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torsdag 25 augusti 2011

Inositolipyrofosfaatit ovat metabolisessa turn over tapahtumassa lähettiaineita

Di-fosfo-inositolipolyfosfaatit mahdollisia aineenvaihdunnallisia välittäjäaineita . Nämä ovat toiselta nimeltä inositolipyrofosfaatteja.

Mol Pharmacol. 2009 Aug;76(2):236-52. Epub 2009 May 13. Diphosphoinositol polyphosphates: metabolic messengers?


Inositide Signaling Group, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA.

Abstract (suomennosta)

The diphosphoinositol polyphosphates ("inositol pyrophosphates") are a specialized subgroup of the inositol phosphate signaling family.

Inositolifosfaattien signaaliperheen erikoistunut alaryhmä on inositolipyrofosfaatit, difosfoinositoli-polyfosfaatit.

This review proposes that many of the current data concerning the metabolic turnover and biological effects of the diphosphoinositol polyphosphates are linked by a common theme: these polyphosphates act as metabolic messengers.

Katsauksessa tehdään oletus, että moni nykytieto inositolipyrofosfaattien aineenvaihdunnallisesta vaihtuvuudesta ja biologisista vaikutuksista linkkiytyy yleisteemaan: nämä polyfosfaatit toimivat metabolisina välittäjäaineina.

This review will also discuss the latest proposals concerning possible molecular mechanisms of action of this intriguing class of molecules.

Viimeisimpiä oletuksia näiden kiinnostavien molekyylien mahdollisista molekulaarisista mekanismeista käsitellään myös

[PubMed - indexed for MEDLINE]

PMCID: PMC2713120

Free PMC Article

Ihmisen IP6 /IP7K olemassa

J Biol Chem. 2007 Oct 19;282(42):30754-62. Epub 2007 Aug 9. Cloning and characterization of two human VIP1-like inositol hexakisphosphate and diphosphoinositol pentakisphosphate kinases.


Department of Pharmacology, Duke University Medical Center, Durham, North Carolina, 27710, USA.


Eukaryotes possess numerous inositol phosphate (IP) and diphosphoinositol phosphate (PP-IPs or inositol pyrophosphates) species that act as chemical codes important for intracellular signaling pathways. Production of IP and PP-IP molecules occurs through several classes of evolutionarily conserved inositol phosphate kinases. Here we report the characterization of a human inositol hexakisphosphate (IP6) and diphosphoinositol pentakisphosphate (PP-IP5 or IP7) kinase with similarity to the yeast enzyme Vip1, a recently identified IP6/IP7 kinase (Mulugu, S., Bai, W., Fridy, P. C., Bastidas, R. J., Otto, J. C., Dollins, D. E., Haystead, T. A., Ribeiro, A. A., and York, J. D. (2007) Science 316, 106-109). Recombinant human VIP1 exhibits in vitro IP6 and IP7 kinase activities and restores IP7 synthesis when expressed in mutant yeast. Expression of human VIP1 in HEK293T cells engineered to produce high levels of IP7 results in dramatic increases in bisdiphosphoinositol tetrakisphosphate (PP2-IP4 or IP8).

Northern blot analysis indicates that human VIP1 is expressed in a variety of tissues and is enriched in skeletal muscle, heart, and brain.

Ihmisen VIP1 entsyymiä (= human inositol hexakisphosphate (IP6) and diphosphoinositol pentakisphosphate (PP-IP5 or IP7) kinase) esiintyy useissa kudoksissa ja sitä on rikastuneena tahdonalaisissa lihaksissa, sydämessä ja aivoissa.

The subcellular distribution of tagged human VIP1 is indicative of a cytoplasmic non-membrane localization pattern.

We also characterized human and mouse VIP2, an additional gene product with nearly 90% similarity to VIP1 in the kinase domain, and observed both IP6 and IP7 kinase activities. Our data demonstrate that human VIP1 and VIP2 function as IP6 and IP7 kinases that act along with the IP6K/Kcs1-class of kinases to convert IP6 to IP8 in mammalian cells, a process that has been found to occur in response to various stimuli and signaling events.

Ihmisen VIP2 entsyymi omaa IP6 ja IP7 kinaasiaktiivisuuden ja voi muuttaa inositolifosfaattia IP6 ( fytiiniä) IP8 muotoon.

[PubMed - indexed for MEDLINE]

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Kasvien IP6-kinaasigeeniä etsitään

BMC Proc. 2011 May 28;5 Suppl 2:S1.

IP6K gene identification in plant genomes by tag searching.


DEIS, Università della Calabria, Via Pietro Bucci 41C Rende (CS) Italy.



Plants have played a special role in inositol polyphosphate (IP) research since in plant seeds was discovered the first IP, the fully phosphorylated inositol ring of phytic acid (IP6). It is now known that phytic acid is further metabolized by the IP6 Kinases (IP6Ks) to generate IP containing pyro-phosphate moiety. The IP6K are evolutionary conserved enzymes identified in several mammalian, fungi and amoebae species. Although IP6K has not yet been identified in plant chromosomes, there are many clues suggesting its presences in vegetal cells.


In this paper we propose a new approach to search for the plant IP6K gene, that lead to the identification in plant genome of a nucleotide sequence corresponding to a specific tag of the IP6K family. Such a tag has been found in all IP6K genes identified up to now, as well as in all genes belonging to the Inositol Polyphosphate Kinases superfamily (IPK). The tag sequence corresponds to the inositol-binding site of the enzyme, and it can be considered as characterizing all IPK genes. To this aim we applied a technique based on motif discovery. We exploited DLSME, a software recently proposed, which allows for the motif structure to be only partially specified by the user. First we applied the new method on mitochondrial DNA (mtDNA) of plants, where such a gene could have been nested, possibly encrypted and hidden by virtue of the editing and/or trans-splicing processes. Then we looked for the gene in nuclear genome of two model plants, Arabidopsis thaliana and Oryza sativa.


The analysis we conducted in plant mitochondria provided the negative, though we argue relevant, result that IP6K does not actually occur in vegetable mtDNA. Very interestingly, the tag search in nuclear genomes lead us to identify a promising sequence in chromosome 5 of Oryza sativa. Further analyses are in course to confirm that this sequence actually corresponds to IP6K mammalian gene.


PMCID: PMC3090757

Free PMC Article