Cells use signalling networks to translate with high fidelity extracellular signals into specific cellular functions. Signalling networks are often composed of multiple signalling pathways that act in concert to regulate a particular cellular function. In the centre of the networks are the receptors that receive and transduce the signals. A versatile family of receptors that detect a remarkable variety of signals are the G protein-coupled receptors (GPCRs). Virtually all cells express several GPCRs that use the same biochemical machinery to transduce their signals. Considering the specificity and fidelity of signal transduction, a central question in cell signalling is how signalling specificity is achieved, in particular among GPCRs that use the same biochemical machinery. Ca2+ signalling is particularly suitable to address such questions, since [Ca2+]i can be recorded with excellent spatial and temporal resolutions in living cells and tissues and now in living animals. Ca2+ is a unique second messenger in that both biochemical and biophysical components form the Ca2+ signalling complex to regulate its concentration. Both components act in concert to generate repetitive [Ca2+]i oscillations that can be either localized or in the form of global, propagating Ca2+ waves. Most of the key proteins that form Ca2+ signalling complexes are known and their activities are reasonably well understood on the biochemical and biophysical levels. We review here the information gained from studying Ca2+ signalling by GPCRs to gain further understanding of the mechanisms used to generate cellular signalling specificity.
All Science Journal Classification (ASJC) codes
- Cell Biology