STIM1 (red) in the ER approaches Orai1 (green) in the plasma membrane upon loss of ER Ca2+ stores (bottom).

An ER protein scoots around to a site next to the plasma membrane (PM) to trigger calcium signaling, as shown by Wu et al. (page 803) and Luik et al. (page 815).

Cytoplasmic Ca2+ signals often come in two waves—a burst from the ER followed by a longer influx of extracellular Ca2+ through the PM's Ca2+ release–activated Ca2+ (CRAC) channels. The influx is triggered by the depletion of ER Ca2+ stores, which is sensed by a transmembrane ER Ca2+ sensor called STIM1. The new results reveal how STIM1 conveys the Ca2+ drop all the way from the ER to the PM.

Wu et al. show that Ca2+ store depletion causes STIM1 to relocate to ER...

The Rockefeller University Press
2006
The Rockefeller University Press
2006
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