title: Phosphate, inositol and polyphosphates.
abstract: Eukaryotic cells have ubiquitously utilized the myo-inositol backbone to generate a diverse array of signalling molecules. This is achieved by arranging phosphate groups around the six-carbon inositol ring. There is virtually no biological process that does not take advantage of the uniquely variable architecture of phosphorylated inositol. In inositol biology, phosphates are able to form three distinct covalent bonds: phosphoester, phosphodiester and phosphoanhydride bonds, with each providing different properties. The phosphoester bond links phosphate groups to the inositol ring, the variable arrangement of which forms the basis of the signalling capacity of the inositol phosphates. Phosphate groups can also form the structural bridge between myo-inositol and diacylglycerol through the phosphodiester bond. The resulting lipid-bound inositol phosphates, or phosphoinositides, further expand the signalling potential of this family of molecules. Finally, inositol is also notable for its ability to host more phosphates than it has carbons. These unusual organic molecules are commonly referred to as the inositol pyrophosphates (PP-IPs), due to the presence of high-energy phosphoanhydride bonds (pyro- or diphospho-). PP-IPs themselves constitute a varied family of molecules with one or more pyrophosphate moiety/ies located around the inositol. Considering the relationship between phosphate and inositol, it is no surprise that members of the inositol phosphate family also regulate cellular phosphate homoeostasis. Notably, the PP-IPs play a fundamental role in controlling the metabolism of the ancient polymeric form of phosphate, inorganic polyphosphate (polyP). Here we explore the intimate links between phosphate, inositol phosphates and polyP, speculating on the evolution of these relationships.
authors: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K.
authors: Thomas M
authors: TM
authors: Livermore
authors: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K.
authors: Cristina
authors: C
authors: Azevedo
authors: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K.
authors: Bernadett
authors: B
authors: Kolozsvari
authors: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K.
authors: Miranda S C
authors: MS
authors: Wilson
authors: Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, U.K. dmcbado@ucl.ac.uk.
authors: Adolfo
authors: A
authors: Saiardi
mesh_terms: D000818:Animals; D006801:Humans; D007295:Inositol Phosphates / Q000737:chemistry / Q000378:metabolism*; D011122:Polyphosphates / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007295:Inositol Phosphates; D011122:Polyphosphates
keywords: calcium; evolution; inositol; metabolism; phosphate