Inositol pyrophosphates: Why so many phosphates?. (January 2015)

• Record Type: Journal Article
• Authors: Shears, Stephen B.
• Is Part Of: Advances in biological regulation. Volume 57(2015)
• Page Start: 203
• Page End: 216
• Publication Date: 2015-01
• Subjects: Inositol pyrophosphates -- Structure -- Analogs -- Diphosphoinositol polyphosphates -- Cell-signaling -- Kinase -- Phosphorylation; Cellular control mechanisms -- Periodicals; Biological control systems -- Periodicals; Molecular biology -- Periodicals; Periodicals; 571.74
• DOI: 10.1016/j.jbior.2014.09.015
• Languages: English
• ISSNs: 2212-4926

Abstract

Abstract: The inositol pyrophosphates (PP-InsPs) are a specialized group of "energetic" signaling molecules found in yeasts, plants and animals. PP-InsPs boast the most crowded three dimensional phosphate arrays found in Nature; multiple phosphates and diphosphates are crammed around the six-carbon, inositol ring. Yet, phosphate esters are also a major energy currency in cells. So the synthesis of PP-InsPs, and the maintenance of their levels in the face of a high rate of ongoing turnover, all requires significant bioenergetic input. What are the particular properties of PP-InsPs that repay this investment of cellular energy? Potential answers to that question are discussed here, against the backdrop of a recent hypothesis that signaling by PP-InsPs is evolutionarily ancient. The latter idea is extended herein, with the proposal that the primordial origins of PP-InsPs is reflected in the apparent lack of isomeric specificity of certain of their actions. Nevertheless, there are other aspects of signaling by these polyphosphates that are more selective for a particular PP-InsP isomer. Consideration of the nature of both specific and non-specific effects of PP-InsPs can help rationalize why such molecules possess so many phosphates.