 | 加藤 明宣 （カトウ アキノリ）
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最新ゲノム解析技術を改良し、病原菌における新規抗菌剤の効き方や、遺伝子の新しい働きを解明する研究に取り組んでいます。また、薬の副作用を軽減するアプタマー医薬品開発を推進しています。
研究者情報
学位
ホームページURL
科研費研究者番号
- 00454645
J-Global ID
研究キーワード
- 比較ゲノム 情報伝達 遺伝子発現調節 Comparative genomics Signal transduction Gene regulation
現在の研究分野（キーワード）
- 最新ゲノム解析技術を改良し、病原菌における新規抗菌剤の効き方や、遺伝子の新しい働きを解明する研究に取り組んでいます。また、薬の副作用を軽減するアプタマー医薬品開発を推進しています。
研究分野
研究活動情報
論文
- Akinori KatoThe Journal of General and Applied Microbiology 2024年03月 [査読有り]
- Akinori KatoJournal of Genomics 12 26 - 34 2024年01月 [査読有り]
- Yoshitani K; Ishii E; Taniguchi K; Sugimoto H; Shiro Y; Akiyama Y; Kato A; Utsumi R; Eguchi YBioscience, biotechnology, and biochemistry 83 4 684 - 694 2019年04月 [査読有り]
The PhoQ/PhoP two-component signal transduction system is conserved in various Gram-negative bacteria and is often involved in the expression of virulence in pathogens. The small inner membrane protein SafA activates PhoQ in Escherichia coli independently from other known signals that control PhoQ activity. We have previously shown that SafA directly interacts with the sensor domain of the periplasmic region of PhoQ (PhoQ-SD) for activation, and that a D179R mutation in PhoQ-SD attenuates PhoQ activation by SafA. In this study, structural comparison of wild-type PhoQ-SD and D179R revealed a difference in the cavity (SD (sensory domain) pocket) found in the central core of this domain. This was the only structural difference between the two proteins. Site-directed mutagenesis of the residues surrounding the SD pocket has supported the SD pocket as a site involved in PhoQ activity. Furthermore, the SD pocket has also been shown to be involved in SafA-mediated PhoQ control. - Akinori Kato; Shuhei Ueda; Taku Oshima; Yoichi Inukai; Toshihide Okajima; Masayuki Igarashi; Yoko Eguchi; Ryutaro UtsumiJOURNAL OF GENERAL AND APPLIED MICROBIOLOGY 63 4 212 - 221 2017年 [査読有り]
The WalK/WalR two-component system is essential for cell wall metabolism and thus for cell growth in Bacillus subtilis. Waldiomycin was previously isolated as an antibiotic that targeted WalK, the cognate histidine kinase (HK) of the response regulator, WalR, in B. subtilis. To gain further insights into the action of waldiomycin on WalK and narrow down its site of action, mutations were introduced in the H-box region, a well-conserved motif of the bacterial HKs of WalK. The half-maximal inhibitory concentrations (IC(50)s) of waldiomycin against purified WalK protein with triple substitutions in the H-box region, R377M/R378M/S385A and R377M/R378M/R389M, were 26.4 and 55.1 times higher than that of the wild-type protein, respectively, indicating that these residues of WalK are crucial for the inhibitory effect of waldiomycin on its kinase activity. Surprisingly, this antibiotic severely affected cell growth in a minimum inhibitory concentration (MIC) assay, but not transcription of WalR-regulated genes or cell morphology in B. subtilis strains that harbored the H-box triple substitutions on the bacterial chromosome. We hypothesized that waldiomycin targets other HKs as well, which may, in turn, sensitize B. subtilis cells with the H-box triple mutant alleles of the walK gene to waldiomycin. Waldiomycin inhibited other HKs such as PhoR and ResE, and, to a lesser extent, CitS, whose H-box region is less conserved. These results suggest that waldiomycin perturbs multiple cellular processes in B. subtilis by targeting the H-box region of WalK and other HKs. - Shunpei Miwa; Eri Kihira; Akinori Yoshioka; Kaoru Nakasone; Sho Okamoto; Masaki Hatano; Masayuki Igarashi; Yoko Eguchi; Akinori Kato; Natsuko Ichikawa; Mitsuo Sekine; Nobuyuki Fujita; Yu Kanesaki; Hirofumi Yoshikawa; Ryutaro UtsumiJOURNAL OF BACTERIOLOGY 198 11 1604 - 1609 2016年06月 [査読有り]
Tropolone, a phytotoxin produced by Burkholderia plantarii, causes rice seedling blight. To identify genes involved in tropolone synthesis, we systematically constructed mutations in the genes encoding 55 histidine kinases and 72 response regulators. From the resulting defective strains, we isolated three mutants, KE1, KE2, and KE3, in which tropolone production was repressed. The deleted genes of these mutants were named troR1, troK, and troR2, respectively. The mutant strains did not cause rice seedling blight, and complementation experiments indicated that TroR1, TroK, and TroR2 were involved in the synthesis of tropolone in B. plantarii. However, tropolone synthesis was repressed in the TroR1 D52A, TroK H253A, and TroR2 D46A site-directed mutants. These results suggest that the putative sensor kinase (TroK) and two response regulators (TroR1 and TroR2) control the production of tropolone in B. plantarii. IMPORTANCE A two-component system is normally composed of a sensor histidine kinase (HK) and a cognate response regulator (RR) pair. In this study, HK (TroK) and two RRs (TroR1 and TroR2) were found to be involved in controlling tropolone production in B. plantarii. These three genes may be part of a bacterial signal transduction network. Such networks are thought to exist in other bacteria to regulate phytotoxin production, as well as environmental adaptation and signal transduction. - Akinori Kato; Nami Higashino; Ryutaro UtsumiJOURNAL OF GENERAL AND APPLIED MICROBIOLOGY 62 6 286 - 296 2016年 [査読有り]
Bacteria utilize varying combinations of two-component regulatory systems, many of which respond and adapt closely to stress conditions, thus expanding their niche steadily. While mechanisms of recognition and avoidance of the specific Fe3+ signal by the PmrA/PmrB system is well understood, those of the CpxR/CpxA system are more complex because they can be induced by various stress conditions, which, in turn, expresses a variety of phenotypes. Here, we highlight another aspect of the CpxR/CpxA system; mutations in degP and yqjA genes, which are under the control of the system, exhibit an iron sensitive phenotype in the mutant background defective in the PmrA-dependent gene products that alter the pyrophosphate status of the lipid A moiety of lipopolysaccharide in Salmonella enterica. Therefore, after the PmrA/PmrB-mediated Fe3+-dependent control of the pyrophosphate status on the cell surface, the CpxR/CpxA system is one of the second layers of envelope stress response that allows adaptation to high Fe3+ conditions in this bacterium. - Akinori KatoJOURNAL OF GENERAL AND APPLIED MICROBIOLOGY 62 5 225 - 232 2016年 [査読有り]
Recombineering has been used to facilitate the development of in vivo cloning methods. However, the method relies heavily on PCR, which still generates a much higher error rate than DNA replication in vivo, even when amplifying large DNA inserts. Here, a precise technique is reported in Salmonella enterica that enables the cloning of up to at least 19 kb target chromosomal DNA segments that had been marked by FRTs, which were derived from two consecutive lambda Red-mediated recombination events. P22 phage was utilized to transduce the target DNA segments from donor strains to recipient strains harboring a derivative of bacterial artificial chromosome (BAC) containing a FRT and a plasmid expressing Flp recombinase. This method was successful in cloning a gene cluster responsible for lipopolysaccharide (LPS) modifications that confer polymyxin B resistance and in complementing its mutant. Further optimized procedures should be widely applicable because large insert fragments are precise clones of the wildtype genome. - Akinori Kato; Hironori Hayashi; Wataru Nomura; Haruka Emori; Kei Hagihara; Ryutaro UtsumiBMC MICROBIOLOGY 12 224 2012年10月 [査読有り]
Background: Bacteria integrate numerous environmental stimuli when generating cellular responses. Increasing numbers of examples describe how one two-component system (TCS) responds to signals detected by the sensor of another TCS. However, the molecular mechanisms underlying this phenomenon remain poorly defined. Results: Here, we report a connector-like factor that affects the activity of the CpxR/CpxA two-component system in Salmonella enterica serovar Typhimurium. We isolated a clone that induced the expression of a cpxP-lac gene fusion from a high-copy-number plasmid pool of random Salmonella genomic fragments. A 63-amino acid protein, CacA, was responsible for the CpxA/CpxR-dependent activation of the cpxP gene. The CpxR-activated genes cpxP and spy exhibited approximately 30% and 50% reductions in transcription, respectively, in a clean cacA deletion mutant strain in comparison to wild-type. From 33 response regulator (RR) deletion mutants, we identified that the RssB regulator represses cacA transcription. Substitution mutations in a conserved -10 region harboring the RNA polymerase recognition sequence, which is well conserved with a known RpoS -10 region consensus sequence, rendered the cacA promoter RpoS-independent. The CacA-mediated induction of cpxP transcription was affected in a trxA deletion mutant, which encodes thioredoxin 1, suggesting a role for cysteine thiol disulfide exchange(s) in CacA-dependent Cpx activation. Conclusions: We identified CacA as an activator of the CpxR/CpxA system in the plasmid clone. We propose that CacA may integrate the regulatory status of RssB/RpoS into the CpxR/CpxA system. Future investigations are necessary to thoroughly elucidate how CacA activates the CpxR/CpxA system. - Kato A; Chen HD; Latifi T; Groisman EAMol Cell. 47 6 897 - 908 2012年09月 [査読有り]
Gram-negative bacteria often modify their lipopolysaccharide (LPS), thereby increasing resistance to antimicrobial agents and avoidance of the host immune system. However, it is unclear how bacteria adjust the levels and activities of LPS-modifying enzymes in response to the modification status of their LPS. We now address this question by investigating the major regulator of LPS modifications in Salmonella enterica. We report that the PmrA/PmrB system controls expression of a membrane peptide that inhibits the activity of LpxT, an enzyme responsible for increasing the LPS negative charge. LpxT's inhibition and the PmrA-dependent incorporation of positively charged L-4-aminoarabinose into the LPS decrease Fe3+ binding to the bacterial cell. Because Fe3+ is an activating ligand for the sensor PmrB, transcription of PmrA-dependent LPS-modifying genes is reduced. This mechanism enables bacteria to sense their cell surface by its effect on the availability of an inducing signal for the system regulating cell-surface modifications. - Won-Sik Yeo; Igor Zwir; Henry V. Huang; Dongwoo Shin; Akinori Kato; Eduardo A. GroismanMOLECULAR CELL 45 3 409 - 421 2012年02月 [査読有り]
PhoP and PhoQ comprise a two-component system in the bacterium Salmonella enterica. PhoQ is the sensor kinase/phosphatase that modifies the phosphorylation state of the regulator PhoP in response to stimuli. The amount of phosphorylated PhoP surges after activation, then declines to reach a steady-state level. We now recapitulate this surge in vitro by incubating PhoP and PhoQ with ATP and ADP. Mathematical modeling identified PhoQ's affinity for ADP as the key parameter dictating phosphorylated PhoP levels, as ADP promotes PhoQ's phosphatase activity toward phosphorylated PhoP. The lid covering the nucleotide-binding pocket of PhoQ governs the kinase to phosphatase switch because a lid mutation that decreased ADP binding compromised PhoQ's phosphatase activity in vitro and resulted in sustained expression of PhoP-dependent mRNAs in vivo. This feedback mechanism may curtail futile ATP consumption because ADP not only stimulates PhoQ's phosphatase activity but also inhibits ATP binding necessary for the kinase reaction. - Akinori Kato; Eduardo A. GroismanBACTERIAL SIGNAL TRANSDUCTION: NETWORKS AND DRUG TARGETS 631 7 - 21 2008年 [招待有り]
The PhoQ/PhoP two-component regulatory system is a major regulator of virulence in the enteric pathogen Salmonella enterica serovar Typhimurium. It also controls the adaptation to low Me environments by governing the expression and/or activity of Mg2+ transporters and of enzymes modifying the Mg2+-binding sites on the bacterial cell surface. The regulator PhoP modifies expression of similar to 3% of the Salmonella genes in response to the periplasmic Mg2+ concentration detected by the PhoQ protein. Genes that are directly controlled by the Phol? protein often differ in their promoter structures, resulting in distinct expression levels and kinetics in response to the low Mg2+ inducing signal. PhoP regulates a large number of genes indirectly: via other transcription factors and two-component systems that form a panoply of regulatory architectures including transcriptional cascades, feedforward loops and the use of connector proteins that modify the activity of response regulators. These architectures confer distinct expression properties that may be important contributors to Salmonella's lifestyle. - Yoko Eguchi; Junji Itou; Masatake Yamane; Ryo Demizu; Fumiyuki Yamato; Ario Okada; Hirotada Mori; Akinori Kato; Ryutaro UtsumiPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 104 47 18712 - 18717 2007年11月 [査読有り]
Two-component signal-transduction systems (TCSs) of bacteria are considered to form an intricate signal network to cope with various environmental stresses. One example of such a network in Escherichia coli is the signal transduction cascade from the EvgS/EvgA system to the PhoQ/PhoP system, where activation of the EvgS/ EvgA system promotes expression of PhoP-activated genes. As a factor connecting this signal transduction cascade, we have identified a small inner membrane protein (65 aa), B1500. Expression of the b1500 gene is directly regulated by the EvgS/EvgA system, and b1500 expression from a heterologous promoter simultaneously activated the expression of mgtA and other PhoP regulon genes. This activation was PhoQ/PhoP-dependent and EvgS/EvgA-independent. Furthermore, deletion of b1500 from an EvgS-activated strain suppressed mgtA expression. B1500 is localized in the inner membrane, and bacterial two-hybrid data showed that B1500 formed a complex with the sensor PhoQ. These results indicate that the small membrane protein, B1500, connected the signal transduction between EvgS/EvgA and PhoQ/PhoP systems by directly interacting with PhoQ, thus activating the PhoQ/PhoP system. - Akinori Kato; Alexander Y. Mitrophanov; Eduardo A. GroismanPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 104 29 12063 - 12068 2007年07月 [査読有り]
Organisms rely on a variety of regulatory architectures to control gene transcription. Whereas the functional characteristics of particular architectures are well understood, the properties of newly discovered regulatory designs cannot be easily predicted. One emerging design depends on small proteins that connect two-component regulatory systems, which constitute the dominant form of bacterial signal transduction. These connectors enable one system to respond to the signal perceived by a different system. To understand the functional properties of such connector-mediated architectures, we investigated the pathway controlled by the PhoP-dependent connector protein PmrD of Salmonella enterica and contrasted it to the circuit in which genes are regulated directly by the transcription factor PhoP. The PmrD-mediated pathway displayed both signal amplification and persistence of expression when compared with the direct pathway. Mathematical modeling of the two pathways allowed us to identify critical factors responsible for signal amplification. - Zwir, I; D Shin; A Kato; K Nishino; T Latifi; F Solomon; JM Hare; H Huang; EA GroismanPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 102 8 2862 - 2867 2005年02月 [査読有り]
Genetic and genomic approaches have been successfully used to assign genes to distinct regulatory networks. However, the present challenge of distinguishing differentially regulated genes within a network is particularly hard because members of a given network tend to have similar regulatory features. We have addressed this challenge by developing a method, termed Gene Promoter Scan, that discriminates coregulated promoters by simultaneously considering both multiple cis promoter features and gene expression. Here, we apply this method to probe the regulatory networks governed by the PhoP/PhoQ two-component system in the enteric bacteria Escherichia coli and Salmonella enterica. Our analysis uncovered members of the PhoP regulon and interactions with other regulatory systems that were not discovered in previous approaches. The predictions made by Gene Promoter Scan were experimentally validated to establish that the PhoP protein uses multiple mechanisms to control gene transcription, regulates acid resistance determinants, and is a central element in a highly connected network. - A Kato; EA GroismanGENES & DEVELOPMENT 18 18 2302 - 2313 2004年09月 [査読有り]
A fundamental question in signal transduction is how an organism integrates multiple signals into a cellular response. Here we report the mechanism by which the Salmonella PmrA/PmrB two-component system responds to the signal controlling the PhoP/PhoQ two-component system. We establish that the PhoP-activated PmrD protein binds to the phosphorylated form of the response regulator PmrA, preventing both its intrinsic dephosphorylation and that promoted by its cognate sensor kinase PmrB. This results in PmrA-mediated transcription because phosphorylated PmrA exhibits higher affinity for its target promoters than unphosphorylated PmrA. A PmrD-independent form of the PmrA protein was resistant to PmrB-catalyzed dephosphorylation and promoted transcription of PmrA-activated genes in the absence of inducing signals. This is the first example of a protein that enables a two-component system to respond to the signal governing a different two-component system by protecting the phosphorylated form of a response regulator. - S Minagawa; H Ogasawara; A Kato; K Yamamoto; Y Eguchi; T Oshima; H Mori; A Ishihama; R UtsumiJOURNAL OF BACTERIOLOGY 185 13 3696 - 3702 2003年07月 [査読有り]
Transcription profile microarray analysis in Escherichia coli was performed to identify the member genes of the Mg2+ stimulon that respond to the availability of external Mg2+ in a PhoP/PhoQ two-component system-dependent manner. The mRNA levels of W3110 in the presence of 30 MM MgCl2, WP3022 (phoP defective), and WQ3007 (phoQ defective) were compared with those of W3110 in the absence of MgCl2. The expression ratios of a total of 232 genes were <0.75 in all three strains (the supplemental data are shown at http://www.nara.kindai.ac.jp/nogei/seiken/array.html), suggesting that the PhoP/PhoQ system is involved directly or indirectly in the transcription of these genes. Of those, 26 contained the PhoP box-like sequences with the direct repeats of (T/G)GTTTA within 500 bp upstream of the initiation codon. Furthermore, SI nuclease assays of 26 promoters were performed to verify six new Mg2+ stimulon genes, hemL, nagA, rstAB, slyB, vboR, and yrbL, in addition to the phoPQ, mgrB, and mgtA genes reported previously. In gel shift and DNase I footprinting assays, all of these genes were found to be regulated directly by PhoP. Thus, we concluded that the phoPQ, mgrB, mgtA, hemL, nagA, rstAB, slyB, vboR, and yrbL genes make up the Mg2+ stimulon in E. coli. - A Kato; T Latifi; EA GroismanPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 100 8 4706 - 4711 2003年04月 [査読有り]
A fundamental question in biology is how an organism integrates multiple signals to mediate an appropriate cellular response. The PmrA/PmrB two-component system of Salmonella enterica can be activated independently by Fe3+, which is sensed by the PmrB protein, and in low Mg2+, which is sensed by the PhoQ protein. The low-Mg2+ activation requires pmrD, a PhoP/PhoQ-activated gene that activates the response regulator PmrA at a posttranscriptional level. We now report that pmrD expression is negatively regulated by the PmrA/PmrB system. Conditions that activate the PmrA protein independently of pmrD, such as exposure to Fe3+, resulted in lower levels of pmrD transcription. The PmrA protein foot-printed the pmrD promoter upstream of the PhoP-binding site but did not interfere with binding of the PhoP protein. Mutation of the PmrA-binding site in the pmrD promoter abolished PmrA-mediated repression. Negative regulation of the PhoP/PhoQ-activated pmrD gene by the PmrA/PmrB system closes a regulatory circuit designed to maintain proper cellular levels of activated PmrA protein and constitutes a singular example of a multicomponent feedback loop. - A Kato; H Ohnishi; K Yamamoto; E Furuta; H Tanabe; R UtsumiBIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 64 6 1203 - 1209 2000年06月 [査読有り]
Spontaneous mutations have been isolated in Escherichia coli that result in the constitutive expression of an emrKY promoter. These mutations were found to be single-nucleotide substitutions within the linker region of the sensor protein EvgS, which is part of a two-component regulatory system along with EvgA. in the linker mutants (evgS1 and evgS4), emrKY expression became constitutive and MIC against sodium deoxycholate was 20 mg/ml, eight-fold higher than in the wild type. Furthermore, the start site of transcription from the promoter of emrKY was identified; EvgA was shown to bind at the -52 to -84 region by the footprinting experiment. - A Kato; H Tanabe; R UtsumiJOURNAL OF BACTERIOLOGY 181 17 5516 - 5520 1999年09月 [査読有り]
We identified Mg2+-responsive promoters of the phoPQ, mgtA, and mgrB genes of Escherichia coli K-12 by S1 nuclease analysis. Expression of these genes was induced by magnesium limitation and depended on PhoP and PhoQ. The transcription start sites mere also determined, which allowed us to find a (T/G)GTTTA direct repeat in their corresponding promoter regions. - H Tanabe; K Yamasaki; A Katoh; S Yoshioka; R UtsumiBIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 62 2 286 - 290 1998年02月 [査読有り]
The evgAS operon of Escherichia coli encodes the EvgA response regulator and the EvgS sensory kinase, which are members of one of the two-component signal transduction systems of Escherichia coli. In this study, we identified the evg promoter and the EvgA-responsive element. Primer extension analysis found two evg transcritional initiation sites, designated P1 (+1) and P2 (-10), and placed them 114 bp and 124 bp upstream of evgA, respectively. A gel retardation assay demonstrated that EvgA specifically bound to an inverted repeat located between -102 and -128 counting from P1. We also did a beta-galactosidase induction experiment using a promoter-probing vector and found that the EvgA-binding sequence was important to stimulate the evg promoter. These results suggest that the expression of evgAS is positively regulated by its own product, EvgA. - H Tanabe; T Masuda; K Yamasaki; A Katoh; S Yoshioka; R UtsumiBIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 62 1 78 - 82 1998年01月 [査読有り]
EvgA and EvgS constitute one two-component signal transduction system in Escherichia coli. Although probable signaling domains of these proteins have been estimated, the molecular mechanism of their inteaction remains to be elucidated. Here, we investigated protein to protein interactions between EvgA and EvgS and also between the EvgAS system and other related signaling pathways by means of surface plasmon resonance. EvgA and EvgS interacted directly and inhibition of phosphorylation of their functional domains abolished formation of the EvgAS complex. No interaction was observed either between EvgA and Bordetella BvgS or BvgA and EvgS. OmpR, a response regulator for the osmoregulative gene expression of E. coli, had similar but not identical behavior towards EvgS to that of EvgA. These results indicate that interaction between the signaling proteins is closely related to phosphorylation of the functional domain of the proteins. - H Tanabe; K Yamasaki; M Furue; K Yamamoto; A Katoh; M Yamamoto; S Yoshioka; H Tagami; H Aiba; R UtsumiJOURNAL OF GENERAL AND APPLIED MICROBIOLOGY 43 5 257 - 263 1997年10月 [査読有り]
The genes emrK and emrY were found between genes dsdA and evgA at 51 min on the Escherichia coli chromosome and form an operon. EmrK and EmrY are 50.4 and 63.3% identical in amino acid sequences to EmrA and EmrB, respectively, which together make up a multidrug resistant pump. To show that the emrKY operon can be expressed, we cloned the promoter with pMC1403 and constructed an emrK-lacZ' protein fusion plasmid, pMKD1. In E. coli MC4100 containing pMKD1, its expression was increased in the presence of a subinhibitory concentration of tetracycline, chloramphenicol or salicylate, but not by carbonylcyanide m-chlorophenylhydrazone, nalidixic acid or kanamycin. Furthermore, we have shown that emrKY transcription dependent on the growth phase is actually induced by tetracycline using a S1 nuclease protection assay. - R Utsumi; T Horie; A Katoh; Y Kaino; H Tanabe; M NodaBIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 60 2 309 - 315 1996年02月 [査読有り]
The ompC gene expression is induced by increasing temperature as well as osmotic pressure, In this study, a mutant (TD2) defective in this thermoresponse was isolated with transposon Tn10; the mutation was complemented by pMAN55 or pMAN56 containing micF and mapped at 48 min on Escherichia coli K-12, Furthermore, a new gene (hrsA) that suppressed the mutation was cloned. Its nucleotide sequence was analyzed and it was located close to the suc operon at 16.7 min corresponding to #18F11 (Kohara bank) on E. coli genome, In TD2 containing the hrsA on a multicopy plasmid, the ompC expression was induced and dependent on OmpR with increased temperature, The HrsA was found to have Enzyme IIB, IIB, and IIC domains that are homologous to Enzyme II, involved in the fructose-specific PTS (phosphotransferase system), The putative phosphorylation sites (His87 and Cys192) were also conserved in HrsA.
MISC
- 加藤明宣; Eduardo A. Groisman ライフサイエンス 新着論文レビュー 47 (6) 897 -908 2012年09月 [招待有り]
- A Kato, EA Groisman Faculty Opinions 2004年09月
共同研究・競争的資金等の研究課題
- 文部科学省：科学研究費補助金(若手研究(A))研究期間 : 2011年 -2014年代表者 : 加藤 明宣平成23年度に実施した研究の成果として、まず、近縁病原細菌における情報伝達クロスレギュレーション進化の体系的解析を進める上で基礎となる二成分制御系(two-component system, TCS)遺伝ストックの構築を開始した。まず、サルモネラにおいてレスポンスレギュレーター(RR)/センサー・ヒスチヂンキナーゼ(HK)ダブル欠損株の構築が行われ、欠損の確認が進行中である。また、種々の菌株でレポーターアッセイを行う際、共通に用いられるRRの代表的ターゲット遺伝子のプロモーター/GFPレポーターシステムの構築を行った。次に共同研究の成果として、二成分制御系のセンサーHKがシグナルを受容後、自己リン酸化によって生じる副産物ADPによりフィードバッック調節を受ける分子機構についての研究成果をMolecular Cellに発表した。また、リポポリサッカライド修飾と二成分糸御系の活性化状態を繋ぐsmall geneについての研究成果を得ている。センサーを抑制するsmall RNAが、LPS修飾酵素を抑制する疎水性ペプチドをコードし、多段階的なフィードバック調節を形成していることを明らかとした。更に、phosphotransferase system (PTS)とTCS間でのクロスレギュレーションを仲介する因子RcsGについての単離と解析が行われた。これらの研究成果は学術誌においても近く公表される見込みである。
- 文部科学省：科学研究費補助金(若手研究(スタートアップ))研究期間 : 2007年 -2008年代表者 : 加藤 明宣二成分制御系は、多くの感染性細菌において病原性調節に深く関わっている。最近、二成分制御系間の高度調節様式として、ネットワーク調節機構の存在が明らかとなって来た。本研究では、二成分制御系を繋ぐ因子コネクターの同定とその役割についての解析が行われた。これまでに、サルモネラにおいて、コネクタ一様因子のCacA、PacAが単離され、その機能解析が進行中である。また、コネクターPmrDを含む分子ネットワークデザインの進化的定量解析に関する研究成果、及び、大腸菌の新規膜コネクターB1500の同定と機能解析の研究成果をそれぞれ、米国科学アカデミー紀要(計2報)に発表した。