2023
The release of inhibition model reproduces kinetics and plasticity of neurotransmitter release in central synapses
Norman C, Krishnakumar S, Timofeeva Y, Volynski K. The release of inhibition model reproduces kinetics and plasticity of neurotransmitter release in central synapses. Communications Biology 2023, 6: 1091. PMID: 37891212, PMCID: PMC10611806, DOI: 10.1038/s42003-023-05445-2.Peer-Reviewed Original ResearchConceptsFusion clampSV exocytosisSynaptic vesiclesNeurotransmitter releaseSNARE complexSNARE proteinsSV fusionPhysiological timescalesSynaptotagmin-1Synergistic regulationMolecular biochemistryComplete assemblyPresynaptic proteinsSynaptotagmin-7Molecular architectureCalcium bindingExocytosisDual bindingProteinCentral synapsesBindingPlasticitySynaptotagminSnareVesiclesRoles for diacylglycerol in synaptic vesicle priming and release revealed by complete reconstitution of core protein machinery
Sundaram R, Chatterjee A, Bera M, Grushin K, Panda A, Li F, Coleman J, Lee S, Ramakrishnan S, Ernst A, Gupta K, Rothman J, Krishnakumar S. Roles for diacylglycerol in synaptic vesicle priming and release revealed by complete reconstitution of core protein machinery. Proceedings Of The National Academy Of Sciences Of The United States Of America 2023, 120: e2309516120. PMID: 37590407, PMCID: PMC10450444, DOI: 10.1073/pnas.2309516120.Peer-Reviewed Original ResearchConceptsCore protein machineryRelease-ready vesiclesSynaptic vesicle primingVesicle primingProtein machinerySingle-molecule imagingSNAREpin assemblyFunctional intermediatesFunctional reconstitutionMunc13DiacylglycerolCoordinated actionMunc18VesiclesMachineryComplete reconstitutionNew roleSelective effectDetailed characterizationChaperonesRate of caReconstitutionVAMP2ComplexinMutations
2022
Native Planar Asymmetric Suspended Membrane for Single‐Molecule Investigations: Plasma Membrane on a Chip (Small 51/2022)
Sundaram R, Bera M, Coleman J, Weerakkody J, Krishnakumar S, Ramakrishnan S. Native Planar Asymmetric Suspended Membrane for Single‐Molecule Investigations: Plasma Membrane on a Chip (Small 51/2022). Small 2022, 18 DOI: 10.1002/smll.202270277.Peer-Reviewed Original ResearchGiant plasma membrane vesiclesTotal internal reflection fluorescence microscopyMembrane protein assemblyPlasma membrane vesiclesReflection fluorescence microscopyDifferent cell typesSingle-molecule investigationsProtein functionProtein assembliesInner leafletPlasma membraneMembrane vesiclesCell typesLipid architectureFluorescence microscopyLipid membranesMolecule investigationsMembraneSilicon-based platformVesiclesAssemblyCellsBilayersLeafletsSynaptotagmin rings as high-sensitivity regulators of synaptic vesicle docking and fusion
Zhu J, McDargh ZA, Li F, Krishnakumar SS, Rothman JE, O’Shaughnessy B. Synaptotagmin rings as high-sensitivity regulators of synaptic vesicle docking and fusion. Proceedings Of The National Academy Of Sciences Of The United States Of America 2022, 119: e2208337119. PMID: 36103579, PMCID: PMC9499556, DOI: 10.1073/pnas.2208337119.Peer-Reviewed Original ResearchConceptsVesicle dockingPlasma membrane domainsSynaptic vesiclesCalcium sensor synaptotagminSynaptic vesicle dockingInhibitor of fusionFusion clampSensor synaptotagminMembrane domainsTrigger fusionPlasma membraneC2AB domainAnionic phospholipid bilayersNeuronal synapsesMembrane compositionPhospholipid monolayersATP levelsVesiclesExocytotic releaseDockingPhospholipid bilayersMolecular determinants of complexin clamping and activation function
Bera M, Ramakrishnan S, Coleman J, Krishnakumar SS, Rothman JE. Molecular determinants of complexin clamping and activation function. ELife 2022, 11: e71938. PMID: 35442188, PMCID: PMC9020821, DOI: 10.7554/elife.71938.Peer-Reviewed Original ResearchConceptsSynaptotagmin-1Single-vesicle fusionAccessory helixFusion clampHelical domainMolecular detailsComplexinMutational analysisVesicle releaseFusion kineticsMolecular determinantsSpecific interactionsInhibitory functionProbability of fusionRapid CaSNAREpinsAssembly processFusionClamping functionDomainHelixVesiclesFunctionMembraneInteraction
2021
Vesicle capture by membrane‐bound Munc13‐1 requires self‐assembly into discrete clusters
Li F, Sundaram R, Gatta AT, Coleman J, Ramakrishnan S, Krishnakumar SS, Pincet F, Rothman JE. Vesicle capture by membrane‐bound Munc13‐1 requires self‐assembly into discrete clusters. FEBS Letters 2021, 595: 2185-2196. PMID: 34227103, DOI: 10.1002/1873-3468.14157.Peer-Reviewed Original ResearchConceptsMunc13-1Vesicle captureSpecific plasma membrane domainsStep-wise photobleachingC-domainMunc13-1 proteinPlasma membrane domainsSynaptic vesicle dockingC-terminal CVesicle dockingMembrane domainsTIRF microscopySoluble proteinVesicle membraneActive zoneMultiple copiesSynaptic vesiclesFunctional significanceSmall unilamellar vesiclesLipid bilayersVesiclesUnilamellar vesiclesProteinDiscrete clustersCopiesSymmetrical arrangement of proteins under release-ready vesicles in presynaptic terminals
Radhakrishnan A, Li X, Grushin K, Krishnakumar SS, Liu J, Rothman JE. Symmetrical arrangement of proteins under release-ready vesicles in presynaptic terminals. Proceedings Of The National Academy Of Sciences Of The United States Of America 2021, 118: e2024029118. PMID: 33468631, PMCID: PMC7865176, DOI: 10.1073/pnas.2024029118.Peer-Reviewed Original ResearchConceptsPlasma membraneSynaptic vesiclesSV fusionRelease-ready vesiclesFusion machinerySingle SNAREpinSV releaseExocytosis machineryMolecular eventsNative conditionsProtein componentsCultured hippocampal neuronsPriming reactionPresynaptic CaVesiclesFundamental processesProtein densityProtein massRelease of neurotransmittersNeurotransmitter releaseMachineryPresynaptic terminalsReleasable poolHippocampal neuronsVariable number
2020
Synergistic roles of Synaptotagmin-1 and complexin in calcium-regulated neuronal exocytosis
Ramakrishnan S, Bera M, Coleman J, Rothman JE, Krishnakumar SS. Synergistic roles of Synaptotagmin-1 and complexin in calcium-regulated neuronal exocytosis. ELife 2020, 9: e54506. PMID: 32401194, PMCID: PMC7220375, DOI: 10.7554/elife.54506.Peer-Reviewed Original ResearchConceptsSynaptotagmin-1Vesicular fusion machinerySingle-vesicle fusionFusion of vesiclesSNARE complexFusion machineryNeuronal exocytosisOligomer bindsRegulatory proteinsVesicle fusionSNAREpinsSynchronous fusionSynaptic vesiclesNovel mechanismVesiclesComplexinKinetic delayPrimary interfaceSynergistic roleFusionExocytosisMachineryProteinBindsMechanism
2019
Symmetrical organization of proteins under docked synaptic vesicles
Li X, Radhakrishnan A, Grushin K, Kasula R, Chaudhuri A, Gomathinayagam S, Krishnakumar SS, Liu J, Rothman JE. Symmetrical organization of proteins under docked synaptic vesicles. FEBS Letters 2019, 593: 144-153. PMID: 30561792, PMCID: PMC6353562, DOI: 10.1002/1873-3468.13316.Peer-Reviewed Original ResearchConceptsCryo-electron tomography analysisSymmetrical organizationCalcium-regulated exocytosisMunc18 proteinsProtein machineryFusion machinerySingle SNAREpinCircular oligomersMutational analysisRadial positioningSynaptic vesiclesRelease machineryMachinerySynaptotagminProteinRing hypothesisVesiclesObserved arrangementUnderlying mechanismSNAREpinsComplexinNerve growthExocytosisGrowthSynaptotagmin oligomers are necessary and can be sufficient to form a Ca2+‐sensitive fusion clamp
Ramakrishnan S, Bera M, Coleman J, Krishnakumar SS, Pincet F, Rothman JE. Synaptotagmin oligomers are necessary and can be sufficient to form a Ca2+‐sensitive fusion clamp. FEBS Letters 2019, 593: 154-162. PMID: 30570144, PMCID: PMC6349546, DOI: 10.1002/1873-3468.13317.Peer-Reviewed Original Research
2016
Nanodisc-cell fusion: control of fusion pore nucleation and lifetimes by SNARE protein transmembrane domains
Wu Z, Auclair SM, Bello O, Vennekate W, Dudzinski NR, Krishnakumar SS, Karatekin E. Nanodisc-cell fusion: control of fusion pore nucleation and lifetimes by SNARE protein transmembrane domains. Scientific Reports 2016, 6: 27287. PMID: 27264104, PMCID: PMC4893671, DOI: 10.1038/srep27287.Peer-Reviewed Original ResearchConceptsFusion poreTransmembrane domainPore dynamicsProtein transmembrane domainNeurotransmitter-filled vesiclesT-SNAREsPlasma membraneRecycling kineticsPore lifetimePore currentsFlickering poresPore stabilityMultiple timesZipperingNanodiscsDomainProteinVesiclesMembraneCellsAssaysCognatesPore propertiesPores