1
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Foley K, McKee C, Mayer A, Ganguly A, Barnett D, Ward N, Zhang Y, Nairn A, Xia H. PP1β opposes classic PP1 function, inhibiting spine maturation and promoting LTP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.26.525737. [PMID: 36747779 PMCID: PMC9901188 DOI: 10.1101/2023.01.26.525737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1 (PP1) regulates synaptic plasticity and has been described as a molecular constraint on learning and memory. There are three neuronal isoforms, PP1α, PP1β, and PP1γ, but little is known about their individual functions. PP1α and PP1γ are assumed to mediate the effects of PP1 on learning and memory based on their enrichment at dendritic spines and their preferential binding to neurabin and spinophilin, major PP1 synaptic scaffolding proteins. However, it was recently discovered that human de novo PP1β mutations cause intellectual disability, suggesting an important but ill-defined role for PP1β. In this study, we investigated the functions of each PP1 isoform in hippocampal synaptic physiology using conditional CA1-specific knockout mice. In stark contrast to classic PP1 function, we found that PP1β promotes synaptic plasticity as well as spatial memory. These changes in synaptic plasticity and memory are accompanied by changes in GluA1 phosphorylation, GluN2A levels, and dendritic spine density and morphology, including silent synapse number. These functions of PP1β reveal a previously unidentified signaling pathway regulating spine maturation and plasticity, broadening our understanding of the complex role of PP1 in synaptic physiology.
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2
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Christensen KR, Combs B, Richards C, Grabinski T, Alhadidy MM, Kanaan NM. Phosphomimetics at Ser199/Ser202/Thr205 in Tau Impairs Axonal Transport in Rat Hippocampal Neurons. Mol Neurobiol 2023; 60:3423-3438. [PMID: 36859689 PMCID: PMC10122714 DOI: 10.1007/s12035-023-03281-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/16/2023] [Indexed: 03/03/2023]
Abstract
Our understanding of the biological functions of the tau protein now includes its role as a scaffolding protein involved in signaling regulation, which also has implications for tau-mediated dysfunction and degeneration in Alzheimer's disease and other tauopathies. Recently, we found that pseudophosphorylation at sites linked to the pathology-associated AT8 phosphoepitope of tau disrupts normal fast axonal transport through a protein phosphatase 1 (PP1)-dependent pathway in squid axoplasm. Activation of the pathway and the resulting transport deficits required tau's N-terminal phosphatase-activating domain (PAD) and PP1 but the connection between tau and PP1 was not well defined. Here, we studied functional interactions between tau and PP1 isoforms and their effects on axonal transport in mammalian neurons. First, we found that wild-type tau interacted with PP1α and PP1γ primarily through its microtubule-binding repeat domain. Pseudophosphorylation of tau at S199/S202/T205 (psTau) increased PAD exposure, enhanced interactions with PP1γ, and increased active PP1γ levels in mammalian cells. Expression of psTau also significantly impaired axonal transport in primary rat hippocampal neurons. Deletion of PAD in psTau significantly reduced the interaction with PP1γ, eliminated increases of active PP1γ levels, and rescued axonal transport impairment in neurons. These data suggest that a functional consequence of phosphorylation within S199-T205 in tau, which occurs in AD and several other tauopathies, may be aberrant interaction with and activation of PP1γ and subsequent axonal transport disruption in a PAD-dependent fashion.
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Affiliation(s)
- Kyle R Christensen
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Benjamin Combs
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Collin Richards
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Tessa Grabinski
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
| | - Mohammed M Alhadidy
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas M Kanaan
- Department of Translational Neuroscience, Michigan State University, 400 Monroe Ave NW, Grand Rapids, MI, 49503, USA.
- Neuroscience Program, Michigan State University, East Lansing, MI, 48824, USA.
- Hauenstein Neuroscience Center, Mercy Health Saint Mary's, Grand Rapids, MI, 49503, USA.
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3
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Foley K, Altimimi H, Hou H, Zhang Y, McKee C, Papasergi-Scott MM, Yang H, Mayer A, Ward N, MacLean DM, Nairn AC, Stellwagen D, Xia H. Protein phosphatase-1 inhibitor-2 promotes PP1γ positive regulation of synaptic transmission. Front Synaptic Neurosci 2022; 14:1021832. [PMID: 36276179 PMCID: PMC9582336 DOI: 10.3389/fnsyn.2022.1021832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Inhibitor-2 (I-2) is a prototypic inhibitor of protein phosphatase-1 (PP1), a major serine-threonine phosphatase that regulates synaptic plasticity and learning and memory. Although I-2 is a potent inhibitor of PP1 in vitro, our previous work has elucidated that, in vivo, I-2 may act as a positive regulator of PP1. Here we show that I-2 and PP1γ, but not PP1α, positively regulate synaptic transmission in hippocampal neurons. Moreover, we demonstrated that I-2 enhanced PP1γ interaction with its major synaptic scaffold, neurabin, by Förster resonance energy transfer (FRET)/Fluorescence lifetime imaging microscopy (FLIM) studies, while having a limited effect on PP1 auto-inhibitory phosphorylation. Furthermore, our study indicates that the effect of I-2 on PP1 activity in vivo is dictated by I-2 threonine-72 phosphorylation. Our work thus demonstrates a molecular mechanism by which I-2 positively regulates PP1 function in synaptic transmission.
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4
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Frontotemporal Lobar Dementia Mutant Tau Impairs Axonal Transport through a Protein Phosphatase 1γ-Dependent Mechanism. J Neurosci 2021; 41:9431-9451. [PMID: 34607969 PMCID: PMC8580143 DOI: 10.1523/jneurosci.1914-20.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/19/2021] [Accepted: 08/21/2021] [Indexed: 11/21/2022] Open
Abstract
Pathologic tau modifications are characteristic of Alzheimer's disease and related dementias, but mechanisms of tau toxicity continue to be debated. Inherited mutations in tau cause early onset frontotemporal lobar dementias (FTLD-tau) and are commonly used to model mechanisms of tau toxicity in tauopathies. Previous work in the isolated squid axoplasm model demonstrated that several pathogenic forms of tau inhibit axonal transport through a mechanism involving activation of protein phosphatase 1 (PP1). Here, we determined that P301L and R5L FTLD mutant tau proteins elicit a toxic effect on axonal transport as monomeric proteins. We evaluated interactions of wild-type or mutant tau with specific PP1 isoforms (α, β, and γ) to examine how the interaction contributes to this toxic effect using primary rat hippocampal neurons from both sexes. Pull-down and bioluminescence resonance energy transfer experiments revealed selective interactions of wild-type tau with PP1α and PP1γ isoforms, but not PP1β, which were significantly increased by the P301L tau mutation. The results from proximity ligation assays confirmed the interaction in primary hippocampal neurons. Moreover, expression of FTLD-linked mutant tau in these neurons enhanced levels of active PP1, also increasing the pausing frequency of fluorescently labeled vesicles in both anterograde and retrograde directions. Knockdown of PP1γ, but not PP1α, rescued the cargo-pausing effects of P301L and R5L tau, a result replicated by deleting a phosphatase-activating domain in the amino terminus of P301L tau. These findings support a model of tau toxicity involving aberrant activation of a specific PP1γ-dependent pathway that disrupts axonal transport in neurons. SIGNIFICANCE STATEMENT Tau pathology is closely associated with neurodegeneration in Alzheimer's disease and other tauopathies, but the toxic mechanisms remain a debated topic. We previously proposed that pathologic tau forms induce dysfunction and degeneration through aberrant activation of a PP1-dependent pathway that disrupts axonal transport. Here, we show that tau directly interacts with specific PP1 isoforms, increasing levels of active PP1. Pathogenic tau mutations enhance this interaction, further increasing active PP1 levels and impairing axonal transport in isolated squid axoplasm and primary hippocampal neurons. Mutant-tau-mediated impairment of axonal transport was mediated by PP1γ and a phosphatase-activating domain located at the amino terminus of tau. This work has important implications for understanding and potentially mitigating tau-mediated neurotoxicity in tauopathies.
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5
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Regulation of Synaptic Transmission and Plasticity by Protein Phosphatase 1. J Neurosci 2021; 41:3040-3050. [PMID: 33827970 DOI: 10.1523/jneurosci.2026-20.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/22/2023] Open
Abstract
Protein phosphatases, by counteracting protein kinases, regulate the reversible phosphorylation of many substrates involved in synaptic plasticity, a cellular model for learning and memory. A prominent phosphatase regulating synaptic plasticity and neurologic disorders is the serine/threonine protein phosphatase 1 (PP1). PP1 has three isoforms (α, β, and γ, encoded by three different genes), which are regulated by a vast number of interacting subunits that define their enzymatic substrate specificity. In this review, we discuss evidence showing that PP1 regulates synaptic transmission and plasticity, as well as presenting novel models of PP1 regulation suggested by recent experimental evidence. We also outline the required targeting of PP1 by neurabin and spinophilin to achieve substrate specificity at the synapse to regulate AMPAR and NMDAR function. We then highlight the role of inhibitor-2 in regulating PP1 function in plasticity, including its positive regulation of PP1 function in vivo in memory formation. We also discuss the distinct function of the three PP1 isoforms in synaptic plasticity and brain function, as well as briefly discuss the role of inhibitory phosphorylation of PP1, which has received recent emphasis in the regulation of PP1 activity in neurons.
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Marakhonov AV, Přechová M, Konovalov FA, Filatova AY, Zamkova MA, Kanivets IV, Solonichenko VG, Semenova NA, Zinchenko RA, Treisman R, Skoblov MY. Mutation in PHACTR1 associated with multifocal epilepsy with infantile spasms and hypsarrhythmia. Clin Genet 2021; 99:673-683. [PMID: 33463715 PMCID: PMC8629116 DOI: 10.1111/cge.13926] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 11/28/2022]
Abstract
A young boy with multifocal epilepsy with infantile spasms and hypsarrhythmia with minimal organic lesions of brain structures underwent DNA diagnosis using whole‐exome sequencing. A heterozygous amino‐acid substitution p.L519R in a PHACTR1 gene was identified. PHACTR1 belongs to a protein family of G‐actin binding protein phosphatase 1 (PP1) cofactors and was not previously associated with a human disease. The missense single nucleotide variant in the proband was shown to occur de novo in the paternal allele. The mutation was shown in vitro to reduce the affinity of PHACTR1 for G‐actin, and to increase its propensity to form complexes with the catalytic subunit of PP1. These properties are associated with altered subcellular localization of PHACTR1 and increased ability to induce cytoskeletal rearrangements. Although the molecular role of the PHACTR1 in neuronal excitability and differentiation remains to be defined, PHACTR1 has been previously shown to be involved in Slack channelopathy pathogenesis, consistent with our findings. We conclude that this activating mutation in PHACTR1 causes a severe type of sporadic multifocal epilepsy in the patient.
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Affiliation(s)
- Andrey V Marakhonov
- Laboratory of Genetic Epidemiology, Laboratory of Functional Genomics, Department of Genetic Counseling, Research Centre for Medical Genetics, Moscow, Russia
| | - Magdalena Přechová
- Laboratory of Integrative Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.,Signalling and Transcription Laboratory, Francis Crick Institute, London, UK
| | | | - Alexandra Yu Filatova
- Laboratory of Genetic Epidemiology, Laboratory of Functional Genomics, Department of Genetic Counseling, Research Centre for Medical Genetics, Moscow, Russia
| | - Maria A Zamkova
- Laboratory of Regulatory Mechanisms in Immunity, Institute of Carcinogenesis, N.N. Blokhin Russian Cancer Research Center, Moscow, Russia
| | - Ilya V Kanivets
- Laboratory of Molecular Pathology, Genomed Ltd., Moscow, Russia.,Medical Genetic Centre, Filatov Moscow Pediatric Clinical Hospital, Moscow, Russia
| | | | - Natalia A Semenova
- Laboratory of Genetic Epidemiology, Laboratory of Functional Genomics, Department of Genetic Counseling, Research Centre for Medical Genetics, Moscow, Russia
| | - Rena A Zinchenko
- Laboratory of Genetic Epidemiology, Laboratory of Functional Genomics, Department of Genetic Counseling, Research Centre for Medical Genetics, Moscow, Russia.,N.A. Semashko National Research Institute of Public Health, Moscow, Russia
| | - Richard Treisman
- Signalling and Transcription Laboratory, Francis Crick Institute, London, UK
| | - Mikhail Yu Skoblov
- Laboratory of Genetic Epidemiology, Laboratory of Functional Genomics, Department of Genetic Counseling, Research Centre for Medical Genetics, Moscow, Russia
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Miyata T, Kikuchi K, Ihara D, Kaito M, Ishibashi Y, Hakamata T, Yamada T, Ishikawa M, Mizukoshi M, Shoji S, Fukuchi M, Tsuda M, Hida Y, Ohtsuka T, Kaneda M, Tabuchi A. Neuron-enriched phosphatase and actin regulator 3 (Phactr3)/ nuclear scaffold-associated PP1-inhibiting protein (Scapinin) regulates dendritic morphology via its protein phosphatase 1-binding domain. Biochem Biophys Res Commun 2020; 528:322-329. [DOI: 10.1016/j.bbrc.2020.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023]
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8
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Lin CH, Lin WD, Chou IC, Lee IC, Fan HC, Hong SY. Epileptic spasms in PPP1CB-associated Noonan-like syndrome: a case report with clinical and therapeutic implications. BMC Neurol 2018; 18:150. [PMID: 30236064 PMCID: PMC6148994 DOI: 10.1186/s12883-018-1157-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/14/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Noonan syndrome-like disorder with loose anagen hair-2 (NSLH2) is an extremely rare disease caused by a heterozygous mutation in the PPP1CB gene on chromosome 2p23. The syndrome causes not only numerous dysmorphic features but also hypotonia, developmental delay, and even intellectual disability. We report the first case of NSLH2 in Asia and the 16th in the world. Moreover, the first case of PPP1CB-related infantile spasms. The clinical and therapeutic significance is outlined in this paper. CASE PRESENTATION We found a male infant presented with severe intractable epileptic spasms. Although certain clinical features of somatic dysmorphism were noted, numerous laboratory and neuroimaging studies failed to identify the cause. To determine the underlying etiology, whole-exome sequencing was conducted. We identified a de novo heterozygous mutation, NM_206876.1: c.548A > C (p.Glu183Ala), in the PPP1CB gene. His seizures were almost refractory to conventional antiepileptic drugs but relative seizure control was eventually achieved with a ketogenic diet. CONCLUSION This result expands the clinical spectrum of NSLH2 and strengthens the association between the PPP1CB gene and epileptic seizures. Furthermore, we suggest that the ketogenic diet can offer seizure reduction in particular drug-resistant epilepsy syndromes. Additional studies are warranted to clarify the pathogenic mechanisms underlying this PPP1CB mutation in epileptic seizures.
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Affiliation(s)
- Chien-Heng Lin
- Division of Pediatrics Pulmonology, China Medical University, Children's Hospital, Taichung, Taiwan
| | - Wei-De Lin
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
| | - I-Ching Chou
- Division of Pediatrics Neurology, China Medical University, Children's Hospital, Taichung, Taiwan.,Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Inn-Chi Lee
- Department of Pediatrics, Chung Shan Medical University Hospital and Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Hueng-Chuen Fan
- Department of Pediatrics, Tungs' Taichung Metroharbor Hospital, Wuchi, 435, Taichung, Taiwan.,Department of Nursing, Jen-Teh Junior College of Medicine, Nursing and Management, 356, Miaoli, Taiwan
| | - Syuan-Yu Hong
- Division of Pediatrics Neurology, China Medical University, Children's Hospital, Taichung, Taiwan. .,Department of Pediatrics, China Medical University Hospital, 2 Yuh-Der Road, Taichung, 404, Taiwan.
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9
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HIV-1 Protein Tat 1-72 Impairs Neuronal Dendrites via Activation of PP1 and Regulation of the CREB/BDNF Pathway. Virol Sin 2018; 33:261-269. [PMID: 29737506 DOI: 10.1007/s12250-018-0031-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/02/2018] [Indexed: 12/18/2022] Open
Abstract
Despite the success of combined antiretroviral therapy in recent years, the prevalence of human immunodeficiency virus (HIV)-associated neurocognitive disorders in people living with HIV-1 is increasing, significantly reducing the health-related quality of their lives. Although neurons cannot be infected by HIV-1, shed viral proteins such as transactivator of transcription (Tat) can cause dendritic damage. However, the detailed molecular mechanism of Tat-induced neuronal impairment remains unknown. In this study, we first showed that recombinant Tat (1-72 aa) induced neurotoxicity in primary cultured mouse neurons. Second, exposure to Tat1-72 was shown to reduce the length and number of dendrites in cultured neurons. Third, Tat1-72 (0-6 h) modulates protein phosphatase 1 (PP1) expression and enhances its activity by decreasing the phosphorylation level of PP1 at Thr320. Finally, Tat1-72 (24 h) downregulates CREB activity and CREB-mediated gene (BDNF, c-fos, Egr-1) expression. Together, these findings suggest that Tat1-72 might impair cognitive function by regulating the activity of PP1 and the CREB/BDNF pathway.
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10
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Physiological and Pathological Roles of CaMKII-PP1 Signaling in the Brain. Int J Mol Sci 2017; 19:ijms19010020. [PMID: 29271887 PMCID: PMC5795971 DOI: 10.3390/ijms19010020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 01/25/2023] Open
Abstract
Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII), a multifunctional serine (Ser)/threonine (Thr) protein kinase, regulates diverse activities related to Ca2+-mediated neuronal plasticity in the brain, including synaptic activity and gene expression. Among its regulators, protein phosphatase-1 (PP1), a Ser/Thr phosphatase, appears to be critical in controlling CaMKII-dependent neuronal signaling. In postsynaptic densities (PSDs), CaMKII is required for hippocampal long-term potentiation (LTP), a cellular process correlated with learning and memory. In response to Ca2+ elevation during hippocampal LTP induction, CaMKIIα, an isoform that translocates from the cytosol to PSDs, is activated through autophosphorylation at Thr286, generating autonomous kinase activity and a prolonged Ca2+/CaM-bound state. Moreover, PP1 inhibition enhances Thr286 autophosphorylation of CaMKIIα during LTP induction. By contrast, CaMKII nuclear import is regulated by Ser332 phosphorylation state. CaMKIIδ3, a nuclear isoform, is dephosphorylated at Ser332 by PP1, promoting its nuclear translocation, where it regulates transcription. In this review, we summarize physio-pathological roles of CaMKII/PP1 signaling in neurons. CaMKII and PP1 crosstalk and regulation of gene expression is important for neuronal plasticity as well as survival and/or differentiation.
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11
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Glausier JR, Roberts RC, Lewis DA. Ultrastructural analysis of parvalbumin synapses in human dorsolateral prefrontal cortex. J Comp Neurol 2017; 525:2075-2089. [PMID: 28074478 PMCID: PMC5397325 DOI: 10.1002/cne.24171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 12/11/2022]
Abstract
Coordinated activity of neural circuitry in the primate dorsolateral prefrontal cortex (DLPFC) supports a range of cognitive functions. Altered DLPFC activation is implicated in a number of human psychiatric and neurological illnesses. Proper DLPFC activity is, in part, maintained by two populations of neurons containing the calcium-binding protein parvalbumin (PV): local inhibitory interneurons that form Type II synapses, and long-range glutamatergic inputs from the thalamus that form Type I synapses. Understanding the contributions of each PV neuronal population to human DLPFC function requires a detailed examination of their anatomical properties. Consequently, we performed an electron microscopic analysis of (1) the distribution of PV immunoreactivity within the neuropil, (2) the properties of dendritic shafts of PV-IR interneurons, (3) Type II PV-IR synapses from PV interneurons, and (4) Type I PV-IR synapses from long-range projections, within the superficial and middle laminar zones of the human DLPFC. In both laminar zones, Type II PV-IR synapses from interneurons comprised ∼60% of all PV-IR synapses, and Type I PV-IR synapses from putative thalamocortical terminals comprised the remaining ∼40% of PV-IR synapses. Thus, the present study suggests that innervation from PV-containing thalamic nuclei extends across superficial and middle layers of the human DLPFC. These findings contrast with previous ultrastructural studies in monkey DLPFC where Type I PV-IR synapses were not identified in the superficial laminar zone. The presumptive added modulation of DLPFC circuitry by the thalamus in human may contribute to species-specific, higher-order functions.
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Affiliation(s)
- Jill R. Glausier
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Rosalinda C. Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - David A. Lewis
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
- Department of Neuroscience, University of Pittsburgh School of Arts and Sciences, Pittsburgh, PA 15213
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12
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Long-term depression-associated signaling is required for an in vitro model of NMDA receptor-dependent synapse pruning. Neurobiol Learn Mem 2016; 138:39-53. [PMID: 27794462 DOI: 10.1016/j.nlm.2016.10.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/20/2016] [Accepted: 10/25/2016] [Indexed: 02/06/2023]
Abstract
Activity-dependent pruning of synaptic contacts plays a critical role in shaping neuronal circuitry in response to the environment during postnatal brain development. Although there is compelling evidence that shrinkage of dendritic spines coincides with synaptic long-term depression (LTD), and that LTD is accompanied by synapse loss, whether NMDA receptor (NMDAR)-dependent LTD is a required step in the progression toward synapse pruning is still unknown. Using repeated applications of NMDA to induce LTD in dissociated rat neuronal cultures, we found that synapse density, as measured by colocalization of fluorescent markers for pre- and postsynaptic structures, was decreased irrespective of the presynaptic marker used, post-treatment recovery time, and the dendritic location of synapses. Consistent with previous studies, we found that synapse loss could occur without apparent net spine loss or cell death. Furthermore, synapse loss was unlikely to require direct contact with microglia, as the number of these cells was minimal in our culture preparations. Supporting a model by which NMDAR-LTD is required for synapse loss, the effect of NMDA on fluorescence colocalization was prevented by phosphatase and caspase inhibitors. In addition, gene transcription and protein translation also appeared to be required for loss of putative synapses. These data support the idea that NMDAR-dependent LTD is a required step in synapse pruning and contribute to our understanding of the basic mechanisms of this developmental process.
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13
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Ma L, Bayram Y, McLaughlin HM, Cho MT, Krokosky A, Turner CE, Lindstrom K, Bupp CP, Mayberry K, Mu W, Bodurtha J, Weinstein V, Zadeh N, Alcaraz W, Powis Z, Shao Y, Scott DA, Lewis AM, White JJ, Jhangiani SN, Gulec EY, Lalani SR, Lupski JR, Retterer K, Schnur RE, Wentzensen IM, Bale S, Chung WK. De novo missense variants in PPP1CB are associated with intellectual disability and congenital heart disease. Hum Genet 2016; 135:1399-1409. [PMID: 27681385 DOI: 10.1007/s00439-016-1731-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022]
Abstract
Intellectual disabilities are genetically heterogeneous and can be associated with congenital anomalies. Using whole-exome sequencing (WES), we identified five different de novo missense variants in the protein phosphatase-1 catalytic subunit beta (PPP1CB) gene in eight unrelated individuals who share an overlapping phenotype of dysmorphic features, macrocephaly, developmental delay or intellectual disability (ID), congenital heart disease, short stature, and skeletal and connective tissue abnormalities. Protein phosphatase-1 (PP1) is a serine/threonine-specific protein phosphatase involved in the dephosphorylation of a variety of proteins. The PPP1CB gene encodes a PP1 subunit that regulates the level of protein phosphorylation. All five altered amino acids we observed are highly conserved among the PP1 subunit family, and all are predicted to disrupt PP1 subunit binding and impair dephosphorylation. Our data suggest that our heterozygous de novo PPP1CB pathogenic variants are associated with syndromic intellectual disability.
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Affiliation(s)
- Lijiang Ma
- Department of Pediatrics, Columbia University Medical Center, 1150 St. Nicholas Avenue, New York, NY, 10032, USA
| | - Yavuz Bayram
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | | | - Alyson Krokosky
- Walter Reed National Military Medical Center, Bethesda, MD, USA
| | | | - Kristin Lindstrom
- Division of Genetics and Metabolism, Phoenix Children's Hospital, Phoenix, AZ, USA
| | | | | | - Weiyi Mu
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Joann Bodurtha
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Veronique Weinstein
- Division of Genetics and Metabolism, Children's National Medical Center, Washington, DC, USA
| | | | | | - Zöe Powis
- Ambry Genetics, Aliso Viejo, CA, USA
| | - Yunru Shao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Andrea M Lewis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Janson J White
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shalani N Jhangiani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Elif Yilmaz Gulec
- Medical Genetics Section, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Seema R Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Texas Children's Hospital, Houston, TX, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | | | | | | | | | - Wendy K Chung
- Department of Pediatrics, Columbia University Medical Center, 1150 St. Nicholas Avenue, New York, NY, 10032, USA.
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14
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mGluR4-containing corticostriatal terminals: synaptic interactions with direct and indirect pathway neurons in mice. Brain Struct Funct 2016; 221:4589-4599. [PMID: 26832920 DOI: 10.1007/s00429-016-1187-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/07/2016] [Indexed: 10/22/2022]
Abstract
Glutamatergic afferents from the cerebral cortex are the main excitatory drive of striatal projection neurons. The metabotropic glutamate receptor 4 (mGluR4) presynaptically modulates transmission at corticostriatal synapses, and is considered as a potent drug target for Parkinson's disease and other brain disorders. To better characterize the anatomical substrate that underlies the functional effects of mGluR4 in the striatum, we undertook electron microscopic localization studies of mGluR4 expression in the mouse striatum. Our data demonstrate that more than 80 % mGluR4-immunoreactive structures are accounted for by unmyelinated axons and axon terminals, and that almost 50 % putative glutamatergic terminals (i.e. forming asymmetric synapses) express mGluR4 in the mouse striatum. Using vGluT1 as a presynaptic marker of glutamatergic corticostriatal boutons, our findings indicate: (1) all striatal mGluR4-positive terminals co-express vGluT1 immunoreactivity, (2) 44.3 % total striatal glutamatergic terminals co-express vGluT1 and mGluR4, and (3) mGluR4 is expressed in 73.4 % of total striatal vGluT1-positive terminals. To determine if mGluR4 terminals target preferentially direct vs. indirect pathway neurons, mGluR4 immunostaining was combined with D1 receptor immunoreactivity. These data showed that around 30 % mGluR4-immunoreactive glutamatergic terminals target D1 receptor-positive spines (i.e. direct pathway neurons), while almost 70 % formed synapses with D1 receptor-negative spines (i.e. putative indirect pathway neurons). Thus, these immuno-electron microscopic studies suggest that pre-synaptic mGluR4 in striatal glutamatergic terminals is expressed almost exclusively in cortical boutons to subserve regulatory influences upon a large contingent of corticostriatal terminals that preferentially target putative "indirect" pathway striatal projection neurons in mice. These observations provide a rationale for the use of mGluR4 allosteric potentiator as a potential therapy in Parkinson's disease.
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15
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Silva JV, Freitas MJ, Felgueiras J, Fardilha M. The power of the yeast two-hybrid system in the identification of novel drug targets: building and modulating PPP1 interactomes. Expert Rev Proteomics 2015; 12:147-58. [PMID: 25795147 DOI: 10.1586/14789450.2015.1024226] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Since the description of the yeast two-hybrid (Y2H) method, it has become more and more evident that it is the most commonly used method to identify protein-protein interactions (PPIs). The improvements in the original Y2H methodology in parallel with the idea that PPIs are promising drug targets, offer an excellent opportunity to apply the principles of this molecular biology technique to the pharmaceutical field. Additionally, the theoretical developments in the networks field make PPI networks very useful frameworks that facilitate many discoveries in biomedicine. This review highlights the relevance of Y2H in the determination of PPIs, specifically phosphoprotein phosphatase 1 interactions, and its possible outcomes in pharmaceutical research.
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Affiliation(s)
- Joana Vieira Silva
- Signal Transduction Laboratory, Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Aveiro, Portugal
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16
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Gershoni-Emek N, Mazza A, Chein M, Gradus-Pery T, Xiang X, Li KW, Sharan R, Perlson E. Proteomic Analysis of Dynein-Interacting Proteins in Amyotrophic Lateral Sclerosis Synaptosomes Reveals Alterations in the RNA-Binding Protein Staufen1. Mol Cell Proteomics 2015; 15:506-22. [PMID: 26598648 DOI: 10.1074/mcp.m115.049965] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Indexed: 12/12/2022] Open
Abstract
Synapse disruption takes place in many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). However, the mechanistic understanding of this process is still limited. We set out to study a possible role for dynein in synapse integrity. Cytoplasmic dynein is a multisubunit intracellular molecule responsible for diverse cellular functions, including long-distance transport of vesicles, organelles, and signaling factors toward the cell center. A less well-characterized role dynein may play is the spatial clustering and anchoring of various factors including mRNAs in distinct cellular domains such as the neuronal synapse. Here, in order to gain insight into dynein functions in synapse integrity and disruption, we performed a screen for novel dynein interactors at the synapse. Dynein immunoprecipitation from synaptic fractions of the ALS model mSOD1(G93A) and wild-type controls, followed by mass spectrometry analysis on synaptic fractions of the ALS model mSOD1(G93A) and wild-type controls, was performed. Using advanced network analysis, we identified Staufen1, an RNA-binding protein required for the transport and localization of neuronal RNAs, as a major mediator of dynein interactions via its interaction with protein phosphatase 1-beta (PP1B). Both in vitro and in vivo validation assays demonstrate the interactions of Staufen1 and PP1B with dynein, and their colocalization with synaptic markers was altered as a result of two separate ALS-linked mutations: mSOD1(G93A) and TDP43(A315T). Taken together, we suggest a model in which dynein's interaction with Staufen1 regulates mRNA localization along the axon and the synapses, and alterations in this process may correlate with synapse disruption and ALS toxicity.
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Affiliation(s)
- Noga Gershoni-Emek
- From the ‡Sagol School of Neuroscience and Department of Physiology and Pharmacology, Sackler School of Medicine and
| | - Arnon Mazza
- §Blavatnik School of Computer Science, Tel Aviv University, Israel
| | - Michael Chein
- From the ‡Sagol School of Neuroscience and Department of Physiology and Pharmacology, Sackler School of Medicine and
| | - Tal Gradus-Pery
- From the ‡Sagol School of Neuroscience and Department of Physiology and Pharmacology, Sackler School of Medicine and
| | - Xin Xiang
- ¶Department of Biochemistry and Molecular Biology, the Uniformed Services University of Health Sciences, Bethesda, MD
| | - Ka Wan Li
- ‖Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, the Netherlands
| | - Roded Sharan
- §Blavatnik School of Computer Science, Tel Aviv University, Israel
| | - Eran Perlson
- From the ‡Sagol School of Neuroscience and Department of Physiology and Pharmacology, Sackler School of Medicine and
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17
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Martins F, Rebelo S, Santos M, Cotrim CZ, da Cruz e Silva EF, da Cruz e Silva OAB. BRI2 and BRI3 are functionally distinct phosphoproteins. Cell Signal 2015; 28:130-44. [PMID: 26515131 DOI: 10.1016/j.cellsig.2015.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/24/2015] [Indexed: 01/21/2023]
Abstract
Three BRI protein family members have been identified. Among these are BRI3 and BRI2, the latter is associated with Familial Danish and Familial British dementias. 'In silico' sequence analysis identified putative PP1 binding sites in BRI2 and BRI3. This is singularly important, given that protein phosphorylation is a major mechanism regulating intracellular processes. Protein phosphatase 1 (PP1) interacting proteins (PIPs) are fundamental in determining substrate specificity and subcellular localization of this phosphatase. More than 200 PIPs have thus far been reported. Both BRI2 and BRI3 are type II transmembrane glycoproteins relevant in neuronal systems. Using Myc-BRI2 and Myc-BRI3, wild type and PP1 binding mutant constructs, it was possible to show, for the first time, that in fact BRI2 and BRI3 bind PP1. The complexes BRI2:PP1 and BRI3:PP1 were validated in vitro and in vivo. The subcellular distribution of BRI2 and BRI3 is similar; both localize to the perinuclear area and Golgi apparatus in non-neuronal cells. However, in SH-SY5Y cells, BRI2 and BRI3 could also be detected in elongated cellular projections ('processes') and in rat cortical neurons both are broadly distributed throughout the cell body, neuritis and the nucleus. Consistently, co-localization of BRI2 and BRI3 with PP1 was evident. The functional significance of these complexes is apparent given that both BRI proteins are substrates of PP1, thus simultaneously this is the first report of BRI2 and BRI3 as phosphoproteins. Moreover, we show that when BRI2 is phosphorylated a significant increase in neuronal outgrowth and differentiation is evident. Interestingly, the Alzheimer's amyloid precursor protein (APP), forms a trimeric complex composed of PP1 and Fe65, with PP1 having the capacity to dephosphorylate APP at Thr668 residue. The emerging consensus appears to be that PP1 containing complexes are crucial in regulating signaling events underlying neuropathological conditions.
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Affiliation(s)
- Filipa Martins
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal.
| | - Mariana Santos
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Cândida Zita Cotrim
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Edgar F da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Odete A B da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
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18
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Shioda N, Sawai M, Ishizuka Y, Shirao T, Fukunaga K. Nuclear Translocation of Calcium/Calmodulin-dependent Protein Kinase IIδ3 Promoted by Protein Phosphatase-1 Enhances Brain-derived Neurotrophic Factor Expression in Dopaminergic Neurons. J Biol Chem 2015; 290:21663-75. [PMID: 26163515 DOI: 10.1074/jbc.m115.664920] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Indexed: 02/05/2023] Open
Abstract
We have reported previously that dopamine D2 receptor stimulation activates calcium/calmodulin-dependent protein kinase II (CaMKII) δ3, a CaMKII nuclear isoform, increasing BDNF gene expression. However, the mechanisms underlying that activity remained unclear. Here we report that CaMKIIδ3 is dephosphorylated at Ser(332) by protein phosphatase 1 (PP1), promoting CaMKIIδ3 nuclear translocation. Neuro-2a cells transfected with CaMKIIδ3 showed cytoplasmic and nuclear staining, but the staining was predominantly nuclear when CaMKIIδ3 was coexpressed with PP1. Indeed, PP1 and CaMKIIδ3 coexpression significantly increased nuclear CaMKII activity and enhanced BDNF expression. In support of this idea, chronic administration of the dopamine D2 receptor partial agonist aripiprazole increased PP1 activity and promoted nuclear CaMKIIδ3 translocation and BDNF expression in the rat brain substantia nigra. Moreover, aripiprazole treatment enhanced neurite extension and inhibited cell death in cultured dopaminergic neurons, effects blocked by PP1γ knockdown. Taken together, nuclear translocation of CaMKIIδ3 following dephosphorylation at Ser(332) by PP1 likely accounts for BDNF expression and subsequent neurite extension and survival of dopaminergic neurons.
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Affiliation(s)
- Norifumi Shioda
- From the Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan and
| | - Masahiro Sawai
- From the Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan and
| | - Yuta Ishizuka
- the Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
| | - Tomoaki Shirao
- the Department of Neurobiology and Behavior, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
| | - Kohji Fukunaga
- From the Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, 980-8578, Japan and
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19
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Lowenthal MS, Markey SP, Dosemeci A. Quantitative mass spectrometry measurements reveal stoichiometry of principal postsynaptic density proteins. J Proteome Res 2015; 14:2528-38. [PMID: 25874902 DOI: 10.1021/acs.jproteome.5b00109] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Quantitative studies are presented of postsynaptic density (PSD) fractions from rat cerebral cortex with the ultimate goal of defining the average copy numbers of proteins in the PSD complex. Highly specific and selective isotope dilution mass spectrometry assays were developed using isotopically labeled polypeptide concatemer internal standards. Interpretation of PSD protein stoichiometry was achieved as a molar ratio with respect to PSD-95 (SAP-90, DLG4), and subsequently, copy numbers were estimated using a consensus literature value for PSD-95. Average copy numbers for several proteins at the PSD were estimated for the first time, including those for AIDA-1, BRAGs, and densin. Major findings include evidence for the high copy number of AIDA-1 in the PSD (144 ± 30)-equivalent to that of the total GKAP family of proteins (150 ± 27)-suggesting that AIDA-1 is an element of the PSD scaffold. The average copy numbers for NMDA receptor sub-units were estimated to be 66 ± 18, 27 ± 9, and 45 ± 15, respectively, for GluN1, GluN2A, and GluN2B, yielding a total of 34 ± 10 NMDA channels. Estimated average copy numbers for AMPA channels and their auxiliary sub-units TARPs were 68 ± 36 and 144 ± 38, respectively, with a stoichiometry of ∼1:2, supporting the assertion that most AMPA receptors anchor to the PSD via TARP sub-units. This robust, quantitative analysis of PSD proteins improves upon and extends the list of major PSD components with assigned average copy numbers in the ongoing effort to unravel the complex molecular architecture of the PSD.
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Affiliation(s)
- Mark S Lowenthal
- †Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sanford P Markey
- †Biomolecular Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.,‡Laboratory of Neurotoxicology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ayse Dosemeci
- §Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, United States
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20
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Korrodi-Gregório L, Esteves SLC, Fardilha M. Protein phosphatase 1 catalytic isoforms: specificity toward interacting proteins. Transl Res 2014; 164:366-91. [PMID: 25090308 DOI: 10.1016/j.trsl.2014.07.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 01/21/2023]
Abstract
The coordinated and reciprocal action of serine-threonine protein kinases and protein phosphatases produces transitory phosphorylation, a fundamental regulatory mechanism for many biological processes. Phosphoprotein phosphatase 1 (PPP1), a major serine-threonine phosphatase, in particular, is ubiquitously distributed and regulates a broad range of cellular functions, including glycogen metabolism, cell cycle progression, and muscle relaxation. PPP1 has evolved effective catalytic machinery but in vitro lacks substrate specificity. In vivo, its specificity is achieved not only by the existence of different PPP1 catalytic isoforms, but also by binding of the catalytic moiety to a large number of regulatory or targeting subunits. Here, we will address exhaustively the existence of diverse PPP1 catalytic isoforms and the relevance of their specific partners and consequent functions.
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Affiliation(s)
- Luís Korrodi-Gregório
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
| | - Sara L C Esteves
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal
| | - Margarida Fardilha
- Laboratório de Transdução de Sinais, Departamento de Biologia, Secção Autónoma de Ciências de Saúde, Centro de Biologia Celular, Universidade de Aveiro, Aveiro, Portugal.
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21
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Santos M, Rebelo S, Van Kleeff PJM, Kim CE, Dauer WT, Fardilha M, da Cruz e Silva OA, da Cruz e Silva EF. The nuclear envelope protein, LAP1B, is a novel protein phosphatase 1 substrate. PLoS One 2013; 8:e76788. [PMID: 24116158 PMCID: PMC3792071 DOI: 10.1371/journal.pone.0076788] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/03/2013] [Indexed: 12/11/2022] Open
Abstract
Protein phosphatase 1 (PP1) binding proteins are quintessential regulators, determining substrate specificity and defining subcellular localization and activity of the latter. Here, we describe a novel PP1 binding protein, the nuclear membrane protein lamina associated polypeptide 1B (LAP1B), which interacts with the DYT1 dystonia protein torsinA. The PP1 binding domain in LAP1B was here identified as the REVRF motif at amino acids 55-59. The LAP1B:PP1 complex can be immunoprecipitated from cells in culture and rat cortex and the complex was further validated by yeast co-transformations and blot overlay assays. PP1, which is enriched in the nucleus, binds to the N-terminal nuclear domain of LAP1B, as shown by immunocolocalization and domain specific binding studies. PP1 dephosphorylates LAP1B, confirming the physiological relevance of this interaction. These findings place PP1 at a key position to participate in the pathogenesis of DYT1 dystonia and related nuclear envelope-based diseases.
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Affiliation(s)
- Mariana Santos
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Paula J. M. Van Kleeff
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
| | - Connie E. Kim
- Departments of Neurology and Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - William T. Dauer
- Departments of Neurology and Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Margarida Fardilha
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
| | - Odete A. da Cruz e Silva
- Health Sciences Department, Centre for Cell Biology, Neuroscience Laboratory, University of Aveiro, Aveiro, Portugal
| | - Edgar F. da Cruz e Silva
- Health Sciences Department, Centre for Cell Biology, Signal Transduction Laboratory, University of Aveiro, Aveiro, Portugal
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22
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Monroe JD, Heathcote RD. Protein phosphatases regulate the growth of developing neurites. Int J Dev Neurosci 2013; 31:250-7. [DOI: 10.1016/j.ijdevneu.2013.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/04/2013] [Accepted: 01/21/2013] [Indexed: 01/01/2023] Open
Affiliation(s)
- Jerry D. Monroe
- Department of Biological SciencesUniversity of Wisconsin–Milwaukee Box 413MilwaukeeWI53201USA
| | - R. David Heathcote
- Department of Biological SciencesUniversity of Wisconsin–Milwaukee Box 413MilwaukeeWI53201USA
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23
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Esteves SLC, Korrodi-Gregório L, Cotrim CZ, van Kleeff PJM, Domingues SC, da Cruz e Silva OAB, Fardilha M, da Cruz e Silva EF. Protein phosphatase 1γ isoforms linked interactions in the brain. J Mol Neurosci 2012; 50:179-97. [PMID: 23080069 DOI: 10.1007/s12031-012-9902-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 10/03/2012] [Indexed: 01/03/2023]
Abstract
Posttranslational protein modifications, in particular reversible protein phosphorylation, are important regulatory mechanisms involved in cellular signaling transduction pathways. Thousands of human proteins are phosphorylatable and the tight regulation of phosphorylation states is crucial for cell maintenance and development. Protein phosphorylation occurs primarily on serine, threonine, and tyrosine residues, through the antagonistic actions of protein kinases and phosphatases. The catalytic subunit of protein phosphatase 1 (PP1), a major Ser/Thr-phosphatase, associates with a large variety of regulatory subunits that define substrate specificity and determine specific cellular pathway responses. PP1 has been shown to bind to different proteins in the brain in order to execute key and differential functions. This work reports the identification of proteins expressed in the human brain that interact with PP1γ1 and PP1γ2 isoforms by the yeast two-hybrid method. An extensive search of PP1-binding motifs was performed for the proteins identified, revealing already known PP1 regulators but also novel interactors. Moreover, our results were integrated with the data of PP1γ interacting proteins from several public web databases, permitting the development of physical maps of the novel interactions. The PP1γ interactome thus obtained allowed for the identification of novel PP1 interacting proteins, supporting novel functions of PP1γ isoforms in the human brain.
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Affiliation(s)
- Sara L C Esteves
- Signal Transduction Laboratory, Centre for Cell Biology, Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
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24
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Harris KM, Weinberg RJ. Ultrastructure of synapses in the mammalian brain. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a005587. [PMID: 22357909 DOI: 10.1101/cshperspect.a005587] [Citation(s) in RCA: 275] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The morphology and molecular composition of synapses provide the structural basis for synaptic function. This article reviews the electron microscopy of excitatory synapses on dendritic spines, using data from rodent hippocampus, cerebral cortex, and cerebellar cortex. Excitatory synapses have a prominent postsynaptic density, in contrast with inhibitory synapses, which have less dense presynaptic or postsynaptic specializations and are usually found on the cell body or proximal dendritic shaft. Immunogold labeling shows that the presynaptic active zone provides a scaffold for key molecules involved in the release of neurotransmitter, whereas the postsynaptic density contains ligand-gated ionic channels, other receptors, and a complex network of signaling molecules. Delineating the structure and molecular organization of these axospinous synapses represents a crucial step toward understanding the mechanisms that underlie synaptic transmission and the dynamic modulation of neurotransmission associated with short- and long-term synaptic plasticity.
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Affiliation(s)
- Kristen M Harris
- Center for Learning and Memory, Neurobiology Section, University of Texas, Austin, 78712, USA.
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25
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Regulation of postsynaptic gephyrin cluster size by protein phosphatase 1. Mol Cell Neurosci 2010; 44:201-9. [PMID: 20206270 DOI: 10.1016/j.mcn.2010.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 02/22/2010] [Accepted: 02/23/2010] [Indexed: 01/21/2023] Open
Abstract
The scaffolding protein gephyrin is essential for the clustering of glycine and GABA(A) receptors (GABA(A)Rs) at inhibitory synapses. Here, we provide evidence that the size of the postsynaptic gephyrin scaffold is controlled by dephosphorylation reactions. Treatment of cultured hippocampal neurons with the protein phosphatase inhibitors calyculin A and okadaic acid reduced the size of postsynaptic gephyrin clusters and increased cytoplasmic gephyrin staining. Protein phosphatase 1 (PP1) was found to colocalize with gephyrin at selected postsynaptic sites and to interact with gephyrin in transfected cells and brain extracts. Alanine or glutamate substitution of the two established serine/threonine phosphorylation sites in gephyrin failed to affect its clustering at inhibitory synapses and its ability to recruit gamma2 subunit containing GABA(A)Rs. Our data are consistent with the postsynaptic gephyrin scaffold acting as a platform for PP1, which regulates gephyrin cluster size by dephosphorylation of gephyrin- or cytoskeleton-associated proteins.
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26
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Glausier JR, Maddox M, Hemmings HC, Nairn AC, Greengard P, Muly EC. Localization of dopamine- and cAMP-regulated phosphoprotein-32 and inhibitor-1 in area 9 of Macaca mulatta prefrontal cortex. Neuroscience 2010; 167:428-38. [PMID: 20156529 DOI: 10.1016/j.neuroscience.2010.02.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 12/21/2009] [Accepted: 02/09/2010] [Indexed: 01/29/2023]
Abstract
The actions of dopamine D1 family receptors (D1R) depend upon a signal transduction cascade that modulates the phosphorylation state of important effector proteins, such as glutamate receptors and ion channels. This is accomplished both through activation of protein kinase A (PKA) and the inhibition of protein phosphatase-1 (PP1). Inhibition of PP1 occurs through PKA-mediated phosphorylation of dopamine- and cAMP-regulated phosphoprotein 32 kDa (DARPP-32) or the related protein inhibitor-1 (I-1), and the availability of DARPP-32 is essential to the functional outcome of D1R activation in the basal ganglia. While D1R activation is critical for prefrontal cortex (PFC) function, especially working memory, the functional role played by DARPP-32 or I-1 is less clear. In order to examine this more thoroughly, we have utilized immunoelectron microscopy to quantitatively determine the localization of DARPP-32 and I-1 in the neuropil of the rhesus monkey PFC. Both were distributed widely in the different components of the neuropil, but were enriched in dendritic shafts. I-1 label was more frequently identified in axon terminals than was DARPP-32, and DARPP-32 label was more frequently identified in glia than was I-1. We also quantified the extent to which these proteins were found in dendritic spines. DARPP-32 and I-1 were present in small subpopulations of dendritic spines, (4.4% and 7.7% and respectively), which were substantially smaller than observed for D1R in our previous studies (20%). Double-label experiments did not find evidence for colocalization of D1R and DARPP-32 or I-1 in spines or terminals. Thus, at the least, not all prefrontal spines which contain D1R also contain I-1 or DARPP-32, suggesting important differences in D1R signaling in the PFC compared to the striatum.
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Affiliation(s)
- J R Glausier
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA 30329, USA
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27
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Ji B, Zhang Z, Zhang M, Zhu H, Zhou K, Yang J, Li Y, Sun L, Feng G, Wang Y, He L, Wan C. Differential expression profiling of the synaptosome proteome in a rat model of antipsychotic resistance. Brain Res 2009; 1295:170-8. [DOI: 10.1016/j.brainres.2009.07.097] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 06/30/2009] [Accepted: 07/24/2009] [Indexed: 11/17/2022]
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28
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Priddle TH, Crow TJ. The protocadherin 11X/Y gene pair as a putative determinant of cerebral dominance in Homo sapiens. FUTURE NEUROLOGY 2009. [DOI: 10.2217/fnl.09.23] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cerebral torque, a bias from right frontal to left occipital across the anterior–posterior axis is arguably the defining feature of the human brain, and the foundation for language. What is its genetic basis? Handedness and anatomical data suggest that this torque is specific to humans relative to the extant great apes. Asymmetry deficits associated with sex chromosome aneuploidies implicate loci on both the X and Y chromosomes. A block from the Xq21.3 band was duplicated to the Y chromosome 6 million years ago (close to, and a possible cause of the chimpanzee/hominin separation) containing the human-specific gene pair PCDH11X/Y. PCDH11Y has been subject to positive selection through hominin evolution including 18 amino-acid changes to the longest isoform of the protein. The PCDH11X protein has been subject to five substitutions including two cysteines in the ectodomain. The gene pair can account for sex differences, for example, in cerebral asymmetry and language.
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Affiliation(s)
- Tom H Priddle
- University of Oxford, Warneford Hospital, Oxford, OX3 7JX, UK
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Brown AM, Baucum AJ, Bass MA, Colbran RJ. Association of protein phosphatase 1 gamma 1 with spinophilin suppresses phosphatase activity in a Parkinson disease model. J Biol Chem 2008; 283:14286-94. [PMID: 18372251 PMCID: PMC2386916 DOI: 10.1074/jbc.m801377200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 03/26/2008] [Indexed: 11/06/2022] Open
Abstract
Sustained nigrostriatal dopamine depletion increases the serine/threonine phosphorylation of multiple striatal proteins that play a role in corticostriatal synaptic plasticity, including Thr(286) phosphorylation of calcium/calmodulin-dependent protein kinase IIalpha (CaMKIIalpha). Mechanisms underlying these changes are unclear, but protein phosphatases play a critical role in the acute modulation of striatal protein phosphorylation. Here we show that dopamine depletion for periods ranging from 3 weeks to 10 months significantly reduces the total activity of protein phosphatase (PP) 1, but not of PP2A, in whole lysates of rat striatum, as measured using multiple substrates, including Thr(286)-autophosphorylated CaMKIIalpha. Striatal PP1 activity is partially inhibited by a fragment of the PP1-binding protein neurabin-I, Nb-(146-493), because of the selective inhibition of the PP1gamma(1) isoform. The fraction of PP1 activity that is insensitive to Nb-(146-493) was unaffected by dopamine depletion, demonstrating that dopamine depletion specifically reduces the activity of PP1 isoforms that are sensitive to Nb-(146-493) (i.e. PP1gamma(1)). However, total striatal levels of PP1gamma(1) or any other PP1 isoform were unaffected by dopamine depletion, and our previous studies showed that total levels of the PP1 regulatory/targeting proteins DARPP-32, spinophilin, and neurabin were also unchanged. Rather, co-immunoprecipitation experiments demonstrated that dopamine depletion increases the association of PP1gamma(1) with spinophilin in striatal extracts. In combination, these data demonstrate that striatal dopamine depletion inhibits a specific synaptic phosphatase by increasing PP1gamma(1) interaction with spinophilin, perhaps contributing to hyperphosphorylation of synaptic proteins and disruptions of synaptic plasticity and/or dendritic morphology.
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Affiliation(s)
- Abigail M Brown
- Department of Molecular Physiology and Biophysics, Center for Molecular Neuroscience, Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Kim CH, Lee J, Lee JY, Roche KW. Metabotropic glutamate receptors: phosphorylation and receptor signaling. J Neurosci Res 2008; 86:1-10. [PMID: 17663464 DOI: 10.1002/jnr.21437] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) play important roles in neurotransmission, neuronal development, synaptic plasticity, and neurological disorders. Recent studies have revealed a sophisticated interplay between mGluRs and protein kinases: activation of mGluRs regulates the activity of a number of kinases, and direct phosphorylation of mGluRs affects receptor signaling, trafficking, and desensitization. Here we review the emerging literature on mGluR phosphorylation, signaling, and synaptic function.
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Affiliation(s)
- Chul Hoon Kim
- Department of Pharmacology, Brain Research Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
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31
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Carmody LC, Baucum AJ, Bass MA, Colbran RJ. Selective targeting of the gamma1 isoform of protein phosphatase 1 to F-actin in intact cells requires multiple domains in spinophilin and neurabin. FASEB J 2008; 22:1660-71. [PMID: 18216290 DOI: 10.1096/fj.07-092841] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Protein phosphatase 1 (PP1) catalytic subunits dephosphorylate specific substrates in discrete subcellular compartments to modulate many cellular processes. Canonical PP1-binding motifs (R/K-V/I-X-F) in a family of proteins mediate subcellular targeting, and the amino acids that form the binding pocket for the canonical motif are identical in all PP1 isoforms. However, PP1gamma1 but not PP1beta is selectively localized to F-actin-rich dendritic spines in neurons. Although the F-actin-binding proteins neurabin I and spinophilin (neurabin II) also bind PP1, their role in PP1 isoform selective targeting in intact cells is poorly understood. We show here that spinophilin selectively targets PP1gamma1, but not PP1beta, to F-actin-rich cortical regions of intact cells. Mutation of a PP1gamma1 selectivity determinant (N(464)EDYDRR(470) in spinophilin: conserved as residues 473-479 in neurabin) to VKDYDTW severely attenuated PP1gamma1 interactions with neurabins in vitro and in cells and disrupted PP1gamma1 targeting to F-actin. This domain is not involved in the weaker interactions of neurabins with PP1beta. In contrast, mutation of the canonical PP1-binding motif attenuated interactions of neurabins with both isoforms. Thus, selective targeting of PP1gamma1 to F-actin by neurabins in intact cells requires both the canonical PP1-binding motif and an auxiliary PP1gamma1-selectivity determinant.
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Affiliation(s)
- Leigh C Carmody
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Novoyatleva T, Heinrich B, Tang Y, Benderska N, Butchbach MER, Lorson CL, Lorson MA, Ben-Dov C, Fehlbaum P, Bracco L, Burghes AHM, Bollen M, Stamm S. Protein phosphatase 1 binds to the RNA recognition motif of several splicing factors and regulates alternative pre-mRNA processing. Hum Mol Genet 2007; 17:52-70. [PMID: 17913700 DOI: 10.1093/hmg/ddm284] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative splicing emerges as one of the most important mechanisms to generate transcript diversity. It is regulated by the formation of protein complexes on pre-mRNA. We demonstrate that protein phosphatase 1 (PP1) binds to the splicing factor transformer2-beta1 (tra2-beta1) via a phylogenetically conserved RVDF sequence located on the RNA recognition motif (RRM) of tra2-beta1. PP1 binds directly to tra2-beta1 and dephosphorylates it, which regulates the interaction between tra2-beta1 and other proteins. Eight other proteins, including SF2/ASF and SRp30c, contain an evolutionary conserved PP1 docking motif in the beta-4 strand of their RRMs indicating that binding to PP1 is a new function of some RRMs. Reducing PP1 activity promotes usage of numerous alternative exons, demonstrating a role of PP1 activity in splice site selection. PP1 inhibition promotes inclusion of the survival of motoneuron 2 exon 7 in a mouse model expressing the human gene. This suggests that reducing PP1 activity could be a new therapeutic principle to treat spinal muscular atrophy and other diseases caused by missplicing events. Our data indicate that the binding of PP1 to evolutionary conserved motifs in several RRMs is the link between known signal transduction pathways regulating PP1 activity and pre-mRNA processing.
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Browne G, Fardilha M, Oxenham S, Wu W, Helps N, da Cruz E Silva O, Cohen P, Cruz E Silva E. SARP, a new alternatively spliced protein phosphatase 1 and DNA interacting protein. Biochem J 2007; 402:187-96. [PMID: 17123353 PMCID: PMC1783986 DOI: 10.1042/bj20060600] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PP1 (protein phosphatase 1) is a ubiquitously expressed serine/threonine-specific protein phosphatase whose activity towards different substrates appears to be mediated via binding to specific proteins that play critical regulatory and targeting roles. In the present paper we report the cloning and characterization of a new protein, termed SARP (several ankyrin repeat protein), which is shown to interact with all isoforms of PP1 by a variety of techniques. A region encompassing a consensus PP1-binding motif in SARP (K354VHF357) modulates endogenous SARP-PP1 activity in mammalian cells. This SARP-PP1 interaction motif lies partially within the first ankyrin repeat in contrast with other proteins [53BP2 (p53 binding protein 2), MYPT1/M(110)/MBS (myosin binding protein of PP1) and TIMAP (transforming growth factor beta inhibited, membrane-associated protein)], where a PP1-binding motif precedes the ankyrin repeats. Alternative mRNA splicing produces several isoforms of SARP from a single human gene at locus 11q14. SARP1 and/or SARP2 (92-95 kDa) are ubiquitously expressed in all tissues with high levels in testis and sperm, where they are shown to interact with both PP1gamma1 and PP1gamma2. SARP3 (65 kDa) is most abundant in brain where SARP isoforms interact with both PP1alpha and PP1gamma1. SARP is highly abundant in the nucleus of mammalian cells, consistent with the putative nuclear localization signal at the N-terminus. The presence of a leucine zipper near the C-terminus of SARP1 and SARP2, and the binding of mammalian DNA to SARP2, suggests that SARP1 and SARP2 may be transcription factors or DNA-associated proteins that modulate gene expression.
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Affiliation(s)
- Gareth J. Browne
- *Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | - Margarida Fardilha
- †Laboratório de Transdução de Sinais, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Senga K. Oxenham
- *Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | - Wenjuan Wu
- †Laboratório de Transdução de Sinais, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Nicholas R. Helps
- *Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
| | - Odete A. B. da Cruz E Silva
- ‡Laboratório de Neurociências, Centro de Biologia Celular, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Patricia T. W. Cohen
- *Medical Research Council Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, U.K
- To whom correspondence should be addressed (email )
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OLZMANN JAMESA, BORDELON JILLR, MULY ECHRIS, REES HOWARDD, LEVEY ALLANI, LI LIAN, CHIN LIHSHEN. Selective enrichment of DJ-1 protein in primate striatal neuronal processes: implications for Parkinson's disease. J Comp Neurol 2007; 500:585-99. [PMID: 17120294 PMCID: PMC2597443 DOI: 10.1002/cne.21191] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mutations in DJ-1 cause autosomal recessive, early-onset Parkinson's disease (PD). The precise function and distribution of DJ-1 in the central nervous system remain unclear. In this study, we performed a comprehensive analysis of DJ-1 expression in human, monkey, and rat brains with antibodies that recognize distinct, evolutionarily conserved epitopes of DJ-1. We found that DJ-1 displays region-specific neuronal and glial labeling in human and nonhuman primate brain, sharply contrasting with the primarily neuronal expression pattern observed throughout rat brain. Further immunohistochemical analysis of DJ-1 expression in human and nonhuman primate brains showed that DJ-1 protein is expressed in neurons within the substantia nigra pars compacta and striatum, two regions critically involved in PD pathogenesis. Moreover, immunoelectron microscopic analysis revealed a selective enrichment of DJ-1 within primate striatal axons, presynaptic terminals, and dendritic spines with respect to the DJ-1 expression in prefrontal cortex. Together, these findings indicate neuronal and synaptic expression of DJ-1 in primate subcortical brain regions and suggest a physiological role for DJ-1 in the survival and/or function of nigral-striatal neurons.
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Affiliation(s)
- JAMES A. OLZMANN
- Department of Pharmacology, Emory University, Atlanta, Georgia, 30322
| | - JILL R. BORDELON
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, Georgia, 30322, USA
| | - E. CHRIS MULY
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, Georgia, 30322, USA
- Division of Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, 30322, USA
| | - HOWARD D. REES
- Department of Neurology, Center for Neurodegenerative Disease, Emory University, Atlanta, Georgia, 30322, USA
| | - ALLAN I. LEVEY
- Department of Neurology, Center for Neurodegenerative Disease, Emory University, Atlanta, Georgia, 30322, USA
| | - LIAN LI
- Department of Pharmacology, Emory University, Atlanta, Georgia, 30322
| | - LIH-SHEN CHIN
- Department of Pharmacology, Emory University, Atlanta, Georgia, 30322
- Correspondence to: Lih-Shen Chin, PhD Department of Pharmacology Emory University School of Medicine 1510 Clifton Road Atlanta, GA 30322−3090 Tel: 404−727−0361 Fax: 404−727−0365 E-mail:
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35
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Jong YJI, Schwetye KE, O'Malley KL. Nuclear localization of functional metabotropic glutamate receptor mGlu1 in HEK293 cells and cortical neurons: role in nuclear calcium mobilization and development. J Neurochem 2007; 101:458-69. [PMID: 17250682 DOI: 10.1111/j.1471-4159.2006.04382.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Group I metabotropic glutamate receptor (mGlu1) plays an important role in neuromodulation, development, and synaptic plasticity. Using immunocytochemistry, subcellular fractionation, and western blot analysis, the present study shows that mGlu1a receptors are present on nuclear membranes in stably transfected human embryonic kidney 293 (HEK293) cells as well as being endogenously expressed on rat cortical nuclei. Both glutamate and the group I agonist, quisqualate, directly activate nuclear mGlu1 receptors leading to a characteristic oscillatory pattern of calcium flux in isolated HEK nuclei and a slow rise to plateau in isolated cortical nuclei. In either case calcium responses could be terminated upon application of the mGlu1-selective antagonist, 7-(hydroxyamino)cyclopropa[b]chromen-1a-carboxylate ethyl ester. Responses could also be blocked by ryanodine and inositol 1,4,5-triphosphate receptor inhibitors, demonstrating the involvement of these calcium channels. Agonist activation of intracellular receptors was driven by Na(+)-dependent and -independent processes in nuclei isolated from either HEK or cortical neurons. Finally, mGlu1 nuclear receptors were dramatically up-regulated in the course of post-natal development. Therefore, like the other Group I receptor, mGlu5, mGlu1 can function as an intracellular receptor, suggesting a more encompassing role for nuclear G protein-coupled receptors and downstream signaling elements in the regulation of nuclear events.
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Affiliation(s)
- Yuh-Jiin I Jong
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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36
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Mansuy IM, Shenolikar S. Protein serine/threonine phosphatases in neuronal plasticity and disorders of learning and memory. Trends Neurosci 2006; 29:679-86. [PMID: 17084465 DOI: 10.1016/j.tins.2006.10.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 07/28/2006] [Accepted: 10/19/2006] [Indexed: 01/12/2023]
Abstract
Phosphorylation and dephosphorylation of cellular proteins by protein kinases and phosphatases represent important mechanisms for controlling major biological events. In the nervous system, protein phosphatases are contained in highly dynamic complexes localized within specialized subcellular compartments and they ensure timely dephosphorylation of multiple neuronal phosphoproteins. This modulates the responsiveness of individual synapses to neural activity and controls synaptic plasticity. These enzymes in turn play a key role in many forms of learning and memory, and their dysfunction contributes to cognitive deficits associated with aging and dementias or neurodegenerative diseases. Here, we review key modes of regulation of neuronal protein serine/threonine phosphatases and their contribution to disorders of learning and memory.
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Affiliation(s)
- Isabelle M Mansuy
- Brain Research Institute, Medical Faculty of the University Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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Burger C, López MC, Feller JA, Baker HV, Muzyczka N, Mandel RJ. Changes in transcription within the CA1 field of the hippocampus are associated with age-related spatial learning impairments. Neurobiol Learn Mem 2006; 87:21-41. [PMID: 16829144 DOI: 10.1016/j.nlm.2006.05.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 05/04/2006] [Accepted: 05/20/2006] [Indexed: 11/20/2022]
Abstract
Aged rats display a broad range of behavioral performance in spatial learning. The aim of this study was to identify candidate genes that are associated with learning and memory impairments. We first categorized aged-superior learners and age learning-impaired rats based on their performance in the Morris water maze (MWM) and then isolated messenger RNA from the CA1 hippocampal region of each animal to interrogate Affymetrix microarrays. Microarray analysis identified a set of 50 genes that was transcribed differently in aged-superior learners that had successfully learned the spatial strategy in the MWM compared to aged learning-impaired animals that were unable to learn and a variety of groups designed to control for all non-learning aspects of exposure to the water maze paradigm. A detailed analysis of the navigation patterns of the different groups of animals during acquisition and probe trials of the MWM task was performed. Young animals used predominantly an allocentric (spatial) search strategy and aged-superior learners appeared to use a combination of allocentric and egocentric (response) strategies, whereas aged-learning impaired animals displayed thigmotactic behavior. The significant 50 genes that we identified were tentatively classified into four groups based on their putative role in learning: transcription, synaptic morphology, ion conductivity and protein modification. Thus, this study has potentially identified a set of genes that are responsible for the learning impairments in aged rats. The role of these genes in the learning impairments associated with aging will ultimately have to be validated by manipulating gene expression in aged rats. Finally, these 50 genes were functioning in the context of an aging CA1 region where over 200 genes was found to be differentially expressed compared to a young CA1.
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Affiliation(s)
- Corinna Burger
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Box 100266, Gainesville, FL 32610, USA.
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Clark D, Dedova I, Cordwell S, Matsumoto I. A proteome analysis of the anterior cingulate cortex gray matter in schizophrenia. Mol Psychiatry 2006; 11:459-70, 423. [PMID: 16491132 DOI: 10.1038/sj.mp.4001806] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Anterior Cingulate Cortex (ACC, Brodmans Area 24) is implicated in the pathogenesis of schizophrenia due to its normal functions and connectivity together with reports of structural, morphological and neurotransmitter aberrations within this brain area in the disease state. Two-dimensional gel electrophoresis (2DE) was employed to scan and compare the ACC gray matter proteomes between schizophrenia (n = 10) and control (n = 10) post-mortem human tissue. This proteomic approach has detected 42 protein spots with altered levels in the schizophrenia cohort, which to our knowledge is the first proteomic analysis of the ACC in schizophrenia. Thirty nine of these proteins were subsequently identified using mass spectrometry and functionally classified into metabolism and oxidative stress, cytoskeletal, synaptic, signalling, trafficking and glial-specific groups. Some of the identified proteins have previously been implicated in the disease pathogenesis and some offer new insights into schizophrenia. Investigating these proteins, the genes encoding these proteins, their functions and interactions may shed light on the molecular mechanisms underlying the heterogeneous symptoms characteristic of schizophrenia.
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Affiliation(s)
- D Clark
- Department of Pathology, The University of Sydney, Sydney, NSW, Australia
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Brown AM, Deutch AY, Colbran RJ. Dopamine depletion alters phosphorylation of striatal proteins in a model of Parkinsonism. Eur J Neurosci 2005; 22:247-56. [PMID: 16029214 PMCID: PMC4819997 DOI: 10.1111/j.1460-9568.2005.04190.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Nigrostriatal dopamine depletion disrupts striatal medium spiny neuron morphology in Parkinson's disease and modulates striatal synaptic plasticity in animal models of parkinsonism. We demonstrate that long-term nigrostriatal dopamine depletion in the rat induces evolving changes in the phosphorylation of striatal proteins critical for synaptic plasticity. Dopamine depletion increased the phosphorylation of the alpha isoform of calcium-calmodulin-dependent protein kinase II (CaMKIIalpha) at Thr286, a site associated with enhanced autonomous kinase activity, but did not alter total levels of CaMKIIalpha or other synaptic proteins. Dopamine depletion decreased CaMKIIalpha levels in postsynaptic density-enriched fractions without significant changes in other proteins. The activity of protein phosphatase 1 (PP1), a postsynaptic phosphatase that dephosphorylates CaMKII, is regulated by DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of 32 kDa). Dopamine depletion had no effect on DARPP-32 phosphorylation at Thr34, but increased DARPP-32 phosphorylation at Thr75. Levodopa administration reversed the increased phosphorylation of both CaMKIIalpha and DARPP-32. Normal ageing increased the levels of PP1(gamma1 isoform) but decreased levels of the PP1gamma1-targeting proteins spinophilin and neurabin. Elevated phosphorylations of CaMKIIalpha and DARPP-32 were maintained for up to 20 months after dopamine depletion. However, phosphorylation of the CaMKII-PP1 substrate, Ser831 in the glutamate receptor GluR1 subunit, was increased only after sustained (9-20 months) dopamine depletion. Interaction of ageing-related changes in PP1 with the dopamine depletion-induced changes in CaMKIIalpha may account for enhanced GluR1 phosphorylation only after long-term dopamine depletion. These evolving changes may impact striatal synaptic plasticity, Parkinson's disease progression and the changing efficacy and side-effects associated with dopamine replacement therapy.
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Affiliation(s)
- Abigail M. Brown
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
| | - Ariel Y. Deutch
- Departments of Psychiatry and Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
- Center for Integrative and Cognitive Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
| | - Roger J. Colbran
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, TN 37232–0615, USA
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