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The endoplasmic reticulum-plasma membrane tethering protein TMEM24 is a regulator of cellular Ca2+ homeostasis
- Source :
- Journal of Cell Science, article-version (VoR) Version of Record
- Publication Year :
- 2022
- Publisher :
- Uppsala universitet, Institutionen för medicinsk cellbiologi, 2022.
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Abstract
- Endoplasmic reticulum (ER)–plasma membrane (PM) contacts are sites of lipid exchange and Ca2+ transport, and both lipid transport proteins and Ca2+ channels specifically accumulate at these locations. In pancreatic β-cells, both lipid and Ca2+ signaling are essential for insulin secretion. The recently characterized lipid transfer protein TMEM24 (also known as C2CD2L) dynamically localizes to ER–PM contact sites and provides phosphatidylinositol, a precursor of phosphatidylinositol-4-phosphate [PI(4)P] and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], to the PM. β-cells lacking TMEM24 exhibit markedly suppressed glucose-induced Ca2+ oscillations and insulin secretion, but the underlying mechanism is not known. We now show that TMEM24 only weakly interacts with the PM, and dissociates in response to both diacylglycerol and nanomolar elevations of cytosolic Ca2+. Loss of TMEM24 results in hyper-accumulation of Ca2+ in the ER and in excess Ca2+ entry into mitochondria, with resulting impairment in glucose-stimulated ATP production.<br />Summary: TMEM24 reversibly localizes to ER–PM contact sites and participates in the regulation of both ER and mitochondrial Ca2+ homeostasis and in glucose-dependent ATP production in insulin-secreting cells.
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Journal of Cell Science, article-version (VoR) Version of Record
- Accession number :
- edsair.pmid.dedup....a9894b6dff7fbd712a1207bf8eb87fae