C terminus function in GPCRs

Answer 7

regulation of receptor function

Question 8

What do receptor families share

Answer 8

one or more homologous domains

Question 9

States of GPCRs

Answer 9

resting and active

Question 10

Which regions open up the GPCR

Answer 10

TM5 and TM6

Question 11

TM3 function in GPCR

Answer 11

central location, crucial for transduction of ligand binding

Question 12

What domains does TM3 send the transduction to

Answer 12

TM5 and TM6

Question 13

What else can contribute to ligand binding

Answer 13

Extracellular N terminus

Question 14

PAR receptor

Answer 14

GPCR for thrombin

Question 15

What activates PAR receptors

Answer 15

proteinases

Question 16

PAR receptor function

Answer 16

blood clotting and wound healing

Question 17

Thrombin

Answer 17

protease (enzyme)

Question 18

Thrombin function

Answer 18

cleaves amino terminus of receptor

Question 19

Effect of cleaving amino terminus of PAR receptor

Answer 19

activates receptor

Question 20

What two receptors are involved in blood clotting

Answer 20

thrombin receptor and ADP

Question 21

Blood thinners interfere with which receptors

Answer 21

thrombin receptor and ADP

Question 22

Which patients require blood thinners

Answer 22

patients at risk of stroke or clotting

Question 23

ADP receptor type

Answer 23

purinergic

Question 24

Allosteric modulator

Answer 24

molecules that act away from ligand binding site

Question 25

Impact of allosteric modulator

Answer 25

may impact receptor function

Question 26

Describe the resting GPCR

Answer 26

three inactive components

Question 27

How is the resting GPCR activated

Answer 27

ligand binding and exchange of GDP for GTP

Question 28

End result of active GPCR

Answer 28

three separate active components

Question 29

inactive alpha subunit Gprotein characteristics

Answer 29

alpha subunit has high affinity for GDP

Question 30

GEF

Answer 30

guanine exchange factor

Question 31

GEF function

Answer 31

causes GDP to fall off and GTP to come on

Question 32

RGS

Answer 32

regulators of G protein signalling

Question 33

How is receptor signalling system adapted

Answer 33

feedback

Question 34

Olfactory receptors activation

Answer 34

transduced through same trimeric G protein

Question 35

What do RGS proteins stimulate

Answer 35

GTPase activity

Question 36

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

Answer 36

rate of GDP hydrolysis by Ga

Question 37

What do G proteins control production of

Answer 37

second messengers, and ion channels

Question 38

What are effectors of trimeric G proteins

Answer 38

enzymes

Question 39

What do G proteins effectors (enzymes) control levels of

Answer 39

second messengers

Question 40

What is local concentration fo 2nd messengers determined by

Answer 40

rate of production, rate of diffusion and rate of removal

Question 41

What regulates cAMP production

Answer 41

adenylyl cyclase

Question 42

What removes cAMP

Answer 42

phosphodiesterase

Question 43

What does activated adenylyl cyclase catalyse

Answer 43

ATP into cAMP

Question 44

How many isoforms of adenylate cyclase are there

Answer 44

10

Question 45

What activates adenylate cyclase

Answer 45

Gas

Question 46

What inhibits adenylyl cyclase

Answer 46

Gai

Question 47

What does B2 adreno-receptor regulate

Answer 47

metabolism in liver and skeletal muscle

Question 48

What does stimulation of cAMP and adenylate cyclase activate

Answer 48

PKA

Question 49

PKA function in metabolism

Answer 49

sets up signalling cascade that phosphorylates enzymes controlling glycogen metabolism

Question 50

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

Answer 50

receptor and signalling molecules expressed in that cell