Open AccessInorganic Polyphosphate Modulates TRPM8 Channels
Author(s) -
Eleonora Zakharian,
Baskaran Thyagarajan,
Robert J. French,
Evgeny Pavlov,
Tibor Rohács
Publication year - 2009
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0005404
Subject(s) - polyphosphate , trpm8 , transient receptor potential channel , biophysics , ion channel , phosphatidylinositol , chemistry , biochemistry , phosphatidylinositol 4,5 bisphosphate , hek 293 cells , patch clamp , lipid bilayer , microbiology and biotechnology , biology , receptor , signal transduction , phosphate , trpv1 , membrane
Polyphosphate (polyP) is an inorganic polymer built of tens to hundreds of phosphates, linked by high-energy phosphoanhydride bonds. PolyP forms complexes and modulates activities of many proteins including ion channels. Here we investigated the role of polyP in the function of the transient receptor potential melastatin 8 (TRPM8) channel. Using whole-cell patch-clamp and fluorescent calcium measurements we demonstrate that enzymatic breakdown of polyP by exopolyphosphatase (scPPX1) inhibits channel activity in human embryonic kidney and F-11 neuronal cells expressing TRPM8. We demonstrate that the TRPM8 channel protein is associated with polyP. Furthermore, addition of scPPX1 altered the voltage-dependence and blocked the activity of the purified TRPM8 channels reconstituted into planar lipid bilayers, where the activity of the channel was initiated by cold and menthol in the presence of phosphatidylinositol 4,5-biphosphate (PtdIns(4,5)P 2 ). The biochemical analysis of the TRPM8 protein also uncovered the presence of poly-(R)-3-hydroxybutyrate (PHB), which is frequently associated with polyP. We conclude that the TRPM8 protein forms a stable complex with polyP and its presence is essential for normal channel activity.