Kyushu University Academic Staff Educational and Research Activities Database
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Kazutoshi Kasho Last modified date:2023.10.06

Assistant Professor / Section of Pharmaceutical Care and Informatics
Department of Pharmaceutical Health Care and Sciences
Faculty of Pharmaceutical Sciences

Graduate School
薬学府 医療薬科学専攻 生命薬学
Undergraduate School

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 Reseacher Profiling Tool Kyushu University Pure
Academic Degree
Ph. D.
Country of degree conferring institution (Overseas)
Field of Specialization
Biochemistry, Molecular Biology, Molecular Genetics
ORCID(Open Researcher and Contributor ID)
Total Priod of education and research career in the foreign country
Research Interests
  • Basic research about mitochondrial genome maintenance
    keyword : Mitochondria, mtDNA, PrimPol, PolDIP2, in vitro reconstitution
  • Analysis for cell cycle-coordinated regulation of DNA replication initiation in Escherichia coli
    keyword : DNA replication, DnaA, cell cycle
Academic Activities
1. Kazutoshi Kasho, Shogo Ozaki, Tsutomu Katayama, IHF and Fis as Escherichia coli Cell Cycle Regulators: Activation of the Replication Origin oriC and the Regulatory Cycle of the DnaA Initiator., International journal of molecular sciences, 10.3390/ijms241411572, Vol.24, No.14, 2023.07, This review summarizes current knowledge about the mechanisms of timely binding and dissociation of two nucleoid proteins, IHF and Fis, which play fundamental roles in the initiation of chromosomal DNA replication in Escherichia coli. Replication is initiated from a unique replication origin called oriC and is tightly regulated so that it occurs only once per cell cycle. The timing of replication initiation at oriC is rigidly controlled by the timely binding of the initiator protein DnaA and IHF to oriC. The first part of this review presents up-to-date knowledge about the timely stabilization of oriC-IHF binding at oriC during replication initiation. Recent advances in our understanding of the genome-wide profile of cell cycle-coordinated IHF binding have revealed the oriC-specific stabilization of IHF binding by ATP-DnaA oligomers at oriC and by an initiation-specific IHF binding consensus sequence at oriC. The second part of this review summarizes the mechanism of the timely regulation of DnaA activity via the chromosomal loci DARS2 (DnaA-reactivating sequence 2) and datA. The timing of replication initiation at oriC is controlled predominantly by the phosphorylated form of the adenosine nucleotide bound to DnaA, i.e., ATP-DnaA, but not ADP-ADP, is competent for initiation. Before initiation, DARS2 increases the level of ATP-DnaA by stimulating the exchange of ADP for ATP on DnaA. This DARS2 function is activated by the site-specific and timely binding of both IHF and Fis within DARS2. After initiation, another chromosomal locus, datA, which inactivates ATP-DnaA by stimulating ATP hydrolysis, is activated by the timely binding of IHF. A recent study has shown that ATP-DnaA oligomers formed at DARS2-Fis binding sites competitively dissociate Fis via negative feedback, whereas IHF regulation at DARS2 and datA still remains to be investigated. This review summarizes the current knowledge about the specific role of IHF and Fis in the regulation of replication initiation and proposes a mechanism for the regulation of timely IHF binding and dissociation at DARS2 and datA..
1. Kazutoshi Kasho, Lukas Krasauskas, Vytautas Smirnovas, Gorazd Stojkovič, Ludmilla A Morozova-Roche, Sjoerd Wanrooij, Human Polymerase δ-Interacting Protein 2 (PolDIP2) Inhibits the Formation of Human Tau Oligomers and Fibrils., International journal of molecular sciences, 10.3390/ijms22115768, 22, 11, 2021.05.
2. Kazutoshi Kasho, Gorazd Stojkovič, Cristina Velázquez-Ruiz, Maria Isabel Martínez-Jiménez, Mara Doimo, Timothée Laurent, Andreas Berner, Aldo E Pérez-Rivera, Louise Jenninger, Luis Blanco, Sjoerd Wanrooij, A unique arginine cluster in PolDIP2 enhances nucleotide binding and DNA synthesis by PrimPol., Nucleic acids research, 10.1093/nar/gkab049, 49, 4, 2179-2191, 2021.02.
3. Ryo Sugiyama, Kazutoshi Kasho, Kenya Miyoshi, Shogo Ozaki, Wataru Kagawa, Hitoshi Kurumizaka, Tsutomu Katayama, A novel mode of DnaA-DnaA interaction promotes ADP dissociation for reactivation of replication initiation activity., Nucleic acids research, 10.1093/nar/gkz795, 47, 21, 11209-11224, 2019.12.
4. Kazutoshi Kasho, Hiroyuki Tanaka, Ryuji Sakai, Tsutomu Katayama, Cooperative DnaA Binding to the Negatively Supercoiled datA Locus Stimulates DnaA-ATP Hydrolysis., The Journal of biological chemistry, 10.1074/jbc.M116.762815, 292, 4, 1251-1266, 2017.01.
5. Yukie Inoue, Hiroyuki Tanaka, Kazutoshi Kasho, Taku Oshima, Tsutomu Katayama, Chromosomal location of the DnaA-reactivating sequence DARS2 is important to regulate timely initiation of DNA replication in Escherichia coli, Genes to Cells, 10.1111/gtc.12395, 21, 9, 1015-1023, 2016.09.
6. Kazutoshi Kasho, Kazuyuki Fujimitsu, Toshihiro Matoba, Taku Oshima, Tsutomu Katayama, Timely binding of IHF and Fis to DARS2 regulates ATP-DnaA production and replication initiation., Nucleic acids research, 10.1093/nar/gku1051, 42, 21, 13134-49, 2014.12, In Escherichia coli, the ATP-bound form of DnaA (ATP-DnaA) promotes replication initiation. During replication, the bound ATP is hydrolyzed to ADP to yield the ADP-bound form (ADP-DnaA), which is inactive for initiation. The chromosomal site DARS2 facilitates the regeneration of ATP-DnaA by catalyzing nucleotide exchange between free ATP and ADP bound to DnaA. However, the regulatory mechanisms governing this exchange reaction are unclear. Here, using in vitro reconstituted experiments, we show that two nucleoid-associated proteins, IHF and Fis, bind site-specifically to DARS2 to activate coordinately the exchange reaction. The regenerated ATP-DnaA was fully active in replication initiation and underwent DnaA-ATP hydrolysis. ADP-DnaA formed heteromultimeric complexes with IHF and Fis on DARS2, and underwent nucleotide dissociation more efficiently than ATP-DnaA. Consistently, mutant analyses demonstrated that specific binding of IHF and Fis to DARS2 stimulates the formation of ATP-DnaA production, thereby promoting timely initiation. Moreover, we show that IHF-DARS2 binding is temporally regulated during the cell cycle, whereas Fis only binds to DARS2 in exponentially growing cells. These results elucidate the regulation of ATP-DnaA and replication initiation in coordination with the cell cycle and growth phase..
7. Kazutoshi Kasho, Tsutomu Katayama, DnaA binding locus datA promotes DnaA-ATP hydrolysis to enable cell cycle-coordinated replication initiation., Proceedings of the National Academy of Sciences of the United States of America, 10.1073/pnas.1212070110, 110, 3, 936-41, 2013.01, The initiation of chromosomal DNA replication is rigidly regulated to ensure that it occurs in a cell cycle-coordinated manner. To ensure this in Escherichia coli, multiple systems regulate the activity of the replication initiator ATP-DnaA. The level of ATP-DnaA increases before initiation after which it drops via DnaA-ATP hydrolysis, yielding initiation-inactive ADP-DnaA. DnaA-ATP hydrolysis is crucial to regulation of initiation and mainly occurs by a replication-coupled feedback mechanism named RIDA (regulatory inactivation of DnaA). Here, we report a second DnaA-ATP hydrolysis system that occurs at the chromosomal site datA. This locus has been annotated as a reservoir for DnaA that binds many DnaA molecules in a manner dependent upon the nucleoid-associated factor IHF (integration host factor), resulting in repression of untimely initiations; however, there is no direct evidence for the binding of many DnaA molecules at this locus. We reveal that a complex consisting of datA and IHF promotes DnaA-ATP hydrolysis in a manner dependent on specific inter-DnaA interactions. Deletion of datA or the ihf gene increased ATP-DnaA levels to the maximal attainable levels in RIDA-defective cells. Cell-cycle analysis suggested that IHF binds to datA just after replication initiation at a time when RIDA is activated. We propose a model in which cell cycle-coordinated ATP-DnaA inactivation is regulated in a concerted manner by RIDA and datA..
1. Kazutoshi Kasho, Yukie Inoue, Kazuyuki Fujimitsu, Taku Oshima, Tsutomu Katayama, Regulation of timely replication initiation by a nucleoid protein IHF on DnaA activating and inactivating DNA elements, DARS2 and datA in Escherichia coli, The 10th 3R Symposium, 2016.11.
2. Kazutoshi Kasho, Kazuyuki Fujimitsu, Tsutomu Katayama, Regulation for timely activation of the E. coli replication initiator DnaA by a specific DNA element DARS2, The 9th 3R Symposium, 2014.11.