Hiroyuki Hori

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The tRNA(Gm18) methyltransferase (TrmH) catalyzes the 2'-O methylation of guanosine 18 (Gua18) of tRNA. We solved the crystal structure of Thermus thermophilus TrmH complexed with S-adenosyl-L-methionine at 1.85 A resolution. The catalytic domain contains a deep trefoil knot, which mutational analyses revealed to be crucial for the formation of the(More)
Transfer RNA (Gm18) methyltransferase (TrmH (SpoU)) catalyzes the transfer of a methyl group from S-adenosyl-l-methionine (AdoMet) to the 2'-OH of guanosine 18 in tRNA. This enzyme is a member of the SpoU family of RNA methyltransferases. Recent computational researches have shown that three amino acid sequence motifs are conserved among the SpoU members.(More)
SH-2-containing inositol 5'-phosphatase 2 (SHIP-2) is a physiologically important lipid phosphatase that functions to hydrolyze phosphatidylinositol (PI) 3-kinase product PI(3,4,5)P3 to PI(3,4)P2 in the negative regulation of insulin signaling. We investigated whether SHIP-2 is associated with the insulin resistance of diabetic db/db mice. The amount of(More)
BACKGROUND A number of epidemiologic studies of Parkinson 's disease (PD) have been conducted worldwide over the years. Although every study reported the rise in prevalence and incidence rate of PD with the increasing age, the overall estimates were different across countries. The variation in reported data may partly be contributed by case ascertainment,(More)
BACKGROUND Parkinson's disease (PD) is a common neurodegenerative disorder in older people, and half of the world's older population lives in Asia. However, the epidemiology of PD in Asian countries is poorly understood. This review assembles evidence on the prevalence and incidence of PD in Asian countries and identifies gaps in our present knowledge. (More)
Transfer RNA (Gm18) methyltransferase (TrmH) catalyzes the methyl transfer from S-adenosyl-L-methionine (AdoMet) to the 2'-OH group of the G18 ribose in tRNA. To identify amino acid residues responsible for the tRNA recognition, we have carried out the alanine substitution mutagenesis of the basic amino acid residues that are conserved only in TrmH enzymes(More)
Thermoplasma acidophilum is a thermo-acidophilic archaeon. We purified tRNA(Leu) (UAG) from T. acidophilum using a solid-phase DNA probe method and determined the RNA sequence after determining via nucleoside analysis and m(7)G-specific aniline cleavage because it has been reported that T. acidophilum tRNA contains m(7)G, which is generally not found in(More)
Lipid phosphatase SHIP2 [Src homology 2 (SH2)-containing inositol 5'-phosphatase 2] has been shown to be a physiologically critical negative regulator of insulin signaling. We investigated the molecular mechanism by which SHIP2 negatively regulates insulin-induced phosphorylation of Akt, a key downstream molecule of phosphatidylinositol 3-kinase important(More)
Rat heme-binding protein 23 (HBP23)/peroxiredoxin (Prx I) belongs to the 2-Cys peroxiredoxin type I family and exhibits peroxidase activity coupled with reduced thioredoxin (Trx) as an electron donor. We analyzed the dimer-oligomer interconversion of wild-type and mutant HBP23/Prx I by gel filtration and found that the C52S and C173S mutants existed mostly(More)
N(7)-methylguanine at position 46 (m(7)G46) in tRNA is produced by tRNA (m(7)G46) methyltransferase (TrmB). To clarify the role of this modification, we made a trmB gene disruptant (DeltatrmB) of Thermus thermophilus, an extreme thermophilic eubacterium. The absence of TrmB activity in cell extract from the DeltatrmB strain and the lack of the m(7)G46(More)