Zinc (Zn2+) ions are increasingly recognized as playing an important role in cellular physiology. Whereas the free Zn2+ concentration in the cytosol has been established to be 0.1-1 nM, the free Zn2+ concentration in subcellular organelles is not well-established. Here, we extend the eCALWY family of genetically encoded Förster Resonance Energy Transfer (FRET) Zn2+ probes to permit measurements in the endo(sarco)plasmic reticulum (ER) and mitochondrial matrix. Deployed in a variety of mammalian cell types, these probes reveal resting mitochondrial free [Zn2+] values of ∼300 pM, somewhat lower than in the cytosol but 3 orders of magnitude higher than recently reported using an alternative FRET-based sensor. By contrast, free ER [Zn2+] was found to be ≥5 nM, which is >5000-fold higher than recently reported but consistent with the proposed role of the ER as a mobilizable Zn2+ store. Treatment of β-cells or cardiomyocytes with sarco(endo)plasmic reticulum Ca2+-ATPase inhibitors, mobilization of ER Ca2+ after purinergic stimulation with ATP, or manipulation of ER redox, exerted no detectable effects on [Zn2+]ER. These fi ndings question the previously proposed role of Ca2+ in Zn2+ mobilization from the ER and suggest that high ER Zn2+ levels may be an important aspect of cellular homeostasis. (Figure Presented).
|Autori interni:||BUGLIANI, MARCO|
|Autori:||Pauline Chabosseau;Erkan Tuncay;Gargi Meur;Elisa A. Bellomo;Anne Hessels;Stephen Hughes;Paul R.V. Johnson;Marco Bugliani;Piero Marchetti;Belma Turan;Alexander R. Lyon;Maarten Merkx;Guy A. Rutter|
|Titolo:||Mitochondrial and ER-Targeted eCALWY Probes Reveal High Levels of Free Zn2+|
|Anno del prodotto:||2014|
|Digital Object Identifier (DOI):||10.1021/cb5004064|
|Appare nelle tipologie:||1.1 Articolo in rivista|