Featured Publications
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 roleFusionExocytosisMachineryProteinBindsMechanismMolecular 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
2024
Photosensitive Nanoprobes for Rapid High Purity Isolation and Size‐Specific Enrichment of Synthetic and Extracellular Vesicle Subpopulations (Adv. Funct. Mater. 34/2024)
Weerakkody J, Tseng T, Topper M, Thoduvayil S, Radhakrishnan A, Pincet F, Kyriakides T, Gunasekara R, Ramakrishnan S. Photosensitive Nanoprobes for Rapid High Purity Isolation and Size‐Specific Enrichment of Synthetic and Extracellular Vesicle Subpopulations (Adv. Funct. Mater. 34/2024). Advanced Functional Materials 2024, 34 DOI: 10.1002/adfm.202470191.Peer-Reviewed Original ResearchVesicle biogenesisExtracellular vesicle subpopulationsLipid nanoprobesVesicle subpopulationsNative extracellular vesiclesVesicle populationsSeparate vesiclesPurity isolationExtracellular vesiclesVesiclesCellular originHydrophobic interactionsBiogenesisSize variabilitySubpopulationsIsolatesExtracellularPhotosensitive Nanoprobes for Rapid High Purity Isolation and Size‐Specific Enrichment of Synthetic and Extracellular Vesicle Subpopulations
Weerakkody J, Tseng T, Topper M, Thoduvayil S, Radhakrishnan A, Pincet F, Kyriakides T, Gunasekara R, Ramakrishnan S. Photosensitive Nanoprobes for Rapid High Purity Isolation and Size‐Specific Enrichment of Synthetic and Extracellular Vesicle Subpopulations. Advanced Functional Materials 2024, 34 PMID: 39372670, PMCID: PMC11452007, DOI: 10.1002/adfm.202400390.Peer-Reviewed Original ResearchExtracellular vesicle subpopulationsVesicle subpopulationsIsolation of vesiclesPurity extracellular vesiclesRelease of vesiclesAnalysis of nucleic acidsNear-native formLarge-scale isolationLipid nanoprobesDownstream analysisPurity isolationEfficient isolationVesiclesSynthetic vesiclesNucleic acidsExtracellular vesiclesIsolation methodIsolatesBiomarker discoveryExposure to lightSubpopulationsEnrichmentProteinComplex biological mediaCleavage
2023
Synaptophysin chaperones the assembly of 12 SNAREpins under each ready-release vesicle
Bera M, Radhakrishnan A, Coleman J, Sundaram R, Ramakrishnan S, Pincet F, Rothman J. Synaptophysin chaperones the assembly of 12 SNAREpins under each ready-release vesicle. Proceedings Of The National Academy Of Sciences Of The United States Of America 2023, 120: e2311484120. PMID: 37903271, PMCID: PMC10636311, DOI: 10.1073/pnas.2311484120.Peer-Reviewed Original ResearchConceptsSpecific molecular functionsSynaptic vesicle protein synaptophysinTarget membrane bilayerSensor synaptotagminSNARE proteinsMolecular functionsMembrane proteinsSNAREpinsReceptor vesiclesSingle-molecule measurementsGene knockoutMembrane bilayerLipid bilayersProtein synaptophysinVesiclesDetergent extractsHexamer structureSYPMechanism of actionProteinAssemblyChaperonesSynaptotagminExocytosisBilayersRoles 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
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 clustersCopies
2019
Synaptotagmin 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
2018
High-Throughput Monitoring of Single Vesicle Fusion Using Freestanding Membranes and Automated Analysis
Ramakrishnan S, Gohlke A, Li F, Coleman J, Xu W, Rothman JE, Pincet F. High-Throughput Monitoring of Single Vesicle Fusion Using Freestanding Membranes and Automated Analysis. Langmuir 2018, 34: 5849-5859. PMID: 29694054, DOI: 10.1021/acs.langmuir.8b00116.Peer-Reviewed Original ResearchConceptsMembrane fusionFusion eventsSoluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteinsSNARE-dependent membrane fusionIndividual vesicle fusion eventsFactor attachment protein receptor proteinsN-ethylmaleimide-sensitive factor attachment protein receptor proteinsT-SNARE proteinsSingle-vesicle fusionProtein receptor proteinsVesicle fusion eventsMobility of proteinsVesicle dockingContent releaseVesicle fusionHigh-throughput monitoringPlanar membranesReceptor proteinLipid mixingProteinLipid bilayersVesiclesCorrect reconstitutionMembraneAqueous compartment