Reactome: A Curated Pathway Database

Inositol phosphate metabolism (R-HSA-1483249)

Species Homo sapiens


Inositol phosphates (IPs) are molecules involves in signalling processes in eukaryotes. myo-Inositol consists of a six-carbon cyclic alcohol with an axial 2-hydroxy and five equatorial hydroxyls. Mono-, di-, and triphosphorylation of the inositol ring generates a wide variety of stereochemically distinct signalling entities. Inositol 1,4,5-trisphosphate (I(1,4,5)P3), is formed when the phosphoinositide phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is hydrolysed by a phospholipase C isozyme. An array of inositol trisphosphate (IP3) and tetrakisphosphate (IP4) molecules are synthesised by the action of various kinases and phosphatases in the cytosol. These species then transport between the cytosol and the nucleus where they are acted on by inositol polyphosphate multikinase (IPMK), inositol-pentakisphosphate 2-kinase (IPPK), inositol hexakisphosphate kinase 1 (IP6K1) and 2 (IP6K2), to produce IP5, IP6, IP7, and IP8 molecules. Some of these nuclear produced IPs transport back to the cytosol where they are converted to an even wider variety of IPs, by kinases and phosphatases, including the di- and triphospho inositol phosphates aka pyrophosphates (Irvine & Schell 2001, Bunney & Katan 2010, Alcazar-Romain & Wente 2008, York 2006, Monserrate and York 2010).

Locations in the PathwayBrowser
Additional Information
GO Biological Process inositol phosphate metabolic process (0043647)
Literature References
pubMedId Title Journal Year
11331907 Back in the water: the return of the inositol phosphates Nat Rev Mol Cell Biol 2001
20414202 Phosphoinositide signalling in cancer: beyond PI3K and PTEN Nat Rev Cancer 2010
17943301 Inositol polyphosphates: a new frontier for regulating gene expression Chromosoma 2008
16781889 Regulation of nuclear processes by inositol polyphosphates Biochim Biophys Acta 2006
20359876 Inositol phosphate synthesis and the nuclear processes they affect Curr Opin Cell Biol 2010