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Ramagoma RB, Makgoo L, Mbita Z. KLHL20 and its role in cell homeostasis: A new perspective and therapeutic potential. Life Sci 2024:123041. [PMID: 39233199 DOI: 10.1016/j.lfs.2024.123041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 08/22/2024] [Accepted: 08/31/2024] [Indexed: 09/06/2024]
Abstract
Ubiquitin ligases are proteins with the ability to trigger non-degradative signaling or proteasomal destruction by attracting substrates and facilitating ubiquitin transfer onto target proteins. Over the years, there has been a continuous discovery of new ubiquitin ligases, and Kelch-like protein 20 (KLHL20) is one of the most recent discoveries that have several biological roles which include its role in ubiquitin ligase activities. KLHL20 binds as a substrate component of ubiquitin ligase Cullin3 (Cul3). Several substrates for ubiquitin ligases (KLHL20 based) have been reported, these include Unc-51 Like Autophagy Activating Kinase 1 (ULK1), promyelocytic leukemia (PML), and Death Associated Protein Kinase 1 (DAPK1). KLHL20 shows multiple cell functions linked to several human diseases through ubiquitination of these substrates. Current literature shows that KLHL20 ubiquitin ligase regulates malignancies in humans and also suggests how important it is to develop regulating agents for tumour-suppressive KLHL20 to prevent tumourigenesis, Recent research has highlighted its potential therapeutic implications in several areas. In oncology, KLHL20's regulatory role in protein degradation pathways suggests that its targeting could offer novel strategies for cancer treatment by modulating the stability of proteins involved in tumour growth and survival. In neurodegenerative diseases, KLHL20's function in maintaining protein homeostasis positions it as a potential target for therapies aimed at managing protein aggregation and cellular stress. Here, we review the functions of KLHL20 during the carcinogenesis process, looking at its role in cancer progression, and regulation of ubiquitination events mediated by KLHL20 in human cancers, as well as its potential therapeutic interventions.
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Affiliation(s)
- Rolivhuwa Bishop Ramagoma
- The University of Limpopo, Department of Biochemistry, Microbiology, and Biotechnology, Private Bag x1106, Sovenga 0727, South Africa
| | - Lilian Makgoo
- The University of Limpopo, Department of Biochemistry, Microbiology, and Biotechnology, Private Bag x1106, Sovenga 0727, South Africa
| | - Zukile Mbita
- The University of Limpopo, Department of Biochemistry, Microbiology, and Biotechnology, Private Bag x1106, Sovenga 0727, South Africa.
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2
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Zhou Y, Zhang Q, Zhao Z, Hu X, You Q, Jiang Z. Targeting kelch-like (KLHL) proteins: achievements, challenges and perspectives. Eur J Med Chem 2024; 269:116270. [PMID: 38490062 DOI: 10.1016/j.ejmech.2024.116270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/07/2024] [Accepted: 02/19/2024] [Indexed: 03/17/2024]
Abstract
Kelch-like proteins (KLHLs) are a large family of BTB-containing proteins. KLHLs function as the substrate adaptor of Cullin 3-RING ligases (CRL3) to recognize substrates. KLHLs play pivotal roles in regulating various physiological and pathological processes by modulating the ubiquitination of their respective substrates. Mounting evidence indicates that mutations or abnormal expression of KLHLs are associated with various human diseases. Targeting KLHLs is a viable strategy for deciphering the KLHLs-related pathways and devising therapies for associated diseases. Here, we comprehensively review the known KLHLs inhibitors to date and the brilliant ideas underlying their development.
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Affiliation(s)
- Yangguo Zhou
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Qiong Zhang
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Ziquan Zhao
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Xiuqi Hu
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Qidong You
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
| | - Zhengyu Jiang
- Jiang Su Key Laboratory of Drug Design and Optimization and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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3
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Vukolova MN, Yen LY, Khmyz MI, Sobolevsky AI, Yelshanskaya MV. Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis-emerging role of AMPA and kainate subtypes of ionotropic glutamate receptors. Front Cell Dev Biol 2023; 11:1252953. [PMID: 38033869 PMCID: PMC10683763 DOI: 10.3389/fcell.2023.1252953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/05/2023] [Indexed: 12/02/2023] Open
Abstract
Ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission and are implicated in various neurological disorders. In this review, we discuss the role of the two fastest iGluRs subtypes, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors, in the pathogenesis and treatment of Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis. Although both AMPA and kainate receptors represent promising therapeutic targets for the treatment of these diseases, many of their antagonists show adverse side effects. Further studies of factors affecting the selective subunit expression and trafficking of AMPA and kainate receptors, and a reasonable approach to their regulation by the recently identified novel compounds remain promising directions for pharmacological research.
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Affiliation(s)
- Marina N. Vukolova
- Department of Pathophysiology, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Laura Y. Yen
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
- Cellular and Molecular Physiology and Biophysics Graduate Program, Columbia University, New York, NY, United States
| | - Margarita I. Khmyz
- N. V. Sklifosovsky Institute of Clinical Medicine, I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Alexander I. Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
| | - Maria V. Yelshanskaya
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
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4
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Abstract
Neural communication and modulation are complex processes. Ionotropic glutamate receptors (iGluRs) significantly contribute to mediating the fast-excitatory branch of neurotransmission in the mammalian brain. Kainate receptors (KARs), a subfamily of the iGluRs, act as modulators of the neuronal circuitry by playing important roles at both the post- and presynaptic sites of specific neurons. The functional tetrameric receptors are formed by two different gene families, low agonist affinity (GluK1-GluK3) and high agonist affinity (GluK4-GluK5) subunits. These receptors garnered attention in the past three decades, and since then, much work has been done to understand their localization, interactome, physiological functions, and regulation. Cloning of the receptor subunits (GluK1-GluK5) in the early 1990s led to recombinant expression of kainate receptors in heterologous systems. This facilitated understanding of the functional differences between subunit combinations, splice variants, trafficking, and drug discovery. Structural studies of individual domains and recent full-length homomeric and heteromeric kainate receptors have revealed unique functional mechanisms, which have answered several long-standing questions in the field of kainate receptor biology. In this chapter, we review the current understanding of kainate receptors and associated disorders.
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Affiliation(s)
- Surbhi Dhingra
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India
| | - Juhi Yadav
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India
| | - Janesh Kumar
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University, Pune, Maharashtra, India.
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Lyu S, Xing H, DeAndrade MP, Perez PD, Yokoi F, Febo M, Walters AS, Li Y. The Role of BTBD9 in the Cerebellum, Sleep-like Behaviors and the Restless Legs Syndrome. Neuroscience 2020; 440:85-96. [PMID: 32446853 DOI: 10.1016/j.neuroscience.2020.05.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 04/27/2020] [Accepted: 05/14/2020] [Indexed: 12/28/2022]
Abstract
Recent genome-wide association studies (GWAS) have found cerebellum as a top hit for sleep regulation. Restless legs syndrome (RLS) is a sleep-related sensorimotor disorder characterized by uncomfortable sensations in the extremities, generally at night, which are often relieved by movements. Clinical studies have found that RLS patients have structural and functional abnormalities in the cerebellum. However, whether and how cerebellar pathology contributes to sleep regulation and RLS is not known. GWAS identified polymorphisms in BTBD9 conferring a higher risk of sleep disruption and RLS. Knockout of the BTBD9 homolog in mice (Btbd9) and fly results in motor restlessness and sleep disruption. We performed manganese-enhanced magnetic resonance imaging on the Btbd9 knockout mice and found decreased neural activities in the cerebellum, especially in lobules VIII, X, and the deep cerebellar nuclei. Electrophysiological recording of Purkinje cells (PCs) from Btbd9 knockout mice revealed an increased number of non-tonic PCs. Tonic PCs showed increased spontaneous activity and intrinsic excitability. To further investigate the cerebellar contribution to RLS and sleep-like behaviors, we generated PC-specific Btbd9 knockout mice (Btbd9 pKO) and performed behavioral studies. Btbd9 pKO mice showed significant motor restlessness during the rest phase but not in the active phase. Btbd9 pKO mice also had an increased probability of waking at rest. Unlike the Btbd9 knockout mice, there was no increased thermal sensation in the Btbd9 pKO. Our results indicate that the Btbd9 knockout influences the PC activity; dysfunction in the cerebellum may contribute to the motor restlessness found in the Btbd9 knockout mice.
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Affiliation(s)
- Shangru Lyu
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Hong Xing
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Mark P DeAndrade
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Pablo D Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fumiaki Yokoi
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Arthur S Walters
- Division of Sleep Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yuqing Li
- Norman Fixel Institute for Neurological Diseases, Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
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Bolling MC, Jonkman MF. KLHL24: Beyond Skin Fragility. J Invest Dermatol 2019; 139:22-24. [PMID: 30579426 DOI: 10.1016/j.jid.2018.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/15/2018] [Accepted: 08/15/2018] [Indexed: 02/05/2023]
Abstract
KLHL24 mutations have recently been associated with epidermolysis bullosa simplex. Initial studies focused on skin fragility. However, the picture of KLHL24 mutations causing extracutaneous human disease is emerging, with dilated cardiomyopathy as a strong association. In addition, neurological disease is suspected as well. Careful clinical follow-up and functional studies of (mutated) KLHL24 in these tissues are needed.
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Affiliation(s)
- Maria C Bolling
- University of Groningen, University Medical Center Groningen, Department of Dermatology, Center for Blistering Diseases, Groningen, The Netherlands
| | - Marcel F Jonkman
- University of Groningen, University Medical Center Groningen, Department of Dermatology, Center for Blistering Diseases, Groningen, The Netherlands.
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7
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Kelch-like proteins: Physiological functions and relationships with diseases. Pharmacol Res 2019; 148:104404. [DOI: 10.1016/j.phrs.2019.104404] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/15/2019] [Accepted: 08/19/2019] [Indexed: 02/07/2023]
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Anazi S, Maddirevula S, Faqeih E, Alsedairy H, Alzahrani F, Shamseldin HE, Patel N, Hashem M, Ibrahim N, Abdulwahab F, Ewida N, Alsaif HS, Al Sharif H, Alamoudi W, Kentab A, Bashiri FA, Alnaser M, AlWadei AH, Alfadhel M, Eyaid W, Hashem A, Al Asmari A, Saleh MM, AlSaman A, Alhasan KA, Alsughayir M, Al Shammari M, Mahmoud A, Al-Hassnan ZN, Al-Husain M, Osama Khalil R, Abd El Meguid N, Masri A, Ali R, Ben-Omran T, El Fishway P, Hashish A, Ercan Sencicek A, State M, Alazami AM, Salih MA, Altassan N, Arold ST, Abouelhoda M, Wakil SM, Monies D, Shaheen R, Alkuraya FS. Clinical genomics expands the morbid genome of intellectual disability and offers a high diagnostic yield. Mol Psychiatry 2017; 22:615-624. [PMID: 27431290 DOI: 10.1038/mp.2016.113] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 12/13/2022]
Abstract
Intellectual disability (ID) is a measurable phenotypic consequence of genetic and environmental factors. In this study, we prospectively assessed the diagnostic yield of genomic tools (molecular karyotyping, multi-gene panel and exome sequencing) in a cohort of 337 ID subjects as a first-tier test and compared it with a standard clinical evaluation performed in parallel. Standard clinical evaluation suggested a diagnosis in 16% of cases (54/337) but only 70% of these (38/54) were subsequently confirmed. On the other hand, the genomic approach revealed a likely diagnosis in 58% (n=196). These included copy number variants in 14% (n=54, 15% are novel), and point mutations revealed by multi-gene panel and exome sequencing in the remaining 43% (1% were found to have Fragile-X). The identified point mutations were mostly recessive (n=117, 81%), consistent with the high consanguinity of the study cohort, but also X-linked (n=8, 6%) and de novo dominant (n=19, 13%). When applied directly on all cases with negative molecular karyotyping, the diagnostic yield of exome sequencing was 60% (77/129). Exome sequencing also identified likely pathogenic variants in three novel candidate genes (DENND5A, NEMF and DNHD1) each of which harbored independent homozygous mutations in patients with overlapping phenotypes. In addition, exome sequencing revealed de novo and recessive variants in 32 genes (MAMDC2, TUBAL3, CPNE6, KLHL24, USP2, PIP5K1A, UBE4A, TP53TG5, ATOH1, C16ORF90, SLC39A14, TRERF1, RGL1, CDH11, SYDE2, HIRA, FEZF2, PROCA1, PIANP, PLK2, QRFPR, AP3B2, NUDT2, UFC1, BTN3A2, TADA1, ARFGEF3, FAM160B1, ZMYM5, SLC45A1, ARHGAP33 and CAPS2), which we highlight as potential candidates on the basis of several lines of evidence, and one of these genes (SLC39A14) was biallelically inactivated in a potentially treatable form of hypermanganesemia and neurodegeneration. Finally, likely causal variants in previously published candidate genes were identified (ASTN1, HELZ, THOC6, WDR45B, ADRA2B and CLIP1), thus supporting their involvement in ID pathogenesis. Our results expand the morbid genome of ID and support the adoption of genomics as a first-tier test for individuals with ID.
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Affiliation(s)
- S Anazi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S Maddirevula
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - E Faqeih
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - H Alsedairy
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F Alzahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H E Shamseldin
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Ewida
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H S Alsaif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Al Sharif
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - W Alamoudi
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - A Kentab
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - F A Bashiri
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - M Alnaser
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - A H AlWadei
- Pediatric Neurology Department, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - M Alfadhel
- Department of Pediatrics, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - W Eyaid
- Department of Pediatrics, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - A Hashem
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - A Al Asmari
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - M M Saleh
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - A AlSaman
- Pediatric Neurology Department, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - K A Alhasan
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - M Alsughayir
- Department of Psychiatry, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - M Al Shammari
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - A Mahmoud
- Pediatric Neurology Department, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Z N Al-Hassnan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Al-Husain
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - R Osama Khalil
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA.,National Research Center, Cairo, Egypt
| | | | - A Masri
- Department of Pediatrics, Faculty of Medicine, The University of Jordan, Amman, Jordan
| | - R Ali
- Clinical & Metabolic Genetics, Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - T Ben-Omran
- Clinical & Metabolic Genetics, Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - P El Fishway
- Department of Neurosurgery, Program on Neurogenetics, Yale University School of Medicine, New Haven, CT, USA
| | - A Hashish
- National Research Center, Cairo, Egypt
| | - A Ercan Sencicek
- Department of Neurosurgery, Program on Neurogenetics, Yale University School of Medicine, New Haven, CT, USA
| | - M State
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA
| | - A M Alazami
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M A Salih
- Department of Pediatrics, College of Medicine & King Khalid University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - N Altassan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S T Arold
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Center (CBRC), Division of Biological and Environmental Sciences and Engineering (BESE), Thuwal, Saudi Arabia
| | - M Abouelhoda
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S M Wakil
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - D Monies
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - R Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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9
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He Y, Maier K, Leppert J, Hausser I, Schwieger-Briel A, Weibel L, Theiler M, Kiritsi D, Busch H, Boerries M, Hannula-Jouppi K, Heikkilä H, Tasanen K, Castiglia D, Zambruno G, Has C. Monoallelic Mutations in the Translation Initiation Codon of KLHL24 Cause Skin Fragility. Am J Hum Genet 2016; 99:1395-1404. [PMID: 27889062 DOI: 10.1016/j.ajhg.2016.11.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/07/2016] [Indexed: 11/28/2022] Open
Abstract
The genetic basis of epidermolysis bullosa, a group of genetic disorders characterized by the mechanically induced formation of skin blisters, is largely known, but a number of cases still remain genetically unsolved. Here, we used whole-exome and targeted sequencing to identify monoallelic mutations, c.1A>G and c.2T>C, in the translation initiation codon of the gene encoding kelch-like protein 24 (KLHL24) in 14 individuals with a distinct skin-fragility phenotype and skin cleavage within basal keratinocytes. Remarkably, mutation c.1A>G occurred de novo and was recurrent in families originating from different countries. The striking similarities of the clinical features of the affected individuals point to a unique and very specific pathomechanism. We showed that mutations in the translation initiation codon of KLHL24 lead to the usage of a downstream translation initiation site with the same reading frame and formation of a truncated polypeptide. The pathobiology was examined in keratinocytes and fibroblasts of the affected individuals and via expression of mutant KLHL24, and we found mutant KLHL24 to be associated with abnormalities of intermediate filaments in keratinocytes and fibroblasts. In particular, KLHL24 mutations were associated with irregular and fragmented keratin 14. Recombinant overexpression of normal KLHL24 promoted keratin 14 degradation, whereas mutant KLHL24 showed less activity than the normal molecule. These findings identify KLHL24 mutations as a cause of skin fragility and identify a role for KLHL24 in maintaining the balance between intermediate filament stability and degradation required for skin integrity.
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Affiliation(s)
- Yinghong He
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Kristin Maier
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Juna Leppert
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Ingrid Hausser
- Department of Pathology, University of Heidelberg, Heidelberg 69120, Germany
| | - Agnes Schwieger-Briel
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Lisa Weibel
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Martin Theiler
- Department of Paediatric Dermatology, University Children's Hospital Zurich, Zurich 8091, Switzerland; Department of Dermatology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Dimitra Kiritsi
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany
| | - Hauke Busch
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Freiburg 79104, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Comprehensive Cancer Center Freiburg, Freiburg 79106, Germany
| | - Melanie Boerries
- Systems Biology of the Cellular Microenvironment Group, Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University Freiburg, Freiburg 79104, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany; Comprehensive Cancer Center Freiburg, Freiburg 79106, Germany
| | - Katariina Hannula-Jouppi
- Department of Dermatology and Allergology, University of Helsinki and Helsinki University Hospital, Helsinki 00014, Finland; Folkhälsan Institute of Genetics, University of Helsinki, Helsinki 00014, Finland
| | - Hannele Heikkilä
- Department of Dermatology and Allergology, University of Helsinki and Helsinki University Hospital, Helsinki 00014, Finland
| | - Kaisa Tasanen
- Department of Dermatology, PEDEGO Research Unit, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu 90014, Finland
| | - Daniele Castiglia
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Rome 00167, Italy
| | - Giovanna Zambruno
- Genetic and Rare Diseases Research Area, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome 00165, Italy
| | - Cristina Has
- Department of Dermatology, University Medical Center Freiburg, Freiburg 79104, Germany.
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10
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Lin Z, Li S, Feng C, Yang S, Wang H, Ma D, Zhang J, Gou M, Bu D, Zhang T, Kong X, Wang X, Sarig O, Ren Y, Dai L, Liu H, Zhang J, Li F, Hu Y, Padalon-Brauch G, Vodo D, Zhou F, Chen T, Deng H, Sprecher E, Yang Y, Tan X. Stabilizing mutations of KLHL24 ubiquitin ligase cause loss of keratin 14 and human skin fragility. Nat Genet 2016; 48:1508-1516. [DOI: 10.1038/ng.3701] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/26/2016] [Indexed: 12/30/2022]
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11
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Basson J, Sung YJ, Fuentes LDL, Schwander K, Cupples LA, Rao DC. Influence of Smoking Status and Intensity on Discovery of Blood Pressure Loci Through Gene-Smoking Interactions. Genet Epidemiol 2015; 39:480-488. [PMID: 25940791 DOI: 10.1002/gepi.21904] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/27/2015] [Accepted: 04/01/2015] [Indexed: 11/06/2022]
Abstract
BACKGROUND Genetic variation accounts for approximately 30% of blood pressure (BP) variability but most of that variability has not been attributed to specific variants. Interactions between genes and BP-associated factors may explain some "missing heritability." Cigarette smoking increases BP after short-term exposure and decreases BP with longer exposure. Gene-smoking interactions have discovered novel BP loci, but the contribution of smoking status and intensity to gene discovery is unknown. METHODS We analyzed gene-smoking intensity interactions for association with systolic BP (SBP) in three subgroups from the Framingham Heart Study: current smokers only (N = 1,057), current and former smokers ("ever smokers," N = 3,374), and all subjects (N = 6,710). We used three smoking intensity variables defined at cutoffs of 10, 15, and 20 cigarettes per day (CPD). We evaluated the 1 degree-of-freedom (df) interaction and 2df joint test using generalized estimating equations. RESULTS Analysis of current smokers using a CPD cutoff of 10 produced two loci associated with SBP. The rs9399633 minor allele was associated with increased SBP (5 mmHg) in heavy smokers (CPD > 10) but decreased SBP (7 mmHg) in light smokers (CPD ≤ 10). The rs11717948 minor allele was associated with decreased SBP (8 mmHg) in light smokers but decreased SBP (2 mmHg) in heavy smokers. Across all nine analyses, 19 additional loci reached P < 1 × 10(-6). DISCUSSION Analysis of current smokers may have the highest power to detect gene-smoking interactions, despite the reduced sample size. Associations of loci near SASH1 and KLHL6/KLHL24 with SBP may be modulated by tobacco smoking.
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Affiliation(s)
- Jacob Basson
- Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yun Ju Sung
- Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lisa de Las Fuentes
- Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Karen Schwander
- Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - L Adrienne Cupples
- The Framingham Heart Study, Framingham, MA, 01702, USA.,Department of Biostatistics, Boston University School of Public Health, Boston, MA, 02118, USA
| | - D C Rao
- Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri, USA
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12
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An interstitial de-novo microdeletion of 3q26.33q27.3 causing severe intrauterine growth retardation. Clin Dysmorphol 2015; 24:68-74. [DOI: 10.1097/mcd.0000000000000075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Kang MG, Byun K, Kim JH, Park NH, Heinsen H, Ravid R, Steinbusch HW, Lee B, Park YM. Proteogenomics of the human hippocampus: The road ahead. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:788-97. [PMID: 25770686 DOI: 10.1016/j.bbapap.2015.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 02/10/2015] [Accepted: 02/15/2015] [Indexed: 12/26/2022]
Abstract
The hippocampus is one of the most essential components of the human brain and plays an important role in learning and memory. The hippocampus has drawn great attention from scientists and clinicians due to its clinical importance in diseases such as Alzheimer's disease (AD), non-AD dementia, and epilepsy. Understanding the function of the hippocampus and related disease mechanisms requires comprehensive knowledge of the orchestration of the genome, epigenome, transcriptome, proteome, and post-translational modifications (PTMs) of proteins. The past decade has seen remarkable advances in the high-throughput sequencing techniques that are collectively called next generation sequencing (NGS). NGS enables the precise analysis of gene expression profiles in cells and tissues, allowing powerful and more feasible integration of expression data from the gene level to the protein level, even allowing "-omic" level assessment of PTMs. In addition, improved bioinformatics algorithms coupled with NGS technology are finally opening a new era for scientists to discover previously unidentified and elusive proteins. In the present review, we will focus mainly on the proteomics of the human hippocampus with an emphasis on the integrated analysis of genomics, epigenomics, transcriptomics, and proteomics. Finally, we will discuss our perspectives on the potential and future of proteomics in the field of hippocampal biology. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.
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Affiliation(s)
- Myoung-Goo Kang
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Graduate School of Medical Science & Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Kyunghee Byun
- Center for Genomics and Proteomics, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-840, Republic of Korea
| | - Jae Ho Kim
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea
| | - Nam Hyun Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea
| | - Helmut Heinsen
- Morphological Brain Research Unit, Department of Psychiatry, Universität of Würzburg, Würzburg, Germany
| | - Rivka Ravid
- Brain Bank Consultant, Amsterdam, The Netherlands
| | - Harry W Steinbusch
- School for Mental Health and Neuroscience, Department of Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Bonghee Lee
- Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea.
| | - Young Mok Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 305-811, Republic of Korea; Mass Spectrometry Research Center, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea; Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea.
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14
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Pahl S, Tapken D, Haering SC, Hollmann M. Trafficking of kainate receptors. MEMBRANES 2014; 4:565-95. [PMID: 25141211 PMCID: PMC4194049 DOI: 10.3390/membranes4030565] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 08/04/2014] [Accepted: 08/12/2014] [Indexed: 11/17/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) mediate the vast majority of excitatory neurotransmission in the central nervous system of vertebrates. In the protein family of iGluRs, kainate receptors (KARs) comprise the probably least well understood receptor class. Although KARs act as key players in the regulation of synaptic network activity, many properties and functions of these proteins remain elusive until now. Especially the precise pre-, extra-, and postsynaptic localization of KARs plays a critical role for neuronal function, as an unbalanced localization of KARs would ultimately lead to dysregulated neuronal excitability. Recently, important advances in the understanding of the regulation of surface expression, function, and agonist-dependent endocytosis of KARs have been achieved. Post-translational modifications like PKC-mediated phosphorylation and SUMOylation have been reported to critically influence surface expression and endocytosis, while newly discovered auxiliary proteins were shown to shape the functional properties of KARs.
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Affiliation(s)
- Steffen Pahl
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Daniel Tapken
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Simon C Haering
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Michael Hollmann
- Department of Biochemistry I, Ruhr University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
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15
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Abstract
Our understanding of the molecular properties of kainate receptors and their involvement in synaptic physiology has progressed significantly over the last 30 years. A plethora of studies indicate that kainate receptors are important mediators of the pre- and postsynaptic actions of glutamate, although the mechanisms underlying such effects are still often a topic for discussion. Three clear fields related to their behavior have emerged: there are a number of interacting proteins that pace the properties of kainate receptors; their activity is unconventional since they can also signal through G proteins, behaving like metabotropic receptors; they seem to be linked to some devastating brain diseases. Despite the significant progress in their importance in brain function, kainate receptors remain somewhat puzzling. Here we examine discoveries linking these receptors to physiology and their probable implications in disease, in particular mood disorders, and propose some ideas to obtain a deeper understanding of these intriguing proteins.
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16
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Sun C, Qiao H, Zhou Q, Wang Y, Wu Y, Zhou Y, Li Y. Modulation of GluK2a subunit-containing kainate receptors by 14-3-3 proteins. J Biol Chem 2013; 288:24676-90. [PMID: 23861400 PMCID: PMC3750165 DOI: 10.1074/jbc.m113.462069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 07/11/2013] [Indexed: 11/06/2022] Open
Abstract
Kainate receptors (KARs) are one of the ionotropic glutamate receptors that mediate excitatory postsynaptic currents (EPSCs) with characteristically slow kinetics. Although mechanisms for the slow kinetics of KAR-EPSCs are not totally understood, recent evidence has implicated a regulatory role of KAR-associated proteins. Here, we report that decay kinetics of GluK2a-containing receptors is modulated by closely associated 14-3-3 proteins. 14-3-3 binding requires PKC-dependent phosphorylation of serine residues localized in the carboxyl tail of the GluK2a subunit. In transfected cells, 14-3-3 binding to GluK2a slows desensitization kinetics of both homomeric GluK2a and heteromeric GluK2a/GluK5 receptors. Moreover, KAR-EPSCs at mossy fiber-CA3 synapses decay significantly faster in the 14-3-3 functional knock-out mice. Collectively, these results demonstrate that 14-3-3 proteins are an important regulator of GluK2a-containing KARs and may contribute to the slow decay kinetics of native KAR-EPSCs.
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Affiliation(s)
- Changcheng Sun
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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17
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Mandrile G, Dubois A, Hoffman JD, Uliana V, Di Maria E, Malacarne M, Coviello D, Faravelli F, Zwolinski S, Hellens S, Wright M, Forzano F. 3q26.33–3q27.2 microdeletion: A new microdeletion syndrome? Eur J Med Genet 2013; 56:216-21. [DOI: 10.1016/j.ejmg.2013.01.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 01/12/2013] [Indexed: 11/28/2022]
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18
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Effects of 18-kDa translocator protein knockdown on gene expression of glutamate receptors, transporters, and metabolism, and on cell viability affected by glutamate. Pharmacogenet Genomics 2012; 22:606-19. [PMID: 22732722 DOI: 10.1097/fpc.0b013e3283544531] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Previously, several important roles for glutamate have been described for the biology of primary brain tumors. For example, glutamate has been suggested to promote glioma cell proliferation by the activation of the 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid (AMPA) subtype of glutamate receptors. In the present study, we determined the potential regulatory roles of the 18-kDa translocator protein (TSPO) in the glutamatergic system in relation to cell death of brain tumor cells through knockdown of the TSPO by genetic manipulation. MATERIALS AND METHODS With microarray analysis and validation of gene expression of particular genes using real-time PCR, we found effects because of small inhibitory RNA knockdown of the TSPO in human U118MG glioblastoma cells on gene expression of glutamate receptors, glutamate transporters, and enzymes for glutamate metabolism. We also applied antisense RNA to silence TSPO in rat C6 glioblastoma cells and assayed the effects on DNA fragmentation, indicative of apoptosis, because of glutamate exposure. RESULTS In particular, the effects of TSPO silencing in human U118MG cells related to glutamate metabolism indicate a net effect of a reduction in glutamate levels, which may potentially protect the cells in question from cell death. The TSPO knockdown in C6 cells showed that TSPO is required for the induction of apoptosis because of glutamate exposure. CONCLUSION These findings show that interactions between the TSPO and the glutamatergic system may play a role in tumor development of glioblastoma cells. This may also have implications for our understanding of the involvement of the TSPO in secondary brain damage and neurodegenerative diseases.
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19
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Dancing partners at the synapse: auxiliary subunits that shape kainate receptor function. Nat Rev Neurosci 2012; 13:675-86. [PMID: 22948074 DOI: 10.1038/nrn3335] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Kainate receptors are a family of ionotropic glutamate receptors whose physiological roles differ from those of other subtypes of glutamate receptors in that they predominantly serve as modulators, rather than mediators, of synaptic transmission. Neuronal kainate receptors exhibit unusually slow kinetic properties that have been difficult to reconcile with the behaviour of recombinant kainate receptors. Recently, however, the neuropilin and tolloid-like 1 (NETO1) and NETO2 proteins were identified as auxiliary kainate receptor subunits that shape both the biophysical properties and synaptic localization of these receptors.
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20
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Tomita S, Castillo PE. Neto1 and Neto2: auxiliary subunits that determine key properties of native kainate receptors. J Physiol 2012; 590:2217-23. [PMID: 22431337 DOI: 10.1113/jphysiol.2011.221101] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Kainate receptors (KARs) are a subfamily of ionotropic glutamate receptors (iGluRs) that mediate excitatory synaptic transmission, regulate neurotransmitter release, and show a remarkably selective distribution in the brain. Compared to other iGluRs, the precise contribution of KARs to brain function is less understood. Unlike recombinant KARs, native KARs exhibit characteristically slow channel kinetics. The underlying explanation for this dissimilar kinetics has remained elusive until recently. New research has identified Neto1 and Neto2 as KAR auxiliary subunits that determine unique properties of synaptic KARs, including their slow kinetics and high affinity for agonist. Whether these auxiliary subunits regulate KAR trafficking and targeting at the synapse is less clear. By regulating channel gating, Neto1 and Neto2 can increase the diversity of KAR functional properties. These auxiliary subunits may represent a starting point for a better understanding of the role played by neuronal KARs under normal and pathological conditions, but also, they may provide an alternative target for the development of new drugs regulating KARs and brain function.
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Affiliation(s)
- Susumu Tomita
- Program in Cellular Neuroscience, Neurodegeneration and Repair (CNNR), Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA.
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21
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22
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González-González IM, Konopacki FA, Rocca DL, Doherty AJ, Jaafari N, Wilkinson KA, Henley JM. Kainate receptor trafficking. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/wmts.23] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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23
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Reese LC, Laezza F, Woltjer R, Taglialatela G. Dysregulated phosphorylation of Ca(2+) /calmodulin-dependent protein kinase II-α in the hippocampus of subjects with mild cognitive impairment and Alzheimer's disease. J Neurochem 2011; 119:791-804. [PMID: 21883216 DOI: 10.1111/j.1471-4159.2011.07447.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is a progressive, neurodegenerative disorder and the most prevalent senile dementia. The early symptom of memory dysfunction involves synaptic loss, thought to be mediated by soluble amyloid-beta (Aβ) oligomers. These aggregate species target excitatory synapses and their levels correlate with disease severity. Studies in cell culture and rodents have shown that oligomers increase intracellular calcium (Ca(2+)), impairing synaptic plasticity. Yet, the molecular mechanism mediating Aβ oligomers' toxicity in the aged brain remains unclear. Here, we apply quantitative immunofluorescence in human brain tissue from clinically diagnosed mild cognitive impaired (MCI) and AD patients to investigate the distribution of phosphorylated (active) Ca(2+) /calmodulin-dependent protein kinase-α (p(Thr286)CaMKII), a critical enzyme for activity-dependent synaptic remodeling associated with cognitive function. We show that p(Thr286)CaMKII immunoreactivity is redistributed from dendritic arborizations to neural perikarya of both MCI and AD hippocampi. This finding correlates with cognitive assessment scores, suggesting that it may be a molecular read-out of the functional deficits in early AD. Treatment with oligomeric Aβ replicated the observed phenotype in mice and resulted in a loss of p(Thr286)CaMKII from synaptic spines of primary hippocampal neurons. Both outcomes were prevented by inhibiting the phosphatase calcineurin (CaN). Collectively, our results support a model in which the synaptotoxicity of Aβ oligomers in human brain involves the CaN-dependent subcellular redistribution of p(Thr286)CaMKII. Therapies designed to normalize the homeostatic imbalance of neuronal phosphatases and downstream dephosphorylation of synaptic p(Thr286)CaMKII should be considered to prevent and treat early AD.
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Affiliation(s)
- Lindsay C Reese
- Department of Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-1043, USA
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24
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Abstract
Pore-forming subunits of ion channels show channel activity in heterologous cells. However, recombinant and native channels often differ in their channel properties. These discrepancies are resolved by the identification of channel auxiliary subunits. In this review article, an auxiliary subunit of ligand-gated ion channels is defined using four criteria: (1) as a Non-pore-forming subunit, (2) direct and stable interaction with a pore-forming subunit, (3) modulation of channel properties and/or trafficking in heterologous cells, (4) necessity in vivo. We focus particularly on three classes of ionotropic glutamate receptors and their transmembrane interactors. Precise identification of auxiliary subunits and reconstruction of native glutamate receptors will open new directions to understanding the brain and its functions.
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Affiliation(s)
- Dan Yan
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
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25
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Abstract
Ionotropic glutamate receptors of AMPA, NMDA, and kainate receptor (KAR) subtypes mediate fast excitatory synaptic transmission in the vertebrate CNS. Auxiliary proteins have been identified for AMPA and NMDA receptor complexes, but little is known about KAR complex proteins. We previously identified the CUB (complement C1r/C1s, Uegf, Bmpl) domain protein, Neto1, as an NMDA receptor-associated polypeptide. Here, we show that Neto1 is also an auxiliary subunit for endogenous synaptic KARs. We found that Neto1 and KARs coimmunoprecipitated from brain lysates, from postsynaptic densities (PSDs) and, in a manner dependent on Neto1 CUB domains, when coexpressed in heterologous cells. In Neto1-null mice, there was an ∼50% reduction in the abundance of GluK2-KARs in hippocampal PSDs. Neto1 strongly localized to CA3 stratum lucidum, and loss of Neto1 resulted in a selective deficit in KAR-mediated neurotransmission at mossy fiber-CA3 pyramidal cell (MF-CA3) synapses: KAR-mediated EPSCs in Neto1-null mice were reduced in amplitude and decayed more rapidly than did those in wild-type mice. In contrast, the loss of Neto2, which also localizes to stratum lucidum and interacts with KARs, had no effect on KAR synaptic abundance or MF-CA3 transmission. Indeed, MF-CA3 KAR deficits in Neto1/Neto2-double-null mutant mice were indistinguishable from Neto1 single-null mice. Thus, our findings establish Neto1 as an auxiliary protein required for synaptic function of KARs. The ability of Neto1 to regulate both NMDARs and KARs reveals a unique dual role in controlling synaptic transmission by serving as an auxiliary protein for these two classes of ionotropic glutamate receptors in a synapse-specific fashion.
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26
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Metabotropic actions of kainate receptors in dorsal root ganglion cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011. [PMID: 21713668 DOI: 10.1007/978-1-4419-9557-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Kainate receptors are widely distributed in the CNS, but also in the PNS. Dorsal root ganglia are enriched in this subtype of glutamate ionotropic receptors. In addition to their activity as ligand-gated ion channels, kainate receptors exhibit other properties already characterized in other systems, such as hippocampus, i.e., their ability to induce a metabotropic cascade signalling, through G-protein and PKC activation. With a very similar actuation mechanism as formerly described in the CNS, kainate receptors in the DRG also present other differentiated features, such as the Ca(2+) channel blockade and a self-regulation property. The peculiarity of these neurons has served to progress the study of kainate receptors. Nevertheless, many other physiological functions of these receptors remain unclear, as does the related molecular nature of the metabotropic cascade and the involvement of this signalling pathway with sensory transmission of pain.
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27
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Straub C, Hunt DL, Yamasaki M, Kim KS, Watanabe M, Castillo PE, Tomita S. Distinct functions of kainate receptors in the brain are determined by the auxiliary subunit Neto1. Nat Neurosci 2011; 14:866-73. [PMID: 21623363 PMCID: PMC3125417 DOI: 10.1038/nn.2837] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 04/14/2011] [Indexed: 12/11/2022]
Abstract
Ionotropic glutamate receptors principally mediate fast excitatory transmission in the brain. Among the three classes of ionotropic glutamate receptors, kainate receptors (KARs) display a categorical brain distribution, which has been historically defined by 3H-radiolabeled kainate binding. Compared with recombinant KARs expressed in heterologous cells, synaptic KARs exhibit characteristically slow rise-time and decay kinetics. However, the mechanisms responsible for these unique KAR properties remain unclear. Here we found that both the distinct high affinity biding pattern in the mouse brain and the channel properties of native KARs are determined by the KAR auxiliary subunit Neto1. Through modulation of agonist binding affinity and off-kinetics of KARs, but not trafficking of KARs, Neto1 determines both KAR high affinity binding pattern and the distinctively slow kinetics of postsynaptic KARs. By regulating KAR-EPSC kinetics, Neto1 can control synaptic temporal summation, spike generation and fidelity.
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Affiliation(s)
- Christoph Straub
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
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28
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Copits BA, Robbins JS, Frausto S, Swanson GT. Synaptic targeting and functional modulation of GluK1 kainate receptors by the auxiliary neuropilin and tolloid-like (NETO) proteins. J Neurosci 2011; 31:7334-40. [PMID: 21593317 PMCID: PMC3131203 DOI: 10.1523/jneurosci.0100-11.2011] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/30/2011] [Accepted: 04/01/2011] [Indexed: 02/02/2023] Open
Abstract
Auxiliary proteins modify the biophysical function and pharmacological properties of ionotropic glutamate receptors and likely are important components of receptor signaling complexes in vivo. The neuropilin and tolloid-like proteins (NETO) 1 and NETO2, two closely related CUB domain-containing integral membrane proteins, were identified recently as auxiliary proteins that slowed GluK2a kainate receptor current kinetics without impacting receptor membrane localization. Here we demonstrate that NETO2 profoundly slows the desensitization rate of GluK1 kainate receptors, promotes plasma membrane localization of transfected receptors in heterologous cells and rat hippocampal neurons, and targets GluK1-containing receptors to synapses. Conversely, the closely related protein NETO1 increases the rate of GluK1 receptor desensitization. Incorporation of NETO proteins into kainate receptor-signaling complexes therefore extends the temporal range of receptor gating by over an order of magnitude. The presence of these auxiliary proteins could underlie some of the unusual aspects of kainate receptor function in the mammalian CNS.
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Affiliation(s)
- Bryan A. Copits
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - John S. Robbins
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Shanti Frausto
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - Geoffrey T. Swanson
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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29
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Contractor A, Mulle C, Swanson GT. Kainate receptors coming of age: milestones of two decades of research. Trends Neurosci 2011; 34:154-63. [PMID: 21256604 DOI: 10.1016/j.tins.2010.12.002] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 12/16/2010] [Accepted: 12/18/2010] [Indexed: 11/18/2022]
Abstract
Two decades have passed since the first report of the cloning of a kainate-type glutamate receptor (KAR) subunit. The intervening years have seen a rapid growth in our understanding of the biophysical properties and function of KARs in the brain. This research has led to an appreciation that KARs play very distinct roles at synapses relative to other members of the glutamate-gated ion channel receptor family, despite structural and functional commonalities. The surprisingly diverse and complex nature of KAR signaling underlies their unique impact upon neuronal networks through their direct and indirect effects on synaptic transmission, and their prominent role in regulating cell excitability. This review pieces together highlights from the two decades of research subsequent to the cloning of the first subunit, and provides an overview of our current understanding of the role of KARs in the CNS and their potential importance to neurological and neuropsychiatric disorders.
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Affiliation(s)
- Anis Contractor
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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30
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Mondin M, Carta M, Normand E, Mulle C, Coussen F. Profilin II regulates the exocytosis of kainate glutamate receptors. J Biol Chem 2010; 285:40060-71. [PMID: 20937818 PMCID: PMC3000988 DOI: 10.1074/jbc.m110.140442] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 10/01/2010] [Indexed: 11/06/2022] Open
Abstract
The trafficking of ionotropic glutamate receptors to and from synaptic sites is regulated by proteins that interact with their cytoplasmic C-terminal domain. Profilin IIa (PfnIIa), an actin-binding protein expressed in the brain and recruited to synapses in an activity-dependent manner, was shown previously to interact with the C-terminal domain of the GluK2b subunit splice variant of kainate receptors (KARs). Here, we characterize this interaction and examine the role of PfnIIa in the regulation of KAR trafficking. PfnIIa directly and specifically binds to the C-terminal domain of GluK2b through a diproline motif. Expression of PfnIIa in transfected COS-7 cells and in cultured hippocampal neurons from PfnII-deficient mice decreases the level of extracellular of homomeric GluK2b as well as heteromeric GluK2a/GluK2b KARs. Our data suggest a novel mechanism by which PfnIIa exerts a dual role on the trafficking of KARs, by a generic inhibition of clathrin-mediated endocytosis through its interaction with dynamin-1, and by controlling KARs exocytosis through a direct and specific interaction with GluK2b.
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Affiliation(s)
- Magali Mondin
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Mario Carta
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Elisabeth Normand
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Christophe Mulle
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
| | - Françoise Coussen
- From the Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
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31
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Han Y, Wang C, Park JS, Niu L. Channel-opening kinetic mechanism for human wild-type GluK2 and the M867I mutant kainate receptor. Biochemistry 2010; 49:9207-16. [PMID: 20863077 PMCID: PMC2988652 DOI: 10.1021/bi100819v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
GluK2 is a kainate receptor subunit that is alternatively spliced at the C-terminus. Previous studies implicated GluK2 in autism. In particular, the methionine-to-isoleucine replacement at amino acid residue 867 (M867I) that can only occur in the longest isoform of the human GluK2 (hGluK2), as the disease (autism) mutation, is thought to cause gain-of-function. However, the kinetic properties of the wild-type hGluK2 and the functional consequence of this gain-of-function mutation at the molecular level are not well understood. To investigate whether the M867I mutation affects the channel properties of the human GluK2 kainate receptor, we have systematically characterized the rate and the equilibrium constants pertinent to channel opening and channel desensitization for this mutant and the wild-type hGluK2 receptor, along with the wild-type rat GluK2 kainate receptor (rGluK2) as the control. Our results show that the M867I mutation does not affect either the rate or the equilibrium constants of the channel opening but does slow down the channel desensitization rate by ~1.6-fold at saturating glutamate concentrations. It is possible that a consequence of this mutation on the desensitization rate is linked to facilitating the receptor trafficking and membrane expression, given the close proximity of M867 to the forward trafficking motif in the C-terminal sequence. By comparing the kinetic data of the wild-type human and rat GluK2 receptors, we also find that the human GluK2 has a ~3-fold smaller channel-opening rate constant but an identical channel-closing rate constant and thus a channel-opening probability of 0.85 vs 0.96 for rGluK2. Furthermore, the intrinsic equilibrium dissociation constant K(1) for hGluK2, like the EC(50) value, is ~2-fold lower than rGluK2. Our results therefore suggest that the human GluK2 is relatively a slowly activating channel but more sensitive to glutamate, as compared to the rat ortholog, despite the fact that the human and rat forms share 99% sequence homology.
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Affiliation(s)
- Yan Han
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222
| | - Congzhou Wang
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222
| | - Jae Seon Park
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222
| | - Li Niu
- Department of Chemistry and Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222
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32
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Perrais D, Veran J, Mulle C. Gating and permeation of kainate receptors: differences unveiled. Trends Pharmacol Sci 2010; 31:516-22. [PMID: 20850188 DOI: 10.1016/j.tips.2010.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 07/20/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
Abstract
Kainate receptors (KARs) represent, together with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl D-aspartate (NMDA) receptors, one of the three families of ionotropic glutamate receptors. Recent advances in the study of their biophysical properties have revealed a surprising diversity. KAR-mediated excitatory postsynaptic currents (EPSCs) are often much slower than AMPA receptor-mediated EPSCs, and this is probably due to the slow deactivation rate of KARs containing the GluK4 or GluK5 subunits. By contrast, GluK3-containing receptors, unlike other AMPA/kainate receptors, desensitize faster at low agonist concentrations, making these receptors insensitive to glutamate spillover from neighboring synapses. Moreover, KARs have a wide range of sensitivities to intracellular polyamines and consequently of voltage dependent activation. Finally, newly discovered associated proteins, such as Neto1 and 2, have marked effects on receptor properties, increasing further the potential diversity of KAR functional properties. Altogether, this functional diversity of KARs could have profound consequences on their ability to shape synaptic transmission under physiological and pathological conditions.
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Affiliation(s)
- David Perrais
- Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 33077 Bordeaux, France.
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33
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Zhang W, St-Gelais F, Grabner CP, Trinidad JC, Sumioka A, Morimoto-Tomita M, Kim KS, Straub C, Burlingame AL, Howe JR, Tomita S. A transmembrane accessory subunit that modulates kainate-type glutamate receptors. Neuron 2009; 61:385-96. [PMID: 19217376 PMCID: PMC2803770 DOI: 10.1016/j.neuron.2008.12.014] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 11/07/2008] [Accepted: 12/15/2008] [Indexed: 12/01/2022]
Abstract
Glutamate receptors play major roles in excitatory transmission in the vertebrate brain. Among ionotropic glutamate receptors (AMPA, kainate, NMDA), AMPA receptors mediate fast synaptic transmission and require TARP auxiliary subunits. NMDA receptors and kainate receptors play roles in synaptic transmission, but it remains uncertain whether these ionotropic glutamate receptors also have essential subunits. Using a proteomic screen, we have identified NETO2, a brain-specific protein of unknown function, as an interactor with kainate-type glutamate receptors. NETO2 modulates the channel properties of recombinant and native kainate receptors without affecting trafficking of the receptors and also modulates kainate-receptor-mediated mEPSCs. Furthermore, we found that kainate receptors regulate the surface expression of NETO2 and that NETO2 protein levels and surface expression are decreased in mice lacking the kainate receptor GluR6. The results show that NETO2 is a kainate receptor subunit with significant effects on glutamate signaling mechanisms in brain.
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Affiliation(s)
- Wei Zhang
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Fannie St-Gelais
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Chad P. Grabner
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jonathan C. Trinidad
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Akio Sumioka
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Megumi Morimoto-Tomita
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Kwang S. Kim
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Christoph Straub
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Alma L. Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - James R. Howe
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susumu Tomita
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
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Laezza F, Wilding TJ, Sequeira S, Craig AM, Huettner JE. The BTB/kelch protein, KRIP6, modulates the interaction of PICK1 with GluR6 kainate receptors. Neuropharmacology 2008; 55:1131-9. [PMID: 18692513 PMCID: PMC2685165 DOI: 10.1016/j.neuropharm.2008.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 06/21/2008] [Accepted: 07/07/2008] [Indexed: 11/18/2022]
Abstract
Neuronal proteins of the BTB/kelch and PDZ domain families interact with different regions of the cytoplasmic C-terminal domain of the GluR6 kainate receptor subunit. The BTB/kelch protein KRIP6 binds within a 58 amino acid segment of GluR6 proximal to the plasma membrane. In contrast, PDZ domain proteins, such as PICK1 and PSD95, interact with the last 4 residues of the GluR6 C-terminus. KRIP6 reduces peak currents mediated by recombinant GluR6 receptors and by native kainate receptors in neurons, whereas PICK1 stabilizes kainate receptors at synapses. Thus, protein-protein interactions at the C-terminal domain of GluR6 are important for regulating kainate receptor physiology. Here, we show by co-clustering and co-immunoprecipitation that KRIP6 interacts with PICK1 in heterologous cells. In addition, we demonstrate a novel modulation of GluR6 receptors by PICK1 resulting in increased peak current and relative desensitization of GluR6-mediated currents, phenotypes opposite to those produced by KRIP6. Importantly, these effects cancel out when KRIP6 and PICK1 are co-expressed together with GluR6. KRIP6 and PICK1 strongly co-cluster and co-immunoprecipitate regardless of the presence of GluR6. Immunofluorescence analysis reveals that GluR6 can either join the KRIP6-PICK1 clusters or remain separate; however, co-expression of KRIP6 reduces the fraction of PICK1 that co-immunoprecipitates with GluR6. Taken together, these results indicate that, in addition to a previously demonstrated direct interaction with the GluR6 C-terminal domain, KRIP6 regulates kainate receptors by inhibiting PICK1 modulation via competition or a mutual blocking effect.
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Affiliation(s)
- Fernanda Laezza
- Department of Cell Biology and Physiology, Washington University, St Louis, MO 63110, USA.
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35
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Barberis A, Sachidhanandam S, Mulle C. GluR6/KA2 kainate receptors mediate slow-deactivating currents. J Neurosci 2008; 28:6402-6. [PMID: 18562611 PMCID: PMC6670893 DOI: 10.1523/jneurosci.1204-08.2008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 05/05/2008] [Accepted: 05/05/2008] [Indexed: 11/21/2022] Open
Abstract
Kainate receptors (KARs) are ionotropic glutamate receptors contributing to EPSCs with a slow-decaying component that is likely essential for synaptic integration. The slow kinetics of KAR-EPSCs markedly contrasts with the fast kinetics reported for recombinant KARs expressed in heterologous systems, for reasons that remain unexplained. Here we have studied the properties of recombinant heteromeric GluR6/KA2 receptors, which compose synaptic KARs. We report that, in response to brief glutamate applications, currents mediated by recombinant GluR6/KA2 receptors, but not GluR6 receptors, decay with a time course similar to KAR-EPSCs. Model simulations suggest that, after brief agonist exposures, GluR6/KA2 currents undergo slow deactivation caused by the stabilization of partially bound open states. We propose, therefore, that the GluR6/KA2 gating features could contribute to the slow KAR-EPSC decay kinetics.
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Affiliation(s)
- Andrea Barberis
- Laboratoire Physiologie Cellulaire de la Synapse, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5091, Bordeaux Neuroscience Institute, University of Bordeaux 2, 33077 Bordeaux, France
| | - Shankar Sachidhanandam
- Laboratoire Physiologie Cellulaire de la Synapse, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5091, Bordeaux Neuroscience Institute, University of Bordeaux 2, 33077 Bordeaux, France
| | - Christophe Mulle
- Laboratoire Physiologie Cellulaire de la Synapse, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5091, Bordeaux Neuroscience Institute, University of Bordeaux 2, 33077 Bordeaux, France
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36
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Coussen F. Molecular determinants of kainate receptor trafficking. Neuroscience 2008; 158:25-35. [PMID: 18358623 DOI: 10.1016/j.neuroscience.2007.12.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 12/21/2007] [Accepted: 12/26/2007] [Indexed: 11/19/2022]
Abstract
Glutamate receptors of the kainate subtype are ionotropic receptors that play a key role in the modulation of neuronal network activity. The role of kainate receptors depends on their precise membrane and subcellular localization in presynaptic, extrasynaptic and postsynaptic domains. These receptors are composed of the combination of five subunits, three of them having several splice variants. The subunits and splice variants show great divergence in their C-terminal cytoplasmic tail domains, which have been implicated in intracellular trafficking of homomeric and heteromeric receptors. Differential trafficking of kainate receptors to specific neuronal compartments likely relies on interactions between the different kainate receptor subunits with distinct subsets of protein partners that interact with C-terminal domains. These C-terminal domains have also been implicated in the degradation of kainate receptors. Finally, the phosphorylation of the C-terminal domain regulates receptor trafficking and function. This review summarizes our knowledge on the regulation of membrane delivery and trafficking of kainate receptors implicating C-terminal domains of the different isoforms and focuses on the identification and characterization of the function of interacting partners.
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Affiliation(s)
- F Coussen
- CNRS UMR 5091, Laboratoire "Physiologie Cellulaire de la Synapse," Bordeaux Neuroscience Institute, University of Bordeaux 2, Bordeaux, France.
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