What is the Origin of Intracellular Calcium Mobilization?

The concept originates from cell biology and signal transduction research, with the realization in the mid-20th century that calcium ions were not merely structural components but potent signaling molecules. The term mobilization specifically refers to the active movement of the ion from a sequestered state. Its importance in endocrinology was established by discovering that many peptide hormones utilize this mechanism to execute their functions.

What is the Mechanism of Intracellular Calcium Mobilization?

The mechanism begins when a hormone, such as Luteinizing Hormone (LH) or Gonadotropin-Releasing Hormone (GnRH), binds to a G-protein coupled receptor (GPCR) on the cell surface. This binding activates the enzyme phospholipase C (PLC), which generates inositol trisphosphate (IP₃). The IP₃ then binds to specific receptors on the endoplasmic reticulum membrane, acting as a key to open the calcium channels and trigger the sudden, massive efflux of stored calcium into the cytosol. This calcium surge rapidly alters enzyme activity, gene expression, and hormone secretion itself.

Intracellular Calcium Mobilization ∞ Area

Intracellular Calcium Mobilization

Meaning

Intracellular Calcium Mobilization is a fundamental cellular signaling event involving the rapid release of stored calcium ions (Ca²⁺) from internal reservoirs, primarily the endoplasmic reticulum, into the cell’s cytoplasm. This transient increase in cytosolic calcium concentration acts as a crucial second messenger, initiating a cascade of downstream biochemical responses that dictate the cell’s immediate function. It is a rapid and potent mechanism for translating an external hormonal signal into an immediate cellular action.