Journal article
An ATP-responsive metabolic cassette comprised of inositol tris/tetrakisphosphate kinase 1 (ITPK1) and inositol pentakisphosphate 2-kinase (IPK1) buffers diphosphosphoinositol phosphate levels
- Abstract:
- Inositol polyphosphates are ubiquitous molecular signals in metazoans, as are their pyrophosphorylated derivatives that bear a so-called ‘high-energy’ phosphoanhydride bond. A structural rationale is provided for the ability of Arabidopsis inositol tris/tetrakisphosphate kinase 1 to discriminate between symmetric and enantiomeric substrates in the production of diverse symmetric and asymmetric myo-inositol phosphate and diphospho-myo-inositol phosphate (inositol pyrophosphate) products. Simple tools are applied to chromatographic resolution and detection of known and novel diphosphoinositol phosphates without resort to radiolabeling approaches. It is shown that inositol tris/tetrakisphosphate kinase 1 and inositol pentakisphosphate 2-kinase comprise a reversible metabolic cassette converting Ins(3,4,5,6)P4 into 5-InsP7 and back in a nucleotide-dependent manner. Thus, inositol tris/tetrakisphosphate kinase 1 is a nexus of bioenergetics status and inositol polyphosphate/diphosphoinositol phosphate metabolism. As such, it commands a role in plants that evolution has assigned to a different class of enzyme in mammalian cells. The findings and the methods described will enable a full appraisal of the role of diphosphoinositol phosphates in plants and particularly the relative contribution of reversible inositol phosphate hydroxykinase and inositol phosphate phosphokinase activities to plant physiology.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, 3.0MB, Terms of use)
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- Publisher copy:
- 10.1042/BCJ20200423
Authors
- Publisher:
- Portland Press
- Journal:
- Biochemical Journal More from this journal
- Volume:
- 477
- Issue:
- 14
- Pages:
- 2621-2638
- Publication date:
- 2020-07-24
- Acceptance date:
- 2020-07-06
- DOI:
- EISSN:
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1470-8728
- ISSN:
-
0264-6021
- Language:
-
English
- Keywords:
- Pubs id:
-
1116650
- Local pid:
-
pubs:1116650
- Deposit date:
-
2020-07-06
Terms of use
- Copyright holder:
- Whitfield et al.
- Copyright date:
- 2020
- Rights statement:
- © 2020 The Author(s). This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY).
- Licence:
- CC Attribution (CC BY)
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