2022
Developmental Transitions Coordinate Assembly of the Coxiella burnetii Dot/Icm Type IV Secretion System
Park D, Steiner S, Shao M, Roy CR, Liu J. Developmental Transitions Coordinate Assembly of the Coxiella burnetii Dot/Icm Type IV Secretion System. Infection And Immunity 2022, 90: e00410-22. PMID: 36190257, PMCID: PMC9584302, DOI: 10.1128/iai.00410-22.Peer-Reviewed Original ResearchConceptsSmall cell variantLarge cell variantDot/Icm type IV secretion systemCell variantIntracellular replicationActive large cell variantHost cellsIntracellular bacterial pathogenType IV secretion systemDot/Icm T4SSObligate intracellular bacterial pathogenC. burnetiiCoxiella burnetiiBiphasic developmental cycleUnique biphasic developmental cycleInfectionNew host cellsSecretion systemBacterial pathogensInfectious formHost vacuoleBurnetiiMorphological changesCellsLater stages
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 ResearchConceptsType 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
2020
Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System.
Chetrit D, Park D, Hu B, Liu J, Roy CR. Applying Live Cell Imaging and Cryo-Electron Tomography to Resolve Spatiotemporal Features of the Legionella pneumophila Dot/Icm Secretion System. Journal Of Visualized Experiments 2020 PMID: 32225141, DOI: 10.3791/60693.Peer-Reviewed Original ResearchConceptsDot/Icm secretion systemCryo-electron tomographySecretion systemCryo-ETDot/Icm systemDot/Icm apparatusDot/IcmSuperfolder green fluorescent proteinLive-cell imagingGreen fluorescent proteinIntact bacterial cellsPolar positioningSecretion complexPolar localizationQuantitative fluorescence microscopyBacterial poleATPase geneCytoplasmic complexDelivery of proteinsDNA substratesTiming of productionIcm systemFluorescent proteinLiving cellsBacterial cellsAnalysis of Dot/Icm Type IVB Secretion System Subassemblies by Cryoelectron Tomography Reveals Conformational Changes Induced by DotB Binding
Park D, Chetrit D, Hu B, Roy CR, Liu J. Analysis of Dot/Icm Type IVB Secretion System Subassemblies by Cryoelectron Tomography Reveals Conformational Changes Induced by DotB Binding. MBio 2020, 11: 10.1128/mbio.03328-19. PMID: 32071271, PMCID: PMC7029142, DOI: 10.1128/mbio.03328-19.Peer-Reviewed Original ResearchConceptsType IV secretion systemSecretion systemCryoelectron tomographyInner membraneDot/Icm apparatusConformational changesDot/IcmEukaryotic host cellsBacterial inner membraneWild-type cellsHost cell membraneWhole-cell contextMultiprotein nanomachineSubtomogram analysisSophisticated nanomachinesCytoplasmic substratesProtein effectorsCell polesDNA substratesSubtomogram averagingATPase complexDNA transferHost infectionStructural basisHost cells
2019
The cytoplasmic domain of MxiG interacts with MxiK and directs assembly of the sorting platform in the Shigella type III secretion system
Tachiyama S, Chang Y, Muthuramalingam M, Hu B, Barta ML, Picking WL, Liu J, Picking WD. The cytoplasmic domain of MxiG interacts with MxiK and directs assembly of the sorting platform in the Shigella type III secretion system. Journal Of Biological Chemistry 2019, 294: 19184-19196. PMID: 31699894, PMCID: PMC6916477, DOI: 10.1074/jbc.ra119.009125.Peer-Reviewed Original ResearchConceptsInner membrane ringType III secretion systemCytoplasmic domainSecretion systemCytoplasmic sorting platformForkhead-associated (FHA) domainShigella type III secretion systemDiverse bacterial pathogensDisruption of interactionsSpa47 ATPaseStructure-function relationshipsExtracellular needleEffector recognitionGram-negative bacteriaEukaryotic cellsT3SS apparatusVirulence effectorsMembrane ringSorting platformInsertional mutagenesisGenetic methodsHomologous interactionsMxiKTip complexBasal bodies
2018
Cryo-electron tomography of periplasmic flagella in Borrelia burgdorferi reveals a distinct cytoplasmic ATPase complex
Qin Z, Tu J, Lin T, Norris SJ, Li C, Motaleb MA, Liu J. Cryo-electron tomography of periplasmic flagella in Borrelia burgdorferi reveals a distinct cytoplasmic ATPase complex. PLOS Biology 2018, 16: e3000050. PMID: 30412577, PMCID: PMC6248999, DOI: 10.1371/journal.pbio.3000050.Peer-Reviewed Original ResearchConceptsCryo-electron tomographyPeriplasmic flagellaATPase complexFlagellar C-ringType III secretion systemCytoplasmic ATPase complexLyme disease spirochete Borrelia burgdorferiMotility of spirochetesExport apparatusSecretion systemStructural insightsBorrelia burgdorferiFlagellaSpirochete Borrelia burgdorferiPathogenic spirochetesC-ringNovel therapeutic strategiesUnique mechanismDistinct morphologiesB. burgdorferiComplexesMultiple spokesAssemblyTherapeutic strategiesBurgdorferiVisualization of the type III secretion mediated Salmonella–host cell interface using cryo-electron tomography
Park D, Lara-Tejero M, Waxham MN, Li W, Hu B, Galán JE, Liu J. Visualization of the type III secretion mediated Salmonella–host cell interface using cryo-electron tomography. ELife 2018, 7: e39514. PMID: 30281019, PMCID: PMC6175578, DOI: 10.7554/elife.39514.Peer-Reviewed Original ResearchConceptsCryo-electron tomographyEffector translocationBacterial-host cell contactType III protein secretion systemProtein secretion systemHost cell interfaceProtein secretion machinesCell membraneComplex host-pathogen interactionsType III secretionHost-pathogen interactionsHost cell membraneTarget cell membraneNegative bacterial pathogensTranslocon poreSecretion machineEffector proteinsSecretion systemHost cellsBacterial pathogensCell contactCell interfaceIntimate associationTranslocationBacteriaA unique cytoplasmic ATPase complex defines the Legionella pneumophila type IV secretion channel
Chetrit D, Hu B, Christie PJ, Roy CR, Liu J. A unique cytoplasmic ATPase complex defines the Legionella pneumophila type IV secretion channel. Nature Microbiology 2018, 3: 678-686. PMID: 29784975, PMCID: PMC5970066, DOI: 10.1038/s41564-018-0165-z.Peer-Reviewed Original ResearchConceptsCytoplasmic complexType IV secretion channelType IV secretion systemInner membrane complexTranslocation of substratesCryo-electron tomographySecretion channelCell polesCytoplasmic ATPaseSecretion systemT4SS functionHexameric assemblyMembrane complexCytoplasmic channelsDNA complexesSubstrate transferT4SSChannel activationATPaseComplexesDistinct stagesAssemblyBiogenesisATPasesFurther analysis
2017
In Situ Molecular Architecture of the Salmonella Type III Secretion Machine
Hu B, Lara-Tejero M, Kong Q, Galán JE, Liu J. In Situ Molecular Architecture of the Salmonella Type III Secretion Machine. Cell 2017, 168: 1065-1074.e10. PMID: 28283062, PMCID: PMC5393631, DOI: 10.1016/j.cell.2017.02.022.Peer-Reviewed Original ResearchConceptsType III secretion machinesSecretion machineNeedle complexType III protein secretion systemCytoplasmic sorting platformProtein secretion systemMulti-protein machinesProtein secretion machinesTarget eukaryotic cellsCryo-electron tomographyDifferent deletion mutantsSub-tomogram averagingSignificant conformational changesMolecular architectureExport apparatusEukaryotic cellsSecretion systemDeletion mutantsSorting platformConformational changesSitu structureMajor insightsMolecular modelingStructural componentsAssembly