Tsunao Tetsuka
Jichi Medical University
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Featured researches published by Tsunao Tetsuka.
Biochimica et Biophysica Acta | 1992
Shin-ichi Tominaga; Takashi Yokota; Ken Yanagisawa; Toshihiko Tsukamoto; Toshimitsu Takagi; Tsunao Tetsuka
Human ST2 cDNA, a homologue of murine ST2 that is only expressed in growth-stimulated BALB/c-3T3 cells and a member of the primary response gene family induced by growth factors, was isolated from the cDNA library of an activated human helper T cell line, 5C10. Human ST2 has 67.6% identity in a 327 amino acid overlap to murine ST2. Furthermore, as in the case of murine ST2, human ST2 encodes a protein remarkably similar in sequence to the extracellular portion of human interleukin 1 receptor, both types 1 and 2. The expression of ST2 in human lymphocytes could trigger further investigations into its physiological role in humans.
Biochimica et Biophysica Acta | 1993
Toshimitsu Takagi; Ken Yanagisawa; Toshihiko Tsukamoto; Tsunao Tetsuka; Shigekazu Nagata; Shin-ichi Tominaga
The murine ST2 gene is expressed in growth-stimulated BALB/c-3T3 cells. This gene encodes a protein that is similar to the extracellular portions of the interleukin-1 receptors (types 1 and 2). In this study, we prepared a polyclonal antibody against the recombinant ST2 protein produced in Escherichia coli. This antibody detected recombinant ST2 protein in the culture fluid of COS7 cells transfected with a mammalian expression vector (pEF-BOS) carrying ST2 cDNA. Using this antibody, we could detect the ST2 protein in the culture fluid of growth-stimulated BALB/c-3T3 cells, and in the medium of continuously growing cells, but not in that of growth-arrested cells. ST2 proteins produced in COS7 cells and BALB/c-3T3 cells were N-glycosylated as predicted from nine putative N-glycosylation sites in its deduced amino-acid sequence.
FEBS Letters | 1994
Shin-ichi Tominaga; Masako Kato-Yamazaki; Ken Yanagisawa; Kiyoshi Kawakami; Tsunao Tetsuka
A comparison of the 5′‐flanking regions of human and mouse ST2 genes revealed the presence of two highly conserved DNA sequences. The promoter activity assay with a luciferase gene as a reporter showed that the deletion of the upstream conserved region diminished the transcriptional activity in growing BALB/c‐3T3 cells. By electrophoretic mobility‐shift analysis, the presence of a factor that binds to the positive regulatory region of the mouse ST2 gene was found in growing but not in quiescent BALB/c‐3T3 cells. These results suggest the functional importance of this conserved region and the requirement of a binding factor for the expression of the ST2 gene.
Biochimica et Biophysica Acta | 1993
Makoto Nakanishi; Tsunao Tetsuka; Yasuo Kagawa; Akihiko Moriyama; Makoto Sasaki; Hajime Hirata
High- and low-affinity Na(+)-dependent neutral L-alpha-amino acid transporters were solubilized with 0.25% octaethylene glycol dodecyl ether (C12E8) after removal of the proteins from the brush-border membrane vesicles with 2% CHAPS and 4 M urea. When the CHAPS-insoluble protein was treated with papain before its solubilization with C12E8, a substantial amount of protein was removed without any decrease of the transport activities. The solubilized transporters were reconstituted into proteoliposomes after removal of C12E8 with Bio-Beads SM2. Several parameters proved to be important for optimal reconstitution efficiency: (a) the type of detergent, and (b) the phospholipid/protein and detergent/protein ratio during reconstitution, and (c) the salt concentration during reconstitution. Reconstituted proteoliposomes showed rapid uptake of neutral L-alpha-amino acids but not imino acid, basic or acidic amino acids driven by an electrochemical potential of Na+ (out > in). The uptakes under low- and high-substrate condition were further augmented by an artificial membrane potential introduced by K+ diffusion via valinomycin (negative interior). Kinetic analysis revealed that both the brush-border membranes and the solubilized fraction involved two carrier-mediated pathways for alanine transport. The kinetic parameters were determined by curve fitting with a computer to be Kt1 = 0.28 mM (0.21 mM) and Kt2 = 43.2 mM (28.4 mM), respectively (those with brush-border membrane vesicles in parentheses). Studies on the specific activities for transport of individual amino acids under low or high substrate concentration and the cross-inhibitory effects of various amino acids on alanine uptake (low concentration) revealed that these transporters possess broad specificity for neutral L-alpha-amino acids.
FEBS Letters | 1993
Ken Yanagisawa; Toshimitsu Takagi; Toshihiko Tsukamoto; Tsunao Tetsuka; Shin-ichi Tominaga
Journal of Biochemistry | 1997
Ken Yanagisawa; Yoshiyuki Naito; Kenji Kuroiwa; Takao Arai; Yusuke Furukawa; Hiroshi Tomizuka; Yasusada Miura; Tadashi Kasahara; Tsunao Tetsuka; Shin-ichi Tominaga
Biochimica et Biophysica Acta | 1991
Shin-ichi Tominaga; Nancy A. Jenkins; Debra J. Gilbert; Neal G. Copeland; Tsunao Tetsuka
Hybridoma | 1995
Kazuko Yoshida; Takao Arai; Takashi Yokota; Norio Komatsu; Yasusada Miura; Ken Yanagisawa; Tsunao Tetsuka; Shin-ichi Tominaga
The Journal of Antibiotics | 1992
Hironori Kikuchi; Tsunao Tetsuka
The Journal of Antibiotics | 1978
Ken Takeda; Setsuko Kawai; Fumio Kato; Tsunao Tetsuka; Kunio Konno