Shoichi Tachiyama
Associate Research ScientistDownloadHi-Res Photo
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Associate Research Scientist
Biography
Dr. Tachiyama earned his Ph.D. in Biochemistry and Biophysics at the University of Kansas in 2020. In his Ph.D. projects, he used biophysical and microbiological approaches to research molecular functions and protein interactions on the cytoplasmic side of the Shigella type III secretion system. In 2020, he joined Dr. Jun Liu’s laboratory at Yale and has continued to research the Shigella T3SS in situ. This research project is conducted in collaboration with Dr. William Picking, University of Kansas. Dr. Tachiyama’s work also focuses on structural details of the flagellar motor in Helicobacter pylori using in-situ approaches, in collaboration with Dr. Timothy Hoover, University of Georgia.
Last Updated on October 22, 2023.
Appointments
Microbial Pathogenesis
Associate Research ScientistPrimary
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Medical Research Interests
Cryoelectron Microscopy; Flagella; Host-Pathogen Interactions; Molecular Structure
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Liu Lab
Research at a Glance
Yale Co-Authors
Frequent collaborators of Shoichi Tachiyama's published research.
Publications Timeline
A big-picture view of Shoichi Tachiyama's research output by year.
Research Interests
Research topics Shoichi Tachiyama is interested in exploring.
Jun Liu, PhD
Aimilia Krypotou
Andrew Goodman, PhD
Eduardo Groisman, PhD
María Lara-Tejero, DVM, PhD
Wenwei Li
13Publications
235Citations
Flagella
Cryoelectron Microscopy
Host-Pathogen Interactions
Publications
2025
A flexible peptide linking the periplasmic and cytoplasmic domains of MxiG controls type III secretion signaling and stable sorting platform assembly in Shigella
Tachiyama S, Muthuramalingam M, Whittier S, Chang Y, Yue J, Younis W, Picking W, Liu J, Picking W. A flexible peptide linking the periplasmic and cytoplasmic domains of MxiG controls type III secretion signaling and stable sorting platform assembly in Shigella. Frontiers In Cellular And Infection Microbiology 2025, 15: 1611779. PMID: 40831705, PMCID: PMC12358396, DOI: 10.3389/fcimb.2025.1611779.Peer-Reviewed Original ResearchAltmetricMeSH Keywords and ConceptsConceptsSorting platformSecretion signalCytoplasmic domainLinker peptideType III secretion systemType III secretion signalInner membrane ringIII secretion systemHost cell contactLibrary of mutantsFlexible linker peptideCentral ATPaseT3SS functionSecretion systemVirulence functionsEffector proteinsPeriplasmic domainSecreted effectorsT3SS injectisomeAdaptor proteinMxiGNeedle formationTransmembrane helicesMembrane ringInjectisomeOuter membrane tube formation by Francisella novicida involves extensive envelope modifications and is linked with type VI secretion and alterations to the host phagosomal membrane
Rashid M, Tachiyama S, Zhu S, Zhao H, McCaig W, Sun J, Li H, Liu J, Thanassi D. Outer membrane tube formation by Francisella novicida involves extensive envelope modifications and is linked with type VI secretion and alterations to the host phagosomal membrane. MBio 2025, 16: e01060-25. PMID: 40387340, PMCID: PMC12153307, DOI: 10.1128/mbio.01060-25.Peer-Reviewed Original ResearchAltmetricMeSH Keywords and ConceptsConceptsType VI secretion systemOuter membrane vesiclesVI secretion systemZoonotic disease tularemiaPhagosomal escapePhagosomal membraneSecretion systemMembrane tubulesMacrophage phagosomesDisease tularemiaCryogenic electron tomographyResponse to amino acid starvationTubular extensionsCellular transformationSpherical outer membrane vesiclesType VI secretionAmino acid starvationCell surfaceDynamic cytoplasmic organellesHost-pathogen interactionsDynamic cytoplasmic structuresIntracellular bacterial pathogensCo-localizationResponse to specific cuesTube formationFlgY, PflA, and PflB form a spoke–ring network in the high-torque flagellar motor of Helicobacter pylori
Tachiyama S, Rosinke K, Khan M, Zhou X, Xin Y, Botting J, Yue J, Roujeinikova A, Hoover T, Liu J. FlgY, PflA, and PflB form a spoke–ring network in the high-torque flagellar motor of Helicobacter pylori. Proceedings Of The National Academy Of Sciences Of The United States Of America 2025, 122: e2421632122. PMID: 40261933, PMCID: PMC12054838, DOI: 10.1073/pnas.2421632122.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsMS ringAccessory proteinsStator complexWild-type H. pyFlagellar motorSalmonella entericaProtein-protein interactionsFlagellar motilityAlphaFold-predicted structuresFlgIBiochemical approachesPflBGastric mucus layerMolecular geneticsPFLACryoelectron tomographyUnique motilityBacterial flagellar motorMucus layerMotilityBacteriaProteinHuman stomachPseudoatomic modelHelicobacter pyloriA Helicobacter pylori flagellar motor accessory is needed to maintain the barrier function of the outer membrane during flagellar rotation
Rosinke K, Tachiyama S, Mrásek J, Liu J, Hoover T. A Helicobacter pylori flagellar motor accessory is needed to maintain the barrier function of the outer membrane during flagellar rotation. PLOS Pathogens 2025, 21: e1012860. PMID: 39792952, PMCID: PMC11756786, DOI: 10.1371/journal.ppat.1012860.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsFlagellar rotationOuter membraneFitness defectsMutant motorsIncreased sensitivity to bacitracinWild-type growth ratesAntibiotic sensitivityPlasmid-borne copyResistant to bacitracinSensitive to bacitracinSoft agar mediumMembrane barrier functionParalyzed flagellaReduced growth rateUncharacterized lipoproteinDeletion analysisFrameshift mutationEscherichia coliAccessory proteinsAgar mediumWild typeGrowth rateMutantsH. pylori B128Flagellar motor
2024
Tetrameric PilZ protein stabilizes stator ring in complex flagellar motor and is required for motility in Campylobacter jejuni
Chen Y, Tachiyama S, Li Y, Feng X, Zhao H, Wu Y, Guo Y, Lara-Tejero M, Hua C, Liu J, Gao B. Tetrameric PilZ protein stabilizes stator ring in complex flagellar motor and is required for motility in Campylobacter jejuni. Proceedings Of The National Academy Of Sciences Of The United States Of America 2024, 122: e2412594121. PMID: 39793078, PMCID: PMC11725899, DOI: 10.1073/pnas.2412594121.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsFlagellar motorPilZ domain-containing proteinsBound cyclic di-GMPCyclic di-GMPC-di-GMPDomain-containing proteinsStator unitsDi-GMPFamily proteinsSuperfamily proteinsBacterial flagellaRing assemblyCellular pathwaysCampylobacter jejuniCryoelectron tomographyCampylobacter jejuni.Subtomogram averagingPilZProteinFlagellaPhylumAncestorMotilityJejuniStructural componentsBacterial flagella hijack type IV pili proteins to control motility
Liu X, Tachiyama S, Zhou X, Mathias R, Bonny S, Khan M, Xin Y, Roujeinikova A, Liu J, Ottemann K. Bacterial flagella hijack type IV pili proteins to control motility. Proceedings Of The National Academy Of Sciences Of The United States Of America 2024, 121: e2317452121. PMID: 38236729, PMCID: PMC10823254, DOI: 10.1073/pnas.2317452121.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and Concepts
2023
FlgV forms a flagellar motor ring that is required for optimal motility of Helicobacter pylori
Botting J, Tachiyama S, Gibson K, Liu J, Starai V, Hoover T. FlgV forms a flagellar motor ring that is required for optimal motility of Helicobacter pylori. PLOS ONE 2023, 18: e0287514. PMID: 37976320, PMCID: PMC10655999, DOI: 10.1371/journal.pone.0287514.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsBacteria require phase separation for fitness in the mammalian gut
Krypotou E, Townsend G, Gao X, Tachiyama S, Liu J, Pokorzynski N, Goodman A, Groisman E. Bacteria require phase separation for fitness in the mammalian gut. Science 2023, 379: 1149-1156. PMID: 36927025, PMCID: PMC10148683, DOI: 10.1126/science.abn7229.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsMammalian gutTranscription termination factor RhoTermination factor RhoGene regulationTranscription terminationMechanisms bacteriaBacteria interactionsHuman commensalValuable targetBacteriaRhoGut microbiotaFitnessNovel clinical applicationsTherapeutic manipulationGutHuman healthCommensalRegulation
2022
The flagellar motor protein FliL forms a scaffold of circumferentially positioned rings required for stator activation
Tachiyama S, Chan KL, Liu X, Hathroubi S, Li W, Peterson B, Khan M, Ottemann K, Liu J, Roujeinikova A. The flagellar motor protein FliL forms a scaffold of circumferentially positioned rings required for stator activation. Proceedings Of The National Academy Of Sciences Of The United States Of America 2022, 119: e2118401119. PMID: 35046042, PMCID: PMC8794807, DOI: 10.1073/pnas.2118401119.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsMeSH KeywordsAmino Acid SequenceBacterial Physiological PhenomenaBacterial ProteinsFlagellaHelicobacter pyloriMembrane ProteinsModels, MolecularMolecular Motor ProteinsMultiprotein ComplexesProtein BindingProtein ConformationProtein Interaction Domains and MotifsProtein TransportStructure-Activity RelationshipConceptsStator unitsStomatin/prohibitin/flotillin/HflK/C (SPFH) domainWild-type cellsSignificant structural similarityPeriplasmic domainAssembly factorsFlagellar motorAccessory proteinsFliLLinker regionActive conformationFlagellar baseC-domainMotBStructural similarityStator assemblyProteinPutative mechanismsElectron tomography reconstructionsIntact motorCellsActivationDomainMotAHelix
2021
Composition and Biophysical Properties of the Sorting Platform Pods in the Shigella Type III Secretion System
Tachiyama S, Skaar R, Chang Y, Carroll BL, Muthuramalingam M, Whittier SK, Barta ML, Picking WL, Liu J, Picking WD. Composition and Biophysical Properties of the Sorting Platform Pods in the Shigella Type III Secretion System. Frontiers In Cellular And Infection Microbiology 2021, 11: 682635. PMID: 34150677, PMCID: PMC8211105, DOI: 10.3389/fcimb.2021.682635.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsType III secretion systemCytoplasmic sorting platformSorting platformSecretion systemTwo-hybrid analysisCryo-electron tomography dataC-terminal domainShigella type III secretion systemFull-length copiesBiophysical propertiesDistinct biophysical propertiesSpa47 ATPaseT3SS injectisomeEffector proteinsSecretion substratesDistinct complexesIntracellular nicheBasal bodiesPrimary virulence factorSpa33Host cellsHeterotrimerPrecise makeupVirulence factorsMxiK
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