Potassium channels

Question 1

How is potassium channel activated

Answer 1

Calcium activated has 6 transmembrane and 1 pore

Question 2

Leak channels

Answer 2

Leak channel is a passive channel and is important for resting membrane potential and there is no gate

Question 3

BK

Answer 3

Big potassium conductance channel

Question 4

SK

Answer 4

Small potassium conductance channel

Question 5

IK

Answer 5

intermediate potassium conductance channel

Question 6

Where are most potassium ions found

Answer 6

Potassium ions are found mostly in intra-cellular site in cytosol

Question 7

voltage activated Kv

Answer 7

Low voltage activated Kv channels activates Kv1,Kv4,Kv7
High voltage activated Kv channels activates Kv2 and Kv3
Kv1 has very little inactivation
Kv4 when it reached peak current it rapidly inactivates

Question 8

What subunits form the ion conducting pore

Answer 8

s6 and s5 form ion conducting pore

Question 9

Voltage sensor paddle

Answer 9

S3a has a slight bend
s3b has a similar orientation as s4 and together form a voltage sensing paddle
When closed the voltage sensor paddle is located in the intracellular site
During voltage gating the voltage sensor paddle is located in the extracellular site

Question 10

2 different mechanisms for the inactivation of Kv channels

Answer 10

N type blocks channel from the intracellular side, The inactivation gate is formed from the end terminals of potassium gates or from beta sub units
C type caused by change in structure from the pore domain itself in selectivity filter

Question 11

b channel

Answer 11

b channel inhibits phosphorylation

Question 12

c channel

Answer 12

c channel can enhance the channel

Question 13

Potassium channels in disease

Answer 13

Controls cell excitability and cardiac patterns

drugs activates channels leading to lower excitability