Voltage-Gated Potassium Channels

These flashcards cover the structure, function, types, and clinical significance of voltage-gated potassium channels as discussed in the lecture.

What is the role of voltage-gated potassium channels (KV) in neurons?

KV channels help in repolarizing the membrane during the falling phase of the action potential.

What are the main types of potassium channels?

There are four main types: voltage-gated K+ (KV), calcium-activated (KCa), inwardly rectifying K+ (Kir), and two-pore potassium (K2P) channels.

What is the resting membrane potential (RMP) of a neuron?

The resting membrane potential is typically around -65 mV.

What occurs during the overshoot phase of an action potential?

During the overshoot, the inside of the neuron becomes positive relative to the outside.

What is N-type inactivation of KV channels?

N-type inactivation involves a ball-and-chain mechanism where a hydrophobic inactivation ball from the N-terminus of the alpha subunit plugs the central pore after the channel opens.

What is C-type inactivation of KV channels?

C-type inactivation is a slow process where conformational changes in the selectivity filter cause it to collapse, stopping K+ from leaving.

How do auxiliary β subunits influence KV channels?

Auxiliary β subunits regulate KV channel surface expression, N-type inactivation, and play roles in redox sensing.

What is the significance of phosphatidylinositol 4,5-bisphosphate (PIP2) for KV channels?

PIP2 prevents N-type inactivation and is necessary for allowing movement of the S4-S5 linker, thus affecting channel functioning.

What is the primary mechanism of potassium selectivity in KV channels?

Potassium ions lose their hydration shells to pass through the selectivity filter, while sodium ions cannot due to their larger hydration shells.

What role do KV channels play in disease pathology?

KV channels are implicated in conditions like epilepsy, memory disorders, chronic pain, cardiac ischemia, and autoimmune diseases.