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 roleFusionExocytosisMachineryProteinBindsMechanism
2024
Photosensitive 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 actionProteinAssemblyChaperonesSynaptotagminExocytosisBilayersDirect determination of oligomeric organization of integral membrane proteins and lipids from intact customizable bilayer
Panda A, Giska F, Duncan A, Welch A, Brown C, McAllister R, Hariharan P, Goder J, Coleman J, Ramakrishnan S, Pincet F, Guan L, Krishnakumar S, Rothman J, Gupta K. Direct determination of oligomeric organization of integral membrane proteins and lipids from intact customizable bilayer. Nature Methods 2023, 20: 891-897. PMID: 37106230, PMCID: PMC10932606, DOI: 10.1038/s41592-023-01864-5.Peer-Reviewed Original ResearchConceptsIntegral membrane proteinsMembrane proteinsOligomeric organizationOligomeric stateNative mass spectrometry analysisFunctional oligomeric stateKey membrane componentMass spectrometry analysisNMS analysisTarget membraneLipid bindingMembrane componentsProteolipid vesiclesMembrane compositionLipid compositionSpectrometry analysisLipid membranesNeurotransmitter releaseProteinMembraneLipidsMembrane propertiesDirect determinationBilayersTransporters
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
Highly Reproducible Physiological Asymmetric Membrane with Freely Diffusing Embedded Proteins in a 3D‐Printed Microfluidic Setup
Heo P, Ramakrishnan S, Coleman J, Rothman JE, Fleury J, Pincet F. Highly Reproducible Physiological Asymmetric Membrane with Freely Diffusing Embedded Proteins in a 3D‐Printed Microfluidic Setup. Small 2019, 15: e1900725. PMID: 30977975, DOI: 10.1002/smll.201900725.Peer-Reviewed Original ResearchConceptsMost biological processesLipid leafletAreas of biologyEmbedded proteinsBiological processesRelevant lipidsProteinAsymmetric bilayersPhysiological conditionsModel membranesPlanar bilayersBilayer formation processInvaluable insightsBilayersConfocal microscopeMembraneLipidsTransmembraneBiologyLeafletsMicrofluidic setupRecapitulation
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