L10 GPCR Signalling

Question 1

Effectors of trimeric G proteins

Answer 1

enzymes

Question 2

What do the effector enzymes of G proteins create

Answer 2

2nd messengers and ion channels

Question 3

IP3

Answer 3

diffusible second messenger

Question 4

IP3 function

Answer 4

controls calcium levels

Question 5

Gqa receptors

Answer 5

a-adrenergic amines, Ach, various neurotransmitters

Question 6

Gqa effectors

Answer 6

activate phospholipase Cb to produce IP3

Question 7

What type of signalling is shared across many receptor families

Answer 7

signalling via lipid derived second messengers

Question 8

Advantage of shared lipid signalling

Answer 8

cross talk and amplification

Question 9

Lipid derived second messenger examples

Answer 9

PIP2, phosphatidylcholine, sphingomyelin

Question 10

What targets membrane lipids

Answer 10

receptor regulated lipases

Question 11

What are the two types of 2nd messengers derived from membrane lipids

Answer 11

i - water soluble, ii - hydrophobic molecules

Question 12

Movement of water soluble lipid derived 2nd messengers

Answer 12

diffuse through the cytoplasm

Question 13

Movement of hydrophobic lipid derived second messengers

Answer 13

remain in membrane

Question 14

Function of lipid kinases

Answer 14

add phosphate groups to lipids

Question 15

DAG

Answer 15

diacylglycerol

Question 16

DAG structure

Answer 16

two fatty acid chains covalently bonded to a glycerol molecule through ester linkages

Question 17

What is the more abundant lipid derived second messenger

Answer 17

Phosphatidylcholine

Question 18

Example of hydrophobic 2nd messenger

Answer 18

DAG

Question 19

Function of DAG

Answer 19

control signalling that occurs in PM

Question 20

GPCR activation of PLC generates…

Answer 20

IP3 and DAG

Question 21

What does specificity in signalling come from

Answer 21

selective expression and cellular localisation of signalling molecules

Question 22

PH domain function

Answer 22

anchors parts of enzyme into PM

Question 23

What is the PH domain important for

Answer 23

recognition

Question 24

What is PKC regulated by

Answer 24

diaceylglycerol and calcium

Question 25

Why is the location of a kinase important

Answer 25

it can only phosphorylate proteins near it

Question 26

What are PKCs

Answer 26

ser/thr kinases

Question 27

What is the PKC C1 domain activated by

Answer 27

DAG

Question 28

What is the PKC C2 domain activated by

Answer 28

Ca2+

Question 29

What is PMA

Answer 29

phorbol ester analogue of DAG

Question 30

PMA function

Answer 30

activate PKCs

Question 31

What does GFP tagged PKC imaging show

Answer 31

agonist dependent translocation to PM

Question 32

What does PKC have built in

Answer 32

inhibitory peptide

Question 33

Location of inhibitory peptide in PKC

Answer 33

when resting - folded into catalytic domain of kinase

Question 34

What residues cannot be phosphorylated

Answer 34

alanine residues

Question 35

Effect of phosphorylation

Answer 35

switches ON/OFF a function

Question 36

What does DAG binding to PKC cause

Answer 36

dissociation of intramolecular pseudosubstrate domain from active site

Question 37

What can phosphorylation of receptors contribute to

Answer 37

desensitisation

Question 38

Function of munc13

Answer 38

controls docking of secretory vesicles at PM

Question 39

What recruits munc13

Answer 39

activation of GqPCRs and synthesis of DAG in PM

Question 40

What causes Lowe syndrome

Answer 40

mutations in OCRL

Question 41

How is a large chemical gradient for calcium created

Answer 41

proteins in lumen of ER bind up Ca2+

Question 42

How is calcium influx into the cytosol regulated in the PM

Answer 42

voltage and ligand gated channels

Question 43

What is STIM

Answer 43

protein in ER that senses calcium