title: PiUS (Pi uptake stimulator) is an inositol hexakisphosphate kinase.
abstract: A cDNA cloned from its ability to stimulate inorganic phosphate uptake in Xenopus oocytes (phosphate uptake stimulator (PiUS)) shows significant similarity with inositol 1,4,5-trisphosphate 3-kinase. However, the expressed PiUS protein showed no detectable activity against inositol 1,4,5-trisphosphate, nor the 1,3,4,5- or 3,4,5, 6-isomers of inositol tetrakisphosphate, whereas it was very active in converting inositol hexakisphosphate (InsP(6)) to inositol heptakisphosphate (InsP(7)). PiUS is a member of a family of enzymes found in many eukaryotes and we discuss the implications of this for the functions of InsP(7) and for the evolution of inositol phosphate kinases.
authors.affiliation: Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Schell
authors.forename: A J
authors.initials: AJ
authors.lastname: Letcher
authors.forename: C A
authors.initials: CA
authors.lastname: Brearley
authors.forename: J
authors.initials: J
authors.lastname: Biber
authors.forename: H
authors.initials: H
authors.lastname: Murer
authors.forename: R F
authors.initials: RF
authors.lastname: Irvine
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D007295:Inositol Phosphates; D008969:Molecular Sequence Data; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D017856:Phosphotransferases (Phosphate Group Acceptor) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010833:Phytic Acid / Q000378:metabolism; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D007295:Inositol Phosphates; D011993:Recombinant Fusion Proteins; C402123:inositol heptakisphosphate; D010833:Phytic Acid; D017856:Phosphotransferases (Phosphate Group Acceptor); C115134:IP6K1 protein, human; C099438:inositol hexakisphosphate kinase