TY - JOUR
T1 - Photolysis of cell-permeant caged inositol pyrophosphates controls oscillations of cytosolic calcium in a β-cell line
AU - Hauke, S.
AU - Dutta, A. K.
AU - Eisenbeis, V. B.
AU - Bezold, D.
AU - Bittner, T.
AU - Wittwer, C.
AU - Thakor, D.
AU - Pavlovic, I.
AU - Schultz, C.
AU - Jessen, H. J.
N1 - Funding Information:
H. J. J. acknowledges nancial support from the Deutsche For-schungsgemeinscha (DFG Grant JE 572/4-1). C. S. acknowledges nancial support from the Deutsche Forschungsgemeinscha (DFG Transregio TRR86). We thank the NMR facilities of Uni Freiburg (Magres) for extended measurement time and the Advanced Light Microscopy Facility at EMBL for expert instrument maintenance. We thank Stephen Shears and Adolfo Saiardi for valuable discussions.
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2019
Y1 - 2019
N2 - Among many cellular functions, inositol pyrophosphates (PP-InsPs) are metabolic messengers involved in the regulation of glucose uptake, insulin sensitivity, and weight gain. However, their mechanisms of action are still poorly understood. So far, the influence of PP-InsPs on cellular metabolism has been studied by overexpression or knockout/inhibition of relevant metabolizing kinases (IP6Ks, PPIP5Ks). These approaches are, inter alia, limited by time-resolution and potential compensation mechanisms. Here, we describe the synthesis of cell-permeant caged PP-InsPs as tools to rapidly modulate intracellular levels of defined isomers of PP-InsPs in a genetically non-perturbed cellular environment. We show that caged prometabolites readily enter live cells where they are enzymatically converted into still inactive, metabolically stable, photocaged PP-InsPs. Upon light-triggered release of 5-PP-InsP5, the major cellular inositol pyrophosphate, oscillations of intracellular Ca2+ levels in MIN6 cells were transiently reduced to spontaneously recover again. In contrast, uncaging of 1-PP-InsP5, a minor cellular isomer, was without effect. These results provide evidence that PP-InsPs play an active role in regulating [Ca2+]i oscillations, a key element in triggering exocytosis and secretion in β-cells.
AB - Among many cellular functions, inositol pyrophosphates (PP-InsPs) are metabolic messengers involved in the regulation of glucose uptake, insulin sensitivity, and weight gain. However, their mechanisms of action are still poorly understood. So far, the influence of PP-InsPs on cellular metabolism has been studied by overexpression or knockout/inhibition of relevant metabolizing kinases (IP6Ks, PPIP5Ks). These approaches are, inter alia, limited by time-resolution and potential compensation mechanisms. Here, we describe the synthesis of cell-permeant caged PP-InsPs as tools to rapidly modulate intracellular levels of defined isomers of PP-InsPs in a genetically non-perturbed cellular environment. We show that caged prometabolites readily enter live cells where they are enzymatically converted into still inactive, metabolically stable, photocaged PP-InsPs. Upon light-triggered release of 5-PP-InsP5, the major cellular inositol pyrophosphate, oscillations of intracellular Ca2+ levels in MIN6 cells were transiently reduced to spontaneously recover again. In contrast, uncaging of 1-PP-InsP5, a minor cellular isomer, was without effect. These results provide evidence that PP-InsPs play an active role in regulating [Ca2+]i oscillations, a key element in triggering exocytosis and secretion in β-cells.
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U2 - 10.1039/c8sc03479f
DO - 10.1039/c8sc03479f
M3 - Article
AN - SCOPUS:85062214208
VL - 10
SP - 2687
EP - 2692
JO - Chemical Science
JF - Chemical Science
SN - 2041-6520
IS - 9
ER -