ligand-gated ion channel signaling pathway

Definition

Target type: biologicalprocess

The series of molecular signals initiated by activation of a ligand-gated ion channel on the surface of a cell. The pathway begins with binding of an extracellular ligand to a ligand-gated ion channel and ends with a molecular function that directly regulates a downstream cellular process, e.g. transcription. [GOC:bhm, PMID:25869137]

Ligand-gated ion channel (LGIC) signaling pathways are essential for rapid communication between cells. These pathways involve specialized membrane proteins called LGICs that act as both receptors and ion channels.

Here's a detailed breakdown of the process:

**1. Ligand Binding:** The process begins with the binding of a specific signaling molecule, known as a ligand, to the LGIC. Ligands can be neurotransmitters, hormones, or other signaling molecules. This binding event initiates a conformational change in the LGIC protein.

**2. Channel Opening:** The conformational change in the LGIC protein triggers the opening of an ion channel, creating a pore through the cell membrane. This pore allows the passage of specific ions, such as sodium (Na+), potassium (K+), calcium (Ca2+), or chloride (Cl-), across the membrane.

**3. Ion Flux:** The opening of the ion channel results in a rapid influx or efflux of ions, depending on the channel's selectivity and the electrochemical gradient across the membrane. This ion flux alters the electrical potential across the membrane, creating an electrical signal.

**4. Signal Transduction:** The change in membrane potential serves as a signal that propagates along the cell membrane. This signal can trigger various cellular processes, including:
- **Neurotransmission:** In neurons, LGICs are crucial for transmitting signals between neurons at synapses.
- **Muscle Contraction:** LGICs play a vital role in muscle contraction by mediating the release of calcium ions.
- **Sensory Perception:** LGICs are involved in sensory perception, such as taste, smell, and touch.

**5. Channel Closure:** The LGIC channel typically remains open for a short period, closing after the ligand detaches or due to other mechanisms. This ensures that the signal is transient and allows for precise control of the cellular response.

**6. Desensitization:** Following prolonged exposure to a ligand, LGICs can undergo desensitization, becoming less responsive to further ligand binding. This mechanism prevents excessive or prolonged signaling.

**7. Receptor Recycling:** After desensitization, the LGICs are often internalized and recycled back to the cell membrane, ensuring the availability of functional receptors.

The specific types of LGICs and their associated ligands are highly diverse, enabling a wide range of cellular functions. The highly regulated and specific nature of LGIC signaling pathways makes them crucial for maintaining normal physiological processes and ensuring rapid and precise communication within the body.'
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Proteins (8)

Compounds (277)