Capacitative calcium entry: from concept to molecules.
Rapid to moderately rapid changes in intracellular Ca2+ concentration, or Ca2+ signals, control a variety of critical cellular functions in the immune system. These signals are comprised of Ca2+ release from intracellular stores coordinated with Ca2+ influx across the plasma membrane. The most common mechanisms by which these two modes of signaling occur is through inositol 1,4,5-trisphosphate (IP3)-induced release of Ca2+ from the endoplasmic reticulum (ER) and store-operated Ca2+ entry across the plasma membrane. The latter process was postulated over 20 years ago, and in just the past few years, the key molecular players have been discovered: STIM proteins serve as sensors of Ca2+ within the ER which communicate with and activate plasma membrane store-operated channels composed of Orai subunits. The process of store-operated Ca2+ entry provides support for oscillating Ca2+ signals from the ER and also provides direct activator Ca2+ that signals to a variety of downstream effectors.
Putney
James W
JW
Laboratory of Signal Transduction, Department of Health and Human Services, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA. putney@niehs.nih.gov
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006801:Humans; D007107:Immune System / Q000166:cytology* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D015398:Signal Transduction
D008565:Membrane Proteins; D002118:Calcium