Coyler

Question 1

What concentration is cAMP within a cell?

Answer 1

0.1-1uM

Question 2

What are the physiological effects of cAMP?

Answer 2

Glucose metabolism from glycogen
Fight or flight response
Trigyceride breakdown

Question 3

How many members of the adenlyl cyclase family are there?

Answer 3

6, with 50-92% identity

Question 4

What is the structure of adenlyl cyclase?

Answer 4

2 NBD domains and 12TM helices

Question 5

What is the turnover of AC?

Answer 5

1000/min

Question 6

How does cAMP have localised effects?

Answer 6

APAK provides a platform to link targets and degradation close to AC

Question 7

What is the main target of cAMP?

Answer 7

PKA

Question 8

What are the targets of cAMP?

Answer 8

cAMP-dependant kinases,
Exchange Protein directly activated by cAMP,
ion channels

Question 9

What are the sites of cAMP/ CaMK responses in muscle cells?

Answer 9

L-Calcium channels
RyR2 Calcium channels
Phospholambam

Question 10

What enzyme does cAMP act on in muscle cells?

Answer 10

CamK11

Question 11

How is cAMP degraded?

Answer 11

Phosphodiesterases

Question 12

What structure is PDE?

Answer 12

58-125kDa, regulatory and targetting domains with catalytic core

Question 13

How many forms of PDE are there?

Answer 13

11 classes, 30 isoforms

Question 14

What is the structure of PKA?

Answer 14

Dimer of R/C
R is autoinhibitory by mimicking substrate, released by fast/slow cAMP sites
C has MgATP site and substrate binding site

Question 15

What specificity does PKA have?

Answer 15

Low specificity for S/T in RRxSxxxx motif

Question 16

What deterrents does PKA specificity have?

Answer 16

Y at 0
F at +4
Acidic residues at -1
K at -1

Question 17

How is cAMP signalling restricted?

Answer 17

PDE degradation
AKAP compartmentalisation
Phosphatases counteracting downstream targets
GPCR/GP inactive form
Internalisation of GPCR

Question 18

How is Adenlyl cyclase activated?

Answer 18

By GPCR stimulation, varying from which GP subunit

Question 19

Is the [cAMP] uniform across a cell?

Answer 19

No-heterogeneous/localised

Question 20

Which pathogens expliot cAMP signalling?

Answer 20

Cholera ADP-ribosylates Gas for permanent inactivation

Pertussis injects soluble AC

Question 21

Which receptors are activated by cAMP in heart?

Answer 21

B1-AR and B2-AR

Question 22

Which heart receptor have the most significant increase in contractility?

Answer 22

400% in B1-AR

Question 23

Which heart receptor is cardioprotective?

Answer 23

B2-AR

Question 24

What are the effects of overstimulation of PKA?

Answer 24

desensititation

Question 25

How does EPac respond to high stimulation?

Answer 25

desensitised

Question 26

Which cAMP target has a switch in activity when overactivated?

Answer 26

CaMK11 switches from contractility to apoptosis

Question 27

What effect does GPCR phosphorylation have on a cell?

Answer 27

Cell growth/hypertrophy.

Question 28

What is IP3?

Answer 28

inositol-1,4,5-triphosphate

Question 29

What percentage of the membrane is PIs?

Answer 29

2-8%

Question 30

Which 2 pathways can stimulate PLC activity?

Answer 30

PTK or GPCR

Question 31

How are GPCRs activated for IP3 signalling?

Answer 31

Ach, 5HT, odour, light

Question 32

Which PLC isoform do RTKs activate?

Answer 32

PLCy phosphorylation at Y771, Y783, Y1254

Question 33

Which G proteins are involved in activating PLCs?

Answer 33

q, By, 11, 14, 16

Question 34

Which PLC isoform does Gaq activate?

Answer 34

beta 1

Question 35

How is PLCy inhibited?

Answer 35

PKA and PKC phosphorylation

Question 36

What physiological effects does IP3 have directly?

Answer 36

fertilisation, platelet aggregation secretion from the adrenal cortex smooth muscle contraction

Question 37

What does DAG activate?

Answer 37

Ca-dependant kinases

Question 38

What does PLC produce?

Answer 38

IP3 and DAG

Question 39

How does IP3 mediate release of Ca?

Answer 39

Opens ligand gated Ca channels in ER

Question 40

Where is the intracellular store of Ca?

Answer 40

In the ER, maintained by SERCA pump and buffer proteins calreticulin and calsequestrin

Question 41

What is the structure of the IP3R?

Answer 41

tetrameric channel with 3 isoforms of 2701-2745 residues

Question 42

How is IP3R regulated?

Answer 42

Cytosolic [Ca} ATP PKA phosphorylation

Question 43

What is the Kd of IP3 for the IP3R?

Answer 43

10nM

Question 44

What is the [intracellular Ca]?

Answer 44

0.1-1uM

Question 45

What is the [Ca] in the blood?

Answer 45

1-2mM

Question 46

How can [cytosolic Ca] be observed?

Answer 46

photoproteins based on aequorin | EGTA derived organic dyes that use acidic groups for chelation

Question 47

How much Ca can be released in cytoplasm?

Answer 47

Quantal/fixed

Question 48

How does Ca release vary with increasing [agonist]?

Answer 48

frequency of release varies

Question 49

What is the capacitive Ca entry?

Answer 49

Quantal release of Ca from ER Decline Opening of blood channels Increase in Ca

Question 50

How does Ca enter cells from blood?

Answer 50

Low Ca causes Orai to release TRPC as open non-specific cation channel Orai binds STIM in ER membrane Clusters of complex lock TRPC in Ca form (Icrac form)

Question 51

What direct effects does Ca have an a cell?

Answer 51

channels, proteases and lipases, | eg TCA, PKC, PDE, contractile proteins

Question 52

Which regulatory proteins does Ca interact with?

Answer 52

calmodulin, annexins

Question 53

What is the structure of CaM?

Answer 53

16.8kDa | 4 EF hands

Question 54

Where is CaM found?

Answer 54

Ubiquitous and abundant

Question 55

What processes in CaM involved in?

Answer 55

Ca transport Glycogen metabolism Cyclic nucleotide metabolism Replaces troponin in smooth muscle contraction

Question 56

How is CaM activated?

Answer 56

conformational change buckles central helix methionine puddle exposed binding of substrate

Question 57

What motif does CaM target?

Answer 57

positive residues-hydrophobes

Question 58

How is CaM involved in neurotransmitter release?

Answer 58

CaMK11 releases synapsin on vesicles for interaction with actin cytoskeleton