calcium ion transmembrane transport via low voltage-gated calcium channel

Definition

Target type: biologicalprocess

A process in which a calcium ion is transported from one side of a membrane to the other by means of a low voltage-gated calcium channel. [GOC:bf, GOC:PARL, PMID:20371816]

Low-voltage-activated (LVA) calcium channels, also known as T-type calcium channels, are a type of voltage-gated calcium channel that plays a crucial role in various physiological processes. These channels are characterized by their low activation threshold, meaning they open at relatively negative membrane potentials compared to other calcium channels. This property allows them to contribute to calcium influx in response to small depolarizations, which is essential for a range of cellular functions.

The molecular structure of LVA calcium channels comprises four subunits: α1, α2δ, β, and γ. The α1 subunit forms the pore through which calcium ions pass, while the other subunits play regulatory roles. The α1 subunit has six transmembrane domains (S1-S6), with the S4 domain acting as the voltage sensor that detects changes in membrane potential. When the membrane depolarizes, the S4 domain moves outward, triggering a conformational change in the channel protein, which opens the pore.

Upon activation, LVA channels mediate calcium influx into the cell, triggering a variety of downstream signaling pathways. This calcium influx can modulate various cellular processes, including:

* **Neurotransmitter release:** LVA channels are crucial for regulating the release of neurotransmitters at synapses. In neurons, they contribute to the initial depolarization of the presynaptic terminal, which triggers the opening of high-voltage-activated calcium channels and subsequent neurotransmitter release.
* **Muscle contraction:** In smooth muscle cells, LVA channels contribute to the generation of action potentials and subsequent contraction. They also play a role in regulating the contractile force and frequency of smooth muscle cells.
* **Cardiac rhythm:** LVA channels are involved in the regulation of heart rate and rhythm. They contribute to pacemaker activity in the sinoatrial node, which controls the heart's intrinsic rhythm.
* **Cell proliferation and differentiation:** LVA channels have been implicated in regulating cell growth and development. In some cell types, they have been shown to promote cell proliferation and differentiation.
* **Gene expression:** Calcium influx through LVA channels can activate intracellular signaling pathways that lead to changes in gene expression.

The activity of LVA channels is regulated by a variety of factors, including membrane potential, intracellular calcium concentration, and various signaling molecules. This complex regulation ensures that LVA channels are appropriately activated and contribute to a wide range of physiological processes.

In summary, low-voltage-activated calcium channels are essential for a wide range of cellular functions, including neurotransmitter release, muscle contraction, cardiac rhythm, and cell proliferation and differentiation. Their unique low-voltage activation threshold allows them to respond to small changes in membrane potential, making them critical for the proper functioning of various tissues and organs.'
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Proteins (1)

Compounds (3)