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.

Fridy PC, Otto JC, Dollins DE, York JD.

Source

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

Abstract

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.

PMID:

17690096

[PubMed - indexed for MEDLINE]

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