Ion Channel Structure and Function

Vocabulary flashcards for ion channel structure and function lecture

Ion Channel

Membrane-spanning protein that allows rapid, selective ion movement down electrochemical gradients, with open and closed states.

Transmembrane Domain

A segment of a protein that crosses the cell membrane; ion channels have several.

Gating

The process by which an ion channel opens and closes, activated by voltage, ligand binding, or physical changes.

Modulation

The alteration of ion channel function by auxiliary subunits, G proteins, or neuromodulators.

Homomeric Multimer

An ion channel complex composed of multiple identical subunits.

Heteromeric Multimer

An ion channel complex composed of different subunits.

Hydrophobic Amino Acids

Amino acids with non-polar side chains that prefer lipid environments, found within the cell membrane.

Hydrophilic Amino Acids

Amino acids with polar or charged side chains that prefer aqueous environments.

Domain

A functional unit of a channel protein.

Subunit

Part of a channel; can be a single protein containing one or more domains.

Transmembrane Segment

A section of a protein domain that spans the cell membrane.

N and C Tails

Terminal segments of a protein subunit that allow association with other proteins or ligands, modulating channel function.

Glycosylation Sites

Locations on a protein where sugars are attached, typically indicating extracellular domains.

Hydrophobicity Plot

A graph showing the hydrophobic and hydrophilic regions of a protein sequence.

Selectivity Filter

A region of an ion channel that determines which ions can pass through the channel.

Voltage Sensor

Part of a voltage-gated ion channel that detects changes in membrane potential and initiates channel opening or closing.

Gating Current

The current produced by the movement of the voltage sensor in response to changes in membrane potential.

Ball and Chain Model

A mechanism of inactivation where a portion of the channel protein blocks the pore after depolarization.

Open Probability

The likelihood that an ion channel is open at any given time.

Auxiliary Subunits

Additional protein subunits that modulate channel function by linking the channel to signaling cascades.