Shyam Krishnakumar, PhD
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Biography
Shyam S. Krishnakumar, PhD is an Assistant Professor at the Department of Neurology & Nanobiology Institute. Dr. Krishnakumar received his M.S in Biotechnology from the Indian Institute of Technology, Bombay, and his Ph.D. in Biochemistry and Structural Biology from Stony Brook University, NY. In his doctoral research, he made several key discoveries describing how the structure and function of transmembrane proteins are defined by the composition of the membrane-spanning domains. Dr. Krishnakumar did his postdoctoral research on the molecular regulation of synaptic vesicle fusion under the guidance of James E. Rothman (Nobel Prize in Physiology or Medicine, 2013) in the Department of Cell Biology, Yale University School of Medicine (Krishnakumar et al. Nat. Struct. Mol. Biol. 2011; eLife 2015). Subsequently, as a Senior Research Scientist, he directed research focused on dissecting the molecular organization of the vesicle release sites in presynaptic terminals (Volynski and Krishnakumar, Curr. Opin. Neurobiol 2018)
In his own lab, Dr. Krishnakumar aims to delineate the molecular mechanisms of synchronicity and use-dependent plasticity of neurotransmitter release and how it is altered in paroxysmal movement disorders. The balance between different modes of neurotransmitter release and short-term plasticity plays an important role in coordinating activity within neuronal networks and provides a basis for synaptic computation. Any alterations that affect the timing or probability of release result in a wide range of neurological disorders. To this end, he employs multidisciplinary biochemical, biophysical, and structural methods, with a specific focus on systematic biochemical reconstitution strategies.
As part of the Yale-UCL collaborative, Dr. Krishnakumar also has a visiting appointment (Honorary Associate Professor) at the Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London. At UCL, he is pursuing a collaborative research program aimed at understanding the pathophysiology of SNARE-associated neurodevelopmental and movement disorders in molecular terms.
Appointments
Education & Training
- PhD
- Stony Brook University (2007)
- MSc
- Indian Inst Of Tech (2001)
Research
Overview
The release of neurotransmitters at the neuronal synapses is tightly controlled by changes in the presynaptic calcium concentration. To achieve this, synaptic vesicles (loaded with neurotransmitters) are already docked in the presynaptic membrane, ready to release the neurotransmitters when the signal (calcium ion) arrives. The protein machinery involved in this process are SNARE proteins, which catalyze the fusion of the vesicles; calcium sensors that synchronize the release of the neurotransmitter to the triggering calcium signal (Synaptotagmin isoforms) and regulatory proteins (Munc18/Munc13/Complexin ) that are involved in the organization of the release site. Our research is focused on elucidating how vesicular release protein machinery decodes the calcium signals and translate them into complex patterns of neurotransmitter release required for brain function.
The controlled release of neurotransmitters is central to information processing in the nervous system and is altered in many psychiatric and neurological disorders as is clear from well-established clinical benefits achieved by drugs that modulate neurotransmitter biochemistry and/or availability. So, we also aim to uncover the molecular and mechanistic basis for neurological disorders.
Our strategy is based on the systematic quantitative analysis of mutations both novel structure-based designer mutants as well as ‘experiments of nature’ - mutations associated with neurological disorders. We employ multidisciplinary biochemical, biophysical, and structural methods (with a specific focus on systematic biochemical reconstitution strategies) along with electrophysiology and high-resolution imaging in cultured neurons (in collaboration with Prof. Kirill Volynski, UCL Queen Square Institue of Neurology)
Medical Research Interests
ORCID
0000-0001-6148-3251- View Lab Website
Krishnakumar Lab
Research at a Glance
Yale Co-Authors
Publications Timeline
Research Interests
Jeff Coleman, PhD
Sathish Ramakrishnan, PhD
Manindra Bera
Frederic Pincet, PhD
Chuck Sindelar, PhD
Erdem Karatekin, PhD
Synaptic Transmission
Publications
2024
Synaptotagmin-1 and synaptotagmin-7 synergistically regulate the timing and plasticity of Ca2+-evoked vesicular release process
Bose D, Bera M, Norman C, Volynski K, Krishnakumar S. Synaptotagmin-1 and synaptotagmin-7 synergistically regulate the timing and plasticity of Ca2+-evoked vesicular release process. Biophysical Journal 2024, 123: 381a. DOI: 10.1016/j.bpj.2023.11.2327.Peer-Reviewed Original ResearchConcepts
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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsFusion 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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsCore protein machineryRelease-ready vesiclesSynaptic vesicle primingVesicle primingProtein machinerySingle-molecule imagingSNAREpin assemblyFunctional intermediatesFunctional reconstitutionMunc13DiacylglycerolCoordinated actionMunc18VesiclesMachineryComplete reconstitutionNew roleSelective effectDetailed characterizationChaperonesRate of caReconstitutionVAMP2ComplexinMutationsDirect 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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsIntegral 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
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 ResearchConceptsGiant 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 ResearchCitationsMeSH Keywords and ConceptsConceptsVesicle 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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsSynaptotagmin-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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsMunc13-1Vesicle 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 ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsPlasma 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
Munc13 binds and recruits SNAP25 to chaperone SNARE complex assembly
Sundaram R, Jin H, Li F, Shu T, Coleman J, Yang J, Pincet F, Zhang Y, Rothman JE, Krishnakumar SS. Munc13 binds and recruits SNAP25 to chaperone SNARE complex assembly. FEBS Letters 2020, 595: 297-309. PMID: 33222163, PMCID: PMC8068094, DOI: 10.1002/1873-3468.14006.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsMeSH KeywordsAnimalsBinding SitesCloning, MolecularEscherichia coliGene ExpressionGenetic VectorsLipid BilayersLiposomesMiceModels, MolecularNerve Tissue ProteinsOptical TweezersPhosphatidylcholinesPhosphatidylethanolaminesPhosphatidylserinesPolyethylene GlycolsProtein BindingProtein Conformation, alpha-HelicalProtein Conformation, beta-StrandProtein Interaction Domains and MotifsRecombinant Fusion ProteinsSynaptosomal-Associated Protein 25Syntaxin 1Vesicle-Associated Membrane Protein 2ConceptsSNARE complex assemblyComplex assemblyMunc13-1 MUN domainDetailed structure-function analysisSNARE protein VAMP2Syntaxin 1/Structure-function analysisSynaptic vesicle fusionOptical tweezers studiesSNARE assemblySNARE motifMUN domainMunc18-1Syntaxin-1Munc13-1FRET spectroscopyLinker regionVesicle fusionDirect bindingPhospholipid bilayersPresynaptic membraneSNAP25AssemblyBindingRecruits
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Krishnakumar Lab
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West Campus Integrative Science & Technology Center
850 West Campus Drive, Ste Room 212
West Haven, CT 06516