Chapter

Phosphoinositides II: The Diverse Biological Functions

Volume 59 of the series Subcellular Biochemistry pp 413-443

Date:

Cell Signalling by Inositol Pyrophosphates

  • Adolfo SaiardiAffiliated withMRC-LMCB, Department of Cell and Developmental Biology, University College London Email author 

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Abstract

Inositol serves as a module for the generation of a high level of molecular diversity through the combinatorial attachment and removal of phosphate groups. The array of potential inositol-containing molecules is further expanded by the generation of diphospho inositol polyphosphates, commonly referred as inositol pyrophosphates. All eukaryotic cells possess inositol pyrophosphates containing one or more diphospho- moieties. The metabolism of this class of molecules is highly dynamic, and the enzymes responsible for their metabolism are evolutionary conserved. This new, exciting class of molecules are uniquely chracterized by a high energetic diphospho- bound that is able to participate in phosphotrasfer reactions thereby generating pyrophosphorylation of protein. However, allosteric mechanisms of action have been also proposed. In the past decade several disparate nuclear and cytoplasmic functions have been attributed to inositol pyrophosphates, ranging from intracellular trafficking to telomere length control and from regulating apoptotic process to stimulating insulin secretion. The extraordinary range of cellular function controlled by inositol pyrophosphate underline their great importance.

Keywords

Kinase Phosphatase IP6 IP7 IP8 Kcs1 Vip1 IP6K PP-IP5K DDP1 DNA recombination Stress responses Telomere Ribosome Trafficking Insulin Phosphate homeostasis Cell death Development Chemotaxis