Research ArticleNeuroscience

STIM2 Regulates Capacitive Ca2+ Entry in Neurons and Plays a Key Role in Hypoxic Neuronal Cell Death

Science Signaling  20 Oct 2009:
Vol. 2, Issue 93, pp. ra67
DOI: 10.1126/scisignal.2000522

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Abstract

Excessive cytosolic calcium ion (Ca2+) accumulation during cerebral ischemia triggers neuronal cell death, but the underlying mechanisms are poorly understood. Capacitive Ca2+ entry (CCE) is a process whereby depletion of intracellular Ca2+ stores causes the activation of plasma membrane Ca2+ channels. In nonexcitable cells, CCE is controlled by the endoplasmic reticulum (ER)–resident Ca2+ sensor STIM1, whereas the closely related protein STIM2 has been proposed to regulate basal cytosolic and ER Ca2+ concentrations and make only a minor contribution to CCE. Here, we show that STIM2, but not STIM1, is essential for CCE and ischemia-induced cytosolic Ca2+ accumulation in neurons. Neurons from Stim2−/− mice showed significantly increased survival under hypoxic conditions compared to neurons from wild-type controls both in culture and in acute hippocampal slice preparations. In vivo, Stim2−/− mice were markedly protected from neurological damage in a model of focal cerebral ischemia. These results implicate CCE in ischemic neuronal cell death and establish STIM2 as a critical mediator of this process.

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