PL

Question 1

Inhibitor of PLC-beta

Answer 1

U-73122

Question 2

Oxo-M

Answer 2

Fairly selective agonist of M1

Question 3

Name three main effects of the mutation R207Q, R207W and E119G

Answer 3

1. Depolarising shift in voltage dependent activation
2. Slowing of activation kinetics
3. Reduced current in response to short depolarisation

Question 4

Describe retigabine binding site

Answer 4

Binds between the S5-S6 region which forms the pore hence selectivity filter

Question 5

Describe the mechanism of the inhibition of M current in nociceptive terminal leading to chronic pain

Answer 5

Activation of PAR-2 —> inhibit M current —> increase cell excitability —> increase signalling to CNS —> increase pain sensation

Question 6

Which region of KCNQ is affected by the mutation

1. E119G
2. R207Q and R207W

Answer 6

1. S1-S2 region

2. S4 region

Question 7

In inhibition of KCNQ by GPCR what is ATP important for?

Answer 7

Regeneration of PIP2 
Enzyme PI(4)P kinase required the presence of ATP to generate PIP2

Question 8

Inhibitor of PI(4)P kinase

What is the consequences of inhibiting this enzyme?

Answer 8

Wortmannin

You don’t get recovery after inhibition of M current

Question 9

Chemical compound that chelates PIP2

Answer 9

Poly-lys

Question 10

How do they manipulate the cell to deplete PIP without producing DAG and IP3?

Answer 10

Using iRap —> you remove phosphate from PIP2 as a method of depletion —> you still have fluorescence movement

Question 11

What is PIP2 absolutely essential for?

Answer 11

Connecting voltage sensor movement to channel activation

Question 12

Where does PIP2 binds to?

Answer 12

S4-S5 linker region - involved in channel opening