Sathish Ramakrishnan, PhD
Assistant ProfessorCards
About
Research
Publications
Featured Publications
PRRT2 Regulates Synaptic Fusion by Directly Modulating SNARE Complex Assembly
Coleman J, Jouannot O, Ramakrishnan SK, Zanetti MN, Wang J, Salpietro V, Houlden H, Rothman JE, Krishnakumar SS. PRRT2 Regulates Synaptic Fusion by Directly Modulating SNARE Complex Assembly. Cell Reports 2018, 22: 820-831. PMID: 29346777, PMCID: PMC5792450, DOI: 10.1016/j.celrep.2017.12.056.Peer-Reviewed Original ResearchConceptsProline-rich transmembrane protein 2SNARE complex assemblyComplex assemblyTrans-SNARE complex assemblyTerminal proline-rich domainSynaptic SNARE proteinsProline-rich domainParoxysmal neurological disordersSynaptic vesicle primingLive-cell imagingTransmembrane protein 2Synaptic fusionSNARE proteinsVesicle primingSingle exocytotic eventsBiophysical analysisFusion assaysMolecular mechanismsFunction mutationsPhysiological roleExocytotic eventsPre-synaptic terminalsPC12 cellsProtein 2Single vesiclesSynergistic 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 functionDomainHelixVesiclesFunctionMembraneInteractionNative Planar Asymmetric Suspended Membrane for Single‐Molecule Investigations: Plasma Membrane on a Chip
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 2022, 18: e2205567. PMID: 36328714, DOI: 10.1002/smll.202205567.Peer-Reviewed Original ResearchConceptsPlasma membraneProtein assembliesNative plasma membrane vesiclesTotal internal reflection fluorescence microscopySingle-molecule levelSingle-molecule investigationsCellular plasma membranePlasma membrane vesiclesSingle-molecule precisionReflection fluorescence microscopyKnowledge of lipidProtein complexesProtein architectureCell signalingMovement of moleculesProtein orientationLipid membranesBiological processesCellular membranesMembrane vesiclesMicroarray platformFluorescence investigationsLipid domainsFluorescence microscopyMembrane
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 mediaCleavageBreaking ground: A new model for dual-phase insulin exocytosis
Thoduvayil S, Weerakkody J, Ramakrishnan S. Breaking ground: A new model for dual-phase insulin exocytosis. Biophysical Journal 2024, 123: 66a. DOI: 10.1016/j.bpj.2023.11.476.Peer-Reviewed Original ResearchIntegrated suspended lipid membrane platform: Harnessing amperometric and single-molecule capabilities for deep insights into fusion dynamics
Weerakkody J, Thoduvayil S, Ramakrishnan S. Integrated suspended lipid membrane platform: Harnessing amperometric and single-molecule capabilities for deep insights into fusion dynamics. Biophysical Journal 2024, 123: 380a. DOI: 10.1016/j.bpj.2023.11.2323.Peer-Reviewed Original Research
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