How does calcium act as a second messenger?
Abstract. Calcium ion (Ca(2+)) plays an important role in stimulus-response reactions of cells as a second messenger. This is done by keeping cytoplasmic Ca(2+) concentration low at rest and by mobilizing Ca(2+) in response to stimulus, which in turn activates the cellular reaction.
Why is calcium such a good second messenger?
Intracellular calcium serves as a second messenger for the control of a variety of cell functions, including secretion, contraction, phototransduction, cell division and differentiation, and potassium and sodium permeability.
Is calcium an intracellular messenger?
Calcium acts as both an extracellular (first) and an intracellular (second) messenger to regulate a diverse array of cellular functions, from cell division and differentiation to cell death.
Why does Ras activity decline after a few minutes even when EGF is still present?
Why does Ras activity decline after a few minutes, even when EGF is still present? Ras activity gradually decreases due to the action of Ras GAPs, which stimulate Ras to hydrolyze GTP to GDP, inactivating Ras.
What is the function of Ras?
Ras proteins function as binary molecular switches that control intracellular signaling networks. Ras-regulated signal pathways control such processes as actin cytoskeletal integrity, cell proliferation, cell differentiation, cell adhesion, apoptosis, and cell migration.
What happens when activate RAS?
Ras, a small GTP-binding protein, is an important component of the signal transduction pathway used by growth factors to initiate cell growth and differentiation. Cell activation with growth factors such as epidermal growth factor (EGF) induces Ras to move from an inactive GDP-bound state to an active GTP-bound state.
What causes an increase in intracellular calcium?
In response to a chemical, electrical, or physical stimulus interaction with a cell surface receptor, intracellular calcium concentrations rise from an influx of extracellular calcium or from intracellular calcium stores such as the endoplasmic or sarcoplasmic reticulum.
How does calcium get into cells?
They make their entrance into the cytoplasm either from outside the cell through the cell membrane via calcium channels (such as calcium-binding proteins or voltage-gated calcium channels), or from some internal calcium storages such as the endoplasmic reticulum and mitochondria.