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 ResearchMeSH KeywordsBlisterDiglyceridesExocytosisHumansSynaptic TransmissionSynaptic VesiclesSynaptotagminsConceptsCore protein machineryRelease-ready vesiclesSynaptic vesicle primingVesicle primingProtein machinerySingle-molecule imagingSNAREpin assemblyFunctional intermediatesFunctional reconstitutionMunc13DiacylglycerolCoordinated actionMunc18VesiclesMachineryComplete reconstitutionNew roleSelective effectDetailed characterizationChaperonesRate of caReconstitutionVAMP2ComplexinMutationsRapid Quantification of First and Second Phase Insulin Secretion Dynamics using an In vitro Platform for Improving Insulin Therapy
Thoduvayil S, Weerakkody J, Sundaram R, Topper M, Bera M, Coleman J, Li X, Mariappan M, Ramakrishnan S. Rapid Quantification of First and Second Phase Insulin Secretion Dynamics using an In vitro Platform for Improving Insulin Therapy. Cell Calcium 2023, 113: 102766. PMID: 37295201, PMCID: PMC10450995, DOI: 10.1016/j.ceca.2023.102766.Peer-Reviewed Original ResearchConceptsCellular pathwaysSecretion dynamicsSmall molecule screeningLuciferase reporter systemInsulin secretion dynamicsHigh-throughput compoundInsulin secretionHigh-throughput quantificationReporter systemGenetic studiesLive cellsDistinct rolesInsulin therapyGlucose-stimulated insulin secretionSmall moleculesEffective insulin therapyPathwaySecretion
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 roleFusionExocytosisMachineryProteinBindsMechanismSynaptotagmin 1 oligomers clamp and regulate different modes of neurotransmitter release
Tagliatti E, Bello OD, Mendonça PRF, Kotzadimitriou D, Nicholson E, Coleman J, Timofeeva Y, Rothman JE, Krishnakumar SS, Volynski KE. Synaptotagmin 1 oligomers clamp and regulate different modes of neurotransmitter release. Proceedings Of The National Academy Of Sciences Of The United States Of America 2020, 117: 3819-3827. PMID: 32015138, PMCID: PMC7035618, DOI: 10.1073/pnas.1920403117.Peer-Reviewed Original Research
2018
Synaptotagmin oligomerization is essential for calcium control of regulated exocytosis
Bello OD, Jouannot O, Chaudhuri A, Stroeva E, Coleman J, Volynski KE, Rothman JE, Krishnakumar SS. Synaptotagmin oligomerization is essential for calcium control of regulated exocytosis. Proceedings Of The National Academy Of Sciences Of The United States Of America 2018, 115: e7624-e7631. PMID: 30038018, PMCID: PMC6094142, DOI: 10.1073/pnas.1808792115.Peer-Reviewed Original ResearchConceptsRegulated exocytosisFusion machineryC2 domain proteinsCore fusion machinerySingle vesicle exocytosisConstitutive exocytosisPrincipal CaVesicular releaseMolecular mechanismsSensitive oligomersExocytosisPheochromocytoma cellsSelective disruptionSpontaneous fusionCritical roleMachineryOligomerizationDirect activationCentral componentStructural featuresConsiderable insightCalcium controlPHluorinSyt1SYT
2010
Phosphatidylinositol 4-Phosphate Controls Both Membrane Recruitment and a Regulatory Switch of the Rab GEF Sec2p
Mizuno-Yamasaki E, Medkova M, Coleman J, Novick P. Phosphatidylinositol 4-Phosphate Controls Both Membrane Recruitment and a Regulatory Switch of the Rab GEF Sec2p. Developmental Cell 2010, 18: 828-840. PMID: 20493815, PMCID: PMC2877039, DOI: 10.1016/j.devcel.2010.03.016.Peer-Reviewed Original ResearchConceptsPI4P levelsRab GTPase Sec4pMembrane recruitmentRegulatory switchExchange factorSecretory pathwayVesicle maturationSec2pSec15pSecretory vesiclesPositive feedback loopYpt32pPhosphatidylinositol 4Vesicles formSec4pVesiclesSecretory sitesFeedback loopRecruitment cascadeCascadeRecruitmentPI4PRabPhosphatidylinositolGuanine
2008
An Internal Domain of Exo70p Is Required for Actin-independent Localization and Mediates Assembly of Specific Exocyst Components
Hutagalung A, Coleman J, Pypaert M, Novick P. An Internal Domain of Exo70p Is Required for Actin-independent Localization and Mediates Assembly of Specific Exocyst Components. Molecular Biology Of The Cell 2008, 20: 153-163. PMID: 18946089, PMCID: PMC2613103, DOI: 10.1091/mbc.e08-02-0157.Peer-Reviewed Original ResearchMeSH KeywordsActinsAmino Acid SequenceCell MembraneExocytosisModels, MolecularMolecular Sequence DataMutationProtein Structure, TertiaryProtein SubunitsRecombinant Fusion ProteinsRho GTP-Binding ProteinsSaccharomyces cerevisiaeSaccharomyces cerevisiae ProteinsSecretory PathwayVesicular Transport ProteinsConceptsExocyst assemblyPlasma membraneHigh copy number suppressorActin-independent pathwayAmino-terminal domainSynthetic lethal interactionsRod-shaped subunitsNumber suppressorVesicle tethersExocyst componentsExocytic sitesActin cablesExo70pSingle geneSecretory vesiclesLethal interactionsSec3pSynthetic lethalityComplete deletionExocystInternal domainSubunitsDeletionMutationsVesicles
2006
The rab Exchange Factor Sec2p Reversibly Associates with the Exocyst
Medkova M, France Y, Coleman J, Novick P. The rab Exchange Factor Sec2p Reversibly Associates with the Exocyst. Molecular Biology Of The Cell 2006, 17: 2757-2769. PMID: 16611746, PMCID: PMC1474791, DOI: 10.1091/mbc.e05-10-0917.Peer-Reviewed Original ResearchConceptsSecretory vesiclesExchange factor Sec2pTemperature-sensitive growthC-terminal halfExocyst complexExocytic sitesRab GTPaseExchange factorMutant resultsMutant correlatesRecycling pathwaySec2pExocystNucleotide exchangePlasma membraneSec4pSec15pVesiclesMislocalizationEffectorsPolarized transportAssociatesGTPaseExocytosisPathwayThe polarity-establishment component Bem1p interacts with the exocyst complex through the Sec15p subunit
France Y, Boyd C, Coleman J, Novick P. The polarity-establishment component Bem1p interacts with the exocyst complex through the Sec15p subunit. Journal Of Cell Science 2006, 119: 876-888. PMID: 16478783, DOI: 10.1242/jcs.02849.Peer-Reviewed Original ResearchConceptsBud growthSrc homology 3 domainTwo-hybrid studiesFirst Src homology 3 domainDirect physical interactionGreen fluorescent proteinExocyst complexGolgi traffickingSec15pSecretory pathwaySpatial regulationBem1pSecretory machineryMaster regulatorFluorescent proteinNew budsMachineryExocystSec4pPhysical interactionSubunitsCase of cellsProteinPathwayCrucial role