low voltage-gated calcium channel activity

Definition

Target type: molecularfunction

Enables the transmembrane transfer of a calcium ion by a low voltage-gated channel. A low voltage-gated channel is a channel whose open state is dependent on low voltage across the membrane in which it is embedded. [GOC:mtg_transport, ISBN:0815340729, PMID:16382099]

Low-voltage-gated calcium channels (LVGCCs) are a type of voltage-gated calcium channel that are activated by relatively small changes in membrane potential, typically in the range of -50 to -40 mV. They are distinct from high-voltage-gated calcium channels (HVGCCs), which require larger depolarizations to open. LVGCCs play a crucial role in a variety of cellular processes, including:

**1. Excitation-Contraction Coupling in Smooth Muscle:**
LVGCCs are responsible for mediating the influx of calcium ions that triggers contraction in smooth muscle cells. When a smooth muscle cell is stimulated, the depolarization of the membrane opens LVGCCs, allowing calcium to enter the cell and bind to calmodulin. This complex then activates myosin light chain kinase (MLCK), which phosphorylates myosin, enabling it to interact with actin and generate contraction.

**2. Neurotransmitter Release:**
LVGCCs are found in presynaptic terminals of neurons and contribute to the release of neurotransmitters. Upon depolarization, LVGCCs open, allowing calcium influx that triggers the fusion of synaptic vesicles containing neurotransmitters with the presynaptic membrane. This process results in the release of neurotransmitters into the synaptic cleft, where they can bind to receptors on the postsynaptic neuron and transmit signals.

**3. Hormone Secretion:**
Similar to neurotransmitter release, LVGCCs play a role in hormone secretion from endocrine cells. Depolarization of endocrine cells can activate LVGCCs, leading to calcium influx and the subsequent release of hormones, such as insulin from pancreatic beta cells.

**4. Pacemaker Activity:**
LVGCCs are involved in the rhythmic activity of pacemaker cells in the heart and other tissues. In the heart, LVGCCs contribute to the spontaneous depolarization of pacemaker cells, setting the rate of heartbeats.

**5. Sensory Transduction:**
LVGCCs are implicated in sensory transduction processes, such as taste and smell. In taste receptor cells, LVGCCs are activated by specific tastants, contributing to the perception of taste.

**6. Cell Proliferation and Differentiation:**
LVGCCs are involved in regulating cell growth and differentiation. They are implicated in the control of cell cycle progression and the induction of specific developmental pathways.

**7. Neuronal Plasticity:**
LVGCCs contribute to neuronal plasticity, the ability of neurons to change their structure and function in response to experience. They are involved in long-term potentiation (LTP), a mechanism of synaptic strengthening associated with learning and memory.

**8. Modulation of Neuronal Activity:**
LVGCCs can modulate neuronal activity by regulating the release of neurotransmitters, affecting synaptic plasticity, and influencing neuronal excitability.

**9. Gene Expression:**
LVGCCs can influence gene expression by affecting the activity of transcription factors, leading to changes in protein synthesis and cell function.

**10. Cellular Signaling:**
LVGCCs play a role in cellular signaling pathways by initiating calcium signaling cascades, which regulate various cellular processes.

**In summary, low-voltage-gated calcium channels are crucial for a wide range of physiological processes, including muscle contraction, neurotransmitter release, hormone secretion, pacemaker activity, sensory transduction, cell proliferation, neuronal plasticity, and modulation of neuronal activity.**'
"

Proteins (2)

Compounds (16)