Inorganic polyphosphate (polyP) is a linear polymer of Pi residues linked together by high-energy phosphoanhydride bonds as in ATP. PolyP is present in all living organisms ranging from bacteria to human and possibly even predating life of this planet. The length of polyP chain can vary from just a few phosphates to several thousand phosphate units long, depending on the organism and the tissue in which it is synthesized. PolyP was extensively studied in prokaryotes and unicellular eukaryotes by Kulaev's group in the Russian Academy of Sciences and by the Nobel Prize Laureate Arthur Kornberg at Stanford University. Recently, we reported that mitochondria of cardiac ventricular myocytes contain significant amounts (280±60 pmol/mg of protein) of polyP with an average length of 25 Pi and that polyP is involved in Ca2+-dependent activation of the mitochondrial permeability transition pore (mPTP). Enzymatic polyP depletion prevented Ca2+-induced mPTP opening during ischaemia; however, it did not affect reactive oxygen species (ROS)-mediated mPTP opening during reperfusion and even enhanced cell death in cardiac myocytes. We found that ROS generation was actually enhanced in polyP-depleted cells demonstrating that polyP protects cardiac myocytes against enhanced ROS formation. Furthermore, polyP concentration was dynamically changed during activation of the mitochondrial respiratory chain and stress conditions such as ischaemia/reperfusion (I/R) and heart failure (HF) indicating that polyP is required for the normal heart metabolism. This review discusses the current literature on the roles of polyP in cardiovascular health and disease.
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February 2016
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Scanning electron micrograph of a cell from the endosperm of a barley grain. The cell is tightly packed with large, disk-shaped (A-type) and much smaller, almost spherical (B-type) starch granules. The smooth areas in this image are the surface of the cell walls of neighbouring endosperm cells. For further details see pp. 157-163. Image kindly provided by Elaine Barclay and Vasilios Andriotis (John Innes Centre, Norwich). - PDF Icon PDF LinkTable of Contents
Review Article|
February 09 2016
Inorganic polyphosphate in cardiac myocytes: from bioenergetics to the permeability transition pore and cell survival
Elena N. Dedkova
Elena N. Dedkova
1
*Department of Pharmacology, University of California-Davis, Davis, CA 95616, U.S.A.
1email ededkova@ucdavis.edu.
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Publisher: Portland Press Ltd
Received:
November 26 2015
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© 2016 Authors; published by Portland Press Limited
2016
Biochem Soc Trans (2016) 44 (1): 25–34.
Article history
Received:
November 26 2015
Citation
Elena N. Dedkova; Inorganic polyphosphate in cardiac myocytes: from bioenergetics to the permeability transition pore and cell survival. Biochem Soc Trans 15 February 2016; 44 (1): 25–34. doi: https://doi.org/10.1042/BST20150218
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