calciumregulated

Calciumregulated is a descriptor used in biology to refer to processes, proteins, or signaling pathways whose activity is controlled by intracellular calcium ions (Ca2+). Calcium functions as a universal second messenger; transient changes in cytosolic Ca2+ concentrations trigger specific cellular responses. The term appears in literature either as calciumregulated, or more commonly as calcium-regulated, with the latter being more widely used.

Calciumregulated effects are mediated by calcium-binding proteins such as calmodulin, which sense Ca2+ and activate downstream enzymes. Calcium-calmodulin complexes activate kinases (CaMKs) and phosphatases (calcineurin), modulating phosphorylation states of target proteins. Calcium can also regulate enzymes directly through binding or influence ion channels and transporters, altering membrane potential and metabolite flow.

Examples of calciumregulated processes include muscle contraction, where Ca2+ binds troponin C in skeletal muscle and promotes actin-myosin interaction; in smooth muscle, Ca2+ activates myosin light-chain kinase via calmodulin. In neurons, Ca2+ triggers neurotransmitter release via synaptotagmin and supports synaptic plasticity through CaMKII and calcineurin pathways. Calcium-activated potassium channels also respond to Ca2+ to modulate excitability.

Regulation of intracellular calcium levels involves stores in the endoplasmic reticulum and mitochondria, and pumps such as SERCA, PMCA, and NCX that restore basal Ca2+ after signaling. Dysregulation of calciumregulated pathways is linked to a range of conditions, including cardiac arrhythmias, neurodegenerative diseases, and muscle disorders.

As a descriptive term, calciumregulated covers a broad set of phenomena and is not a single pathway. It is commonly used to label enzymes, channels, and transcriptional or metabolic processes whose activity depends on calcium signaling.