ligand-gated monoatomic anion channel activity

Definition

Target type: molecularfunction

Enables the transmembrane transfer of an inorganic anion by a channel that opens when a specific ligand has been bound by the channel complex or one of its constituent parts. [GOC:mtg_transport, ISBN:0815340729]

Ligand-gated monoatomic anion channel activity refers to the ability of a channel protein to open and allow the passage of single-atom anions across a cell membrane in response to the binding of a specific ligand. These channels are crucial for various physiological processes, including neurotransmission, muscle contraction, and cell volume regulation.

The molecular function of these channels involves a complex interplay of protein domains, including:

1. **Ligand Binding Domain:** This domain specifically interacts with the ligand molecule, triggering a conformational change in the channel protein. The ligand can be a neurotransmitter, hormone, or other signaling molecule.

2. **Transmembrane Domain:** This domain spans the cell membrane and forms the pore through which anions can pass. The pore is typically lined with charged amino acid residues that interact with the anions and facilitate their movement.

3. **Gating Domain:** This domain controls the opening and closing of the channel pore. Upon ligand binding, the gating domain undergoes a conformational change, opening the pore and allowing anion passage.

4. **Selectivity Filter:** This region within the transmembrane domain determines the specific type of anion that can pass through the channel. It consists of charged amino acid residues that interact with the anion and create a barrier for other ions.

When a ligand binds to the ligand-binding domain, the channel undergoes a conformational change, leading to the opening of the pore. Anions then flow down their electrochemical gradient, moving from the side of the membrane with a higher concentration to the side with a lower concentration. The duration of the channel opening and the number of anions passing through are regulated by the concentration of the ligand, the duration of ligand binding, and the channel's intrinsic properties.

Examples of monoatomic anions transported by these channels include chloride (Cl-), bromide (Br-), and iodide (I-). They are involved in a wide range of physiological processes, including:

- **Neurotransmission:** Ligand-gated anion channels are crucial for mediating inhibitory neurotransmission in the nervous system. For example, GABA receptors are ligand-gated chloride channels that mediate inhibitory postsynaptic potentials.

- **Muscle Contraction:** Chloride channels are involved in regulating muscle contraction by contributing to the repolarization of muscle cells.

- **Cell Volume Regulation:** Anion channels play a role in regulating cell volume by mediating the movement of chloride ions in and out of cells.

- **Other Processes:** Ligand-gated anion channels are also implicated in various other processes, such as taste perception, pain sensation, and cell proliferation.'
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Proteins (1)

Compounds (2)