Ja. Gilabert et Ab. Parekh, Respiring mitochondria determine the pattern of activation and inactivation of the store-operated Ca2+ current I-CRAC, EMBO J, 19(23), 2000, pp. 6401-6407
In eukaryotic cells, hormones and neurotransmitters that engage the phospho
inositide pathway evoke a biphasic increase in intracellular free Ca2+ conc
entration: an initial transient release of Ca2+ from intracellular stores i
s followed by a sustained phase of Ca2+ influx. This influx is generally st
ore dependent. Most attention has focused on the link between the endoplasm
ic reticulum and store-operated Ca2+ channels in the plasma membrane. Here,
me describe that respiring mitochondria are also essential for the activat
ion of macroscopic store-operated Ca2+ currents under physiological conditi
ons of weak intracellular Ca2+ buffering. We further show that Ca2+-depende
nt slow inactivation of Ca2+ influx, a widespread but poorly understood phe
nomenon, is regulated by mitochondrial buffering of cytosolic Ca2+. Thus, b
y enabling macroscopic store-operated Ca2+ current to activate, and then by
controlling its extent and duration, mitochondria play a crucial role in a
ll stages of store-operated Ca2+ influx. Store-operated Ca2+ entry reflects
a dynamic interplay between endoplasmic reticulum, mitochondria and plasma
membrane.