First published online October 24, 2007
Journal of Cell Science 120, 2105e (2007)
© The Company of Biologists Limited
Microtubules STIM-ulate Ca2+ influx
Many important cellular processes are regulated by Ca2+ signalling. Ca2+ can enter certain cells by the store-operated Ca2+ entry (SOCE) pathway, which is activated when depleted intracellular stores send messages to plasma membrane (PM) channels. On p. 3762, James Putney and colleagues report that microtubules facilitate SOCE by optimizing the localization of the Ca2+ sensor stromal interaction molecule 1 (STIM1). The ER is the primary Ca2+ store in mammalian cells. When this is depleted, STIM1 moves within the ER to regions near the PM and activates SOCE channels. In HEK 293 cells, the authors report, fluorescently tagged STIM1 (EYFP-STIM1) colocalizes with
-tubulin in fibrillar structures; this localization is lost after treatment with nocodazole, which depolymerizes microtubules. Nocodazole, they show, inhibits SOCE, but overexpression of EYFP-STIM1 rescues this inhibition. Indeed, nocodazole treatment alone induces SOCE in EYFP-STIM1-expressing cells and relocalization of EYFP-STIM1 towards the PM. The authors conclude that microtubules are not essential for the movement of STIM1 after store depletion but instead facilitate SOCE by optimizing its localization.
Related articles in JCS:
- Role of the microtubule cytoskeleton in the function of the store-operated Ca2+ channel activator STIM1
- Jeremy T. Smyth, Wayne I. DeHaven, Gary S. Bird, and James W. Putney, Jr
JCS 2007 120: 3762-3771.
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