Researchers Database

ota satoshi

    DepartmentofBiochemistry,DivisionofStructuralBiochemistry Assistant Professor
Last Updated :2021/11/23

Researcher Information

J-Global ID

Research Interests

  • ST2   発がん   転移   MerTK   IL-33   Ras   クロマトグラフィー   キネトコア   分子生物学   生化学   タンパク質   がん   動原体   チェックポイント   プロテオミクス   染色体分配   染色体複製   DNA複製   プロテオーム   質量分析   クロマチン   細胞周期   染色体   シグナル伝達   

Research Areas

  • Life sciences / Cell biology
  • Life sciences / Molecular biology
  • Life sciences / Medical biochemistry

Published Papers

  • Satoshi Ohta, Kenji Tago, Takahiro Kuchimaru, Megumi Funakoshi‐Tago, Hisanaga Horie, Chihiro Aoki‐Ohmura, Jitsuhiro Matsugi, Ken Yanagisawa
    The FEBS Journal 2021/11
  • Kenji Tago, Satoshi Ohta, Chihiro Aoki-Ohmura, Megumi Funakoshi-Tago, Miho Sashikawa, Takeshi Matsui, Yuki Miyamoto, Taeko Wada, Tomoyuki Oshio, Mayumi Komine, Jitsuhiro Matsugi, Yusuke Furukawa, Mamitaro Ohtsuki, Junji Yamauchi, Ken Yanagisawa
    Scientific reports 11 (1) 20658 - 20658 2021/10 
    NKIRAS1 and NKIRAS2 (also called as κB-Ras) were identified as members of the atypical RAS family that suppress the transcription factor NF-κB. However, their function in carcinogenesis is still controversial. To clarify how NKIRAS acts on cellular transformation, we generated transgenic mice in which NKIRAS2 was forcibly expressed using a cytokeratin 15 (K15) promoter, which is mainly activated in follicle bulge cells. The ectopic expression of NKIRAS2 was mainly detected in follicle bulges of transgenic mice with NKIRAS2 but not in wild type mice. K15 promoter-driven expression of NKIRAS2 failed to affect the development of epidermis, which was evaluated using the expression of K10, K14, K15 and filaggrin. However, K15 promoter-driven expression of NKIRAS2 effectively suppressed the development of skin tumors induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol 13-acetate (TPA). This observation suggested that NKIRAS seemed to function as a tumor suppressor in follicle bulges. However, in the case of oncogenic HRAS-driven cellular transformation of murine fibroblasts, knockdown of NKIRAS2 expression drastically suppressed HRAS-mutant-provoked cellular transformation, suggesting that NKIRAS2 was required for the cellular transformation of murine fibroblasts. Furthermore, moderate enforced expression of NKIRAS2 augmented oncogenic HRAS-provoked cellular transformation, whereas an excess NKIRAS2 expression converted its functional role into a tumor suppressive phenotype, suggesting that NKIRAS seemed to exhibit a biphasic bell-shaped enhancing effect on HRAS-mutant-provoked oncogenic activity. Taken together, the functional role of NKIRAS in carcinogenesis is most likely determined by not only cellular context but also its expression level.
  • Tominari Kobayashi, Masaharu Takahashi, Satoshi Ohta, Shigeo Nagashima, Putu Prathiwi Primadharsini, Mulyanto, Satoshi Kunita, Kazumoto Murata, Hiroaki Okamoto
    Virus research 302 198483 - 198483 2021/09 
    Rat hepatitis E virus (HEV) has been isolated from wild rats worldwide and the potential of zoonotic transmission has been documented. Escherichia coli (E. coli) is utilized as an effective system for producing HEV-like particles. However, the production of rat HEV ORF2 proteins in E. coli forming virus-like particles (VLPs) has not yet been reported. In this study, nine rat HEV ORF2 proteins of the ratELOMB-131L strain with truncated N- and C-termini (amino acids 339-594, 349-594, 351-594, 354-594, 357-594, 357-599, 357-604, 357-609, and 357-614 of ORF2 protein) were expressed in E. coli and the 357-614 protein self-assembled most efficiently. A bioanalyzer showed that the purified 357-614 protein has a molecular weight of 33.5 kDa and a purity of 93.2%. Electron microscopy revealed that the purified 33.5 kDa protein formed VLPs with a diameter of 21-52 (average 32) nm, and immunoelectron microscopy using an anti-rat HEV ORF2 monoclonal antibody (TA7014) indicated that the observed VLPs were derived from rat HEV ORF2. The VLPs attached to and entered the PLC/PRF/5 cells and blocked the neutralization of rat HEV by TA7014, suggesting that the VLPs possess the antigenic structure of infectious rat HEV particles. In addition, rat HEV VLPs showed high immunogenicity in mice. The present results would be useful for future studies on the development of VLP-based vaccines for HEV prevention in a rat model and for the prevention of rat HEV infection in humans.
  • Kazuhisa Watanabe, Kazuhiro Nakayama, Satoshi Ohta, Ayumi Matsumoto, Hidetoshi Tsuda, Sadahiko Iwamoto
    Scientific reports 11 (1) 8414 - 8414 2021/04 
    Ildr2 was initially identified as a genetic modifier of diabetes susceptibility in B6.DBA Lepob congenic mice, and was associated with decreased β-cell replication rates, reduced β-cell mass, and persistent mild hypoinsulinemic hyperglycemia. However, the molecular mechanisms of how the ILDR2 protein is involved in these effects are largely unknown. We sought to identify ILDR2-interacting proteins to further elucidate the molecular mechanisms underpinning ILDR2 function in pancreatic β-cells. Using TAP tag technology, we purified proteins interacting with ILDR2 in the pancreatic β-cell line MIN6, and identified the endoplasmic reticulum resident chaperones, GRP78 and PDIA1, as novel proteins interacting with ILDR2. We demonstrated that GRP78 interacted with ILDR2 and was possibly involved in ILDR2 stabilization by inhibiting ubiquitin-proteasome degradation. Additionally, adenoviral ILDR2 knockdown led to reduced glucose-responsive insulin secretion in MIN6 β-cells, suggesting ILDR2 may be implicated in a new pathway in hypoinsulinemic hyperglycemia. These data provide evidence for a novel association between GRP78 and ILDR2, and suggest GPR78-ILDR2 may a novel target for diabetic therapeutic modulation in decreased insulin secretion.
  • Tago K, Funakoshi-Tago M, Ohta S, Kawata H, Saitoh H, Horie H, Aoki-Ohmura C, Yamauchi J, Tanaka A, Matsugi J, Yanagisawa K
    Molecular oncology 13 (11) 2493 - 2510 1574-7891 2019/11 [Refereed][Not invited]
  • Akira Kawashima, Tadayoshi Karasawa, Kenji Tago, Hiroaki Kimura, Ryo Kamata, Fumitake Usui-Kawanishi, Sachiko Watanabe, Satoshi Ohta, Megumi Funakoshi-Tago, Ken Yanagisawa, Tadashi Kasahara, Koichi Suzuki, Masafumi Takahashi
    JOURNAL OF IMMUNOLOGY 199 (10) 3614 - 3622 0022-1767 2017/11 [Refereed][Not invited]
    The nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a molecular platform that induces caspase-1 activation and subsequent IL-1b maturation, and is implicated in inflammatory diseases; however, little is known about the negative regulation of NLRP3 inflammasome activation. In this article, we identified an E3 ligase, Ariadne homolog 2 (ARIH2), as a posttranslational negative regulator of NLRP3 inflammasome activity in macrophages. ARIH2 interacted with NLRP3 via its NACHT domain (aa 220-575) in the NLRP3 inflammasome complex. In particular, we found that while using mutants of ARIH2 and ubiquitin, the really interesting new gene 2 domain of ARIH2 was required for NLRP3 ubiquitination linked through K48 and K63. Deletion of endogenous ARIH2 using CRISPR/Cas9 genome editing inhibited NLRP3 ubiquitination and promoted NLRP3 inflammasome activation, resulting in apoptosis-associated speck-like protein containing a caspase recruitment domain oligomerization, pro-IL-1b processing, and IL-1b production. Conversely, ARIH2 overexpression promoted NLRP3 ubiquitination and inhibited NLRP3 inflammasome activation. Our findings reveal a novel mechanism of ubiquitination-dependent negative regulation of the NLRP3 inflammasome by ARIH2 and highlight ARIH2 as a potential therapeutic target for inflammatory diseases.
  • Kenji Tago, Satoshi Ohta, Masaki Kashiwada, Megumi Funakoshi-Tago, Jitsuhiro Matsugi, Shin-Ichi Tominaga, Ken Yanagisawa
    Heliyon 3 (10) e00436  2017/10 [Refereed][Not invited]
    The ST2 gene was originally identified as a primary responsive gene, and the expressions of its gene products are induced by stimulation with growth factors and by oncogenic stresses. In this study, we observed that oncogenic Ras mutant induced the expression of ST2 and ST2L proteins. Interestingly, the enforced expression of ST2 gene products in NIH-3T3 murine fibroblasts remarkably enhanced Ras (G12V)-induced cellular transformation. Furthermore, when the expression of ST2 gene products was silenced by RNA-interference technique, Ras (G12V)-induced cellular transformation was drastically suppressed. According to these observations, it was indicated that the oncogenic Ras-induced expression of ST2 gene products is required for the acceleration of cellular transformation, and this seems to be independent of the stimulation with IL-33, a ligand for ST2/ST2L. Interestingly, knockdown of ST2 gene products caused a reduction in Rb phosphorylation in transformed murine fibroblasts, suggesting the functional involvement of ST2 gene products in cell cycle progression during cellular transformation. Our current study strongly suggests the importance of ST2 gene products in cellular transformation, and the presence of novel mechanism how ST2 gene products affect the cellular transformation and cell proliferation.
  • Kenji Tago, Satoshi Ohta, Megumi Funakoshi-Tago, Chihiro Aoki-Ohmura, Jitsuhiro Matsugi, Shin-ichi Tominaga, Ken Yanagisawa
    FEBS OPEN BIO 7 (2) 293 - 302 2211-5463 2017/02 [Refereed][Not invited]
    The ST2 gene was originally identified as a primary responsive gene induced by stimulation with growth factors and by oncogenic stress. The ST2 gene harbors two distinct promoters - a distal promoter and a proximal promoter. In this study, we identified a novel type of serum-responsive element in the ST2 proximal promoter using reporter gene analysis; this element includes a possible responsive element for STAT family proteins. Indeed, enforced expression of constitutively active STAT3 activated this promoter element and induced the expression of ST2 gene products. Furthermore, an oncogenic Ras (G12V) mutant also caused the expression of ST2 gene products by utilizing the proximal promoter. We also clarified that activation of the ST2 promoter by either growth stimulation or oncogenic Ras was suppressed by the inhibitors for STAT3 and ERK pathways. Our observations strongly suggest the importance of STAT family and ERK pathways for the induction of ST2 gene products by cell growth stimulation.
  • Kazuhisa Watanabe, Kazuhiro Nakayama, Satoshi Ohta, Kenji Tago, Supichaya Boonvisut, Elizabeth J. Millings, Stuart G. Fischer, Charles A. LeDuc, Rudolph L. Leibel, Sadahiko Iwamoto
    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 477 (4) 712 - 716 0006-291X 2016/09 [Refereed][Not invited]
    A diabetes susceptibility gene, immunoglobulin-like domain containing receptor 2 (Ildr2), encodes a transmembrane protein localized to the endoplasmic reticulum membrane that is closely related to hepatic lipid metabolism. The livers of ob/ob mice in which Ildr2 is transiently overexpressed are relieved of hepatic steatosis. However, the molecular mechanisms through which ILDR2 affects these changes in hepatic lipid metabolism remain unknown. This study aimed to identify ILDR2-interacting proteins to further elucidate the molecular mechanisms underlying the role of ILDR2 in lipid homeostasis. We purified ILDR2-containing protein complexes using tandem affinity purification tagging and identified ZNF70, a member of the Kruppel C2H2-type zinc finger protein family, as a novel ILDR2-interacting protein. We demonstrated that ZNF70 interacts with ZFP64 and activates HES1 transcription by binding to the HES1 promoter. In addition, HES1 gene expression is increased in ILDR2-knockdown HepG2 cells, in which ZNF70 is translocated from the cytoplasm to the nucleus, suggesting that ZNF70 migration to the nucleus after dissociating from the ILDR2-ZNF70 complex activates HES1 transcription. These results support a novel link between ILDR2 and HES1 gene expression and suggest that ILDR2 is involved in a novel pathway in hepatic steatosis. (C) 2016 Elsevier Inc. All rights reserved.
  • Satoshi Ohta, Kenji Tago, Megumi Funakoshi-Tago, Jitsuhiro Matsugi, Ken Yanagisawa
    CELLULAR SIGNALLING 28 (8) 1025 - 1036 0898-6568 2016/08 [Refereed][Not invited]
    A member of the interleukin-1 family, interleukin-33 (NF-HEV/IL-33), is a ligand for the receptor, ST2L and stimulates the production of Th2 cytokines. Although IL-33 localizes to the nucleus and may be involved in the regulation of transcription independent of ST2L, its functions in the nucleus currently remain unclear. We herein demonstrated that the expression of IL-33 was markedly enhanced in NIH-3T3 cells transformed by an oncogenic H-Ras mutant (H-Ras (G12V)), and the induced IL-33 was mainly located in the nuclei of these cells. The enforced expression of IL-33 accelerated H-Ras (G12V)-induced transformation in NIH-3T3 cells, and this transforming activity was markedly reduced by the knockdown of IL-33 with shRNA. We subsequently analyzed several signaling molecules regulated by Ras in order to elucidate the mechanism by which IL-33 contributes to Ras (G12V)-induced transformation. We found that the knockdown of IL-33 effectively attenuated the Ras (G12V)-induced expression of cyclin D1. However, the knockdown of IL-33 failed to affect cyclin D1 mRNA expression levels, and epoxomicin, a proteasome. inhibitor, did not cancel the IL-33 knockdown -induced down-regulation of its protein levels. We showed that Ras (G12V)-induced cyclin D1 protein synthesis was markedly suppressed by the knockdown of IL-33. Taken together, the results of the present study strongly suggest a novel role for IL-33 in cellular transformation. (C) 2016 Elsevier Inc All rights reserved.
  • Shin-ichi Tominaga, Satoshi Ohta, Kenji Tago
    Biochemistry and Biophysics Reports 5 8 - 15 2405-5808 2016/03 [Refereed][Not invited]
    The ST2 gene is induced in murine fibroblast cells at the start of cell proliferation. Although IL-33 has been identified as a ligand for one of the two major gene products of ST2 - namely, the transmembrane receptor form ST2L - prompting immunological research on inflammation, the roles of the ST2 gene products in cell proliferation remain to be elucidated.Using a cell proliferation assay system with NIH-3T3 cells, a normal murine fibroblast cell line, we found that treatment with recombinant ST2 caused an acceleration of cell proliferation, suggesting that ST2 acts in an autocrine/paracrine fashion. Strikingly, shRNA-induced knockdown of both ST2 gene products, ST2 and ST2L, reduced cell proliferation. This effect was effectively canceled by the expression of shRNA-resistant ST2, but not shRNA-resistant ST2L.The novel enhancement of cell proliferation by ST2 appears to involve positive feedback. Since the ST2 level is increased in various diseases involving inflammation, future investigations into the role of ST2 gene products in relation to various diseases, including malignancies, may be warranted.
  • H. Ogi, Y. Sakuraba, R. Kitagawa, L. Xiao, C. Shen, M. A. Cynthia, S. Ohta, M. A. Arnold, N. Ramirez, P. J. Houghton, K. Kitagawa
    ONCOGENESIS 4 e149  2157-9024 2015/05 [Refereed][Not invited]
    Sgt1/Sugt1, a cochaperone of Hsp90, is involved in several cellular activities including Cullin E3 ubiqutin ligase activity. The high level of Sgt1 expression in colorectal and gastric tumors suggests that Sgt1 is involved in tumorigenesis. Here, we report that Sgt1 is overexpressed in colon, breast and lung tumor tissues and in Ewing sarcoma and rhabdomyosarcoma xenografts. We also found that Sgt1 heterozygous knockout resulted in suppressed Hras-mediated transformation in vitro and tumor formation in p53(-/-) mouse embryonic fibroblast cells and significantly increased survival of p53(-/-) mice. Moreover, depletion of Sgt1 inhibited the growth of Ewing sarcoma and rhabdomyosarcoma cells and destabilized EWS-FLI1 and PAX3-FOXO1 oncogenic fusion proteins, respectively, which are required for cellular growth. Our results suggest that Sgt1 contributes to cancer development by stabilizing oncoproteins and that Sgt1 is a potential therapeutic target.
  • Shin-ichi Tominaga, Morisada Hayakawa, Hidetoshi Tsuda, Satoshi Ohta, Ken Yanagisawa
    Biochemical and Biophysical Research Communications 430 (3) 969 - 974 0006-291X 2013/01 [Refereed][Not invited]
    Interleukin-33 (IL-33) is a dual-function molecule that regulates gene expression in nuclei and, as a cytokine, conveys proinflammatory signals from outside of cells via its specific receptor ST2L. There are still a lot of questions about localization and processing of IL-33 gene products. In the course of re-evaluating human IL-33 gene, we found distinct promoter usage depending on the cell type, similar to the case in the ST2 gene. Furthermore, we found a novel exon 2E in the conventional intron 2 whose open reading frame corresponded to a transmembrane protein of 131 amino acids. Dependence of exon 2E expression on differentiation of HUVEC cells is of great interest in relation to human IL-33 function. © 2012 Elsevier Inc.
  • Akihisa Nagata, Naoki Takezako, Hiroyuki Tamemoto, Hiromi Ohto-Ozaki, Satoshi Ohta, Shin-ichi Tominaga, Ken Yanagisawa
    CELLULAR & MOLECULAR IMMUNOLOGY 9 (5) 399 - 409 1672-7681 2012/09 [Refereed][Not invited]
    ST2 protein is a soluble splicing variant of ST2L protein, which is the receptor for interleukin-33 (IL-33). Previously, we reported that soluble ST2 suppressed the signal transduction of lipopolysaccharide (LPS) and cytokine production in monocytic cells. To investigate whether or not this inhibitory effect occurs in dendritic cells, which are the key players in innate and adaptive immunity, human monocyte-derived dendritic cells were pre-treated with soluble ST2 protein before LPS stimulation. Although soluble ST2 did not attenuate the LPS-induced maturation of dendritic cells, pre-treatment with soluble ST2 suppressed cytokine production and inhibited LPS signaling. Moreover, the proliferation of naive T cells was inhibited significantly by soluble ST2 pre-treatment. IL-33 had little effect on the cytokine production of immature monocyte-derived dendritic cells. Furthermore, soluble ST2 protein was internalized into dendritic cells, suggesting that soluble ST2 protein acts by a noncanonical mechanism other than the sequestration of IL-33. Cellular & Molecular Immunology (2012) 9, 399-409; doi:10.1038/cmi.2012.29; published online 27 August 2012
  • Yasutoshi Tatsumi, Kai Ezura, Kazumasa Yoshida, Takashi Yugawa, Mako Narisawa-Saito, Tohru Kiyono, Satoshi Ohta, Chikashi Obuse, Masatoshi Fujita
    GENES TO CELLS 13 (10) 1045 - 1059 1356-9597 2008/10 [Refereed][Not invited]
    The origin recognition complex (ORC) binds to replication origins to regulate the cell cycle-dependent assembly of pre-replication complexes (pre-RCs). We have found a novel link between pre-RC assembly regulation and telomere homeostasis in human cells. Biochemical analyses showed that human ORC binds to TRF2, a telomere sequence-binding protein that protects telomeres and functions in telomere length homeostasis, via the ORC1 subunit. Immunostaining further revealed that ORC and TRF2 partially co-localize in nuclei, whereas chromatin immunoprecipitation analyses confirmed that pre-RCs are assembled at telomeres in a cell cycle-dependent manner. Over-expression of TRF2 stimulated ORC and MCM binding to chromatin and RNAi-directed TRF2 silencing resulted in reduced ORC binding and pre-RC assembly at telomeres. As expected from previous reports, TRF2 silencing induced telomere elongation. Interestingly, ORC1 silencing by RNAi weakened the TRF2 binding as well as the pre-RC assembly at telomeres, suggesting that ORC and TRF2 interact with each other to achieve stable binding. Furthermore, ORC1 silencing also resulted in modest telomere elongation. These data suggest that ORC might be involved in telomere homeostasis in human cells.
  • Y. Niikura, S. Ohta, K. J. Vandenbeldt, R. Abdulle, B. F. McEwen, K. Kitagawa
    ONCOGENE 25 (30) 4133 - 4146 0950-9232 2006/07 [Refereed][Not invited]
    The Hsp90 inhibitor 17-allylaminogeldanamycin (17-AAG), which is currently in clinical trials, is thought to exert antitumor activity by simultaneously targeting several oncogenic signaling pathways. Here we report a novel mechanism by which 17-AAG inhibits cell proliferation, and we provide the first evidence that HSP90 is required for the assembly of kinetochore protein complexes in humans. 17-AAG caused delocalization of several kinetochore proteins including CENP-I and CENP-H but excluding CENP-B and CENP-C. Consistently, 17-AAG induced a mitotic arrest that depends on the spindle checkpoint and induced misalignment of chromosomes and aneuploidy. We found that HSP90 associates with SGT1 (suppressor of G2 allele of skp1; SUGT1) in human cells and that depletion of SGT1 sensitizes HeLa cells to 17-AAG. Overexpression of SGT1 restored the localization of specific kinetochore proteins and chromosome alignment in cells treated with 17-AAG. Biochemical and genetic results suggest that HSP90, through its interaction with SGT1 (SUGT1), is required for kinetochore assembly. Furthermore, time-course experiments revealed that transient treatment with 17-AAG between late S andG2/M phases causes substantial delocalization of CENP-H and CENP-I, a finding that strongly suggests that HSP90 participates in kinetochore assembly in a cell cycle-dependent manner.
  • Y Tatsumi, S Ohta, H Kimura, T Tsurimoto, C Obuse
    JOURNAL OF BIOLOGICAL CHEMISTRY 278 (42) 41528 - 41534 0021-9258 2003/10 [Refereed][Not invited]
    Components of ORC ( the origin recognition complex) are highly conserved among eukaryotes and are thought to play an essential role in the initiation of DNA replication. The level of the largest subunit of human ORC (ORC1) during the cell cycle was studied in several human cell lines with a specific antibody. In all cell lines, ORC1 levels oscillate: ORC1 starts to accumulate in mid-G(1) phase, reaches a peak at the G(1)/S boundary, and decreases to a basal level in S phase. In contrast, the levels of other ORC subunits (ORCs 2 - 5) remain constant throughout the cell cycle. The oscillation of ORC1, or the ORC1 cycle, also occurs in cells expressing ORC1 ectopically from a constitutive promoter. Furthermore, the 26 S proteasome inhibitor MG132 blocks the decrease in ORC1, suggesting that the ORC1 cycle is mainly due to 26 S proteasome- dependent degradation. Arrest of the cell cycle in early S phase by hydroxyurea, aphidicolin, or thymidine treatment is associated with basal levels of ORC1, indicating that ORC1 proteolysis starts in early S phase and is independent of S phase progression. These observations indicate that the ORC1 cycle in human cells is highly linked with cell cycle progression, allowing the initiation of replication to be coordinated with the cell cycle and preventing origins from refiring.
  • S Ohta, Y Tatsumi, M Fujita, T Tsurimoto, C Obuse
    JOURNAL OF BIOLOGICAL CHEMISTRY 278 (42) 41535 - 41540 0021-9258 2003/10 [Refereed][Not invited]
    The origin recognition complex (ORC) plays a central role in regulating the initiation of DNA replication in eukaryotes. The level of the ORC1 subunit oscillates throughout the cell cycle, defining an ORC1 cycle. ORC1 accumulates in G(1) and is degraded in S phase, although other ORC subunits (ORCs 2 - 5) remain at almost constant levels. The behavior of ORC components in human cell nuclei with respect to the ORC1 cycle demonstrates that ORCs 2 - 5 form a complex that is present throughout the cell cycle and that associates with ORC1 when it accumulates in G(1) nuclei. ORCs 2 - 5 are found in both nuclease-insoluble and - soluble fractions. The appearance of nuclease-insoluble ORCs 2 - 5 parallels the increase in the level of ORC1 associating with nuclease-insoluble, non-chromatin nuclear structures. Thus, ORCs 2 - 5 are temporally recruited to nuclease-insoluble structures by formation of the ORC1 - 5 complex. An artificial reduction in the level of ORC1 in human cells by RNA interference results in a shift of ORC2 to the nuclease-soluble fraction, and the association of MCM proteins with chromatin fractions is also blocked by this treatment. These results indicate that ORC1 regulates the status of the ORC complex in human nuclei by tethering ORCs 2 - 5 to nuclear structures. This dynamic shift is further required for the loading of MCM proteins onto chromatin. Thus, the pre-replication complex in human cells may be regulated by the temporal accumulation of ORC1 in G(1) nuclei.
  • T Iida, Suetake, I, S Tajima, H Morioka, S Ohta, C Obuse, T Tsurimoto
    GENES TO CELLS 7 (10) 997 - 1007 1356-9597 2002/10 [Refereed][Not invited]
    Background: Proliferating cell nuclear antigen (PCNA) is a ring-shaped protein known as a processivity factor of DNA polymerase delta. In addition to this role, PCNA interacts with a number of other proteins to increase their local concentration at replicated DNA sites. DNA cytosine methyltransferase 1 (Dnmt1), which preserves epigenetic signals by completing the methylation of hemimethylated DNA after DNA replication, has been indicated as one of these PCNA binding proteins by a previous work. However, the molecular mechanisms and functional significance of their association have not yet been studied. Results: Dnmt1 can be readily isolated from nuclear extracts by PCNA affinity chromatography. Studies of the interactions between the two proteins demonstrate that the N-terminal region of Dnmt1, which contains a typical PCNA binding motif, has core PCNA binding activity, and that the remaining portion of the protein exerts a negative influence on the interaction of Dnmt1 with PCNA. The affinity of Dnmt1 for DNA is much higher for DNA bound by PCNA than for free DNA. Furthermore, DNA methylation assays with hemimethylated DNA as a substrate revealed that PCNA clamp-bound DNA is methylated more efficiently by Dnmt1 than is free DNA. Conclusion: These results provide the first biochemical evidence that physical interactions between PCNA and Dnmt1 facilitate the methylation of newly neplicated DNA, on which PCNA remains associated as a functional clamp.
  • S Ohta, Y Shiomi, K Sugimoto, C Obuse, T Tsurimoto
    JOURNAL OF BIOLOGICAL CHEMISTRY 277 (43) 40362 - 40367 0021-9258 2002/10 [Refereed][Not invited]
    Proliferating cell nuclear antigen (PCNA), a eukaryotic DNA replication factor, functions not only as a processivity factor for DNA polymerase 5 but also as a binding partner for multiple other factors. To understand its broad significance, we have carried out systematic studies of PCNA-binding proteins by a combination of affinity chromatography and mass spectrometric analyses. We detected more than 20 specific protein bands of various intensities in fractions bound to PCNA-fixed resin from human cell lysates and determined their peptide sequences by liquid chromatography and tandem mass spectrometry. A search with human protein data bases identified 12 reported PCNA-binding proteins from both cytoplasmic (S100 lysate) and nuclear extracts with substantial significance and four more solely from the nuclear preparation. CHL12, a factor involved in checkpoint response and chromosome cohesion, was a novel example found in both lysates. Further studies with recombinant proteins demonstrated that CHL12 and small subunits of replication factor C form a complex that interacts with PCNA.
  • The Human Homologue of Fission Yeast cdc27, p66, Is a Component of Active Human DNA Polymerased.
    Shikata K, Ohta S, Yamada K, Obuse C, Yoshikawa H, Tsurimoto T
    Journal of Biochemistry 129 699 - 708 2001 [Refereed][Not invited]


  • ST2Lの新規結合タンパク質IFITM3はST2Lのリソソーム分解を介してIL-33シグナルを抑制する
    多胡 憲治, 多胡 めぐみ, 太田 聡, 大村 千尋, 松儀 実広, 富永 眞一, 柳澤 健  日本生化学会大会プログラム・講演要旨集  92回-  [1T07a  -02]  2019/09  [Not refereed][Not invited]
  • がん化型Ras変異体はp38-MSK1/2経路を介してNF-κB活性化を増強する
    多胡 憲治, 多胡 めぐみ, 太田 聡, 河田 浩敏, 堀江 久永, 齊藤 博司, 山内 淳司, 田中 亨, 松儀 実広, 柳澤 健  日本生化学会大会プログラム・講演要旨集  91回-  [3T12a  -05(3P  2018/09  [Not refereed][Not invited]
  • Ras変異体が誘導する発がんシグナルにおける受容体型チロシンキナーゼMer(MerTK)の機能解析
    太田 聡, 多胡 憲治, 松儀 実広, 柳澤 健  生命科学系学会合同年次大会  2017年度-  [2P  -0448]  2017/12  [Not refereed][Not invited]
  • KRasタンパク質のC末端側における新規の点変異は特異な生化学的特性と細胞がん化能を示す
    多胡 憲治, 多胡 めぐみ, 太田 聡, 大村 千尋, 松儀 実広, 柳澤 健  生命科学系学会合同年次大会  2017年度-  [4LT19  -02(3P  2017/12  [Not refereed][Not invited]
  • 【TSLPとIL-33に関する新知見】 細胞のがん化におけるIL-33前駆体の新しい機能とその分子機構に関する新たな知見
    太田 聡, 多胡 憲治, 柳澤 健  臨床免疫・アレルギー科  67-  (3)  275  -281  2017/03  [Not refereed][Not invited]
  • がん化型Ras変異体はNF-κBの転写活性化を促進する
    多胡 憲治, 多胡 めぐみ, 太田 聡, 河田 浩敏, 堀江 久永, 山内 淳司, 田中 亨, 松儀 実広, 柳澤 健  日本生化学会大会プログラム・講演要旨集  89回-  [2T10  -07(2P  2016/09  [Not refereed][Not invited]
  • IL-33前駆体は、がん化型Ras変異体が誘導する形質転換とサイクリンD1のタンパク質合成に必須の役割を担う
    太田 聡, 多胡 憲治, 多胡 めぐみ, 松儀 実広, 柳澤 健  日本生化学会大会・日本分子生物学会年会合同大会講演要旨集  88回・38回-  [1P0110]  -[1P0110]  2015/12  [Not refereed][Not invited]
  • 新規IL-33シグナル調節蛋白質IFITM3の同定
    多胡 憲治, 多胡 めぐみ, 太田 聡, 松儀 実広, 柳澤 健  日本生化学会大会・日本分子生物学会年会合同大会講演要旨集  88回・38回-  [2T21p  -04(2P0198)]  2015/12  [Not refereed][Not invited]
  • がん化型Ras変異体はNF-κBの過剰な活性化を引き起こす
    多胡 憲治, 多胡 めぐみ, 太田 聡, 松儀 実広, 柳澤 健  日本生化学会大会プログラム・講演要旨集  87回-  [4T14a  -14]  2014/10  [Not refereed][Not invited]
  • がん化型Ras変異体が誘起する発がんシグナルはTNFαによるNF-κBの活性化を増強する(Oncogenic signal caused by Ras(G12V) augments the TNFα-induced activation of NF-κB)
    多胡 憲治, 多胡 めぐみ, 太田 聡, 松儀 実広, 柳澤 健  日本生化学会大会プログラム・講演要旨集  86回-  3T13p  -11  2013/09  [Not refereed][Not invited]
  • 太田聡, 多胡憲治, 多胡めぐみ, 松儀実広, 柳澤健  日本分子生物学会年会プログラム・要旨集(Web)  35th-  3P-0461 (WEB ONLY)  2012  [Not refereed][Not invited]

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