title: Phosphorylation of sphingoid long-chain bases in Arabidopsis: functional characterization and expression of the first sphingoid long-chain base Kinase gene in plants.
abstract: Sphingoid long-chain base (LCB) kinase catalyzes the phosphorylation of LCBs to form LCB 1-phosphates. Based on sequence identity to murine sphingosine kinase (mSPHK1), we cloned and characterized the first plant LCB kinase gene from Arabidopsis (AtLCBK1). Using recombinant AtLCBK1 protein from Escherichia coli cells, we confirmed that the enzyme specifically phosphorylated D-erythro-dihydrosphingosine (DHS), but not N-acetyl-DHS or D-threo-DHS. AtLCBK1 also phosphorylated D-erythro-sphingosine, trans-4, trans-8-sphingadienine and phytosphingosine. We found that AtLCBK1 mRNA is highly expressed in flowers. AtLCBK1 transcripts were slightly increased by low humidity or abscisic acid treatments, suggesting that AtLCBK1 is constitutively expressed under these treatments.
authors.affiliation: Department of Biology, Graduate School of Natural Science, Konan University, Kobe, 658-8501 Japan. imai@konan-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Imai
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishiura
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics*; D017124:Conserved Sequence; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
chemical_list: D017853:Phosphotransferases (Alcohol Group Acceptor); C426837:sphingolipid long-chain base kinase