2017
Glutathione-Responsive Selenosulfide Prodrugs as a Platform Strategy for Potent and Selective Mechanism-Based Inhibition of Protein Tyrosine Phosphatases
Tjin CC, Otley KD, Baguley TD, Kurup P, Xu J, Nairn AC, Lombroso PJ, Ellman JA. Glutathione-Responsive Selenosulfide Prodrugs as a Platform Strategy for Potent and Selective Mechanism-Based Inhibition of Protein Tyrosine Phosphatases. ACS Central Science 2017, 3: 1322-1328. PMID: 29296673, PMCID: PMC5746864, DOI: 10.1021/acscentsci.7b00486.Peer-Reviewed Original ResearchStriatal-enriched protein tyrosine phosphataseProtein tyrosineTyrosine phosphatasePhosphatase inhibitorProtein tyrosine phosphataseProtein tyrosine phosphorylation levelsActive site cysteineProtein tyrosine phosphorylationTyrosine phosphorylation levelsHuman PTPsSite cysteinePTP targetsTyrosine phosphorylationRepresentative cysteine proteaseCysteine proteasesHuman diseasesCellular activitiesPhosphorylation levelsVirulence factorsEssential roleSelective mechanismIntracellular GSH concentrationSelective active sitesNeurodegenerative diseasesPTP
2016
STEP activation by Gαq coupled GPCRs opposes Src regulation of NMDA receptors containing the GluN2A subunit
Tian M, Xu J, Lei G, Lombroso PJ, Jackson MF, MacDonald JF. STEP activation by Gαq coupled GPCRs opposes Src regulation of NMDA receptors containing the GluN2A subunit. Scientific Reports 2016, 6: 36684. PMID: 27857196, PMCID: PMC5114553, DOI: 10.1038/srep36684.Peer-Reviewed Original ResearchConceptsStriatal-enriched protein tyrosine phosphataseFamily of kinasesProtein tyrosine phosphataseM1R stimulationN-methyl-D-aspartate receptorsM1 muscarinic acetylcholine receptorSrc recruitmentTyrosine phosphataseSrc regulationNMDAR functionIntracellular Ca2Step activationMuscarinic acetylcholine receptorsGluN2A subunitGαqAcetylcholine receptorsHigh intracellular Ca2Function of NMDARsSynaptic plasticityPhosphataseNMDAR activationActivationReceptorsRecruitmentCa2
2015
Regulation of STEP61 and tyrosine-phosphorylation of NMDA and AMPA receptors during homeostatic synaptic plasticity
Jang SS, Royston SE, Xu J, Cavaretta JP, Vest MO, Lee KY, Lee S, Jeong HG, Lombroso PJ, Chung HJ. Regulation of STEP61 and tyrosine-phosphorylation of NMDA and AMPA receptors during homeostatic synaptic plasticity. Molecular Brain 2015, 8: 55. PMID: 26391783, PMCID: PMC4578242, DOI: 10.1186/s13041-015-0148-4.Peer-Reviewed Original ResearchConceptsN-methyl-D-aspartate receptorsHomeostatic synaptic plasticitySynaptic plasticityTyrosine phosphorylationActivity blockadeDephosphorylation of GluN2BSynaptic scalingProtein tyrosine phosphataseLevel of GluN2BProlonged activity blockadeExcitatory synaptic transmissionHippocampal cultured neuronsIsoxazolepropionic acid (AMPA) receptorsNMDAR subunit GluN2BActivity-dependent regulationTyrosine phosphataseSTEP61 levelsHomeostatic stabilizationSynaptic transmissionExcitatory synapsesAMPA receptorsGluA2 expressionPostsynaptic accumulationCultured neuronsAcid receptorsBDNF Induces Striatal-Enriched Protein Tyrosine Phosphatase 61 Degradation Through the Proteasome
Saavedra A, Puigdellívol M, Tyebji S, Kurup P, Xu J, Ginés S, Alberch J, Lombroso PJ, Pérez-Navarro E. BDNF Induces Striatal-Enriched Protein Tyrosine Phosphatase 61 Degradation Through the Proteasome. Molecular Neurobiology 2015, 53: 4261-4273. PMID: 26223799, PMCID: PMC4738169, DOI: 10.1007/s12035-015-9335-7.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsBrain-Derived Neurotrophic FactorCerebral CortexExtracellular Signal-Regulated MAP KinasesHippocampusMembrane PotentialsMiceNeostriatumNerve Growth FactorNeuronsNeurotrophin 3Phospholipase C gammaPhosphorylationProteasome Endopeptidase ComplexProtein Tyrosine Phosphatases, Non-ReceptorProteolysisReceptors, N-Methyl-D-AspartateUbiquitinationConceptsBrain-derived neurotrophic factorSTEP61 levelsCortical neuronsUbiquitin-proteasome systemStriatal-enriched protein tyrosine phosphatasePrimary cortical neuronsLevels/activitiesNerve growth factorNeurotrophic factorNeurotrophin-3Cultured striatalHippocampal neuronsCell depolarizationGrowth factorERK1/2 phosphorylationNeuronsStriatalTyrosine kinasePhospholipase C-gammaC gammaDifferent mechanismsLevelsBlockadeGluN2BProtein tyrosine phosphataseStriatal‐enriched protein tyrosine phosphatase regulates the PTPα/Fyn signaling pathway
Xu J, Kurup P, Foscue E, Lombroso PJ. Striatal‐enriched protein tyrosine phosphatase regulates the PTPα/Fyn signaling pathway. Journal Of Neurochemistry 2015, 134: 629-641. PMID: 25951993, PMCID: PMC4516628, DOI: 10.1111/jnc.13160.Peer-Reviewed Original ResearchConceptsProtein tyrosine phosphataseProtein kinase ARegulation of FynTyrosine phosphataseReceptor-type protein tyrosine phosphatase alphaProtein tyrosine phosphatase alphaStriatal-enriched protein tyrosine phosphataseRegulatory tyrosine residuesActivation of FynTyrosine kinase FynRegulatory tyrosineProtein tyrosinePTPαKinase FynSynaptic membranesKinase ATyrosine residuesFyn activityFynNovel substratePrimary neuronal culturesSTEP61Synergistic regulationMolecular techniquesNovel mechanismSTEP61 is a substrate of the E3 ligase parkin and is upregulated in Parkinson’s disease
Kurup PK, Xu J, Videira RA, Ononenyi C, Baltazar G, Lombroso PJ, Nairn AC. STEP61 is a substrate of the E3 ligase parkin and is upregulated in Parkinson’s disease. Proceedings Of The National Academy Of Sciences Of The United States Of America 2015, 112: 1202-1207. PMID: 25583483, PMCID: PMC4313846, DOI: 10.1073/pnas.1417423112.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsCorpus StriatumCyclic AMP Response Element-Binding ProteinDown-RegulationGene Expression Regulation, EnzymologicHEK293 CellsHumansMAP Kinase Signaling SystemMiceMice, KnockoutMitogen-Activated Protein Kinase 3MPTP PoisoningProtein Tyrosine Phosphatases, Non-ReceptorRatsRats, Sprague-DawleyUbiquitinationUbiquitin-Protein LigasesUp-RegulationConceptsE3 ubiquitin ligase ParkinSubstantia nigra pars compactaPathophysiology of PDProtein tyrosine phosphataseUbiquitin ligase ParkinSporadic Parkinson's diseaseE3 ligase ParkinRegulation of ParkinParkinson's diseaseTyrosine phosphataseParkin mutantsE3 ligaseProteasome systemDopaminergic neuronsDownstream targetsAutosomal recessive juvenile parkinsonismNovel substrateSTEP61ParkinCellular modelSTEP61 levelsSNc dopaminergic neuronsProtein levelsFunction contributesERK1/2
2013
Striatal-Enriched Protein Tyrosine Phosphatase—STEPs Toward Understanding Chronic Stress-Induced Activation of Corticotrophin Releasing Factor Neurons in the Rat Bed Nucleus of the Stria Terminalis
Dabrowska J, Hazra R, Guo JD, Li C, DeWitt S, Xu J, Lombroso PJ, Rainnie DG. Striatal-Enriched Protein Tyrosine Phosphatase—STEPs Toward Understanding Chronic Stress-Induced Activation of Corticotrophin Releasing Factor Neurons in the Rat Bed Nucleus of the Stria Terminalis. Biological Psychiatry 2013, 74: 817-826. PMID: 24012328, PMCID: PMC3818357, DOI: 10.1016/j.biopsych.2013.07.032.Peer-Reviewed Original ResearchConceptsStriatal-enriched protein tyrosine phosphataseLong-term potentiationProtein tyrosine phosphataseCRF neuronsReverse transcriptase-polymerase chain reactionTranscriptase-polymerase chain reactionRestraint stressTyrosine phosphatasePolymerase chain reactionBed nucleusFactor neuronsStria terminalisWhole-cell patch-clamp electrophysiologyInduction of LTPRole of STEPQuantitative reverse transcriptase-polymerase chain reactionChain reactionNovel treatment strategiesStress-induced anxiety disordersAnxiety-like behaviorSingle-cell reverse transcriptase-polymerase chain reactionPatch-clamp electrophysiologyStress-Induced ActivationRat bed nucleusTyrosine phosphatase STEP
2012
Striatal-enriched Protein-tyrosine Phosphatase (STEP) Regulates Pyk2 Kinase Activity*
Xu J, Kurup P, Bartos JA, Patriarchi T, Hell JW, Lombroso PJ. Striatal-enriched Protein-tyrosine Phosphatase (STEP) Regulates Pyk2 Kinase Activity*. Journal Of Biological Chemistry 2012, 287: 20942-20956. PMID: 22544749, PMCID: PMC3375518, DOI: 10.1074/jbc.m112.368654.Peer-Reviewed Original ResearchConceptsStriatal-enriched protein tyrosine phosphataseProtein tyrosine phosphataseN-Methyl-d-aspartate (NMDA) Receptor TraffickingFocal adhesion kinase familyPyk2 activationProline-rich tyrosine kinase 2Pyk2 kinase activityTyrosine kinase 2Kinase familyKinase membersCytoskeletal reorganizationDiverse functionsKinase activitySTEP KO miceReceptor traffickingKinase 2Tyrosine sitesPyk2 activityEnhanced phosphorylationCell adhesionPyk2PhosphorylationFunctional studiesHematopoietic cellsPostsynaptic densityCalpain and STriatal-Enriched protein tyrosine Phosphatase (STEP) activation contribute to extrasynaptic NMDA receptor localization in a Huntington's disease mouse model
Gladding CM, Sepers MD, Xu J, Zhang LY, Milnerwood AJ, Lombroso PJ, Raymond LA. Calpain and STriatal-Enriched protein tyrosine Phosphatase (STEP) activation contribute to extrasynaptic NMDA receptor localization in a Huntington's disease mouse model. Human Molecular Genetics 2012, 21: 3739-3752. PMID: 22523092, PMCID: PMC3412376, DOI: 10.1093/hmg/dds154.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsCalpainCoculture TechniquesDisease Models, AnimalEnzyme ActivationEnzyme InhibitorsHuntington DiseaseIon Channel GatingMiceModels, BiologicalNeostriatumNeuronsPhosphorylationPhosphotyrosineProtein TransportProtein Tyrosine Phosphatases, Non-ReceptorReceptors, N-Methyl-D-AspartateSynapsesConceptsYAC128 striatumProtein tyrosine phosphatase activationNMDAR localizationCalpain cleavageProtein tyrosine phosphataseTyrosine phosphatase activationEarly synaptic defectsWhole-cell NMDAR currentsDisease mouse modelGluN2B expressionNMDA receptor traffickingMutant huntingtin proteinCalpain inhibitionTyrosine phosphataseHuntington's diseaseFull-length mhttPlasma membranePhosphatase activationC-terminusReceptor traffickingNMDAR traffickingPolyglutamine repeatsMouse modelHuntingtin proteinNMDA receptor localizationInhibition of Hematopoietic Protein Tyrosine Phosphatase Augments and Prolongs ERK1/2 and p38 Activation
Tautz L, Sergienko E, Xu J, Liu W, Dahl R, Critton D, Su Y, Brown B, Chan X, Yang L, Bobkova E, Vasile S, Yuan H, Rascon J, Colayco S, Sidique S, Cosford N, Chung T, Mustelin T, Page R, Lombroso P. Inhibition of Hematopoietic Protein Tyrosine Phosphatase Augments and Prolongs ERK1/2 and p38 Activation. The FASEB Journal 2012, 26: 766.12-766.12. DOI: 10.1096/fasebj.26.1_supplement.766.12.Peer-Reviewed Original ResearchHematopoietic protein tyrosine phosphataseP38 activationProtein tyrosine phosphataseUnique amino acid residuesAmino acid residuesNew drug targetsCell cycle arrestMAP kinases ERK1/2Activation of ERK1/2Tyrosine phosphataseHePTPMutagenesis experimentsMAP kinaseKinases ERK1/2Acid residuesCatalytic pocketDrug targetsTransient activationCycle arrestT-cell acute lymphoblastic leukemiaERK1/2Prolonged activationHuman T cellsPharmacological inhibitionCancer cells
2011
Inhibition of Hematopoietic Protein Tyrosine Phosphatase Augments and Prolongs ERK1/2 and p38 Activation
Sergienko E, Xu J, Liu WH, Dahl R, Critton DA, Su Y, Brown BT, Chan X, Yang L, Bobkova EV, Vasile S, Yuan H, Rascon J, Colayco S, Sidique S, Cosford ND, Chung TD, Mustelin T, Page R, Lombroso PJ, Tautz L. Inhibition of Hematopoietic Protein Tyrosine Phosphatase Augments and Prolongs ERK1/2 and p38 Activation. ACS Chemical Biology 2011, 7: 367-377. PMID: 22070201, PMCID: PMC3288537, DOI: 10.1021/cb2004274.Peer-Reviewed Original ResearchConceptsHematopoietic protein tyrosine phosphataseP38 activationMitogen-activated protein kinases ERK1/2Protein tyrosine phosphataseUnique amino acid residuesSmall molecule modulatorsProtein kinases ERK1/2Amino acid residuesRegulation of MAPKNew drug targetsCell cycle arrestTyrosine phosphataseHePTPMutagenesis experimentsKinases ERK1/2Acid residuesCatalytic pocketCell senescenceDrug targetsTransient activationCycle arrestT-cell acute lymphoblastic leukemiaHematopoietic cellsERK1/2Prolonged activationStriatal-Enriched Protein Tyrosine Phosphatase Expression and Activity in Huntington's Disease: A STEP in the Resistance to Excitotoxicity
Saavedra A, Giralt A, Rué L, Xifró X, Xu J, Ortega Z, Lucas JJ, Lombroso PJ, Alberch J, Pérez-Navarro E. Striatal-Enriched Protein Tyrosine Phosphatase Expression and Activity in Huntington's Disease: A STEP in the Resistance to Excitotoxicity. Journal Of Neuroscience 2011, 31: 8150-8162. PMID: 21632937, PMCID: PMC3472648, DOI: 10.1523/jneurosci.3446-10.2011.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsBrainCalcineurinCell DeathDisease Models, AnimalGene Expression RegulationGene Products, tatHuntingtin ProteinHuntington DiseaseMiceMice, Neurologic MutantsMice, TransgenicMicroinjectionsNerve Tissue ProteinsNuclear ProteinsPhosphorylationProtein Tyrosine Phosphatases, Non-ReceptorQuinolinic AcidSignal TransductionConceptsStriatal-enriched protein tyrosine phosphataseCell deathSTEP expressionPhosphorylation levelsProtein Tyrosine Phosphatase ExpressionProtein tyrosine phosphataseSTEP phosphorylationTyrosine phosphataseProtein kinasePhosphorylated ERK2Phosphatase expressionHuntington's diseaseSTEP proteinMutant huntingtinCalcineurin activityPhosphorylationExon 1STEP protein levelsDisease mouse modelProtein levelsMouse modelMouse striatumTAT-STEPHuntington's disease mouse modelExpression
2010
A STEP forward in neural function and degeneration
Baum ML, Kurup P, Xu J, Lombroso PJ. A STEP forward in neural function and degeneration. Communicative & Integrative Biology 2010, 3: 419-422. PMID: 21057629, PMCID: PMC2974069, DOI: 10.4161/cib.3.5.12692.Peer-Reviewed Original ResearchStriatal-enriched phosphataseProtein tyrosine phosphataseTyrosine kinase FynMAP kinases ERK1/2Tyrosine phosphataseKinase FynLocal translationKinases ERK1/2NR1/NR2BProteolytic cleavageNormal regulationNeurodegenerative diseasesSubunitsSynaptic plasticityPhosphataseRegulationGluR2 receptorsNR2B subunitSynaptic strengtheningUbiquitinationRecent progressNeural functionFynPhosphorylationGluR2 subunit
2009
Extrasynaptic NMDA Receptors Couple Preferentially to Excitotoxicity via Calpain-Mediated Cleavage of STEP
Xu J, Kurup P, Zhang Y, Goebel-Goody SM, Wu PH, Hawasli AH, Baum ML, Bibb JA, Lombroso PJ. Extrasynaptic NMDA Receptors Couple Preferentially to Excitotoxicity via Calpain-Mediated Cleavage of STEP. Journal Of Neuroscience 2009, 29: 9330-9343. PMID: 19625523, PMCID: PMC2737362, DOI: 10.1523/jneurosci.2212-09.2009.Peer-Reviewed Original ResearchMeSH KeywordsAlternative SplicingAnimalsBrainCalpainCell DeathCells, CulturedCyclin-Dependent Kinase 5EndocytosisGlutamic AcidIn Vitro TechniquesMiceMice, KnockoutMitogen-Activated Protein Kinase 1Mitogen-Activated Protein Kinase 3NeuronsP38 Mitogen-Activated Protein KinasesProtein Tyrosine Phosphatases, Non-ReceptorRatsRats, Sprague-DawleyReceptors, N-Methyl-D-AspartateSynapsesConceptsStriatal-enriched protein tyrosine phosphataseCalpain cleavage sitesP38 activationCell deathCleavage siteExtracellular signal-regulated kinase 1/2Protein tyrosine phosphataseSignal-regulated kinase 1/2Promotes cell survivalActivation of p38Tyrosine phosphataseSubstrate bindingKinase 1/2ERK1/2 activationCalpain cleavageCell survivalNovel mechanismCalpain-mediated proteolysisReceptors coupleP38NMDAR stimulationPostsynaptic terminalsValid targetCleavage productsSTEP substrates
2008
Expression and function of striatal enriched protein tyrosine phosphatase is profoundly altered in cerebral ischemia
Braithwaite SP, Xu J, Leung J, Urfer R, Nikolich K, Oksenberg D, Lombroso PJ, Shamloo M. Expression and function of striatal enriched protein tyrosine phosphatase is profoundly altered in cerebral ischemia. European Journal Of Neuroscience 2008, 27: 2444-2452. PMID: 18445231, PMCID: PMC2738830, DOI: 10.1111/j.1460-9568.2008.06209.x.Peer-Reviewed Original ResearchConceptsStriatal enriched protein tyrosine phosphataseProtein tyrosine phosphataseTyrosine phosphatasePost-transcriptional levelNovel speciesPhosphorylation stateImportant proteinsMature formKey substrateNMDA receptor subunitsReceptor subunitsActive formSynaptic functionComplex cascadeCritical roleERKMRNA levelsProteinMRNAPERKPhosphataseCleavageCentral nervous systemNervous systemSubunits