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Tsai YC, ElGrawani W, Muheim C, Spinnler A, Campbell BFN, Lasic D, Hleihil M, Brown SA, Tyagarajan SK. Modulation of sleep/wake patterns by gephyrin phosphorylation status. Eur J Neurosci 2024. [PMID: 39032002 DOI: 10.1111/ejn.16464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 06/13/2024] [Accepted: 07/01/2024] [Indexed: 07/22/2024]
Abstract
Sleep/wake cycles intricately shape physiological activities including cognitive brain functions, yet the precise molecular orchestrators of sleep remain elusive. Notably, the clinical impact of benzodiazepine drugs underscores the pivotal role of GABAergic neurotransmission in sleep regulation. However, the specific contributions of distinct GABAA receptor subtypes and their principal scaffolding protein, gephyrin, in sleep dynamics remain unclear. The evolving role of synaptic phospho-proteome alterations at excitatory and inhibitory synapses suggests a potential avenue for modulating gephyrin and, consequently, GABAARs for sleep through on-demand kinase recruitment. Our study unveils the distinctive roles of two prevalent GABAA receptor subtypes, α1- and α2-GABAARs, in influencing sleep duration and electrical sleep activity. Notably, the absence of α1-GABAARs emerges as central in sleep regulation, manifesting significant alterations in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep during dark or active phases, accompanied by altered electroencephalogram (EEG) patterns across various frequencies. Gephyrin proteomics analysis reveals sleep/wake-dependent interactions with a repertoire of known and novel kinases. Crucially, we identify the regulation of gephyrin interaction with ERK1/2, and phosphorylations at serines 268 and 270 are dictated by sleep/wake cycles. Employing AAV-eGFP-gephyrin or its phospho-null variant (S268A/S270A), we disrupt sleep either globally or locally to demonstrate gephyrin phosphorylation as a sleep regulator. In summary, our findings support the local cortical sleep hypothesis and we unveil a molecular mechanism operating at GABAergic synapses, providing critical insights into the intricate regulation of sleep.
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Affiliation(s)
- Yuan-Chen Tsai
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Waleed ElGrawani
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Christine Muheim
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Andrea Spinnler
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Benjamin F N Campbell
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Denis Lasic
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Mohammad Hleihil
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Steven A Brown
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
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2
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Lu KP, Zhou XZ. Pin1-catalyzed conformational regulation after phosphorylation: A distinct checkpoint in cell signaling and drug discovery. Sci Signal 2024; 17:eadi8743. [PMID: 38889227 DOI: 10.1126/scisignal.adi8743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 05/30/2024] [Indexed: 06/20/2024]
Abstract
Protein phosphorylation is one of the most common mechanisms regulating cellular signaling pathways, and many kinases and phosphatases are proven drug targets. Upon phosphorylation, protein functions can be further regulated by the distinct isomerase Pin1 through cis-trans isomerization. Numerous protein targets and many important roles have now been elucidated for Pin1. However, no tools are available to detect or target cis and trans conformation events in cells. The development of Pin1 inhibitors and stereo- and phospho-specific antibodies has revealed that cis and trans conformations have distinct and often opposing cellular functions. Aberrant conformational changes due to the dysregulation of Pin1 can drive pathogenesis but can be effectively targeted in age-related diseases, including cancers and neurodegenerative disorders. Here, we review advances in understanding the roles of Pin1 signaling in health and disease and highlight conformational regulation as a distinct signal transduction checkpoint in disease development and treatment.
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Affiliation(s)
- Kun Ping Lu
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
| | - Xiao Zhen Zhou
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
- Lawson Health Research Institute, Schulich School of Medicine & Dentistry, Western University, London, ON N6G 2V4, Canada
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3
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Tsai YC, Hleihil M, Otomo K, Abegg A, Cavaccini A, Panzanelli P, Cramer T, Ferrari KD, Barrett MJP, Bosshard G, Karayannis T, Weber B, Tyagarajan SK, Stobart JL. The gephyrin scaffold modulates cortical layer 2/3 pyramidal neuron responsiveness to single whisker stimulation. Sci Rep 2024; 14:4169. [PMID: 38379020 PMCID: PMC10879104 DOI: 10.1038/s41598-024-54720-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/15/2024] [Indexed: 02/22/2024] Open
Abstract
Gephyrin is the main scaffolding protein at inhibitory postsynaptic sites, and its clusters are the signaling hubs where several molecular pathways converge. Post-translational modifications (PTMs) of gephyrin alter GABAA receptor clustering at the synapse, but it is unclear how this affects neuronal activity at the circuit level. We assessed the contribution of gephyrin PTMs to microcircuit activity in the mouse barrel cortex by slice electrophysiology and in vivo two-photon calcium imaging of layer 2/3 (L2/3) pyramidal cells during single-whisker stimulation. Our results suggest that, depending on the type of gephyrin PTM, the neuronal activities of L2/3 pyramidal neurons can be differentially modulated, leading to changes in the size of the neuronal population responding to the single-whisker stimulation. Furthermore, we show that gephyrin PTMs have their preference for selecting synaptic GABAA receptor subunits. Our results identify an important role of gephyrin and GABAergic postsynaptic sites for cortical microcircuit function during sensory stimulation.
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Affiliation(s)
- Yuan-Chen Tsai
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Mohammad Hleihil
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Kanako Otomo
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Andrin Abegg
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Anna Cavaccini
- Brain Research Institute, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Patrizia Panzanelli
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, Italy
| | - Teresa Cramer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Matthew J P Barrett
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Giovanna Bosshard
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Theofanis Karayannis
- Brain Research Institute, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Center for Neuroscience Zurich (ZNZ), Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Jillian L Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- College of Pharmacy, University of Manitoba, Winnipeg, MB, R3E 0T5, Canada.
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Li S, Wei X, Huang H, Ye L, Ma M, Sun L, Lu Y, Wu Y. Neuroplastin exerts antiepileptic effects through binding to the α1 subunit of GABA type A receptors to inhibit the internalization of the receptors. J Transl Med 2023; 21:707. [PMID: 37814294 PMCID: PMC10563248 DOI: 10.1186/s12967-023-04596-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 10/04/2023] [Indexed: 10/11/2023] Open
Abstract
BACKGROUND Seizures are associated with a decrease in γ-aminobutyric type A acid receptors (GABAaRs) on the neuronal surface, which may be regulated by enhanced internalization of GABAaRs. When interactions between GABAaR subunit α-1 (GABRA1) and postsynaptic scaffold proteins are weakened, the α1-containing GABAaRs leave the postsynaptic membrane and are internalized. Previous evidence suggested that neuroplastin (NPTN) promotes the localization of GABRA1 on the postsynaptic membrane. However, the association between NPTN and GABRA1 in seizures and its effect on the internalization of α1-containing GABAaRs on the neuronal surface has not been studied before. METHODS An in vitro seizure model was constructed using magnesium-free extracellular fluid, and an in vivo model of status epilepticus (SE) was constructed using pentylenetetrazole (PTZ). Additionally, in vitro and in vivo NPTN-overexpression models were constructed. Electrophysiological recordings and internalization assays were performed to evaluate the action potentials and miniature inhibitory postsynaptic currents of neurons, as well as the intracellular accumulation ratio of α1-containing GABAaRs in neurons. Western blot analysis was performed to detect the expression of GABRA1 and NPTN both in vitro and in vivo. Immunofluorescence co-localization analysis and co-immunoprecipitation were performed to evaluate the interaction between GABRA1 and NPTN. RESULTS The expression of GABRA1 was found to be decreased on the neuronal surface both in vivo and in vitro seizure models. In the in vitro seizure model, α1-containing GABAaRs showed increased internalization. NPTN expression was found to be positively correlated with GABRA1 expression on the neuronal surface both in vivo and in vitro seizure models. In addition, NPTN overexpression alleviated seizures and NPTN was shown to bind to GABRA1 to form protein complexes that can be disrupted during seizures in both in vivo and in vitro models. Furthermore, NPTN was found to inhibit the internalization of α1-containing GABAaRs in the in vitro seizure model. CONCLUSION Our findings provide evidence that NPTN may exert antiepileptic effects by binding to GABRA1 to inhibit the internalization of α1-containing GABAaRs.
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Affiliation(s)
- Sijun Li
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Xing Wei
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Hongmi Huang
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Lin Ye
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Meigang Ma
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Lanfeng Sun
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Yuling Lu
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China
| | - Yuan Wu
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Guangxi Medical University, Shuangyong Road No.6, Nanning, Guangxi, China.
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5
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Chen XR, Igumenova TI. Regulation of eukaryotic protein kinases by Pin1, a peptidyl-prolyl isomerase. Adv Biol Regul 2023; 87:100938. [PMID: 36496344 PMCID: PMC9992314 DOI: 10.1016/j.jbior.2022.100938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
The peptidyl-prolyl isomerase Pin1 cooperates with proline-directed kinases and phosphatases to regulate multiple oncogenic pathways. Pin1 specifically recognizes phosphorylated Ser/Thr-Pro motifs in proteins and catalyzes their cis-trans isomerization. The Pin1-catalyzed conformational changes determine the stability, activity, and subcellular localization of numerous protein substrates. We conducted a survey of eukaryotic protein kinases that are regulated by Pin1 and whose Pin1 binding sites have been identified. Our analyses reveal that Pin1 target sites in kinases do not fall exclusively within the intrinsically disordered regions of these enzymes. Rather, they fall into three groups based on their location: (i) within the catalytic kinase domain, (ii) in the C-terminal kinase region, and (iii) in regulatory domains. Some of the kinases downregulated by Pin1 activity are tumor-suppressing, and all kinases upregulated by Pin1 activity are functionally pro-oncogenic. These findings further reinforce the rationale for developing Pin1-specific inhibitors as attractive pharmaceuticals for cancer therapy.
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Affiliation(s)
- Xiao-Ru Chen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
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6
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Chen Y, Hou X, Pang J, Yang F, Li A, Lin S, Lin N, Lee TH, Liu H. The role of peptidyl-prolyl isomerase Pin1 in neuronal signaling in epilepsy. Front Mol Neurosci 2022; 15:1006419. [PMID: 36304997 PMCID: PMC9592815 DOI: 10.3389/fnmol.2022.1006419] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Epilepsy is a common symptom of many neurological disorders and can lead to neuronal damage that plays a major role in seizure-related disability. The peptidyl-prolyl isomerase Pin1 has wide-ranging influences on the occurrence and development of neurological diseases. It has also been suggested that Pin1 acts on epileptic inhibition, and the molecular mechanism has recently been reported. In this review, we primarily focus on research concerning the mechanisms and functions of Pin1 in neurons. In addition, we highlight the significance and potential applications of Pin1 in neuronal diseases, especially epilepsy. We also discuss the molecular mechanisms by which Pin1 controls synapses, ion channels and neuronal signaling pathways to modulate epileptic susceptibility. Since neurotransmitters and some neuronal signaling pathways, such as Notch1 and PI3K/Akt, are vital to the nervous system, the role of Pin1 in epilepsy is discussed in the context of the CaMKII-AMPA receptor axis, PSD-95-NMDA receptor axis, NL2/gephyrin-GABA receptor signaling, and Notch1 and PI3K/Akt pathways. The effect of Pin1 on the progression of epilepsy in animal models is discussed as well. This information will lead to a better understanding of Pin1 signaling pathways in epilepsy and may facilitate development of new therapeutic strategies.
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Affiliation(s)
- Yuwen Chen
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Xiaojun Hou
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fuzhou Children’s Hospital of Fujian Medical University, Fuzhou, China
| | - Jiao Pang
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Fan Yang
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Department of Laboratory Medicine, Xiang’an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China
| | - Angcheng Li
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Suijin Lin
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Na Lin
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Tae Ho Lee
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Hekun Liu
- Institute of Basic Medicine, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- *Correspondence: Hekun Liu,
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7
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Kouchi Z, Kojima M. Function of SYDE C2-RhoGAP family as signaling hubs for neuronal development deduced by computational analysis. Sci Rep 2022; 12:4325. [PMID: 35279680 PMCID: PMC8918327 DOI: 10.1038/s41598-022-08147-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 03/02/2022] [Indexed: 11/21/2022] Open
Abstract
Recent investigations of neurological developmental disorders have revealed the Rho-family modulators such as Syde and its interactors as the candidate genes. Although the mammalian Syde proteins are reported to possess GTPase-accelerating activity for RhoA-family proteins, diverse species-specific substrate selectivities and binding partners have been described, presumably based on their evolutionary variance in the molecular organization. A comprehensive in silico analysis of Syde family proteins was performed to elucidate their molecular functions and neurodevelopmental networks. Predicted structural modeling of the RhoGAP domain may account for the molecular constraints to substrate specificity among Rho-family proteins. Deducing conserved binding motifs can extend the Syde interaction network and highlight diverse but Syde isoform-specific signaling pathways in neuronal homeostasis, differentiation, and synaptic plasticity from novel aspects of post-translational modification and proteolysis.
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8
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Ravasenga T, Ruben M, Regio V, Polenghi A, Petrini EM, Barberis A. Spatial regulation of coordinated excitatory and inhibitory synaptic plasticity at dendritic synapses. Cell Rep 2022; 38:110347. [PMID: 35139381 PMCID: PMC8844559 DOI: 10.1016/j.celrep.2022.110347] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 09/16/2021] [Accepted: 01/14/2022] [Indexed: 12/02/2022] Open
Abstract
The induction of synaptic plasticity at an individual dendritic glutamatergic spine can affect neighboring spines. This local modulation generates dendritic plasticity microdomains believed to expand the neuronal computational capacity. Here, we investigate whether local modulation of plasticity can also occur between glutamatergic synapses and adjacent GABAergic synapses. We find that the induction of long-term potentiation at an individual glutamatergic spine causes the depression of nearby GABAergic inhibitory synapses (within 3 μm), whereas more distant ones are potentiated. Notably, L-type calcium channels and calpain are required for this plasticity spreading. Overall, our data support a model whereby input-specific glutamatergic postsynaptic potentiation induces a spatially regulated rearrangement of inhibitory synaptic strength in the surrounding area through short-range heterosynaptic interactions. Such local coordination of excitatory and inhibitory synaptic plasticity is expected to influence dendritic information processing and integration. LTP of individual dendritic spines causes iLTD at neighboring GABAergic synapses Interaction between single-spine LTP and iLTD occurs in the spatial range of ±3 μm This iLTD depends on the local dendritic calcium increase and calpain activation iLTD is associated with reduced gephyrin clustering and increased GABAAR mobility
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Affiliation(s)
- Tiziana Ravasenga
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Massimo Ruben
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Vincenzo Regio
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Alice Polenghi
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Enrica Maria Petrini
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Andrea Barberis
- Neuroscience and Brain Technologies Department, Fondazione Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
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Kiss E, Kins S, Gorgas K, Orlik M, Fischer C, Endres K, Schlicksupp A, Kirsch J, Kuhse J. Artemisinin-treatment in pre-symptomatic APP-PS1 mice increases gephyrin phosphorylation at Ser270: a modification regulating postsynaptic GABA AR density. Biol Chem 2021; 403:73-87. [PMID: 33878252 DOI: 10.1515/hsz-2021-0153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 03/29/2021] [Indexed: 01/26/2023]
Abstract
Artemisinins, a group of plant-derived sesquiterpene lactones, are efficient antimalarial agents. They also share anti-inflammatory and anti-viral activities and were considered for treatment of neurodegenerative disorders like Alzheimer's disease (AD). Additionally, artemisinins bind to gephyrin, the multifunctional scaffold of GABAergic synapses, and modulate inhibitory neurotransmission in vitro. We previously reported an increased expression of gephyrin and GABAA receptors in early pre-symptomatic stages of an AD mouse model (APP-PS1) and in parallel enhanced CDK5-dependent phosphorylation of gephyrin at S270. Here, we studied the effects of artemisinin on gephyrin in the brain of young APP-PS1 mice. We detected an additional increase of gephyrin protein level, elevated gephyrin phosphorylation at Ser270, and an increased amount of GABAAR-γ2 subunits after artemisinin-treatment. Interestingly, the CDK5 activator p35 was also upregulated. Moreover, we demonstrate decreased density of postsynaptic gephyrin and GABAAR-γ2 immunoreactivities in cultured hippocampal neurons expressing gephyrin with alanine mutations at two CDK5 phosphorylation sites. In addition, the activity-dependent modulation of synaptic protein density was abolished in neurons expressing gephyrin lacking one or both of these phosphorylation sites. Thus, our results reveal that artemisinin modulates expression as well as phosphorylation of gephyrin at sites that might have important impact on GABAergic synapses in AD.
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Affiliation(s)
- Eva Kiss
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany.,Department of Cellular and Molecular Biology, University of Medicine, Pharmacy, Science and Technology "G.E. Palade" of Târgu Mures, Str. Gheorghe Marinescu nr. 38, 540 139Târgu Mureș, Romania
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67633 Kaiserslautern, Germany
| | - Karin Gorgas
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
| | - Maret Orlik
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
| | - Carolin Fischer
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
| | - Andrea Schlicksupp
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
| | - Joachim Kirsch
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
| | - Jochen Kuhse
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120Heidelberg, Germany
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10
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Zhou S, Cai Y, Liu X, Jin L, Wang X, Ma W, Zhang T. Role of H2B mono-ubiquitination in the initiation and progression of cancer. Bull Cancer 2021; 108:385-398. [PMID: 33685627 DOI: 10.1016/j.bulcan.2020.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 01/07/2023]
Abstract
Numerous epigenetic alterations are observed in cancer cells, and dysregulation of mono-ubiquitination of histone H2B (H2Bub1) has often been linked to tumorigenesis. H2Bub1 is a dynamic post-translational histone modification associated with transcriptional elongation and DNA damage response. Histone H2B monoubiquitination occurs in the site of lysine 120, written predominantly by E3 ubiquitin ligases RNF20/RNF40 and deubiquitinated by ubiquitin specific peptidase 22 (USP22). RNF20/40 is often altered in the primary tumors including colorectal cancer, breast cancer, ovarian cancer, prostate cancer, and lung cancer, and the loss of H2Bub1 is usually associated with poor prognosis in tumor patients. The purpose of this review is to summarize the current knowledge of H2Bub1 in transcription, DNA damage response and primary tumors. This review also provides novel options for exploiting the potential therapeutic target H2Bub1 in personalized cancer therapy.
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Affiliation(s)
- Sa Zhou
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China
| | - Yuqiao Cai
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China
| | - Xinyi Liu
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China
| | - Lijun Jin
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China
| | - Xiaoqin Wang
- Beijing University of Agriculture, Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture, Beijing 102206, PR China
| | - Wenjian Ma
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China; Qilu Institute of Technology, Shandong 250200, PR China.
| | - Tongcun Zhang
- Tianjin University of Science and Technology, College of Biotechnology, Tianjin 300457, PR China; Wuhan University of Science and Technology, Institute of Biology and Medicine, Wuhan 430081, PR China.
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11
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Lanni C, Masi M, Racchi M, Govoni S. Cancer and Alzheimer's disease inverse relationship: an age-associated diverging derailment of shared pathways. Mol Psychiatry 2021; 26:280-295. [PMID: 32382138 DOI: 10.1038/s41380-020-0760-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/06/2020] [Accepted: 04/24/2020] [Indexed: 02/07/2023]
Abstract
Several epidemiological studies show an inverse association between cancer and Alzheimer's disease (AD). It is debated whether this association is the consequence of biological mechanisms shared by both these conditions or may be related to the pharmacological treatments carried out on the patients. The latter hypothesis, however, is not sustained by the available evidence. Hence, the focus of this review is to analyze common biological mechanisms for both cancer and AD and to build up a biological theory useful to explain the inverse correlation between AD and cancer. The review proposes a hypothesis, according to which several molecular players, prominently PIN1 and p53, have been investigated and considered involved in complex molecular interactions putatively associated with the inverse correlation. On the other hand, p53 involvement in both diseases seems to be a consequence of the aberrant activation of other proteins. Instead, PIN1 may be identified as a novel key regulator at the crossroad between cancer and AD. PIN1 is a peptidyl-prolyl cis-trans isomerase that catalyzes the cis-trans isomerization, thus regulating the conformation of different protein substrates after phosphorylation and modulating protein function. In particular, trans-conformations of Amyloid Precursor Protein (APP) and tau are functional and "healthy", while cis-conformations, triggered after phosphorylation, are pathogenic. As an example, PIN1 accelerates APP cis-to-trans isomerization thus favoring the non-amyloidogenic pathway, while, in the absence of PIN1, APP is processed through the amyloidogenic pathway, thus predisposing to neurodegeneration. Furthermore, a link between PIN1 and tau regulation has been found, since when PIN1 function is inhibited, tau is hyperphosphorylated. Data from brain specimens of subjects affected by mild cognitive impairment and AD have revealed a very low PIN1 expression. Moreover, polymorphisms in PIN1 promoter correlated with an increased PIN1 expression are associated with a delay of sporadic AD age of onset, while a polymorphism related to a reduced PIN1 expression is associated with a decreased risk of multiple cancers. In the case of dementias, in particular of Alzheimer's disease, new biological markers and targets based on the discussed players can be developed based on a theoretical approach relying on different grounds compared to the past. An unbiased expansion of the rationale and of the targets may help to achieve in the field of neurodegenerative dementias similar advances to those attained in the case of cancer treatment.
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Affiliation(s)
- Cristina Lanni
- Department of Drug Sciences, University of Pavia, V.le Taramelli 12/14, 27100, Pavia, Italy
| | - Mirco Masi
- Department of Drug Sciences, University of Pavia, V.le Taramelli 12/14, 27100, Pavia, Italy.,Scuola Universitaria Superiore IUSS Pavia, Piazza della Vittoria 15, 27100, Pavia, Italy
| | - Marco Racchi
- Department of Drug Sciences, University of Pavia, V.le Taramelli 12/14, 27100, Pavia, Italy
| | - Stefano Govoni
- Department of Drug Sciences, University of Pavia, V.le Taramelli 12/14, 27100, Pavia, Italy.
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12
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Fagiani F, Govoni S, Racchi M, Lanni C. The Peptidyl-prolyl Isomerase Pin1 in Neuronal Signaling: from Neurodevelopment to Neurodegeneration. Mol Neurobiol 2020; 58:1062-1073. [PMID: 33083964 PMCID: PMC7878263 DOI: 10.1007/s12035-020-02179-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/14/2020] [Indexed: 12/11/2022]
Abstract
The peptidyl-prolyl isomerase Pin1 is a unique enzyme catalyzing the isomerization of the peptide bond between phosphorylated serine-proline or threonine-proline motifs in proteins, thereby regulating a wide spectrum of protein functions, including folding, intracellular signaling, transcription, cell cycle progression, and apoptosis. Pin1 has been reported to act as a key molecular switch inducing cell-type-specific effects, critically depending on the different phosphorylation patterns of its targets within different biological contexts. While its implication in proliferating cells, and, in particular, in the field of cancer, has been widely characterized, less is known about Pin1 biological functions in terminally differentiated and post-mitotic neurons. Notably, Pin1 is widely expressed in the central and peripheral nervous system, where it regulates a variety of neuronal processes, including neuronal development, apoptosis, and synaptic activity. However, despite studies reporting the interaction of Pin1 with neuronal substrates or its involvement in specific signaling pathways, a more comprehensive understanding of its biological functions at neuronal level is still lacking. Besides its implication in physiological processes, a growing body of evidence suggests the crucial involvement of Pin1 in aging and age-related and neurodegenerative diseases, including Alzheimer's disease, Parkinson disease, frontotemporal dementias, Huntington disease, and amyotrophic lateral sclerosis, where it mediates profoundly different effects, ranging from neuroprotective to neurotoxic. Therefore, a more detailed understanding of Pin1 neuronal functions may provide relevant information on the consequences of Pin1 deregulation in age-related and neurodegenerative disorders.
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Affiliation(s)
- Francesca Fagiani
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy.,Scuola Universitaria Superiore IUSS Pavia, P.zza Vittoria, 15, 27100, Pavia, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy
| | - Marco Racchi
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy
| | - Cristina Lanni
- Department of Drug Sciences, Pharmacology Section, University of Pavia, Viale Taramelli 14, 27100, Pavia, Italy.
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13
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Ahmad SS, Waheed T, Rozeen S, Mahmood S, Kamal MA. Therapeutic Study of Phytochemicals Against Cancer and Alzheimer's Disease Management. Curr Drug Metab 2020; 20:1006-1013. [PMID: 31902351 DOI: 10.2174/1389200221666200103092719] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/19/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Phytochemicals are a significant piece of conventional prescription and have been researched in detail for conceivable consideration in current drug discovery. Medications and plants are firmly identified for traditional prescriptions and ethnomedicines that are basically arranged from plants. Recognizing the medical advantages of phytochemicals is of fundamental advancement in medication and useful sustenance improvement. Secondary metabolites of different plants have been customarily used for the improvement of human wellbeing. The phytochemicals are diets rich, which can upgrade neuroplasticity and protection from neurodegeneration. RESULTS Phytochemicals keep on entering clinical preliminaries or provide leads for the synthesis of medicinal agents. Phytochemicals are a great extent cancer prevention agents in nature at lower concentrations and under favorable cell conditions that adequately avoid the oxidation of different molecules that have an ability to produce free radicals and thus protect the body. CONCLUSION The purpose of this review is to describe the use of phytochemicals against cancer and Alzheimer's disease treatment.
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Affiliation(s)
- Syed Sayeed Ahmad
- Department of Bioengineering, Faculty of Engineering, Integral University, Lucknow, India
| | - Tayyaba Waheed
- Department of Bioscience, Faculty of Sciences, Integral University, Lucknow, India
| | - Sayed Rozeen
- Department of Bioscience, Faculty of Sciences, Integral University, Lucknow, India
| | - Sufia Mahmood
- Department of Bioscience, Faculty of Sciences, Integral University, Lucknow, India
| | - Mohammad Amjad Kamal
- King Fahd Medical Research Center, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia.,Enzymoics, 7 Peterlee Place, Hebersham, NSW 2770, Australia.,Novel Global Community Educational Foundation, Hebersham, Australia
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14
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Specht CG. Fractional occupancy of synaptic binding sites and the molecular plasticity of inhibitory synapses. Neuropharmacology 2019; 169:107493. [PMID: 30648560 DOI: 10.1016/j.neuropharm.2019.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/01/2018] [Accepted: 01/09/2019] [Indexed: 01/20/2023]
Abstract
The postsynaptic density (PSD) at inhibitory synapses is a complex molecular assembly that serves as a platform for the interaction of neurotransmitter receptors, scaffold and adapter proteins, cytoskeletal elements and signalling molecules. The stability of the PSD depends on a multiplicity of interactions linking individual components. At the same time the PSD retains a substantial degree of flexibility. The continuous exchange of synaptic molecules and the preferential addition or removal of certain components induce plastic changes in the synaptic structure. This property necessarily implies that interactors are in dynamic equilibrium and that not all synaptic binding sites are occupied simultaneously. This review discusses the molecular plasticity of inhibitory synapses in terms of the connectivity of their components. Whereas stable protein complexes are marked by stoichiometric relationships between subunits, the majority of synaptic interactions have fractional occupancy, which is here defined as the non-saturation of synaptic binding sites. Fractional occupancy can have several causes: reduced kinetic or thermodynamic stability of the interactions, an imbalance in the concentrations or limited spatio-temporal overlap of interacting proteins, negative cooperativity or mutually exclusive binding. The role of fractional occupancy in the regulation of synaptic structure and function is explored based on recent data about the connectivity of inhibitory receptors and scaffold proteins. I propose that the absolute quantification of interactors and their stoichiometry at identified synapses can provide new mechanistic insights into the dynamic properties of inhibitory PSDs at the molecular level. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Christian G Specht
- École Normale Supérieure, PSL Research University, CNRS, Inserm, Institute of Biology (IBENS), Paris, 75005, France.
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15
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Groeneweg FL, Trattnig C, Kuhse J, Nawrotzki RA, Kirsch J. Gephyrin: a key regulatory protein of inhibitory synapses and beyond. Histochem Cell Biol 2018; 150:489-508. [DOI: 10.1007/s00418-018-1725-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2018] [Indexed: 12/26/2022]
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16
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Kasaragod VB, Schindelin H. Structure-Function Relationships of Glycine and GABA A Receptors and Their Interplay With the Scaffolding Protein Gephyrin. Front Mol Neurosci 2018; 11:317. [PMID: 30258351 PMCID: PMC6143783 DOI: 10.3389/fnmol.2018.00317] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/16/2018] [Indexed: 12/03/2022] Open
Abstract
Glycine and γ-aminobutyric acid (GABA) are the major determinants of inhibition in the central nervous system (CNS). These neurotransmitters target glycine and GABAA receptors, respectively, which both belong to the Cys-loop superfamily of pentameric ligand-gated ion channels (pLGICs). Interactions of the neurotransmitters with the cognate receptors result in receptor opening and a subsequent influx of chloride ions, which, in turn, leads to hyperpolarization of the membrane potential, thus counteracting excitatory stimuli. The majority of glycine receptors and a significant fraction of GABAA receptors (GABAARs) are recruited and anchored to the post-synaptic membrane by the central scaffolding protein gephyrin. This ∼93 kDa moonlighting protein is structurally organized into an N-terminal G-domain (GephG) connected to a C-terminal E-domain (GephE) via a long unstructured linker. Both inhibitory neurotransmitter receptors interact via a short peptide motif located in the large cytoplasmic loop located in between transmembrane helices 3 and 4 (TM3-TM4) of the receptors with a universal receptor-binding epitope residing in GephE. Gephyrin engages in nearly identical interactions with the receptors at the N-terminal end of the peptide motif, and receptor-specific interaction toward the C-terminal region of the peptide. In addition to its receptor-anchoring function, gephyrin also interacts with a rather large collection of macromolecules including different cytoskeletal elements, thus acting as central scaffold at inhibitory post-synaptic specializations. Dysfunctions in receptor-mediated or gephyrin-mediated neurotransmission have been identified in various severe neurodevelopmental disorders. Although biochemical, cellular and electrophysiological studies have helped to understand the physiological and pharmacological roles of the receptors, recent high resolution structures of the receptors have strengthened our understanding of the receptors and their gating mechanisms. Besides that, multiple crystal structures of GephE in complex with receptor-derived peptides have shed light into receptor clustering by gephyrin at inhibitory post-synapses. This review will highlight recent biochemical and structural insights into gephyrin and the GlyRs as well as GABAA receptors, which provide a deeper understanding of the molecular machinery mediating inhibitory neurotransmission.
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Affiliation(s)
- Vikram B Kasaragod
- Institute of Structural Biology, Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Hermann Schindelin
- Institute of Structural Biology, Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
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17
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Pin1 Modulation in Physiological Status and Neurodegeneration. Any Contribution to the Pathogenesis of Type 3 Diabetes? Int J Mol Sci 2018; 19:ijms19082319. [PMID: 30096758 PMCID: PMC6121450 DOI: 10.3390/ijms19082319] [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: 06/27/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 12/29/2022] Open
Abstract
Prolyl isomerases (Peptidylprolyl isomerase, PPIases) are enzymes that catalyze the isomerization between the cis/trans Pro conformations. Three subclasses belong to the class: FKBP (FK506 binding protein family), Cyclophilin and Parvulin family (Pin1 and Par14). Among Prolyl isomerases, Pin1 presents as distinctive feature, the ability of binding to the motif pSer/pThr-Pro that is phosphorylated by kinases. Modulation of Pin1 is implicated in cellular processes such as mitosis, differentiation and metabolism: The enzyme is dysregulated in many diverse pathological conditions, i.e., cancer progression, neurodegenerative (i.e., Alzheimer’s diseases, AD) and metabolic disorders (i.e., type 2 diabetes, T2D). Indeed, Pin1 KO mice develop a complex phenotype of premature aging, cognitive impairment in elderly mice and neuronal degeneration resembling that of the AD in humans. In addition, since the molecule modulates glucose homeostasis in the brain and peripherally, Pin1 KO mice are resistant to diet-induced obesity, insulin resistance, peripheral glucose intolerance and diabetic vascular dysfunction. In this review, we revise first critically the role of Pin1 in neuronal development and differentiation and then focus on the in vivo studies that demonstrate its pivotal role in neurodegenerative processes and glucose homeostasis. We discuss evidence that enables us to speculate about the role of Pin1 as molecular link in the pathogenesis of type 3 diabetes i.e., the clinical association of dementia/AD and T2D.
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18
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Breitinger U, Bahnassawy LM, Janzen D, Roemer V, Becker CM, Villmann C, Breitinger HG. PKA and PKC Modulators Affect Ion Channel Function and Internalization of Recombinant Alpha1 and Alpha1-Beta Glycine Receptors. Front Mol Neurosci 2018; 11:154. [PMID: 29867346 PMCID: PMC5961436 DOI: 10.3389/fnmol.2018.00154] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/23/2018] [Indexed: 01/04/2023] Open
Abstract
Glycine receptors (GlyRs) are important mediators of fast inhibitory neurotransmission in the mammalian central nervous system. Their function is controlled by multiple cellular mechanisms, including intracellular regulatory processes. Modulation of GlyR function by protein kinases has been reported for many cell types, involving different techniques, and often yielding contradictory results. Here, we studied the effects of protein kinase C (PKC) and cAMP-dependent protein kinase A (PKA) on glycine induced currents in HEK293 cells expressing human homomeric α1 and heteromeric α1-β GlyRs using whole-cell patch clamp techniques as well as internalization assays. In whole-cell patch-clamp measurements, modulators were applied in the intracellular buffer at concentrations between 0.1 μM and 0.5 μM. EC50 of glycine increased upon application of the protein kinase activators Forskolin and phorbol-12-myristate-13-acetate (PMA) but decreased in the presence of the PKC inhibitor Staurosporine aglycon and the PKA inhibitor H-89. Desensitization of recombinant α1 receptors was significantly increased in the presence of Forskolin. Staurosporine aglycon, on the other hand decreased desensitization of heteromeric α1-β GlyRs. The time course of receptor activation was determined for homomeric α1 receptors and revealed two simultaneous effects: cells showed a decrease of EC50 after 3–6 min of establishing whole-cell configuration. This effect was independent of protein kinase modulators. All modulators of PKA and PKC, however, produced an additional shift of EC50, which overlay and eventually exceeded the cells intrinsic variation of EC50. The effect of kinase activators was abolished if the corresponding inhibitors were co-applied, consistent with PKA and PKC directly mediating the modulation of GlyR function. Direct effects of PKA- and PKC-modulators on receptor expression on transfected HEK cells were monitored within 15 min of drug application, showing a significant increase of receptor internalization with PKA and PKC activators, while the corresponding inhibitors had no significant effect on receptor surface expression or internalization. Our results confirm the observation that phosphorylation via PKA and PKC has a direct effect on the GlyR ion channel complex and plays an important role in the fine-tuning of glycinergic signaling.
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Affiliation(s)
- Ulrike Breitinger
- Department of Biochemistry, German University in Cairo, New Cairo, Egypt
| | | | - Dieter Janzen
- Institute for Clinical Neurobiology, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Vera Roemer
- Institute for Clinical Neurobiology, Julius-Maximilians University Würzburg, Würzburg, Germany
| | - Cord-Michael Becker
- Department of Biochemistry, Institute of Biochemistry, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Carmen Villmann
- Institute for Clinical Neurobiology, Julius-Maximilians University Würzburg, Würzburg, Germany
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Alpha subunit-dependent glycine receptor clustering and regulation of synaptic receptor numbers. Sci Rep 2017; 7:10899. [PMID: 28883437 PMCID: PMC5589798 DOI: 10.1038/s41598-017-11264-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/21/2017] [Indexed: 02/08/2023] Open
Abstract
Accumulation of glycine receptors at synapses requires the interaction between the beta subunit of the receptor and the scaffold protein gephyrin. Here, we questioned whether different alpha subunits could modulate the receptors' diffusion and propensity to cluster at spinal cord synapses. Using quantitative photoactivated localisation microscopy we found that alpha-1 and alpha-3 containing glycine receptors display the same α3:β2 stoichiometry and gephyrin binding. Despite these similarities, alpha-3 containing receptors are less mobile and cluster at higher density compared to alpha-1, with 1500 versus 1100 complexes µm-2, respectively. Furthermore, we identified a subunit-specific regulation of glycine receptor copy numbers at synapses: when challenged with interleukin 1β, the synaptic occupancy of alpha-1 but not alpha-3 receptors was reduced. This mechanism may play a role in the cell-type dependent regulation of glycinergic currents in response to interleukin 1β and highlights the capacity of the alpha subunits to affect receptor-gephyrin binding at synapses.
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20
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Pin1 Modulates the Synaptic Content of NMDA Receptors via Prolyl-Isomerization of PSD-95. J Neurosci 2017; 36:5437-47. [PMID: 27194325 DOI: 10.1523/jneurosci.3124-15.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 03/14/2016] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED Phosphorylation of serine/threonine residues preceding a proline regulates the fate of its targets through postphosphorylation conformational changes catalyzed by the peptidyl-prolyl cis-/trans isomerase Pin1. By flipping the substrate between two different functional conformations, this enzyme exerts a fine-tuning of phosphorylation signals. Pin1 has been detected in dendritic spines and shafts where it regulates protein synthesis required to sustain the late phase of long-term potentiation (LTP). Here, we demonstrate that Pin1 residing in postsynaptic structures can interact with postsynaptic density protein-95 (PSD-95), a key scaffold protein that anchors NMDA receptors (NMDARs) in PSD via GluN2-type receptor subunits. Pin1 recruitment by PSD-95 occurs at specific serine-threonine/proline consensus motifs localized in the linker region connecting PDZ2 to PDZ3 domains. Upon binding, Pin1 triggers structural changes in PSD-95, thus negatively affecting its ability to interact with NMDARs. In electrophysiological experiments, larger NMDA-mediated synaptic currents, evoked in CA1 principal cells by Schaffer collateral stimulation, were detected in hippocampal slices obtained from Pin1(-/-) mice compared with controls. Similar results were obtained in cultured hippocampal cells expressing a PSD-95 mutant unable to undergo prolyl-isomerization, thus indicating that the action of Pin1 on PSD-95 is critical for this effect. In addition, an enhancement in spine density and size was detected in CA1 principal cells of Pin1(-/-) or in Thy-1GFP mice treated with the pharmacological inhibitor of Pin1 catalytic activity PiB.Our data indicate that Pin1 controls synaptic content of NMDARs via PSD-95 prolyl-isomerization and the expression of dendritic spines, both required for LTP maintenance. SIGNIFICANCE STATEMENT PSD-95, a membrane-associated guanylate kinase, is the major scaffolding protein at excitatory postsynaptic densities and a potent regulator of synaptic strength and plasticity. The activity of PSD-95 is tightly controlled by several post-translational mechanisms including proline-directed phosphorylation. This signaling cascade regulates the fate of its targets through postphosphorylation conformational modifications catalyzed by the peptidyl-prolyl cis-/trans isomerase Pin1. Here, we uncover a new role of Pin1 in glutamatergic signaling. By interacting with PSD-95, Pin1 dampens PSD-95 ability to complex with NMDARs, thus negatively affecting NMDAR signaling and spine morphology. Our findings further emphasize the emerging role of Pin1 as a key modulator of synaptic transmission.
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Ranft J, Almeida LG, Rodriguez PC, Triller A, Hakim V. An aggregation-removal model for the formation and size determination of post-synaptic scaffold domains. PLoS Comput Biol 2017; 13:e1005516. [PMID: 28437460 PMCID: PMC5421815 DOI: 10.1371/journal.pcbi.1005516] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/08/2017] [Accepted: 04/11/2017] [Indexed: 11/30/2022] Open
Abstract
The formation and stability of synapses are key questions in neuroscience. Post-synaptic domains have been classically conceived as resulting from local insertion and turnover of proteins at the synapse. However, insertion is likely to occur outside the post-synaptic domains and advances in single-molecule imaging have shown that proteins diffuse in the plane of the membrane prior to their accumulation at synapses. We quantitatively investigated this scenario using computer simulations and mathematical analysis, taking for definiteness the specific case of inhibitory synapse components, i.e., the glycine receptor (GlyR) and the associated gephyrin scaffolding protein. The observed domain sizes of scaffold clusters can be explained by a dynamic balance between the aggregation of gephyrin proteins diffusing while bound to GlyR and their turnover at the neuron membrane. We also predict the existence of extrasynaptic clusters with a characteristic size distribution that significantly contribute to the size fluctuations of synaptic domains. New super-resolution data for gephyrin proteins established the existence of extrasynaptic clusters the sizes of which are consistent with the model predictions in a range of model parameters. At a general level, our results highlight aggregation with removal as a non-equilibrium phase separation which produces structures of tunable size. Synapses mediate information transmission between neurons and are the physical support of memory. It has been realized that synapses are dynamic biological structures. Neurotransmitter receptors diffuse in the neuron membrane and synaptic scaffolding proteins are constantly renewed. We propose a biophysical model that links these different measured quantities for inhibitory synapse components and show how they determine the size of postsynaptic domains. The model predicts that synaptic scaffolds also exist extrasynaptically and that they contribute to fluctuations of synaptic sizes. We confirm by super-resolution microscopy the existence of extrasynaptic scaffolds. Their measured size distribution agrees with the model predictions for specific parameters. The model should be helpful to better understand the dynamics of synapses and their possible levels of regulation.
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Affiliation(s)
- Jonas Ranft
- Laboratoire Physique Statistique, CNRS, Ecole Normale Supérieure, PSL Research University, Université Pierre et Marie Curie, Paris, France
| | - Leandro G. Almeida
- IBENS, Ecole Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - Pamela C. Rodriguez
- IBENS, Ecole Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
| | - Antoine Triller
- IBENS, Ecole Normale Supérieure, PSL Research University, CNRS, INSERM, Paris, France
- * E-mail: (AT); (VH)
| | - Vincent Hakim
- Laboratoire Physique Statistique, CNRS, Ecole Normale Supérieure, PSL Research University, Université Pierre et Marie Curie, Paris, France
- * E-mail: (AT); (VH)
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22
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Tang L, Zhang Y, Chen G, Xiong Y, Wang X, Zhu B. Down-regulation of Pin1 in Temporal Lobe Epilepsy Patients and Mouse Model. Neurochem Res 2017; 42:1211-1218. [PMID: 28239767 DOI: 10.1007/s11064-016-2158-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/15/2016] [Accepted: 12/19/2016] [Indexed: 12/31/2022]
Abstract
Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is a unique PPIase belonging to the parvulin family, and it isomerizes peptide bond between phospho-(Ser/Thr) and Pro. Pin1 has been linked to the pathogenesis of various human diseases; however, its exact biological functions remain unclear. The aim of the present study is to explore the expression pattern of Pin1 in patients with refractory epilepsy and in a chronic pilocarpine-induced epileptic mouse model. Using Western blot, immunofluorescence and immunoprecipitation analysis, we found that Pin1 protein was mainly distributed in neurons, demonstrated by colocalization with the dendritic marker, MAP2. However, the expression of Pin1 decreased remarkably in epileptic patients and experimental mice. Furthermore, the reciprocal coimmunoprecipitation analysis showed that Pin1 interacted with NR2A and NR2B-containing NMDA receptors not AMPA receptors in epileptic mouse models. Our results are the first to indicate that the expression of Pin1 in epileptic brain tissue could play important roles in epilepsy.
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Affiliation(s)
- Lan Tang
- The Public Health Center, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Yanke Zhang
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Guojun Chen
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China
| | - Yan Xiong
- Department of Neurology, The People's Hospital of Yubei District of Chongqing City, 62 Jianshe Road, Chongqing, 401120, China
| | - Xuefeng Wang
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China. .,Center of Epilepsy, Beijing Institute for Brain Disorders, 10 Xitoutiao, Youanmen, Fengtai District, Beijing, 100069, China.
| | - Binglin Zhu
- Department of Neurology, Chongqing Key Laboratory of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1 Youyi Road, Chongqing, 400016, China.
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Nakahata Y, Eto K, Murakoshi H, Watanabe M, Kuriu T, Hirata H, Moorhouse AJ, Ishibashi H, Nabekura J. Activation-Dependent Rapid Postsynaptic Clustering of Glycine Receptors in Mature Spinal Cord Neurons. eNeuro 2017; 4:ENEURO.0194-16.2017. [PMID: 28197549 PMCID: PMC5292596 DOI: 10.1523/eneuro.0194-16.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 01/05/2017] [Accepted: 01/17/2017] [Indexed: 12/02/2022] Open
Abstract
Inhibitory synapses are established during development but continue to be generated and modulated in strength in the mature nervous system. In the spinal cord and brainstem, presynaptically released inhibitory neurotransmitter dominantly switches from GABA to glycine during normal development in vivo. While presynaptic mechanisms of the shift of inhibitory neurotransmission are well investigated, the contribution of postsynaptic neurotransmitter receptors to this shift is not fully elucidated. Synaptic clustering of glycine receptors (GlyRs) is regulated by activation-dependent depolarization in early development. However, GlyR activation induces hyperpolarization after the first postnatal week, and little is known whether and how presynaptically released glycine regulates postsynaptic receptors in a depolarization-independent manner in mature developmental stage. Here we developed spinal cord neuronal culture of rodents using chronic strychnine application to investigate whether initial activation of GlyRs in mature stage could change postsynaptic localization of GlyRs. Immunocytochemical analyses demonstrate that chronic blockade of GlyR activation until mature developmental stage resulted in smaller clusters of postsynaptic GlyRs that could be enlarged upon receptor activation for 1 h in the mature stage. Furthermore, live cell-imaging techniques show that GlyR activation decreases its lateral diffusion at synapses, and this phenomenon is dependent on PKC, but neither Ca2+ nor CaMKII activity. These results suggest that the GlyR activation can regulate receptor diffusion and cluster size at inhibitory synapses in mature stage, providing not only new insights into the postsynaptic mechanism of shifting inhibitory neurotransmission but also the inhibitory synaptic plasticity in mature nervous system.
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Affiliation(s)
- Yoshihisa Nakahata
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
| | - Kei Eto
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
| | - Hideji Murakoshi
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
- Supportive Center for Brain Research, National Institute for Physiological Science, Okazaki 444-8585, Japan
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
| | - Toshihiko Kuriu
- Department of Neurophysiology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 769-2193, Japan
| | - Hiromi Hirata
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
- Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima 411-8540, Japan
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima 411-8540, Japan
- Department of Chemistry and Biological Science, Graduate School of Science and Engineering, Aoyama Gakuin University, Sagamihara 252-5258, Japan
| | - Andrew J. Moorhouse
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney 2052, Australia
| | - Hitoshi Ishibashi
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
- Department of Physiology, Kitasato University School of Allied Health Sciences, Sagamihara 252-0373, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
- Department of Physiological Sciences, The Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan
- CREST, Japan Science and Technology Agency (JST), Kawaguchi 332-0012, Japan
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24
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Mele M, Leal G, Duarte CB. Role of GABAAR trafficking in the plasticity of inhibitory synapses. J Neurochem 2016; 139:997-1018. [DOI: 10.1111/jnc.13742] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Miranda Mele
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Graciano Leal
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Carlos B. Duarte
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
- Department of Life Sciences; University of Coimbra; Coimbra Portugal
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25
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Alvarez FJ. Gephyrin and the regulation of synaptic strength and dynamics at glycinergic inhibitory synapses. Brain Res Bull 2016; 129:50-65. [PMID: 27612963 DOI: 10.1016/j.brainresbull.2016.09.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/23/2016] [Accepted: 09/05/2016] [Indexed: 01/23/2023]
Abstract
Glycinergic synapses predominate in brainstem and spinal cord where they modulate motor and sensory processing. Their postsynaptic mechanisms have been considered rather simple because they lack a large variety of glycine receptor isoforms and have relatively simple postsynaptic densities at the ultrastructural level. However, this simplicity is misleading being their postsynaptic regions regulated by a variety of complex mechanisms controlling the efficacy of synaptic inhibition. Early studies suggested that glycinergic inhibitory strength and dynamics depend largely on structural features rather than on molecular complexity. These include regulation of the number of postsynaptic glycine receptors, their localization and the amount of co-localized GABAA receptors and GABA-glycine co-transmission. These properties we now know are under the control of gephyrin. Gephyrin is the first postsynaptic scaffolding protein ever discovered and it was recently found to display a large degree of variation and regulation by splice variants, posttranslational modifications, intracellular trafficking and interactions with the underlying cytoskeleton. Many of these mechanisms are governed by converging excitatory activity and regulate gephyrin oligomerization and receptor binding, the architecture of the postsynaptic density (and by extension the whole synaptic complex), receptor retention and stability. These newly uncovered molecular mechanisms define the size and number of gephyrin postsynaptic regions and the numbers and proportions of glycine and GABAA receptors contained within. All together, they control the emergence of glycinergic synapses of different strength and temporal properties to best match the excitatory drive received by each individual neuron or local dendritic compartment.
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Affiliation(s)
- Francisco J Alvarez
- Department of Physiology, Emory University, Atlanta, GA 30322-3110, United States.
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26
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Choii G, Ko J. Gephyrin: a central GABAergic synapse organizer. Exp Mol Med 2015; 47:e158. [PMID: 25882190 DOI: 10.1038/emm.2015.5] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 12/18/2014] [Indexed: 01/22/2023] Open
Abstract
Gephyrin is a central element that anchors, clusters and stabilizes glycine and γ-aminobutyric acid type A receptors at inhibitory synapses of the mammalian brain. It self-assembles into a hexagonal lattice and interacts with various inhibitory synaptic proteins. Intriguingly, the clustering of gephyrin, which is regulated by multiple posttranslational modifications, is critical for inhibitory synapse formation and function. In this review, we summarize the basic properties of gephyrin and describe recent findings regarding its roles in inhibitory synapse formation, function and plasticity. We will also discuss the implications for the pathophysiology of brain disorders and raise the remaining open questions in this field.
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Affiliation(s)
- Gayoung Choii
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Jaewon Ko
- 1] Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea [2] Department of Psychiatry, Yonsei University College of Medicine, Seoul, Korea
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27
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Protein kinase C-dependent growth-associated protein 43 phosphorylation regulates gephyrin aggregation at developing GABAergic synapses. Mol Cell Biol 2015; 35:1712-26. [PMID: 25755278 DOI: 10.1128/mcb.01332-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/24/2015] [Indexed: 11/20/2022] Open
Abstract
Growth-associated protein 43 (GAP43) is known to regulate axon growth, but whether it also plays a role in synaptogenesis remains unclear. Here, we found that GAP43 regulates the aggregation of gephyrin, a pivotal protein for clustering postsynaptic GABA(A) receptors (GABA(A)Rs), in developing cortical neurons. Pharmacological blockade of either protein kinase C (PKC) or neuronal activity increased both GAP43-gephyrin association and gephyrin misfolding-induced aggregation, suggesting the importance of PKC-dependent regulation of GABAergic synapses. Furthermore, we found that PKC phosphorylation-resistant GAP43(S41A), but not PKC phosphorylation-mimicking GAP43(S41D), interacted with cytosolic gephyrin to trigger gephyrin misfolding and its sequestration into aggresomes. In contrast, GAP43(S41D), but not GAP43(S41A), inhibited the physiological aggregation/clustering of gephyrin, reduced surface GABA(A)Rs under physiological conditions, and attenuated gephyrin misfolding under transient oxygen-glucose deprivation (tOGD) that mimics pathological neonatal hypoxia. Calcineurin-mediated GAP43 dephosphorylation that accompanied tOGD also led to GAP43-gephyrin association and gephyrin misfolding. Thus, PKC-dependent phosphorylation of GAP43 plays a critical role in regulating postsynaptic gephyrin aggregation in developing GABAergic synapses.
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28
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Driver JA, Zhou XZ, Lu KP. Pin1 dysregulation helps to explain the inverse association between cancer and Alzheimer's disease. Biochim Biophys Acta Gen Subj 2015; 1850:2069-76. [PMID: 25583562 DOI: 10.1016/j.bbagen.2014.12.025] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 12/26/2014] [Accepted: 12/29/2014] [Indexed: 12/24/2022]
Abstract
BACKGROUND Pin1 is an intracellular signaling molecule which plays a critical but opposite role in the pathogenesis of Alzheimer's disease (AD) and many human cancers. SCOPE OF REVIEW We review the structure and function of the Pin1 enzyme, the diverse roles it plays in cycling cells and neurons, the epidemiologic evidence for the inverse association between cancer and AD, and the potential therapeutic implications of Pin1-based therapies. MAJOR CONCLUSIONS Pin1 is a unique enzyme that has effects on the function of target proteins by "twisting" them into different shapes. Cycling cells use Pin1 to help coordinate cell division. It is over-expressed and/or activated by multiple mechanisms in many common human cancers, and acts on multiple signal pathways to promote tumorigenesis. Inhibition of Pin1 in animal models has profound anti-tumor effects. In contrast, Pin1 is down-regulated or inactivated by multiple mechanisms in AD brains. The absence of Pin1 impairs tau function and amyloid precursor protein processing, leading to tangle- and amyloid-related pathologies and neurodegeneration in an age-dependent manner, resembling human AD. We have developed cis and trans conformation-specific antibodies to provide the first direct evidence that tau exists in distinct cis and trans conformations and that Pin1 accelerates its cis to trans conversion, thereby protecting against tangle formation in AD. GENERAL SIGNIFICANCE Available studies on Pin1 suggest that cancer and AD may share biological pathways that are deregulated in different directions. Pin1 biology opens exciting preventive and therapeutic horizons for both cancer and neurodegeneration. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets.
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Affiliation(s)
- Jane A Driver
- Geriatric Research Education and Clinical Center, VA Boston Healthcare System and the Division of Aging, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Xiao Zhen Zhou
- Cancer Research Institute, Beth Israel Deaconess Cancer Center and Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Kun Ping Lu
- Cancer Research Institute, Beth Israel Deaconess Cancer Center and Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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29
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Isopi E, Legname G. Pin1 and neurodegeneration: a new player for prion disorders? AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.3.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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30
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Salvatico C, Specht CG, Triller A. Synaptic receptor dynamics: From theoretical concepts to deep quantification and chemistry in cellulo. Neuropharmacology 2015; 88:2-9. [DOI: 10.1016/j.neuropharm.2014.09.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 01/22/2023]
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31
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Molecular basis of the alternative recruitment of GABAA versus glycine receptors through gephyrin. Nat Commun 2014; 5:5767. [DOI: 10.1038/ncomms6767] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/04/2014] [Indexed: 01/17/2023] Open
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32
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Pin1-dependent signalling negatively affects GABAergic transmission by modulating neuroligin2/gephyrin interaction. Nat Commun 2014; 5:5066. [PMID: 25297980 PMCID: PMC4197815 DOI: 10.1038/ncomms6066] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 08/25/2014] [Indexed: 01/06/2023] Open
Abstract
The cell adhesion molecule Neuroligin2 (NL2) is localized selectively at GABAergic synapses, where it interacts with the scaffolding protein gephyrin in the post-synaptic density. However, the role of this interaction for formation and plasticity of GABAergic synapses is unclear. Here, we demonstrate that endogenous NL2 undergoes proline-directed phosphorylation at its unique S714-P consensus site, leading to the recruitment of the peptidyl-prolyl cis-trans isomerase Pin1. This signalling cascade negatively regulates NL2's ability to interact with gephyrin at GABAergic post-synaptic sites. As a consequence, enhanced accumulation of NL2, gephyrin and GABAA receptors was detected at GABAergic synapses in the hippocampus of Pin1-knockout mice (Pin1-/-) associated with an increase in amplitude of spontaneous GABAA-mediated post-synaptic currents. Our results suggest that Pin1-dependent signalling represents a mechanism to modulate GABAergic transmission by regulating NL2/gephyrin interaction.
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33
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Petrini EM, Barberis A. Diffusion dynamics of synaptic molecules during inhibitory postsynaptic plasticity. Front Cell Neurosci 2014; 8:300. [PMID: 25294987 PMCID: PMC4171989 DOI: 10.3389/fncel.2014.00300] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/05/2014] [Indexed: 12/24/2022] Open
Abstract
The plasticity of inhibitory transmission is expected to play a key role in the modulation of neuronal excitability and network function. Over the last two decades, the investigation of the determinants of inhibitory synaptic plasticity has allowed distinguishing presynaptic and postsynaptic mechanisms. While there has been a remarkable progress in the characterization of presynaptically-expressed plasticity of inhibition, the postsynaptic mechanisms of inhibitory long-term synaptic plasticity only begin to be unraveled. At postsynaptic level, the expression of inhibitory synaptic plasticity involves the rearrangement of the postsynaptic molecular components of the GABAergic synapse, including GABAA receptors, scaffold proteins and structural molecules. This implies a dynamic modulation of receptor intracellular trafficking and receptor surface lateral diffusion, along with regulation of the availability and distribution of scaffold proteins. This Review will focus on the mechanisms of the multifaceted molecular reorganization of the inhibitory synapse during postsynaptic plasticity, with special emphasis on the key role of protein dynamics to ensure prompt and reliable activity-dependent adjustments of synaptic strength.
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Affiliation(s)
- Enrica Maria Petrini
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
| | - Andrea Barberis
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
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34
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Kalbouneh H, Schlicksupp A, Kirsch J, Kuhse J. Cyclin-dependent kinase 5 is involved in the phosphorylation of gephyrin and clustering of GABAA receptors at inhibitory synapses of hippocampal neurons. PLoS One 2014; 9:e104256. [PMID: 25093719 PMCID: PMC4122414 DOI: 10.1371/journal.pone.0104256] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 07/10/2014] [Indexed: 11/19/2022] Open
Abstract
CDK5 has been implicated in neural functions including growth, neuronal migration, synaptic transmission and plasticity of excitatory chemical synapses. Here we report robust effects of CDK5 on phosphorylation of the postsynaptic scaffold protein gephyrin and clustering of inhibitory GABAA receptors in hippocampal neurons. shRNA-mediated knockdown of CDK5 and pharmacological inhibition of cyclin-dependent kinases reduced phosphorylated gephyrin clusters and postsynaptic γ2-containing GABAA receptors. Phosphorylation of S270 is antagonized by PP1/PP2a phosphatase and site-directed mutagenesis and in vitro phosphorylation experiments indicate that S270 is a putative CDK5 phosphorylation site of gephyrin. Our data suggest that CDK5 plays an essential role for the stability of gephyrin-dependent GABAA receptor clusters in hippocampal neurons.
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Affiliation(s)
- Heba Kalbouneh
- Department of Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Andrea Schlicksupp
- Department of Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Joachim Kirsch
- Department of Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Jochen Kuhse
- Department of Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
- * E-mail:
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35
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Soykan T, Schneeberger D, Tria G, Buechner C, Bader N, Svergun D, Tessmer I, Poulopoulos A, Papadopoulos T, Varoqueaux F, Schindelin H, Brose N. A conformational switch in collybistin determines the differentiation of inhibitory postsynapses. EMBO J 2014; 33:2113-33. [PMID: 25082542 DOI: 10.15252/embj.201488143] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The formation of neuronal synapses and the dynamic regulation of their efficacy depend on the assembly of the postsynaptic neurotransmitter receptor apparatus. Receptor recruitment to inhibitory GABAergic and glycinergic synapses is controlled by the scaffold protein gephyrin and the adaptor protein collybistin. We derived new insights into the structure of collybistin and used these to design biochemical, cell biological, and genetic analyses of collybistin function. Our data define a collybistin-based protein interaction network that controls the gephyrin content of inhibitory postsynapses. Within this network, collybistin can adopt open/active and closed/inactive conformations to act as a switchable adaptor that links gephyrin to plasma membrane phosphoinositides. This function of collybistin is regulated by binding of the adhesion protein neuroligin-2, which stabilizes the open/active conformation of collybistin at the postsynaptic plasma membrane by competing with an intramolecular interaction in collybistin that favors the closed/inactive conformation. By linking trans-synaptic neuroligin-dependent adhesion and phosphoinositide signaling with gephyrin recruitment, the collybistin-based regulatory switch mechanism represents an integrating regulatory node in the formation and function of inhibitory postsynapses.
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Affiliation(s)
- Tolga Soykan
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Daniela Schneeberger
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Giancarlo Tria
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany Centre for Bioinformatics, University of Hamburg, Hamburg, Germany
| | - Claudia Buechner
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Nicole Bader
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany
| | - Ingrid Tessmer
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Alexandros Poulopoulos
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Theofilos Papadopoulos
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Frédérique Varoqueaux
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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36
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Abstract
The neurotransmitters GABA and glycine mediate fast synaptic inhibition by activating ligand-gated chloride channels--namely, type A GABA (GABA(A)) and glycine receptors. Both types of receptors are anchored postsynaptically by gephyrin, which self-assembles into a scaffold and interacts with the cytoskeleton. Current research indicates that postsynaptic gephyrin clusters are dynamic assemblies that are held together and regulated by multiple protein-protein interactions. Moreover, post-translational modifications of gephyrin regulate the formation and plasticity of GABAergic synapses by altering the clustering properties of postsynaptic scaffolds and thereby the availability and function of receptors and other signalling molecules. Here, we discuss the formation and regulation of the gephyrin scaffold, its role in GABAergic and glycinergic synaptic function and the implications for the pathophysiology of brain disorders caused by abnormal inhibitory neurotransmission.
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37
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Zacchi P, Antonelli R, Cherubini E. Gephyrin phosphorylation in the functional organization and plasticity of GABAergic synapses. Front Cell Neurosci 2014; 8:103. [PMID: 24782709 PMCID: PMC3988358 DOI: 10.3389/fncel.2014.00103] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/22/2014] [Indexed: 11/13/2022] Open
Abstract
Gephyrin is a multifunctional scaffold protein essential for accumulation of inhibitory glycine and GABAA receptors at post-synaptic sites. The molecular events involved in gephyrin-dependent GABAA receptor clustering are still unclear. Evidence has been recently provided that gephyrin phosphorylation plays a key role in these processes. Gephyrin post-translational modifications have been shown to influence the structural remodeling of GABAergic synapses and synaptic plasticity by acting on post-synaptic scaffolding properties as well as stability. In addition, gephyrin phosphorylation and the subsequent phosphorylation-dependent recruitment of the chaperone molecule Pin1 provide a mechanism for the regulation of GABAergic signaling. Extensively characterized as pivotal enzyme controlling cell proliferation and differentiation, the prolyl-isomerase activity of Pin1 has been shown to regulate protein synthesis necessary to sustain the late phase of long-term potentiation at excitatory synapses, which suggests its involvement at synaptic sites. In this review we summarize the current state of knowledge of the signaling pathways responsible for gephyrin post-translational modifications. We will also outline future lines of research that might contribute to a better understanding of molecular mechanisms by which gephyrin regulates synaptic plasticity at GABAergic synapses.
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Affiliation(s)
- Paola Zacchi
- Department of Neurosciences, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
| | - Roberta Antonelli
- Department of Neurosciences, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy
| | - Enrico Cherubini
- Department of Neurosciences, Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy ; European Brain Research Institute Roma, Italy
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38
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Yoon WJ, Cho YD, Kim WJ, Bae HS, Islam R, Woo KM, Baek JH, Bae SC, Ryoo HM. Prolyl isomerase Pin1-mediated conformational change and subnuclear focal accumulation of Runx2 are crucial for fibroblast growth factor 2 (FGF2)-induced osteoblast differentiation. J Biol Chem 2014; 289:8828-38. [PMID: 24509851 DOI: 10.1074/jbc.m113.516237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor 2 (FGF2) signaling plays a pivotal role in bone growth/differentiation through the activation of osteogenic master transcription factor Runx2, which is mediated by the ERK/MAPK-dependent phosphorylation and the p300-dependent acetylation of Runx2. In this study, we found that Pin1-dependent isomerization of Runx2 is the critical step for FGF2-induced Runx2 transactivation function. We identified four serine or threonine residues in the C-terminal domain of Runx2 that are responsible for Pin1 binding and structural modification. Confocal imaging studies indicated that FGF2 treatment strongly stimulated the focal accumulation of Pin1 in the subnuclear area, which recruited Runx2. In addition, active forms of RNA polymerase-II also colocalized in the same subnuclear compartment. Dipentamethylene thiuram monosulfide, a Pin1 inhibitor, strongly attenuated their focal accumulation as well as Runx2 transactivation activity. The Pin1-mediated structural modification of Runx2 is an indispensable step connecting phosphorylation and acetylation and, consequently, transcriptional activation of Runx2 by FGF signaling. Thus, the modulation of Pin1 activity may be a target for the regulation of bone formation.
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Affiliation(s)
- Won-Joon Yoon
- From the Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749 and
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39
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Mele M, Ribeiro L, Inácio AR, Wieloch T, Duarte CB. GABA(A) receptor dephosphorylation followed by internalization is coupled to neuronal death in in vitro ischemia. Neurobiol Dis 2014; 65:220-32. [PMID: 24513087 DOI: 10.1016/j.nbd.2014.01.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 01/08/2014] [Accepted: 01/30/2014] [Indexed: 12/22/2022] Open
Abstract
Cerebral ischemia is characterized by an early disruption of GABAergic neurotransmission contributing to an imbalance of the excitatory/inhibitory equilibrium and neuronal death, but the molecular mechanisms involved are not fully understood. Here we report a downregulation of GABA(A) receptor (GABA(A)R) expression, affecting both mRNA and protein levels of GABA(A)R subunits, in hippocampal neurons subjected to oxygen-glucose deprivation (OGD), an in vitro model of ischemia. Similar alterations in the abundance of GABA(A)R subunits were observed in in vivo brain ischemia. OGD reduced the interaction of surface GABA(A)R with the scaffold protein gephyrin, followed by clathrin-dependent receptor internalization. Internalization of GABA(A)R was dependent on glutamate receptor activation and mediated by dephosphorylation of the β3 subunit at serine 408/409. Expression of phospho-mimetic mutant GABA(A)R β3 subunits prevented receptor internalization and protected hippocampal neurons from ischemic cell death. The results show a key role for β3 GABA(A)R subunit dephosphorylation in the downregulation of GABAergic synaptic transmission in brain ischemia, contributing to neuronal death. GABA(A)R phosphorylation might be a therapeutic target to preserve synaptic inhibition in brain ischemia.
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Affiliation(s)
- Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Luís Ribeiro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Ana R Inácio
- Wallenberg Neuroscience Center, Lund University, 221 84 Lund, Sweden
| | - Tadeusz Wieloch
- Wallenberg Neuroscience Center, Lund University, 221 84 Lund, Sweden
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal.
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40
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Specht CG, Izeddin I, Rodriguez PC, El Beheiry M, Rostaing P, Darzacq X, Dahan M, Triller A. Quantitative nanoscopy of inhibitory synapses: counting gephyrin molecules and receptor binding sites. Neuron 2013; 79:308-21. [PMID: 23889935 DOI: 10.1016/j.neuron.2013.05.013] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2013] [Indexed: 12/01/2022]
Abstract
The strength of synaptic transmission is controlled by the number and activity of neurotransmitter receptors. However, little is known about absolute numbers and densities of receptor and scaffold proteins and the stoichiometry of molecular interactions at synapses. Here, we conducted three-dimensional and quantitative nanoscopic imaging based on single-molecule detections to characterize the ultrastructure of inhibitory synapses and to count scaffold proteins and receptor binding sites. We observed a close correspondence between the spatial organization of gephyrin scaffolds and glycine receptors at spinal cord synapses. Endogenous gephyrin was clustered at densities of 5,000-10,000 molecules/μm(2). The stoichiometry between gephyrin molecules and receptor binding sites was approximately 1:1, consistent with a two-dimensional scaffold in which all gephyrin molecules can contribute to receptor binding. The competition of glycine and GABAA receptor complexes for synaptic binding sites highlights the potential of single-molecule imaging to quantify synaptic plasticity on the nanoscopic scale.
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Affiliation(s)
- Christian G Specht
- Biologie Cellulaire de la Synapse, Inserm U1024, Institute of Biology, École Normale Supérieure ENS, 46 rue d'Ulm, Paris 75005, France
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41
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Sander B, Tria G, Shkumatov AV, Kim EY, Grossmann JG, Tessmer I, Svergun DI, Schindelin H. Structural characterization of gephyrin by AFM and SAXS reveals a mixture of compact and extended states. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:2050-60. [DOI: 10.1107/s0907444913018714] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 07/05/2013] [Indexed: 11/10/2022]
Abstract
Gephyrin is a trimeric protein involved in the final steps of molybdenum-cofactor (Moco) biosynthesis and in the clustering of inhibitory glycine and GABAAreceptors at postsynaptic specializations. Each protomer consists of stably folded domains (referred to as the G and E domains) located at either terminus and connected by a proteolytically sensitive linker of ∼150 residues. Both terminal domains can oligomerize in their isolated forms; however, in the context of the full-length protein only the G-domain trimer is permanently present, whereas E-domain dimerization is prevented. Atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) reveal a high degree of flexibility in the structure of gephyrin. The results imply an equilibrium between compact and extended conformational states in solution, with a preference for compact states. CD spectroscopy suggests that a partial compaction is achieved by interactions of the linker with the G and E domains. Taken together, the data provide a rationale for the role of the linker in the overall structure and the conformational dynamics of gephyrin.
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42
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González MI. The possible role of GABAA receptors and gephyrin in epileptogenesis. Front Cell Neurosci 2013; 7:113. [PMID: 23885234 PMCID: PMC3717475 DOI: 10.3389/fncel.2013.00113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 06/26/2013] [Indexed: 12/29/2022] Open
Abstract
The term epileptogenesis refers to a dynamic alteration in neuronal excitability that promotes the appearance of spontaneous seizures. Temporal lobe epilepsy, the most common type of acquired epilepsy, often develops after an insult to the brain such as trauma, febrile seizures, encephalitis, or status epilepticus. During the pre-epileptic state (also referred as latent or silent period) there is a plethora of molecular, biochemical, and structural changes that lead to the generation of recurrent spontaneous seizures (or epilepsy). The specific contribution of these alterations to epilepsy development is unclear, but a loss of inhibition has been associated with the increased excitability detected in the latent period. A rapid increase in neuronal hyperexcitability could be due, at least in part, to a decline in the number of physiologically active GABAA receptors (GABAAR). Altered expression of scaffolding proteins involved in the trafficking and anchoring of GABAAR could directly impact the stability of GABAergic synapses and promote a deficiency in inhibitory neurotransmission. Uncovering the molecular mechanisms operating during epileptogenesis and its possible impact on the regulation of GABAAR and scaffolding proteins may offer new targets to prevent the development of epilepsy.
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Affiliation(s)
- Marco I González
- Division of Neurology and Translational Epilepsy Research Program, Department of Pediatrics, University of Colorado School of Medicine Aurora, CO, USA
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43
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Tyagarajan SK, Ghosh H, Yévenes GE, Imanishi SY, Zeilhofer HU, Gerrits B, Fritschy JM. Extracellular signal-regulated kinase and glycogen synthase kinase 3β regulate gephyrin postsynaptic aggregation and GABAergic synaptic function in a calpain-dependent mechanism. J Biol Chem 2013; 288:9634-9647. [PMID: 23408424 DOI: 10.1074/jbc.m112.442616] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Molecular mechanisms of plasticity at GABAergic synapses are currently poorly understood. To identify signaling cascades that converge onto GABAergic postsynaptic density proteins, we performed MS analysis using gephyrin isolated from rat brain and identified multiple novel phosphorylation and acetylation residues on gephyrin. Here, we report the characterization of one of these phosphoresidues, Ser-268, which when dephosphorylated leads to the formation of larger postsynaptic scaffolds. Using a combination of mutagenesis, pharmacological treatment, and biochemical assays, we identify ERK as the kinase phosphorylating Ser-268 and describe a functional interaction between residues Ser-268 and Ser-270. We further demonstrate that alterations in gephyrin clustering via ERK modulation are reflected by amplitude and frequency changes in miniature GABAergic postsynaptic currents. We unravel novel mechanisms for activity- and ERK-dependent calpain action on gephyrin, which are likely relevant in the context of cellular signaling affecting GABAergic transmission and homeostatic synaptic plasticity in pathology.
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Affiliation(s)
- Shiva K Tyagarajan
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, Zurich, 8057 Switzerland.
| | - Himanish Ghosh
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, Zurich, 8057 Switzerland
| | - Gonzalo E Yévenes
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland
| | - Susumu Y Imanishi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, Zurich, 8057 Switzerland; Institute of Pharmaceutical Sciences, ETH Zurich, Zurich, 8093 Switzerland
| | | | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, Zurich, 8057 Switzerland
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Yamanaka I, Miki M, Asakawa K, Kawakami K, Oda Y, Hirata H. Glycinergic transmission and postsynaptic activation of CaMKII are required for glycine receptor clusteringin vivo. Genes Cells 2013; 18:211-24. [DOI: 10.1111/gtc.12032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/29/2012] [Indexed: 02/06/2023]
Affiliation(s)
- Iori Yamanaka
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
| | - Mariko Miki
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
| | | | | | - Yoichi Oda
- Division of Biological Science; Graduate School of Science; Nagoya University; Nagoya; 464-8602; Japan
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45
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A comprehensive small interfering RNA screen identifies signaling pathways required for gephyrin clustering. J Neurosci 2013; 32:14821-34. [PMID: 23077067 DOI: 10.1523/jneurosci.1261-12.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The postsynaptic scaffold protein gephyrin is clustered at inhibitory synapses and serves for the stabilization of GABA(A) receptors. Here, a comprehensive kinome-wide siRNA screen in a human HeLa cell-based model for gephyrin clustering was used to identify candidate protein kinases implicated in the stabilization of gephyrin clusters. As a result, 12 hits were identified including FGFR1 (FGF receptor 1), TrkB, and TrkC as well as components of the MAPK and mammalian target of rapamycin (mTOR) pathways. For confirmation, the impact of these hits on gephyrin clustering was analyzed in rat primary hippocampal neurons. We found that brain-derived neurotrophic factor (BDNF) acts on gephyrin clustering through MAPK signaling, and this process may be controlled by the MAPK signaling antagonist sprouty2. BDNF signaling through phosphatidylinositol 3-kinase (PI3K)-Akt also activates mTOR and represses GSK3β, which was previously shown to reduce gephyrin clustering. Gephyrin is associated with inactive mTOR and becomes released upon BDNF-dependent mTOR activation. In primary neurons, a reduction in the number of gephyrin clusters due to manipulation of the BDNF-mTOR signaling is associated with reduced GABA(A) receptor clustering, suggesting functional impairment of GABA signaling. Accordingly, application of the mTOR antagonist rapamycin leads to disinhibition of neuronal networks as measured on microelectrode arrays. In conclusion, we provide evidence that BDNF regulates gephyrin clustering via MAPK as well as PI3K-Akt-mTOR signaling.
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Fritschy JM, Panzanelli P, Tyagarajan SK. Molecular and functional heterogeneity of GABAergic synapses. Cell Mol Life Sci 2012; 69:2485-99. [PMID: 22314501 PMCID: PMC11115047 DOI: 10.1007/s00018-012-0926-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 01/16/2012] [Accepted: 01/19/2012] [Indexed: 01/07/2023]
Abstract
Knowledge of the functional organization of the GABAergic system, the main inhibitory neurotransmitter system, in the CNS has increased remarkably in recent years. In particular, substantial progress has been made in elucidating the molecular mechanisms underlying the formation and plasticity of GABAergic synapses. Evidence available ascribes a key role to the cytoplasmic protein gephyrin to form a postsynaptic scaffold anchoring GABA(A) receptors along with other transmembrane proteins and signaling molecules in the postsynaptic density. However, the mechanisms of gephyrin scaffolding remain elusive, notably because gephyrin can auto-aggregate spontaneously and lacks PDZ protein interaction domains found in a majority of scaffolding proteins. In addition, the structural diversity of GABA(A) receptors, which are pentameric channels encoded by a large family of subunits, has been largely overlooked in these studies. Finally, the role of the dystrophin-glycoprotein complex, present in a subset of GABAergic synapses in cortical structures, remains ill-defined. In this review, we discuss recent results derived mainly from the analysis of mutant mice lacking a specific GABA(A) receptor subtype or a core protein of the GABAergic postsynaptic density (neuroligin-2, collybistin), highlighting the molecular diversity of GABAergic synapses and its relevance for brain plasticity and function. In addition, we discuss the contribution of the dystrophin-glycoprotein complex to the molecular and functional heterogeneity of GABAergic synapses.
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Affiliation(s)
- Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, Switzerland.
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47
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Kuhse J, Kalbouneh H, Schlicksupp A, Mükusch S, Nawrotzki R, Kirsch J. Phosphorylation of gephyrin in hippocampal neurons by cyclin-dependent kinase CDK5 at Ser-270 is dependent on collybistin. J Biol Chem 2012; 287:30952-66. [PMID: 22778260 DOI: 10.1074/jbc.m112.349597] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gephyrin is a scaffold protein essential for the postsynaptic clustering of inhibitory glycine and different subtypes of GABA(A) receptors. The cellular and molecular mechanisms involved in gephyrin-mediated receptor clustering are still not well understood. Here we provide evidence that the gephyrin-binding protein collybistin is involved in regulating the phosphorylation of gephyrin. We demonstrate that the widely used monoclonal antibody mAb7a is a phospho-specific antibody that allows the cellular and biochemical analysis of gephyrin phosphorylation at Ser-270. In addition, another neighbored epitope determinant was identified at position Thr-276. Analysis of the double mutant gephyrin(T276A,S277A) revealed significant reduction in gephyrin cluster formation and altered oligomerization behavior of gephyrin. Moreover, pharmacological inhibition of cyclin-dependent kinases in hippocampal neurons reduced postsynaptic gephyrin mAb7a immunoreactivities. In vitro phosphorylation assays and phosphopeptide competition experiments revealed a phosphorylation at Ser-270 depending on enzyme activities of cyclin-dependent kinases CDK1, -2, or -5. These data indicate that collybistin and cyclin-dependent kinases are involved in regulating the phosphorylation of gephyrin at postsynaptic membrane specializations.
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Affiliation(s)
- Jochen Kuhse
- Department of Anatomy and Cell Biology, University of Heidelberg, D-69120 Heidelberg, Germany.
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48
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Abstract
The Wnt/β-catenin pathway promotes proliferation of neural progenitor cells (NPCs) at early stages and induces neuronal differentiation from NPCs at late stages, but the molecular mechanisms that control this stage-specific response are unclear. Pin1 is a prolyl isomerase that regulates cell signaling uniquely by controlling protein conformation after phosphorylation, but its role in neuronal differentiation is not known. Here we found that whereas Pin1 depletion suppresses neuronal differentiation, Pin1 overexpression enhances it, without any effects on gliogenesis from NPCs in vitro. Consequently, Pin1-null mice have significantly fewer upper layer neurons in the motor cortex and severely impaired motor activity during the neonatal stage. A proteomic approach identified β-catenin as a major substrate for Pin1 in NPCs, in which Pin1 stabilizes β-catenin. As a result, Pin1 knockout leads to reduced β-catenin during differentiation but not proliferation of NPCs in developing brains. Importantly, defective neuronal differentiation in Pin1 knockout NPCs is fully rescued in vitro by overexpression of β-catenin but not a β-catenin mutant that fails to act as a Pin1 substrate. These results show that Pin1 is a novel regulator of NPC differentiation by acting on β-catenin and provides a new postphosphorylation signaling mechanism to regulate developmental stage-specific functioning of β-catenin signaling in neuronal differentiation.
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Min SH, Lau AW, Lee TH, Inuzuka H, Wei S, Huang P, Shaik S, Lee DY, Finn G, Balastik M, Chen CH, Luo M, Tron AE, Decaprio JA, Zhou XZ, Wei W, Lu KP. Negative regulation of the stability and tumor suppressor function of Fbw7 by the Pin1 prolyl isomerase. Mol Cell 2012; 46:771-83. [PMID: 22608923 DOI: 10.1016/j.molcel.2012.04.012] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 12/29/2011] [Accepted: 04/12/2012] [Indexed: 01/05/2023]
Abstract
Fbw7 is the substrate recognition component of the Skp1-Cullin-F-box (SCF)-type E3 ligase complex and a well-characterized tumor suppressor that targets numerous oncoproteins for destruction. Genomic deletion or mutation of FBW7 has been frequently found in various types of human cancers; however, little is known about the upstream signaling pathway(s) governing Fbw7 stability and cellular functions. Here we report that Fbw7 protein destruction and tumor suppressor function are negatively regulated by the prolyl isomerase Pin1. Pin1 interacts with Fbw7 in a phoshorylation-dependent manner and promotes Fbw7 self-ubiquitination and protein degradation by disrupting Fbw7 dimerization. Consequently, overexpressing Pin1 reduces Fbw7 abundance and suppresses Fbw7's ability to inhibit proliferation and transformation. By contrast, depletion of Pin1 in cancer cells leads to elevated Fbw7 expression, which subsequently reduces Mcl-1 abundance, sensitizing cancer cells to Taxol. Thus, Pin1-mediated inhibition of Fbw7 contributes to oncogenesis, and Pin1 may be a promising drug target for anticancer therapy.
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Affiliation(s)
- Sang-Hyun Min
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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50
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Tretter V, Mukherjee J, Maric HM, Schindelin H, Sieghart W, Moss SJ. Gephyrin, the enigmatic organizer at GABAergic synapses. Front Cell Neurosci 2012; 6:23. [PMID: 22615685 PMCID: PMC3351755 DOI: 10.3389/fncel.2012.00023] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 04/23/2012] [Indexed: 11/17/2022] Open
Abstract
GABAA receptors are clustered at synaptic sites to achieve a high density of postsynaptic receptors opposite the input axonal terminals. This allows for an efficient propagation of GABA mediated signals, which mostly result in neuronal inhibition. A key organizer for inhibitory synaptic receptors is the 93 kDa protein gephyrin that forms oligomeric superstructures beneath the synaptic area. Gephyrin has long been known to be directly associated with glycine receptor β subunits that mediate synaptic inhibition in the spinal cord. Recently, synaptic GABAA receptors have also been shown to directly interact with gephyrin and interaction sites have been identified and mapped within the intracellular loops of the GABAA receptor α1, α2, and α3 subunits. Gephyrin-binding to GABAA receptors seems to be at least one order of magnitude weaker than to glycine receptors (GlyRs) and most probably is regulated by phosphorylation. Gephyrin not only has a structural function at synaptic sites, but also plays a crucial role in synaptic dynamics and is a platform for multiple protein-protein interactions, bringing receptors, cytoskeletal proteins and downstream signaling proteins into close spatial proximity.
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Affiliation(s)
- Verena Tretter
- Department of Biochemistry and Molecular Biology, Center for Brain Research, Medical University Vienna Vienna, Austria
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