1
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Tureček R, Melichar A, Králíková M, Hrušková B. The role of GABA B receptors in the subcortical pathways of the mammalian auditory system. Front Endocrinol (Lausanne) 2023; 14:1195038. [PMID: 37635966 PMCID: PMC10456889 DOI: 10.3389/fendo.2023.1195038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/24/2023] [Indexed: 08/29/2023] Open
Abstract
GABAB receptors are G-protein coupled receptors for the inhibitory neurotransmitter GABA. Functional GABAB receptors are formed as heteromers of GABAB1 and GABAB2 subunits, which further associate with various regulatory and signaling proteins to provide receptor complexes with distinct pharmacological and physiological properties. GABAB receptors are widely distributed in nervous tissue, where they are involved in a number of processes and in turn are subject to a number of regulatory mechanisms. In this review, we summarize current knowledge of the cellular distribution and function of the receptors in the inner ear and auditory pathway of the mammalian brainstem and midbrain. The findings suggest that in these regions, GABAB receptors are involved in processes essential for proper auditory function, such as cochlear amplifier modulation, regulation of spontaneous activity, binaural and temporal information processing, and predictive coding. Since impaired GABAergic inhibition has been found to be associated with various forms of hearing loss, GABAB dysfunction could also play a role in some pathologies of the auditory system.
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Affiliation(s)
- Rostislav Tureček
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Adolf Melichar
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Michaela Králíková
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Bohdana Hrušková
- Department of Auditory Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czechia
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2
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Members of the KCTD family are major regulators of cAMP signaling. Proc Natl Acad Sci U S A 2022; 119:2119237119. [PMID: 34934014 PMCID: PMC8740737 DOI: 10.1073/pnas.2119237119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Neuromodulation is pivotal for brain function. One of the key pathways engaged by neuromodulators is signaling via second messenger cAMP, which controls a myriad of fundamental reactions. This study identifies KCTD5, a ubiquitin ligase adapter, as a regulatory element in this pathway and determines that it works by an unusual dual mode controlling the activity of cAMP-generating enzyme in neurons through both zinc transport and G protein signaling. Cyclic adenosine monophosphate (cAMP) is a pivotal second messenger with an essential role in neuronal function. cAMP synthesis by adenylyl cyclases (AC) is controlled by G protein–coupled receptor (GPCR) signaling systems. However, the network of molecular players involved in the process is incompletely defined. Here, we used CRISPR/Cas9–based screening to identify that members of the potassium channel tetradimerization domain (KCTD) family are major regulators of cAMP signaling. Focusing on striatal neurons, we show that the dominant isoform KCTD5 exerts its effects through an unusual mechanism that modulates the influx of Zn2+ via the Zip14 transporter to exert unique allosteric effects on AC. We further show that KCTD5 controls the amplitude and sensitivity of stimulatory GPCR inputs to cAMP production by Gβγ-mediated AC regulation. Finally, we report that KCTD5 haploinsufficiency in mice leads to motor deficits that can be reversed by chelating Zn2+. Together, our findings uncover KCTD proteins as major regulators of neuronal cAMP signaling via diverse mechanisms.
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3
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Fritzius T, Stawarski M, Isogai S, Bettler B. Structural Basis of GABA B Receptor Regulation and Signaling. Curr Top Behav Neurosci 2022; 52:19-37. [PMID: 32812202 DOI: 10.1007/7854_2020_147] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
GABAB receptors (GBRs), the G protein-coupled receptors for the inhibitory neurotransmitter γ-aminobutyric acid (GABA), activate Go/i-type G proteins that regulate adenylyl cyclase, Ca2+ channels, and K+ channels. GBR signaling to enzymes and ion channels influences neuronal activity, plasticity processes, and network activity throughout the brain. GBRs are obligatory heterodimers composed of GB1a or GB1b subunits with a GB2 subunit. Heterodimeric GB1a/2 and GB1b/2 receptors represent functional units that associate in a modular fashion with regulatory, trafficking, and effector proteins to generate receptors with distinct physiological functions. This review summarizes current knowledge on the structure, organization, and functions of multi-protein GBR complexes.
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Affiliation(s)
- Thorsten Fritzius
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Michal Stawarski
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Shin Isogai
- Biozentrum, Focal Area Structural Biology and Biophysics, University of Basel, Basel, Switzerland.
- Microbial Downstream Process Development, Lonza AG, Visp, Switzerland.
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland.
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4
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Ravasz L, Kékesi KA, Mittli D, Todorov MI, Borhegyi Z, Ercsey-Ravasz M, Tyukodi B, Wang J, Bártfai T, Eberwine J, Juhász G. Cell Surface Protein mRNAs Show Differential Transcription in Pyramidal and Fast-Spiking Cells as Revealed by Single-Cell Sequencing. Cereb Cortex 2021; 31:731-745. [PMID: 32710103 DOI: 10.1093/cercor/bhaa195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 05/27/2020] [Accepted: 06/28/2020] [Indexed: 12/12/2022] Open
Abstract
The prefrontal cortex (PFC) plays a key role in higher order cognitive functions and psychiatric disorders such as autism, schizophrenia, and depression. In the PFC, the two major classes of neurons are the glutamatergic pyramidal (Pyr) cells and the GABAergic interneurons such as fast-spiking (FS) cells. Despite extensive electrophysiological, morphological, and pharmacological studies of the PFC, the therapeutically utilized drug targets are restricted to dopaminergic, glutamatergic, and GABAergic receptors. To expand the pharmacological possibilities as well as to better understand the cellular and network effects of clinically used drugs, it is important to identify cell-type-selective, druggable cell surface proteins and to link developed drug candidates to Pyr or FS cell targets. To identify the mRNAs of such cell-specific/enriched proteins, we performed ultra-deep single-cell mRNA sequencing (19 685 transcripts in total) on electrophysiologically characterized intact PFC neurons harvested from acute brain slices of mice. Several selectively expressed transcripts were identified with some of the genes that have already been associated with cellular mechanisms of psychiatric diseases, which we can now assign to Pyr (e.g., Kcnn2, Gria3) or FS (e.g., Kcnk2, Kcnmb1) cells. The earlier classification of PFC neurons was also confirmed at mRNA level, and additional markers have been provided.
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Affiliation(s)
- Lilla Ravasz
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary
| | - Katalin Adrienna Kékesi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,Department of Physiology and Neurobiology, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary
| | - Dániel Mittli
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary
| | - Mihail Ivilinov Todorov
- Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary
| | - Zsolt Borhegyi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary
| | - Mária Ercsey-Ravasz
- Faculty of Physics, Babeș-Bolyai University, Cluj-Napoca RO-400084, Romania.,Transylvanian Institute of Neuroscience, Cluj-Napoca RO-400157, Romania
| | - Botond Tyukodi
- Faculty of Physics, Babeș-Bolyai University, Cluj-Napoca RO-400084, Romania.,Martin Fisher School of Physics, Brandeis University, Waltham, MA 02451, USA
| | - Jinhui Wang
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Tamás Bártfai
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
| | - James Eberwine
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Gábor Juhász
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary.,CRU Hungary Ltd., H-2131 Göd, Hungary
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5
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Sereikaite V, Fritzius T, Kasaragod VB, Bader N, Maric HM, Schindelin H, Bettler B, Strømgaard K. Targeting the γ-Aminobutyric Acid Type B (GABA B) Receptor Complex: Development of Inhibitors Targeting the K + Channel Tetramerization Domain (KCTD) Containing Proteins/GABA B Receptor Protein-Protein Interaction. J Med Chem 2019; 62:8819-8830. [PMID: 31509708 DOI: 10.1021/acs.jmedchem.9b01087] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Targeting multiprotein receptor complexes, rather than receptors directly, is a promising concept in drug discovery. This is particularly relevant to the GABAB receptor complex, which plays a prominent role in many brain functions and diseases. Here, we provide the first studies targeting a key protein-protein interaction of the GABAB receptor complex-the interaction with KCTD proteins. By employing the μSPOT technology, we first defined the GABAB receptor-binding epitope mediating the KCTD interaction. Subsequently, we developed a highly potent peptide-based inhibitor that interferes with the KCTD/GABAB receptor complex and efficiently isolates endogenous KCTD proteins from mouse brain lysates. X-ray crystallography and SEC-MALS revealed inhibitor induced oligomerization of KCTD16 into a distinct hexameric structure. Thus, we provide a template for modulating the GABAB receptor complex, revealing a fundamentally novel approach for targeting GABAB receptor-associated neuropsychiatric disorders.
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Affiliation(s)
- Vita Sereikaite
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology , University of Copenhagen , 2100 Copenhagen , Denmark
| | - Thorsten Fritzius
- Department of Biomedicine , University of Basel , CH-4056 Basel , Switzerland
| | - Vikram B Kasaragod
- Rudolf Virchow Center for Experimental Biomedicine , University of Würzburg , 97080 Würzburg , Germany
| | - Nicole Bader
- Rudolf Virchow Center for Experimental Biomedicine , University of Würzburg , 97080 Würzburg , Germany
| | - Hans M Maric
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology , University of Copenhagen , 2100 Copenhagen , Denmark
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine , University of Würzburg , 97080 Würzburg , Germany
| | - Bernhard Bettler
- Department of Biomedicine , University of Basel , CH-4056 Basel , Switzerland
| | - Kristian Strømgaard
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology , University of Copenhagen , 2100 Copenhagen , Denmark
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6
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Pirone L, Smaldone G, Spinelli R, Barberisi M, Beguinot F, Vitagliano L, Miele C, Di Gaetano S, Raciti GA, Pedone E. KCTD1: A novel modulator of adipogenesis through the interaction with the transcription factor AP2α. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:158514. [PMID: 31465887 DOI: 10.1016/j.bbalip.2019.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/09/2019] [Accepted: 08/22/2019] [Indexed: 01/23/2023]
Abstract
Adipogenesis has an important role in regulating energy balance, tissue homeostasis and disease pathogenesis. 3T3-L1 preadipocytes have been widely used as an in vitro model for studying adipocyte differentiation. We here show that KCTD1, a member of the potassium channel containing tetramerization domain proteins, plays an active role in adipogenesis. In particular, we show KCTD1 expression 3T3-L1 cells increases upon adipogenesis induction. Treatment of 3T3-L1 preadipocytes with Kctd1-specific siRNA inhibited the differentiation, as indicated by reduction of expression of the specific adipogenic markers C/ebpα, Pparγ2, Glut4, and Adiponectin. Moreover, we also show that the protein physically interacts with the transcription factor AP2α, a known inhibitor of adipogenesis, both in vitro and in cells. Interestingly, our data indicate that KCTD1 promotes adipogenesis through the interaction with AP2α and by removing it from the nucleus. Collectively, these findings disclose a novel role for KCTD1 and pave the way for novel strategies aimed at modulating adipogenesis.
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Affiliation(s)
- Luciano Pirone
- Istituto di Biostrutture e Bioimmagini, CNR, Napoli, Italy
| | | | - Rosa Spinelli
- URT "Genomica del Diabete", Istituto per l'Endocrinologia e l'Oncologia Sperimentale "Gaetano Salvatore", CNR, Napoli, Italy; Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Italy
| | - Manlio Barberisi
- Dipartimento Scienze Anastesiologiche, Chirurgiche E Dell'emergenza, Università Della Campania-Luigi Vanvitelli, Caserta, Italy
| | - Francesco Beguinot
- URT "Genomica del Diabete", Istituto per l'Endocrinologia e l'Oncologia Sperimentale "Gaetano Salvatore", CNR, Napoli, Italy; Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Italy
| | | | - Claudia Miele
- URT "Genomica del Diabete", Istituto per l'Endocrinologia e l'Oncologia Sperimentale "Gaetano Salvatore", CNR, Napoli, Italy; Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Italy
| | | | - Gregory Alexander Raciti
- URT "Genomica del Diabete", Istituto per l'Endocrinologia e l'Oncologia Sperimentale "Gaetano Salvatore", CNR, Napoli, Italy; Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Italy
| | - Emilia Pedone
- Istituto di Biostrutture e Bioimmagini, CNR, Napoli, Italy.
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7
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The Structural Versatility of the BTB Domains of KCTD Proteins and Their Recognition of the GABA B Receptor. Biomolecules 2019; 9:biom9080323. [PMID: 31370201 PMCID: PMC6722564 DOI: 10.3390/biom9080323] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 02/07/2023] Open
Abstract
Several recent investigations have demonstrated that members of the KCTD (Potassium Channel Tetramerization Domain) protein family are involved in fundamental processes. However, the paucity of structural data available on these proteins has frequently prevented the definition of their biochemical role(s). Fortunately, this scenario is rapidly changing as, in very recent years, several crystallographic structures have been reported. Although these investigations have provided very important insights into the function of KCTDs, they have also raised some puzzling issues. One is related to the observation that the BTB (broad-complex, tramtrack, and bric-à-brac) domain of these proteins presents a remarkable structural versatility, being able to adopt a variety of oligomeric states. To gain insights into this intriguing aspect, we performed extensive molecular dynamics simulations on several BTB domains of KCTD proteins in different oligomeric states (monomers, dimers, tetramers, and open/close pentamers). These studies indicate that KCTD-BTB domains are stable in the simulation timescales, even in their monomeric forms. Moreover, simulations also show that the dynamic behavior of open pentameric states is strictly related to their functional roles and that different KCTDs may form stable hetero-oligomers. Molecular dynamics (MD) simulations also provided a dynamic view of the complex formed by KCTD16 and the GABAB2 receptor, whose structure has been recently reported. Finally, simulations carried out on the isolated fragment of the GABAB2 receptor that binds KCTD16 indicate that it is able to assume the local conformation required for the binding to KCTD.
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8
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Smaldone G, Balasco N, Pirone L, Caruso D, Di Gaetano S, Pedone EM, Vitagliano L. Molecular basis of the scalp-ear-nipple syndrome unraveled by the characterization of disease-causing KCTD1 mutants. Sci Rep 2019; 9:10519. [PMID: 31324836 PMCID: PMC6642198 DOI: 10.1038/s41598-019-46911-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/05/2019] [Indexed: 12/11/2022] Open
Abstract
The scalp-ear-nipple (SEN) syndrome is an autosomal-dominant disorder characterized by cutis aplasia of the scalp and malformations of breast, external ears, digits, and nails. Genetic analyses have shown that the disease is caused by missense mutations of the KCTD1 protein, although the functional/structural basis of SEN insurgence is hitherto unknown. With the aim of unravelling the molecular basis of the SEN syndrome associated with KCTD1 mutations we here expressed and characterized several disease causing mutants. A preliminary dissection of the protein provides insights into the role that individual domains play in KCTD1 stability. The characterization of SEN-causing mutants indicates that, although the mutation sites are located in distant regions of the BTB domain or of the pre-BTB region, all of them are unable to interact with the transcription factor AP-2α, a well-known KCTD1 biological partner. Notably, all mutations, including the one located in the pre-BTB region, produce a significant destabilization of the protein. The structural role of the pre-BTB region in KCTD1 and other proteins of the family is corroborated by its sequence conservation in orthologs and paralogs. Interestingly, SEN-causing mutations also favor the tendency of KCTD1 to adopt structural states that are characterized by the ability to bind the β-amyloid fluorescent dye thioflavin T. The formation of aggregation-prone species may have important implications for the disease etiology. Collectively, these findings provide an intriguing picture of the functional and structural alterations induced by KCTD1 mutations that ultimately lead to disease.
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Affiliation(s)
| | - Nicole Balasco
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Luciano Pirone
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Daniela Caruso
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy.,Università degli Studi della Campania "Luigi Vanvitelli", Viale Abramo Lincoln 5, 81100, Caserta, Italy
| | - Sonia Di Gaetano
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Emilia Maria Pedone
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134, Napoli, Italy.
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9
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Structural basis for auxiliary subunit KCTD16 regulation of the GABA B receptor. Proc Natl Acad Sci U S A 2019; 116:8370-8379. [PMID: 30971491 DOI: 10.1073/pnas.1903024116] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Metabotropic GABAB receptors mediate a significant fraction of inhibitory neurotransmission in the brain. Native GABAB receptor complexes contain the principal subunits GABAB1 and GABAB2, which form an obligate heterodimer, and auxiliary subunits, known as potassium channel tetramerization domain-containing proteins (KCTDs). KCTDs interact with GABAB receptors and modify the kinetics of GABAB receptor signaling. Little is known about the molecular mechanism governing the direct association and functional coupling of GABAB receptors with these auxiliary proteins. Here, we describe the high-resolution structure of the KCTD16 oligomerization domain in complex with part of the GABAB2 receptor. A single GABAB2 C-terminal peptide is bound to the interior of an open pentamer formed by the oligomerization domain of five KCTD16 subunits. Mutation of specific amino acids identified in the structure of the GABAB2-KCTD16 interface disrupted both the biochemical association and functional modulation of GABAB receptors and G protein-activated inwardly rectifying K+ channel (GIRK) channels. These interfacial residues are conserved among KCTDs, suggesting a common mode of KCTD interaction with GABAB receptors. Defining the binding interface of GABAB receptor and KCTD reveals a potential regulatory site for modulating GABAB-receptor function in the brain.
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10
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Structural basis for KCTD-mediated rapid desensitization of GABA B signalling. Nature 2019; 567:127-131. [PMID: 30814734 PMCID: PMC6405316 DOI: 10.1038/s41586-019-0990-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 01/24/2019] [Indexed: 11/23/2022]
Abstract
The GABAB receptor is one of the principal inhibitory neurotransmitter receptors in the brain, and it signals through heterotrimeric G proteins to activate a variety of effectors including G protein-coupled inwardly-rectifying potassium channels (GIRKs)1,2. GABAB receptor signaling is tightly regulated by auxiliary subunits called KCTDs, which control the kinetics of GIRK activation and desensitization3–5. However, the mechanistic basis for KCTD modulation of GABAB signaling remains incompletely understood. Here, using a combination of X-ray crystallography, electron microscopy, functional and biochemical experiments we reveal the molecular details of KCTD binding to both GABAB receptors and Gβγ subunits. KCTDs associate with the receptor by forming an asymmetric pentameric ring around a region of the receptor C-terminal tail, while a second KCTD domain, H1, engages in a symmetric interaction with five copies of Gβγ in which the G protein subunits also directly interact with one another. We further show that KCTD binding to Gβγ is highly cooperative, defining a model in which KCTDs cooperatively strip G proteins from GIRK channels to induce rapid desensitization following receptor activation. These results provide a framework for understanding the molecular basis for the precise temporal control of GABAB signaling by KCTD proteins.
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11
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The essential player in adipogenesis GRP78 is a novel KCTD15 interactor. Int J Biol Macromol 2018; 115:469-475. [PMID: 29665387 DOI: 10.1016/j.ijbiomac.2018.04.078] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/10/2018] [Accepted: 04/13/2018] [Indexed: 01/08/2023]
Abstract
KCTD15 is a member of the K+ Channel Tetramerization Domain family, implicated in crucial physio-pathological processes. Recent evidences suggest that KCTD15 is an obesity-linked protein in humans and its Drosophila homologue is involved in food uptake. KCTD15 molecular mechanism in these processes is still unknown. To fill this gap, KCTD15 was biophysically characterized showing a folded, pentameric region endowed with a remarkable thermal stability. Notably, the C-terminal domain significantly contributes to the stabilization of the BTB N-terminal domain. The availability of large amount of stable recombinant protein also made possible a functional proteomic approach in 3T3-L1 cells to search for novel KCTD15 interactors. These investigations led to the discovery that GRP78 is a KCTD15 partner in all the adipogenesis phases. Our data clearly prove the physical interaction of the two proteins and also indicate that GRP78 plays an active role in the stabilization of KCTD15. Furthermore, the presence in Drosophila of a GRP78 homologue corroborates the physiological role played by the complex KCTD15-GRP78 in the adipogenesis process and indicates that it is evolutionarily conserved. Present results also suggest that KCTD15 may be a new target for obesity control.
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12
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Gokulan K, Khare S, Cerniglia CE, Foley SL, Varughese KI. Structure and Inhibitor Specificity of L,D-Transpeptidase (LdtMt2) from Mycobacterium tuberculosis and Antibiotic Resistance: Calcium Binding Promotes Dimer Formation. AAPS JOURNAL 2018. [DOI: 10.1208/s12248-018-0193-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Zhong Y, Yang J, Xu WW, Wang Y, Zheng CC, Li B, He QY. KCTD12 promotes tumorigenesis by facilitating CDC25B/CDK1/Aurora A-dependent G2/M transition. Oncogene 2017; 36:6177-6189. [PMID: 28869606 PMCID: PMC5671937 DOI: 10.1038/onc.2017.287] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 06/19/2017] [Accepted: 07/14/2017] [Indexed: 02/06/2023]
Abstract
Cell cycle dysregulation leads to uncontrolled cell proliferation and tumorigenesis. Understanding the molecular mechanisms underlying cell cycle progression can provide clues leading to the identification of key proteins involved in cancer development. In this study, we performed proteomics analysis to identify novel regulators of the cell cycle. We found that potassium channel tetramerization domain containing 12 (KCTD12) was significantly upregulated in M phase compared with S phase. We also found that KCTD12 overexpression not only facilitated the G2/M transition and induced cancer cell proliferation, but also promoted the growth of subcutaneous tumors and Ki-67 proliferation index in mice. Regarding the mechanism underlying these phenomena, cyclin-dependent kinase 1 (CDK1) was identified as an interacting partner of KCTD12 by immunoprecipitation and mass spectrometry analysis, which showed that KCTD12 activated CDK1 and Aurora kinase A (Aurora A) and that the effects of KCTD12 on CDK1 phosphorylation and cell proliferation were abrogated by cell division cycle 25B (CDC25B) silencing. In addition, Aurora A phosphorylated KCTD12 at serine 243, thereby initiating a positive feedback loop necessary for KCTD12 to exert its cancer-promoting effects. Furthermore, we analyzed the expression levels of various genes and the correlations between the expression of these genes and survival using tumor tissue microarray and Gene Expression Omnibus (GEO) data sets. The data showed that KCTD12 expression was significantly upregulated in cervical and lung cancers. More importantly, high KCTD12 expression was associated with larger tumor sizes, higher pathological stages and poor patient survival. Collectively, our study demonstrate that KCTD12 binds to CDC25B and activates CDK1 and Aurora A to facilitate the G2/M transition and promote tumorigenesis and that Aurora A phosphorylates KCTD12 at serine 243 to trigger a positive feedback loop, thereby potentiating the effects of KCTD12. Thus, the KCTD12-CDC25B-CDK1-Aurora A axis has important implications for cancer diagnoses and prognoses.
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Affiliation(s)
- Y Zhong
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China.,Department of Pathology, Medical College, Jinan University, Guangzhou, China
| | - J Yang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - W W Xu
- Institute of Biomedicine, Guangdong Provincial Key Laboratory of Bioengineering Medicine, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, China
| | - Y Wang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - C-C Zheng
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - B Li
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Q-Y He
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
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14
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Gaglione R, Pirone L, Farina B, Fusco S, Smaldone G, Aulitto M, Dell'Olmo E, Roscetto E, Del Gatto A, Fattorusso R, Notomista E, Zaccaro L, Arciello A, Pedone E, Contursi P. Insights into the anticancer properties of the first antimicrobial peptide from Archaea. Biochim Biophys Acta Gen Subj 2017. [DOI: 10.1016/j.bbagen.2017.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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15
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Li M, Milligan CJ, Wang H, Walker A, Churilov L, Lawrence AJ, Reid CA, Hopkins SC, Petrou S. KCTD12 modulation of GABA(B) receptor function. Pharmacol Res Perspect 2017; 5:e00319. [PMID: 28713569 PMCID: PMC5508304 DOI: 10.1002/prp2.319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/21/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
Abstract
The molecular composition and functional diversity of native GABAB receptors (GABABR) are still poorly understood, thus hindering development of selective GABABR ligands. Potassium channel tetramerization domain‐containing protein (KCTD) 12 is a GABABR auxiliary subunit and mouse KCTD12 can alter GABABR function. In this study, we sought to characterize the effects of human KCTD12 on GABABR kinetics and pharmacology, using an automated electrophysiological assay. Seizure susceptibility and ethanol consumption were also investigated in a KCTD12 knockout mouse model. Human KCTD12 co‐expression altered the kinetics of GABABR‐mediated GIRK channels, speeding rates of both activation and desensitization. Analysis of concentration‐response curves showed that KCTD12 coexpression did not alter effects of the agonists GABA or baclofen on GABABR. KCTD12 coexpression enhanced the potentiating effects of the positive allosteric modulator CGP7930, and its effects on GABABR activation and desensitization. The function of KCTD12 in vivo was examined, using the KCTD12 knockout mouse model. The knockout mice were more resistant to a pentylenetetrazole proconvulsant challenge suggesting reduced seizure susceptibility. In the two bottle preference test, KCTD12 knockout mice demonstrated a reduced consumption at high ethanol concentrations. In summary, human KCTD12 accelerated the kinetics of GABABR in vitro, in a manner possibly sensitive to allosteric pharmacological modulation. This study also provides novel in vivo evidence that the interaction between KCTD12 and GABABR is of physiological significance, and may be a mechanism to more selectively modulate GABABR.
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Affiliation(s)
- Melody Li
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Carol J Milligan
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Haiyan Wang
- Sunovion Pharmaceuticals Inc Marlborough Massachusetts
| | - Andrew Walker
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Leonid Churilov
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | | | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia.,Department of Anatomy and Neuroscience University of Melbourne Parkville Victoria Australia.,Centre for Neural Engineering University of Melbourne Parkville Victoria Australia
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16
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Bosso A, Pirone L, Gaglione R, Pane K, Del Gatto A, Zaccaro L, Di Gaetano S, Diana D, Fattorusso R, Pedone E, Cafaro V, Haagsman HP, van Dijk A, Scheenstra MR, Zanfardino A, Crescenzi O, Arciello A, Varcamonti M, Veldhuizen EJA, Di Donato A, Notomista E, Pizzo E. A new cryptic host defense peptide identified in human 11-hydroxysteroid dehydrogenase-1 β-like: from in silico identification to experimental evidence. Biochim Biophys Acta Gen Subj 2017; 1861:2342-2353. [PMID: 28454736 DOI: 10.1016/j.bbagen.2017.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Revised: 04/05/2017] [Accepted: 04/24/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND Host defence peptides (HDPs) are evolutionarily conserved components of innate immunity. Human HDPs, produced by a variety of immune cells of hematopoietic and epithelial origin, are generally grouped into two families: beta structured defensins and variably-structured cathelicidins. We report the characterization of a very promising cryptic human HDP, here called GVF27, identified in 11-hydroxysteroid dehydrogenase-1 β-like protein. METHODS Conformational analysis of GVF27 and its propensity to bind endotoxins were performed by NMR, Circular Dichroism, Fluorescence and Dynamic Light Scattering experiments. Crystal violet and WST-1 assays, ATP leakage measurement and colony counting procedures were used to investigate antimicrobial, anti-biofilm, cytotoxicity and hemolytic activities. Anti-inflammatory properties were evaluated by ELISA. RESULTS GVF27 possesses significant antibacterial properties on planktonic cells and sessile bacteria forming biofilm, as well as promising dose dependent abilities to inhibit attachment or eradicate existing mature biofilm. It is unstructured in aqueous buffer, whereas it tends to assume a helical conformation in mimic membrane environments as well as it is able to bind lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Notably it is not toxic towards human and murine cell lines and triggers a significant innate immune response by attenuating expression levels of pro-inflammatory interleukins and release of nitric oxide in LPS induced macrophages. CONCLUSION Human GVF27 may offer significant advantages as leads for the design of human-specific therapeutics. GENERAL SIGNIFICANCE Human cryptic host defence peptides are naturally no immunogenic and for this they are a real alternative for solving the lack of effective antibiotics to control bacterial infections.
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Affiliation(s)
- A Bosso
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy; Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | | | - R Gaglione
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | - K Pane
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | | | | | | | - D Diana
- IBB, CNR, 80134 Naples, Italy
| | - R Fattorusso
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", I-81100 Caserta, Italy
| | | | - V Cafaro
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | - H P Haagsman
- Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | - A van Dijk
- Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | - M R Scheenstra
- Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | - A Zanfardino
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | - O Crescenzi
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - A Arciello
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy
| | - M Varcamonti
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | - E J A Veldhuizen
- Department of Infectious Diseases and Immunology, Utrecht University, 3584 CS Utrecht, Holland
| | - A Di Donato
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | - E Notomista
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy
| | - E Pizzo
- Department of Biology, University of Naples Federico II, 80126 Naples, Italy.
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17
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KCTD Hetero-oligomers Confer Unique Kinetic Properties on Hippocampal GABAB Receptor-Induced K+ Currents. J Neurosci 2016; 37:1162-1175. [PMID: 28003345 DOI: 10.1523/jneurosci.2181-16.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/29/2016] [Accepted: 12/12/2016] [Indexed: 11/21/2022] Open
Abstract
GABAB receptors are the G-protein coupled receptors for the main inhibitory neurotransmitter in the brain, GABA. GABAB receptors were shown to associate with homo-oligomers of auxiliary KCTD8, KCTD12, KCTD12b, and KCTD16 subunits (named after their T1 K+-channel tetramerization domain) that regulate G-protein signaling of the receptor. Here we provide evidence that GABAB receptors also associate with hetero-oligomers of KCTD subunits. Coimmunoprecipitation experiments indicate that two-thirds of the KCTD16 proteins in the hippocampus of adult mice associate with KCTD12. We show that the KCTD proteins hetero-oligomerize through self-interacting T1 and H1 homology domains. Bioluminescence resonance energy transfer measurements in live cells reveal that KCTD12/KCTD16 hetero-oligomers associate with both the receptor and the G-protein. Electrophysiological experiments demonstrate that KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties on G-protein-activated Kir3 currents. During prolonged receptor activation (one min) KCTD12/KCTD16 hetero-oligomers produce moderately desensitizing fast deactivating K+ currents, whereas KCTD12 and KCTD16 homo-oligomers produce strongly desensitizing fast deactivating currents and nondesensitizing slowly deactivating currents, respectively. During short activation (2 s) KCTD12/KCTD16 hetero-oligomers produce nondesensitizing slowly deactivating currents. Electrophysiological recordings from hippocampal neurons of KCTD knock-out mice are consistent with these findings and indicate that KCTD12/KCTD16 hetero-oligomers increase the duration of slow IPSCs. In summary, our data demonstrate that simultaneous assembly of distinct KCTDs at the receptor increases the molecular and functional repertoire of native GABAB receptors and modulates physiologically induced K+ current responses in the hippocampus. SIGNIFICANCE STATEMENT The KCTD proteins 8, 12, and 16 are auxiliary subunits of GABAB receptors that differentially regulate G-protein signaling of the receptor. The KCTD proteins are generally assumed to function as homo-oligomers. Here we show that the KCTD proteins also assemble hetero-oligomers in all possible dual combinations. Experiments in live cells demonstrate that KCTD hetero-oligomers form at least tetramers and that these tetramers directly interact with the receptor and the G-protein. KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties to GABAB receptor-induced Kir3 currents in heterologous cells. KCTD12/KCTD16 hetero-oligomers are abundant in the hippocampus, where they prolong the duration of slow IPSCs in pyramidal cells. Our data therefore support that KCTD hetero-oligomers modulate physiologically induced K+ current responses in the brain.
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18
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Pirone L, Smaldone G, Esposito C, Balasco N, Petoukhov MV, Spilotros A, Svergun DI, Di Gaetano S, Vitagliano L, Pedone EM. Proteins involved in sleep homeostasis: Biophysical characterization of INC and its partners. Biochimie 2016; 131:106-114. [PMID: 27678190 DOI: 10.1016/j.biochi.2016.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/22/2016] [Accepted: 09/22/2016] [Indexed: 12/29/2022]
Abstract
The insomniac protein of Drosophila melanogaster (INC) has a crucial role in sleep homeostasis as flies lacking the inc gene exhibit strikingly reduced and poorly consolidated sleep. Nevertheless, in vitro characterizations of INC biophysical properties and partnerships have not been yet reported. Here we report the heterologous expression of the protein and its characterization using a number of different techniques. Present data indicate that INC is endowed with a remarkable stability, which results from the cooperation of the two protein domains. Moreover, we also demonstrated and quantified the ability of INC to recognize its potential partners Cul3 and dGRASP. Taking into account the molecular organization of the protein, these two partners may be anchored simultaneously. Although there is no evident relationship between the reported INC functions and dGRASP binding, our data suggest that INC may cooperate as ligase adaptor to dGRASP ubiquitination. SAXS data collected on the complex between INC and Cul3, which represent the first structural characterization of this type of assemblies, clearly highlight the highly dynamic nature of these complexes. This strongly suggests that the functional behavior of these proteins cannot be understood if dynamic effects are not considered. Finally, the strict analogy of the biochemical/biophysical properties of INC and of its human homolog KCTD5 may reliably indicate that this latter protein and/or the closely related proteins KCTD2/KCTD17 may play important roles in human sleep regulation.
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Affiliation(s)
- Luciano Pirone
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy
| | | | - Carla Esposito
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy
| | - Nicole Balasco
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy
| | - Maxim V Petoukhov
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Alessandro Spilotros
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Sonia Di Gaetano
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy.
| | - Emilia Maria Pedone
- Institute of Biostructures and Bioimaging, C.N.R., Via Mezzocannone 16, 80134 Napoli, Italy.
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19
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Barone D, Balasco N, Vitagliano L. KCTD5 is endowed with large, functionally relevant, interdomain motions. J Biomol Struct Dyn 2015; 34:1725-35. [PMID: 26336981 DOI: 10.1080/07391102.2015.1090343] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The KCTD family is an emerging class of proteins that are involved in important biological processes whose biochemical and structural properties are rather poorly characterized or even completely undefined. We here used KCTD5, the only member of the family with a known three-dimensional structure, to gain insights into the intrinsic structural stability of the C-terminal domain (CTD) and into the mutual dynamic interplay between the two domains of the protein. Molecular dynamics (MD) simulations indicate that in the simulation timescale (120 ns), the pentameric assembly of the CTD is endowed with a significant intrinsic stability. Moreover, MD analyses also led to the identification of exposed β-strand residues. Being these regions intrinsically sticky, they could be involved in the substrate recognition. More importantly, simulations conducted on the full-length protein provide interesting information of the relative motions between the BTB domain and the CTD of the protein. Indeed, the dissection of the overall motion of the protein is indicative of a large interdomain twisting associated with limited bending movements. Notably, MD data indicate that the entire interdomain motion is pivoted by a single residue (Ser150) of the hinge region that connects the domains. The functional relevance of these motions was evaluated in the context of the functional macromolecular machinery in which KCTD5 is involved. This analysis indicates that the interdomain twisting motion here characterized may be important for the correct positioning of the substrate to be ubiquitinated with respect to the other factors of the ubiquitination machinery.
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Affiliation(s)
- Daniela Barone
- a Institute of Biostructures and Bioimaging, C.N.R. , Via Mezzocannone 16, Naples I-80134 , Italy.,b Dipartimento di Scienze e Tecnologie Ambientali Biologiche e Farmaceutiche , Seconda Università di Napoli , Caserta 81100 , Italy
| | - Nicole Balasco
- a Institute of Biostructures and Bioimaging, C.N.R. , Via Mezzocannone 16, Naples I-80134 , Italy.,b Dipartimento di Scienze e Tecnologie Ambientali Biologiche e Farmaceutiche , Seconda Università di Napoli , Caserta 81100 , Italy
| | - Luigi Vitagliano
- a Institute of Biostructures and Bioimaging, C.N.R. , Via Mezzocannone 16, Naples I-80134 , Italy
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20
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Notomista E, Falanga A, Fusco S, Pirone L, Zanfardino A, Galdiero S, Varcamonti M, Pedone E, Contursi P. The identification of a novel Sulfolobus islandicus CAMP-like peptide points to archaeal microorganisms as cell factories for the production of antimicrobial molecules. Microb Cell Fact 2015; 14:126. [PMID: 26338197 PMCID: PMC4559164 DOI: 10.1186/s12934-015-0302-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/22/2015] [Indexed: 12/03/2022] Open
Abstract
Background Pathogenic bacteria easily develop resistance to c
onventional antibiotics so that even relatively new molecules are quickly losing efficacy. This strongly encourages the quest of new antimicrobials especially for the treatment of chronic infections. Cationic antimicrobial peptides (CAMPs) are small positively charged peptides with an amphipathic structure, active against Gram-positive and Gram-negative bacteria, fungi, as well as protozoa. Results A novel (CAMP)-like peptide (VLL-28) was identified in the primary structure of a transcription factor, Stf76, encoded by pSSVx, a hybrid plasmid–virus from the archaeon Sulfolobus islandicus. VLL-28 displays chemical, physical and functional properties typical of CAMPs. Indeed, it has a broad-spectrum antibacterial activity and acquires a defined structure in the presence of membrane mimetics. Furthermore, it exhibits selective leakage and fusogenic capability on vesicles with a lipid composition similar to that of bacterial membranes. VLL-28 localizes not only on the cell membrane but also in the cytoplasm of Escherichia coli and retains the ability to bind nucleic acids. These findings suggest that this CAMP-like peptide could exert its antimicrobial activity both on membrane and intra cellular targets. Conclusions VLL-28 is the first CAMP-like peptide identified in the archaeal kingdom, thus pointing to archaeal microorganisms as cell factories to produce antimicrobial molecules of biotechnological interest. Furthermore, results from this work show that DNA/RNA-binding proteins could be used as sources of CAMPs. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0302-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eugenio Notomista
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy.
| | - Annarita Falanga
- Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy.
| | - Salvatore Fusco
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy.
| | - Luciano Pirone
- Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. .,C.I.R.C.M.S.B. (Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici), via Celso Ulpiani, 27, 70125, Bari, Italy.
| | - Anna Zanfardino
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy.
| | - Stefania Galdiero
- Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy. .,Department of Pharmacy and CiRPEB, University of Naples Federico II, 80100, Naples, Italy.
| | - Mario Varcamonti
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy.
| | - Emilia Pedone
- Istituto di Biostrutture Bioimmagini, CNR, 80134, Naples, Italy.
| | - Patrizia Contursi
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126, Naples, Italy.
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Cullin 3 Recognition Is Not a Universal Property among KCTD Proteins. PLoS One 2015; 10:e0126808. [PMID: 25974686 PMCID: PMC4431850 DOI: 10.1371/journal.pone.0126808] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/08/2015] [Indexed: 12/13/2022] Open
Abstract
Cullin 3 (Cul3) recognition by BTB domains is a key process in protein ubiquitination. Among Cul3 binders, a great attention is currently devoted to KCTD proteins, which are implicated in fundamental biological processes. On the basis of the high similarity of BTB domains of these proteins, it has been suggested that the ability to bind Cul3 could be a general property among all KCTDs. In order to gain new insights into KCTD functionality, we here evaluated and/or quantified the binding of Cul3 to the BTB of KCTD proteins, which are known to be involved either in cullin-independent (KCTD12 and KCTD15) or in cullin-mediated (KCTD6 and KCTD11) activities. Our data indicate that KCTD6BTB and KCTD11BTB bind Cul3 with high affinity forming stable complexes with 4:4 stoichiometries. Conversely, KCTD12BTB and KCTD15BTB do not interact with Cul3, despite the high level of sequence identity with the BTB domains of cullin binding KCTDs. Intriguingly, comparative sequence analyses indicate that the capability of KCTD proteins to recognize Cul3 has been lost more than once in distinct events along the evolution. Present findings also provide interesting clues on the structural determinants of Cul3-KCTD recognition. Indeed, the characterization of a chimeric variant of KCTD11 demonstrates that the swapping of α2β3 loop between KCTD11BTB and KCTD12BTB is sufficient to abolish the ability of KCTD11BTB to bind Cul3. Finally, present findings, along with previous literature data, provide a virtually complete coverage of Cul3 binding ability of the members of the entire KCTD family.
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22
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Raveh A, Turecek R, Bettler B. Mechanisms of fast desensitization of GABA(B) receptor-gated currents. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:145-65. [PMID: 25637440 DOI: 10.1016/bs.apha.2014.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GABA(B) receptors (GABA(B)Rs) regulate the excitability of most neurons in the central nervous system by modulating the activity of enzymes and ion channels. In the sustained presence of the neurotransmitter γ-aminobutyric acid, GABA(B)Rs exhibit a time-dependent decrease in the receptor response-a phenomenon referred to as homologous desensitization. Desensitization prevents excessive receptor influences on neuronal activity. Much work focused on the mechanisms of GABA(B)R desensitization that operate at the receptor and control receptor expression at the plasma membrane. Over the past few years, it became apparent that GABA(B)Rs additionally evolved mechanisms for faster desensitization. These mechanisms operate at the G protein rather than at the receptor and inhibit G protein signaling within seconds of agonist exposure. The mechanisms for fast desensitization are ideally suited to regulate receptor-activated ion channel responses, which influence neuronal activity on a faster timescale than effector enzymes. Here, we provide an update on the mechanisms for fast desensitization of GABA(B)R responses and discuss physiological and pathophysiological implications.
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Affiliation(s)
- Adi Raveh
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Rostislav Turecek
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland; Department of Auditory Neuroscience, Institute of Experimental Medicine, ASCR, Prague, Czech Republic
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, Pharmazentrum, University of Basel, Basel, Switzerland.
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23
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Adelfinger L, Turecek R, Ivankova K, Jensen AA, Moss SJ, Gassmann M, Bettler B. GABAB receptor phosphorylation regulates KCTD12-induced K⁺ current desensitization. Biochem Pharmacol 2014; 91:369-79. [PMID: 25065880 PMCID: PMC4402209 DOI: 10.1016/j.bcp.2014.07.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 01/08/2023]
Abstract
GABAB receptors assemble from GABAB1 and GABAB2 subunits. GABAB2 additionally associates with auxiliary KCTD subunits (named after their K(+) channel tetramerization-domain). GABAB receptors couple to heterotrimeric G-proteins and activate inwardly-rectifying K(+) channels through the βγ subunits released from the G-protein. Receptor-activated K(+) currents desensitize in the sustained presence of agonist to avoid excessive effects on neuronal activity. Desensitization of K(+) currents integrates distinct mechanistic underpinnings. GABAB receptor activity reduces protein kinase-A activity, which reduces phosphorylation of serine-892 in GABAB2 and promotes receptor degradation. This form of desensitization operates on the time scale of several minutes to hours. A faster form of desensitization is induced by the auxiliary subunit KCTD12, which interferes with channel activation by binding to the G-protein βγ subunits. Here we show that the two mechanisms of desensitization influence each other. Serine-892 phosphorylation in heterologous cells rearranges KCTD12 at the receptor and slows KCTD12-induced desensitization. Likewise, protein kinase-A activation in hippocampal neurons slows fast desensitization of GABAB receptor-activated K(+) currents while protein kinase-A inhibition accelerates fast desensitization. Protein kinase-A fails to regulate fast desensitization in KCTD12 knock-out mice or knock-in mice with a serine-892 to alanine mutation, thus demonstrating that serine-892 phosphorylation regulates KCTD12-induced desensitization in vivo. Fast current desensitization is accelerated in hippocampal neurons carrying the serine-892 to alanine mutation, showing that tonic serine-892 phosphorylation normally limits KCTD12-induced desensitization. Tonic serine-892 phosphorylation is in turn promoted by assembly of receptors with KCTD12. This cross-regulation of serine-892 phosphorylation and KCTD12 activity sharpens the response during repeated receptor activation.
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Affiliation(s)
- Lisa Adelfinger
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland
| | - Rostislav Turecek
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland; Institute of Experimental Medicine, ASCR, Videnska 1083, 14220 Prague 4-Krc, Czech Republic
| | - Klara Ivankova
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland
| | - Anders A Jensen
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland
| | - Stephen J Moss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Martin Gassmann
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland.
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24
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Auxiliary GABAB Receptor Subunits Uncouple G Protein βγ Subunits from Effector Channels to Induce Desensitization. Neuron 2014; 82:1032-44. [DOI: 10.1016/j.neuron.2014.04.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2014] [Indexed: 01/07/2023]
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Thermal and chemical stability of two homologous POZ/BTB domains of KCTD proteins characterized by a different oligomeric organization. BIOMED RESEARCH INTERNATIONAL 2013; 2013:162674. [PMID: 24307990 PMCID: PMC3838848 DOI: 10.1155/2013/162674] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/11/2013] [Accepted: 09/18/2013] [Indexed: 11/18/2022]
Abstract
POZ/BTB domains are widespread modules detected in a variety of different biological contexts. Here, we report a biophysical characterization of the POZ/BTB of KCTD6, a protein that is involved in the turnover of the muscle small ankyrin-1 isoform 5 and, in combination with KCTD11, in the ubiquitination and degradation of HDAC1. The analyses show that the domain is a tetramer made up by subunits with the expected α/β structure. A detailed investigation of its stability, carried out in comparison with the homologous pentameric POZ/BTB domain isolated from KCTD5, highlights a number of interesting features, which are shared by the two domains despite their different organization. Their thermal/chemical denaturation curves are characterized by a single and sharp inflection point, suggesting that the denaturation of the two domains is a cooperative two-state process. Furthermore, both domains present a significant content of secondary structure in their denatured state and a reversible denaturation process. We suggest that the ability of these domains to fold and unfold reversibly, a property that is somewhat unexpected for these oligomeric assemblies, may have important implications for their biological function. Indeed, these properties likely favor the formation of heteromeric associations that may be essential for the intricate regulation of the processes in which these proteins are involved.
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