title: Characterization and comparative analysis of Arabidopsis phosphatidylinositol phosphate 5-kinase 10 reveals differences in Arabidopsis and human phosphatidylinositol phosphate kinases.
abstract: Arabidopsis phosphatidylinositol phosphate (PtdInsP) kinase 10 (AtPIPK10; At4g01190) is shown to be a functional enzyme of the subfamily A, type I AtPtdInsP kinases. It is biochemically distinct from AtPIPK1 (At1g21980), the only other previously characterized AtPtdInsP kinase which is of the B subfamily. AtPIPK10 has the same K(m), but a 10-fold lower V(max) than AtPIPK1 and it is insensitive to phosphatidic acid. AtPIPK10 transcript is most abundant in inflorescence stalks and flowers, whereas AtPIPK1 transcript is present in all tissues. Comparative analysis of recombinant AtPIPK10 and AtPIPK1 with recombinant HsPIPKIalpha reveals that the Arabidopsis enzymes have roughly 200- and 20-fold lower V(max)/K(m), respectively. These data reveal one explanation for the longstanding mystery of the relatively low phosphatidylinositol-(4,5)-bisphosphate:phosphatidylinositol-4-phosphate ratio in terrestrial plants.
authors.affiliation: Botany Department, North Carolina State University, Raleigh, NC 27695-7612, USA. imara_perera@ncsu.edu
authors.forename: Imara Y
authors.initials: IY
authors.lastname: Perera
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Davis
authors.forename: Dia
authors.initials: D
authors.lastname: Galanopoulou
authors.forename: Yang Ju
authors.initials: YJ
authors.lastname: Im
authors.forename: Wendy F
authors.initials: WF
authors.lastname: Boss
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D018129:Phosphatidylinositol Phosphates / Q000737:chemistry; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D018129:Phosphatidylinositol Phosphates; C037178:phosphatidylinositol 4-phosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C502534:PIPK10 protein, Arabidopsis