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Yang HQ, Echeverry FA, ElSheikh A, Gando I, Anez Arredondo S, Samper N, Cardozo T, Delmar M, Shyng SL, Coetzee WA. Subcellular trafficking and endocytic recycling of K ATP channels. Am J Physiol Cell Physiol 2022; 322:C1230-C1247. [PMID: 35508187 PMCID: PMC9169827 DOI: 10.1152/ajpcell.00099.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 11/22/2022]
Abstract
Sarcolemmal/plasmalemmal ATP-sensitive K+ (KATP) channels have key roles in many cell types and tissues. Hundreds of studies have described how the KATP channel activity and ATP sensitivity can be regulated by changes in the cellular metabolic state, by receptor signaling pathways and by pharmacological interventions. These alterations in channel activity directly translate to alterations in cell or tissue function, that can range from modulating secretory responses, such as insulin release from pancreatic β-cells or neurotransmitters from neurons, to modulating contractile behavior of smooth muscle or cardiac cells to elicit alterations in blood flow or cardiac contractility. It is increasingly becoming apparent, however, that KATP channels are regulated beyond changes in their activity. Recent studies have highlighted that KATP channel surface expression is a tightly regulated process with similar implications in health and disease. The surface expression of KATP channels is finely balanced by several trafficking steps including synthesis, assembly, anterograde trafficking, membrane anchoring, endocytosis, endocytic recycling, and degradation. This review aims to summarize the physiological and pathophysiological implications of KATP channel trafficking and mechanisms that regulate KATP channel trafficking. A better understanding of this topic has potential to identify new approaches to develop therapeutically useful drugs to treat KATP channel-related diseases.
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Affiliation(s)
- Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | | | - Assmaa ElSheikh
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Ivan Gando
- Department of Pathology, NYU School of Medicine, New York, New York
| | | | - Natalie Samper
- Department of Pathology, NYU School of Medicine, New York, New York
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - Mario Delmar
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
- Department of Medicine, NYU School of Medicine, New York, New York
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - William A Coetzee
- Department of Pathology, NYU School of Medicine, New York, New York
- Department of Neuroscience & Physiology, NYU School of Medicine, New York, New York
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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Wang R, Deng M, Yang C, Yu Q, Zhang L, Zhu Q, Guo X. A Qa-SNARE complex contributes to soybean cyst nematode resistance via regulation of mitochondria-mediated cell death. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:7145-7162. [PMID: 34165531 DOI: 10.1093/jxb/erab301] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 06/23/2021] [Indexed: 05/27/2023]
Abstract
The resistance to Heterodera glycines 1 (Rhg1) locus is widely used by soybean breeders to reduce yield loss caused by soybean cyst nematode (SCN). α-SNAP (α-soluble NSF attachment protein) within Rhg1 locus contributes to SCN resistance by modulation of cell status at the SCN feeding site; however, the underlying mechanism is largely unclear. Here, we identified an α-SNAP-interacting protein, GmSYP31A, a Qa-SNARE (soluble NSF attachment protein receptor) protein from soybean. Expression of GmSYP31A significantly induced cell death in Nicotiana benthamiana leaves, and co-expression of α-SNAP and GmSYP31A could accelerate cell death. Overexpression of GmSYP31A increased SCN resistance, while silencing or overexpression of a dominant-negative form of GmSYP31A increased SCN sensitivity. GmSYP31A expression also disrupted endoplasmic reticulum-Golgi trafficking, and the exocytosis pathway. Moreover, α-SNAP was also found to interact with GmVDAC1D (voltage-dependent anion channel). The cytotoxicity induced by the expression of GmSYP31A could be relieved either with the addition of an inhibitor of VDAC protein, or by silencing the VDAC gene. Taken together, our data not only demonstrate that α-SNAP works together with GmSYP31A to increase SCN resistance through triggering cell death, but also highlight the unexplored link between the mitochondrial apoptosis pathway and vesicle trafficking.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Miaomiao Deng
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Chao Yang
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Qianqian Yu
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Lei Zhang
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Qun Zhu
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaoli Guo
- State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
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Production and purification of ATP-sensitive potassium channel particles for cryo-electron microscopy. Methods Enzymol 2021; 653:121-150. [PMID: 34099169 DOI: 10.1016/bs.mie.2021.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
ATP-sensitive potassium (KATP) channels are multimeric protein complexes made of four inward rectifying potassium channel (Kir6.x) subunits and four ABC protein sulfonylurea receptor (SURx) subunits. Kir6.x subunits form the potassium ion conducting pore of the channel, and SURx functions to regulate Kir6.x. Kir6.x and SURx are uniquely dependent on each other for expression and function. In pancreatic β-cells, channels comprising SUR1 and Kir6.2 mediate glucose-stimulated insulin secretion and are the targets of antidiabetic sulfonylureas. Mutations in genes encoding SUR1 or Kir6.2 are linked to insulin secretion disorders, with loss- or gain-of-function mutations causing congenital hyperinsulinism or neonatal diabetes mellitus, respectively. Defects in the KATP channel in other tissues underlie human diseases of the cardiovascular and nervous systems. Key to understanding how channels are regulated by physiological and pharmacological ligands and how mutations disrupt channel assembly or gating to cause disease is the ability to observe structural changes associated with subunit interactions and ligand binding. While recent advances in the structural method of single-particle cryo-electron microscopy (cryoEM) offers direct visualization of channel structures, success of obtaining high-resolution structures is dependent on highly concentrated, homogeneous KATP channel particles. In this chapter, we describe a method for expressing KATP channels in mammalian cell culture, solubilizing the channel in detergent micelles and purifying KATP channels using an affinity tag to the SURx subunit for cryoEM structural studies.
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Selvaraj C, Selvaraj G, Kaliamurthi S, Cho WC, Wei DQ, Singh SK. Ion Channels as Therapeutic Targets for Type 1 Diabetes Mellitus. Curr Drug Targets 2020; 21:132-147. [PMID: 31538892 DOI: 10.2174/1389450119666190920152249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 02/07/2023]
Abstract
Ion channels are integral proteins expressed in almost all living cells and are involved in muscle contraction and nutrient transport. They play a critical role in the normal functioning of the excitable tissues of the nervous system and regulate the action potential and contraction events. Dysfunction of genes encodes ion channel proteins, which disrupt the channel function and lead to a number of diseases, among which is type 1 diabetes mellitus (T1DM). Therefore, understanding the complex mechanism of ion channel receptors is necessary to facilitate the diagnosis and management of treatment. In this review, we summarize the mechanism of important ion channels and their potential role in the regulation of insulin secretion along with the limitations of ion channels as therapeutic targets. Furthermore, we discuss the recent investigations of the mechanism regulating the ion channels in pancreatic beta cells, which suggest that ion channels are active participants in the regulation of insulin secretion.
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Affiliation(s)
- Chandrabose Selvaraj
- Department of Bioinformatics, Computer-Aided Drug Design, and Molecular Modeling Lab, Science Block, Alagappa University, Karaikudi, Tamil Nadu, 630004, India
| | - Gurudeeban Selvaraj
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
| | - Satyavani Kaliamurthi
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - Dong-Qing Wei
- Center of Interdisciplinary Sciences-Computational Life Sciences, College of Food Science and Engineering, Henan University of Technology, Zhengzhou, 450001, China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nanshan District, Shenzhen, Guangdong, 518055, China
- Department of Bioinformatics, The State Key Laboratory of Microbial Metabolism, College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Sanjeev Kumar Singh
- Department of Bioinformatics, Computer-Aided Drug Design, and Molecular Modeling Lab, Science Block, Alagappa University, Karaikudi, Tamil Nadu, 630004, India
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Jacobson DA, Shyng SL. Ion Channels of the Islets in Type 2 Diabetes. J Mol Biol 2019; 432:1326-1346. [PMID: 31473158 DOI: 10.1016/j.jmb.2019.08.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 02/06/2023]
Abstract
Ca2+ is an essential signal for pancreatic β-cell function. Ca2+ plays critical roles in numerous β-cell pathways such as insulin secretion, transcription, metabolism, endoplasmic reticulum function, and the stress response. Therefore, β-cell Ca2+ handling is tightly controlled. At the plasma membrane, Ca2+ entry primarily occurs through voltage-dependent Ca2+ channels. Voltage-dependent Ca2+ channel activity is dependent on orchestrated fluctuations in the plasma membrane potential or voltage, which are mediated via the activity of many ion channels. During the pathogenesis of type 2 diabetes the β-cell is exposed to stressful conditions, which result in alterations of Ca2+ handling. Some of the changes in β-cell Ca2+ handling that occur under stress result from perturbations in ion channel activity, expression or localization. Defective Ca2+ signaling in the diabetic β-cell alters function, limits insulin secretion and exacerbates hyperglycemia. In this review, we focus on the β-cell ion channels that control Ca2+ handling and how they impact β-cell dysfunction in type 2 diabetes.
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Affiliation(s)
- David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7415 MRB4 (Langford), 2213 Garland Avenue, Nashville, TN 37232, USA.
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, L224, MRB 624, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Workalemahu T, Enquobahrie DA, Gelaye B, Sanchez SE, Garcia PJ, Tekola-Ayele F, Hajat A, Thornton TA, Ananth CV, Williams MA. Genetic variations and risk of placental abruption: A genome-wide association study and meta-analysis of genome-wide association studies. Placenta 2018; 66:8-16. [PMID: 29884306 PMCID: PMC5995331 DOI: 10.1016/j.placenta.2018.04.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/11/2018] [Accepted: 04/13/2018] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Accumulating epidemiological evidence points to strong genetic susceptibility to placental abruption (PA). However, characterization of genes associated with PA remains incomplete. We conducted a genome-wide association study (GWAS) of PA and a meta-analysis of GWAS. METHODS Participants of the Placental Abruption Genetic Epidemiology (PAGE) study, a population based case-control study of PA conducted in Lima, Peru, were genotyped using the Illumina HumanCore-24 BeadChip platform. Genotypes were imputed using the 1000 genomes reference panel, and >4.9 million SNPs that passed quality control were analyzed. We performed a GWAS in PAGE participants (507 PA cases and 1090 controls) and a GWAS meta-analysis in 2512 participants (959 PA cases and 1553 controls) that included PAGE and the previously reported Peruvian Abruptio Placentae Epidemiology (PAPE) study. We fitted population stratification-adjusted logistic regression models and fixed-effects meta-analyses using inverse-variance weighting. RESULTS Independent loci (linkage-disequilibrium<0.80) suggestively associated with PA (P-value<5e-5) included rs4148646 and rs2074311 in ABCC8, rs7249210, rs7250184, rs7249100 and rs10401828 in ZNF28, rs11133659 in CTNND2, and rs2074314 and rs35271178 near KCNJ11 in the PAGE GWAS. Similarly, independent loci suggestively associated with PA in the GWAS meta-analysis included rs76258369 near IRX1, and rs7094759 and rs12264492 in ADAM12. Functional analyses of these genes showed trophoblast-like cell interaction, as well as networks involved in endocrine system disorders, cardiovascular diseases, and cellular function. CONCLUSIONS We identified several genetic loci and related functions that may play a role in PA risk. Understanding genetic factors underlying pathophysiological mechanisms of PA may facilitate prevention and early diagnostic efforts.
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Affiliation(s)
- Tsegaselassie Workalemahu
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA; Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| | - Daniel A Enquobahrie
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA; Center for Perinatal Studies, Swedish Medical Center, Seattle, WA, USA
| | - Bizu Gelaye
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Sixto E Sanchez
- Facultad de Medicina Humana, Universidad San Martín de Porres, Lima, Peru; Asociación Civil PROESA, Lima, Peru; Instituto Nacional Materno Perinatal, Lima, Peru
| | | | - Fasil Tekola-Ayele
- Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anjum Hajat
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | | | - Cande V Ananth
- Department of Obstetrics and Gynecology, Roy and Diana Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, Joseph L. Mailman School of Public Health, Columbia University, New York, NY, USA
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Plasma membrane insertion of KCa2.3 (SK3) is dependent upon the SNARE proteins, syntaxin-4 and SNAP23. PLoS One 2018; 13:e0196717. [PMID: 29768434 PMCID: PMC5955555 DOI: 10.1371/journal.pone.0196717] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 04/18/2018] [Indexed: 02/03/2023] Open
Abstract
We previously demonstrated endocytosis of KCa2.3 is caveolin-1-, dynamin II- and Rab5-dependent. KCa2.3 then enters Rab35/EPI64C- and RME-1-containing recycling endosomes and is returned to the plasma membrane (PM). Herein, we report on the mechanism by which KCa2.3 is inserted into the PM during recycling and following exit from the Golgi. We demonstrate KCa2.3 colocalizes with SNAP-23 and Syntaxin-4 in the PM of HEK and endothelial cells by confocal immunofluorescence microscopy. We further show KCa2.3 can be co-immunoprecipitated with SNAP-23 and Syntaxin-4. Overexpression of either Syntaxin-4 or SNAP-23 increased PM expression of KCa2.3, whereas shRNA-mediated knockdown of these SNARE proteins significantly decreased PM KCa2.3 expression, as assessed by cell surface biotinylation. Whole-cell patch clamp studies confirmed knockdown of SNAP-23 significantly decreased the apamin sensitive, KCa2.3 current. Using standard biotinylation/stripping methods, we demonstrate shRNA mediated knockdown of SNAP-23 inhibits recycling of KCa2.3 following endocytosis, whereas scrambled shRNA had no effect. Finally, using biotin ligase acceptor peptide (BLAP)-tagged KCa2.3, coupled with ER-resident biotin ligase (BirA), channels could be biotinylated in the ER after which we evaluated their rate of insertion into the PM following Golgi exit. We demonstrate knockdown of SNAP-23 significantly slows the rate of Golgi to PM delivery of KCa2.3. The inhibition of both recycling and PM delivery of newly synthesized KCa2.3 channels likely accounts for the decreased PM expression observed following knockdown of these SNARE proteins. In total, our results suggest insertion of KCa2.3 into the PM depends upon the SNARE proteins, Syntaxin-4 and SNAP-23.
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Stermann T, Menzel F, Weidlich C, Jeruschke K, Weiss J, Altenhofen D, Benninghoff T, Pujol A, Bosch F, Rustenbeck I, Ouwens DM, Thoresen GH, de Wendt C, Lebek S, Schallschmidt T, Kragl M, Lammert E, Chadt A, Al-Hasani H. Deletion of the RabGAP TBC1D1 Leads to Enhanced Insulin Secretion and Fatty Acid Oxidation in Islets From Male Mice. Endocrinology 2018; 159:1748-1761. [PMID: 29481597 DOI: 10.1210/en.2018-00087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 01/26/2018] [Indexed: 01/24/2023]
Abstract
The Rab guanosine triphosphatase-activating protein (RabGAP) TBC1D1 has been shown to be a key regulator of glucose and lipid metabolism in skeletal muscle. Its function in pancreatic islets, however, is not yet fully understood. Here, we aimed to clarify the specific impact of TBC1D1 on insulin secretion and substrate use in pancreatic islets. We analyzed the dynamics of glucose-stimulated insulin secretion (GSIS) and lipid metabolism in isolated islets from Tbc1d1-deficient (D1KO) mice. To further investigate the underlying cellular mechanisms, we conducted pharmacological studies in these islets. In addition, we determined morphology and number of both pancreatic islets and insulin vesicles in β-cells using light and transmission electron microscopy. Isolated pancreatic islets from D1KO mice exhibited substantially increased GSIS compared with wild-type (WT) controls. This was attributed to both enhanced first and second phase of insulin secretion, and this enhanced secretion persisted during repetitive glucose stimuli. Studies with sulfonylureas or KCl in isolated islets demonstrated that TBC1D1 exerts its function via a signaling pathway at the level of membrane depolarization. In line, ultrastructural analysis of isolated pancreatic islets revealed both higher insulin-granule density and number of docked granules in β-cells from D1KO mice compared with WT controls. Like in skeletal muscle, lipid use in isolated islets was enhanced upon D1KO, presumably as a result of a higher mitochondrial fission rate and/or higher mitochondrial activity. Our results clearly demonstrate a dual role of TBC1D1 in controlling substrate metabolism of the pancreatic islet.
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Affiliation(s)
- Torben Stermann
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Franziska Menzel
- German Institute for Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Carmen Weidlich
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
| | - Kay Jeruschke
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
| | - Jürgen Weiss
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
| | - Delsi Altenhofen
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Tim Benninghoff
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Anna Pujol
- Center of Animal Biotechnology and Gene Therapy, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Fatima Bosch
- Center of Animal Biotechnology and Gene Therapy, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technical University Braunschweig, Braunschweig, Germany
| | - D Margriet Ouwens
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
| | - G Hege Thoresen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | - Christian de Wendt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Sandra Lebek
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Tanja Schallschmidt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Martin Kragl
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Eckhard Lammert
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Alexandra Chadt
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Medical Faculty, Duesseldorf, Germany
- German Center for Diabetes Research, Duesseldorf, Germany
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Laloux T, Junqueira B, Maistriaux LC, Ahmed J, Jurkiewicz A, Chaumont F. Plant and Mammal Aquaporins: Same but Different. Int J Mol Sci 2018; 19:E521. [PMID: 29419811 PMCID: PMC5855743 DOI: 10.3390/ijms19020521] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 02/06/2023] Open
Abstract
Aquaporins (AQPs) constitute an ancient and diverse protein family present in all living organisms, indicating a common ancient ancestor. However, during evolution, these organisms appear and evolve differently, leading to different cell organizations and physiological processes. Amongst the eukaryotes, an important distinction between plants and animals is evident, the most conspicuous difference being that plants are sessile organisms facing ever-changing environmental conditions. In addition, plants are mostly autotrophic, being able to synthesize carbohydrates molecules from the carbon dioxide in the air during the process of photosynthesis, using sunlight as an energy source. It is therefore interesting to analyze how, in these different contexts specific to both kingdoms of life, AQP function and regulation evolved. This review aims at highlighting similarities and differences between plant and mammal AQPs. Emphasis is given to the comparison of isoform numbers, their substrate selectivity, the regulation of the subcellular localization, and the channel activity.
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Affiliation(s)
- Timothée Laloux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Bruna Junqueira
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Laurie C Maistriaux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Jahed Ahmed
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Agnieszka Jurkiewicz
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - François Chaumont
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
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Kuo PC, Yang CJ, Lee YC, Chen PC, Liu YC, Wu SN. The comprehensive electrophysiological study of curcuminoids on delayed-rectifier K + currents in insulin-secreting cells. Eur J Pharmacol 2018; 819:233-241. [DOI: 10.1016/j.ejphar.2017.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 12/16/2022]
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Lunati ME, Bedeschi MF, Resi V, Grancini V, Palmieri E, Salera S, Lalatta F, Pugliese G, Orsi E. Impaired glucose metabolism in subjects with the Williams-Beuren syndrome: A five-year follow-up cohort study. PLoS One 2017; 12:e0185371. [PMID: 29053727 PMCID: PMC5650138 DOI: 10.1371/journal.pone.0185371] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Indexed: 01/20/2023] Open
Abstract
Objective The Williams-Beuren syndrome (WS) is associated with impaired glucose metabolism (IGM) early in adulthood. However, the pathophysiology of IGM remains poorly defined, due to the lack of longitudinal studies investigating the contribution of β-cell dysfunction and impaired insulin sensitivity. This study aimed at assessing incidence of IGM and the underlying mechanisms in WS adults. Methods This observational, longitudinal (5-year), cohort study enrolled thirty-one consecutive WS subjects attending a tertiary referral center. An oral glucose tolerance test (OGTT) was performed yearly and used to classify patients as normal or IGM, including impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and diabetes mellitus (DM), and to calculate surrogate measures of insulin secretion and/or sensitivity. Results IGM patients were 18 (58.1%, three DM) at baseline and 19 (61.3%, five DM) at end-of-follow-up. However, 13 individuals changed category of glucose homeostasis in both directions during follow-up (8 progressors, 5 regressors) and 18 did not (8 non-progressors, 10 non-regressors). New cases of IGM and DM were 11.1 and 2.53 per 100 persons-year, respectively, and were treated non-pharmacologically. In the whole cohort and, to a higher extent, in progressors, indices of early-phase insulin secretion and insulin sensitivity decreased significantly from baseline to end-of-follow-up, with concurrent reduction of the oral disposition index and insulin secretion-sensitivity index-2 (ISSI-2), compensating insulin secretion for the level of insulin resistance. No baseline measure independently predicted progression, which correlated with change from baseline in ISSI-2. Compared with patients with normal glucose homeostasis, IGT subjects had impaired insulin sensitivity, whereas insulin secretion was reduced only in those with IFG+IGT or DM. Conclusions IGM incidence is high in young adults with WS, suggesting the need of early screening and timed intervention. As in classical type 2 diabetes, impaired insulin sensitivity and β-cell dysfunction contribute, in this sequence, to progression to IGM and DM.
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Affiliation(s)
- Maria Elena Lunati
- Diabetes Service, Unit of Endocrinology and Metabolic Diseases, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, and Department of Medical Sciences, University of Milan, Milan, Italy
| | - Maria Francesca Bedeschi
- Unit of Medical Genetics, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, Milan, Italy
| | - Veronica Resi
- Diabetes Service, Unit of Endocrinology and Metabolic Diseases, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, and Department of Medical Sciences, University of Milan, Milan, Italy
| | - Valeria Grancini
- Diabetes Service, Unit of Endocrinology and Metabolic Diseases, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, and Department of Medical Sciences, University of Milan, Milan, Italy
| | - Eva Palmieri
- Diabetes Service, Unit of Endocrinology and Metabolic Diseases, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, and Department of Medical Sciences, University of Milan, Milan, Italy
| | - Simona Salera
- Direzione Sanitaria di Presidio, “Cà Granda—Ospedale Maggiore Policlinico” Foundation, Milan, Italy
| | - Faustina Lalatta
- Unit of Medical Genetics, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, Milan, Italy
| | - Giuseppe Pugliese
- Diabetes Unit, Sant’Andrea Hospital, and Department of Clinical and Molecular Medicine, “La Sapienza” University, Rome, Italy
| | - Emanuela Orsi
- Diabetes Service, Unit of Endocrinology and Metabolic Diseases, IRCCS “Cà Granda—Ospedale Maggiore Policlinico” Foundation, and Department of Medical Sciences, University of Milan, Milan, Italy
- * E-mail:
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13
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Velasco M, Díaz-García CM, Larqué C, Hiriart M. Modulation of Ionic Channels and Insulin Secretion by Drugs and Hormones in Pancreatic Beta Cells. Mol Pharmacol 2016; 90:341-57. [PMID: 27436126 DOI: 10.1124/mol.116.103861] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/18/2016] [Indexed: 12/11/2022] Open
Abstract
Pancreatic beta cells, unique cells that secrete insulin in response to an increase in glucose levels, play a significant role in glucose homeostasis. Glucose-stimulated insulin secretion (GSIS) in pancreatic beta cells has been extensively explored. In this mechanism, glucose enters the cells and subsequently the metabolic cycle. During this process, the ATP/ADP ratio increases, leading to ATP-sensitive potassium (KATP) channel closure, which initiates depolarization that is also dependent on the activity of TRP nonselective ion channels. Depolarization leads to the opening of voltage-gated Na(+) channels (Nav) and subsequently voltage-dependent Ca(2+) channels (Cav). The increase in intracellular Ca(2+) triggers the exocytosis of insulin-containing vesicles. Thus, electrical activity of pancreatic beta cells plays a central role in GSIS. Moreover, many growth factors, incretins, neurotransmitters, and hormones can modulate GSIS, and the channels that participate in GSIS are highly regulated. In this review, we focus on the principal ionic channels (KATP, Nav, and Cav channels) involved in GSIS and how classic and new proteins, hormones, and drugs regulate it. Moreover, we also discuss advances on how metabolic disorders such as metabolic syndrome and diabetes mellitus change channel activity leading to changes in insulin secretion.
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Affiliation(s)
- Myrian Velasco
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Manlio Díaz-García
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Larqué
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Marcia Hiriart
- Department of Neurodevelopment and Physiology, Neuroscience Division, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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15
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Liu M, Zhang H, Zhang Q, Huang C, Shi X. Syntaxin 1A mediates isoflurane but not hypoxia preconditioning-induced alleviation of hypoxia-reoxygenation injury in rat cardiomyocytes. Am J Transl Res 2015; 7:1883-1895. [PMID: 26692932 PMCID: PMC4656765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/11/2015] [Indexed: 06/05/2023]
Abstract
Preconditioning with ischemia/hypoxia (IPC/HPC) or clinically available volatile anesthetics such as isoflurane (Iso-PC) could activate cardioprotective signaling pathways, thereby reducing myocardial ischemia/reperfusion (IR) injury. However, their molecular targets remain elusive. We herein investigated the roles of syntaxin 1A (Stx-1A) in cardiomyocyte protection induced by HPC and Iso-PC. Both in vivo myocardial IR model and in vitro cardiomyocyte hypoxia/reoxygenation (HR) model were used to test the effects of IR/HR, IPC/HPC and Iso-PC on Stx-1A protein expression. Stx-1A knockdown and overexpression in cardiomyocytes were achieved by adenovirus infection to define the relationship between Stx-1A levels and IPC/Iso-PC-induced cardioprotection. Cardiac troponin T (cTnT), cell apoptosis rate, and cell viability were introduced as indicators for cardiomyocyte HR injury. Changes of cardioprotective signaling pathways activities including PI3K/AKT/GSK3β, ERK1/2, STAT3 and PKC were also detected using Western blot. Rat cardiomyocyte Stx-1A was upregulated 4 hours after IR or HR. IPC/HPC as well as Iso-PC further increased Stx-1A expression compared with IR/HR. Stx-1A knockdown was accompanied with more cell apoptosis and decreased cell viability while overexpression of Stx-1A seemed cardioprotective. Iso-PC induced decrease in cell apoptosis and increase in cell viability but not HPC-induced cardioprotection was reversed by Stx-1A shRNA transfection. No difference in cell apoptosis or cell viability was found before and after Stx-1A overexpression in each group. Moreover, Stx-1A knockdown were accompanied with increased PI3K/AKT/GSK3β activities irrespective of the treatments. Stx-1A is cardioprotective and a potential target of isoflurane induced cardioprotection. Further studies are needed to test whether stx-1A is regulated by AKT/GSK3β signaling.
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Affiliation(s)
- Meng Liu
- Department of Anesthesiology, Changzheng Hospital Affiliated to Second Military Medical UniversityShanghai 200003, China
- Department of Anesthesiology, 401 Hospital of PLAQingdao 266071, China
| | - Hao Zhang
- Department of Anesthesiology, Second Artillery General Hospital PLABeijing 100088, China
| | - Qingqing Zhang
- Department of Anesthesiology, Changzheng Hospital Affiliated to Second Military Medical UniversityShanghai 200003, China
| | - Caiguo Huang
- Department of Biochemistry and Molecular Biology, College of Basic Medicine, Second Military Medical UniversityShanghai 200433, China
| | - Xueyin Shi
- Department of Anesthesiology, Changzheng Hospital Affiliated to Second Military Medical UniversityShanghai 200003, China
- Department of Anesthesiology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of MedicineShanghai 200092, China
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16
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The role of protein-protein interactions in the intracellular traffic of the potassium channels TASK-1 and TASK-3. Pflugers Arch 2015; 467:1105-20. [PMID: 25559843 DOI: 10.1007/s00424-014-1672-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
Abstract
The intracellular transport of membrane proteins is controlled by trafficking signals: Short peptide motifs that mediate the contact with COPI, COPII or various clathrin-associated coat proteins. In addition, many membrane proteins interact with accessory proteins that are involved in the sorting of these proteins to different intracellular compartments. In the K2P channels, TASK-1 and TASK-3, the influence of protein-protein interactions on sorting decisions has been studied in some detail. Both TASK paralogues interact with the adaptor protein 14-3-3; TASK-1 interacts, in addition, with the adaptor protein p11 (S100A10) and the endosomal SNARE protein syntaxin-8. The role of these interacting proteins in controlling the intracellular traffic of the channels and the underlying molecular mechanisms are summarised in this review. In the case of 14-3-3, the interacting protein masks a retention signal in the C-terminus of the channel; in the case of p11, the interacting protein carries a retention signal that localises the channel to the endoplasmic reticulum; and in the case of syntaxin-8, the interacting protein carries an endocytosis signal that complements an endocytosis signal of the channel. These examples illustrate some of the mechanisms by which interacting proteins may determine the itinerary of a membrane protein within a cell and suggest that the intracellular traffic of membrane proteins may be adapted to the specific functions of that protein by multiple protein-protein interactions.
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17
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Renigunta V, Fischer T, Zuzarte M, Kling S, Zou X, Siebert K, Limberg MM, Rinné S, Decher N, Schlichthörl G, Daut J. Cooperative endocytosis of the endosomal SNARE protein syntaxin-8 and the potassium channel TASK-1. Mol Biol Cell 2014; 25:1877-91. [PMID: 24743596 PMCID: PMC4055267 DOI: 10.1091/mbc.e13-10-0592] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
SNARE proteins can have functions unrelated to membrane fusion. The unassembled form of the SNARE protein syntaxin-8 interacts with the K+ channel TASK-1; both proteins are internalized via clathrin-mediated endocytosis in a cooperative manner. This is a novel mechanism for the control of endocytosis by cargo proteins. The endosomal SNARE protein syntaxin-8 interacts with the acid-sensitive potassium channel TASK-1. The functional relevance of this interaction was studied by heterologous expression of these proteins (and mutants thereof) in Xenopus oocytes and in mammalian cell lines. Coexpression of syntaxin-8 caused a fourfold reduction in TASK-1 current, a corresponding reduction in the expression of TASK-1 at the cell surface, and a marked increase in the rate of endocytosis of the channel. TASK-1 and syntaxin-8 colocalized in the early endosomal compartment, as indicated by the endosomal markers 2xFYVE and rab5. The stimulatory effect of the SNARE protein on the endocytosis of the channel was abolished when both an endocytosis signal in TASK-1 and an endocytosis signal in syntaxin-8 were mutated. A syntaxin-8 mutant that cannot assemble with other SNARE proteins had virtually the same effect as wild-type syntaxin-8. Total internal reflection fluorescence microscopy showed formation and endocytosis of vesicles containing fluorescence-tagged clathrin, TASK-1, and/or syntaxin-8. Our results suggest that the unassembled form of syntaxin-8 and the potassium channel TASK-1 are internalized via clathrin-mediated endocytosis in a cooperative manner. This implies that syntaxin-8 regulates the endocytosis of TASK-1. Our study supports the idea that endosomal SNARE proteins can have functions unrelated to membrane fusion.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Thomas Fischer
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Marylou Zuzarte
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Stefan Kling
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Xinle Zou
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Kai Siebert
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Maren M Limberg
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Günter Schlichthörl
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Jürgen Daut
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
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18
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Martin GM, Chen PC, Devaraneni P, Shyng SL. Pharmacological rescue of trafficking-impaired ATP-sensitive potassium channels. Front Physiol 2013; 4:386. [PMID: 24399968 PMCID: PMC3870925 DOI: 10.3389/fphys.2013.00386] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/09/2013] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (KATP) channels link cell metabolism to membrane excitability and are involved in a wide range of physiological processes including hormone secretion, control of vascular tone, and protection of cardiac and neuronal cells against ischemic injuries. In pancreatic β-cells, KATP channels play a key role in glucose-stimulated insulin secretion, and gain or loss of channel function results in neonatal diabetes or congenital hyperinsulinism, respectively. The β-cell KATP channel is formed by co-assembly of four Kir6.2 inwardly rectifying potassium channel subunits encoded by KCNJ11 and four sulfonylurea receptor 1 subunits encoded by ABCC8. Many mutations in ABCC8 or KCNJ11 cause loss of channel function, thus, congenital hyperinsulinism by hampering channel biogenesis and hence trafficking to the cell surface. The trafficking defects caused by a subset of these mutations can be corrected by sulfonylureas, KATP channel antagonists that have long been used to treat type 2 diabetes. More recently, carbamazepine, an anticonvulsant that is thought to target primarily voltage-gated sodium channels has been shown to correct KATP channel trafficking defects. This article reviews studies to date aimed at understanding the mechanisms by which mutations impair channel biogenesis and trafficking and the mechanisms by which pharmacological ligands overcome channel trafficking defects. Insight into channel structure-function relationships and therapeutic implications from these studies are discussed.
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Affiliation(s)
- Gregory M Martin
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Pei-Chun Chen
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Prasanna Devaraneni
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
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19
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Chen PC, Olson EM, Zhou Q, Kryukova Y, Sampson HM, Thomas DY, Shyng SL. Carbamazepine as a novel small molecule corrector of trafficking-impaired ATP-sensitive potassium channels identified in congenital hyperinsulinism. J Biol Chem 2013; 288:20942-20954. [PMID: 23744072 DOI: 10.1074/jbc.m113.470948] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-sensitive potassium (KATP) channels consisting of sulfonylurea receptor 1 (SUR1) and the potassium channel Kir6.2 play a key role in insulin secretion by coupling metabolic signals to β-cell membrane potential. Mutations in SUR1 and Kir6.2 that impair channel trafficking to the cell surface lead to loss of channel function and congenital hyperinsulinism. We report that carbamazepine, an anticonvulsant, corrects the trafficking defects of mutant KATP channels previously identified in congenital hyperinsulinism. Strikingly, of the 19 SUR1 mutations examined, only those located in the first transmembrane domain of SUR1 responded to the drug. We show that unlike that reported for several other protein misfolding diseases, carbamazepine did not correct KATP channel trafficking defects by activating autophagy; rather, it directly improved the biogenesis efficiency of mutant channels along the secretory pathway. In addition to its effect on channel trafficking, carbamazepine also inhibited KATP channel activity. Upon subsequent removal of carbamazepine, however, the function of rescued channels was recovered. Importantly, combination of the KATP channel opener diazoxide and carbamazepine led to enhanced mutant channel function without carbamazepine washout. The corrector effect of carbamazepine on mutant KATP channels was also demonstrated in rat and human β-cells with an accompanying increase in channel activity. Our findings identify carbamazepine as a novel small molecule corrector that may be used to restore KATP channel expression and function in a subset of congenital hyperinsulinism patients.
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Affiliation(s)
- Pei-Chun Chen
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Erik M Olson
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Qing Zhou
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Yelena Kryukova
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Heidi M Sampson
- Department of Biochemistry, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - David Y Thomas
- Department of Biochemistry, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and.
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20
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Kefaloyianni E, Lyssand JS, Moreno C, Delaroche D, Hong M, Fenyö D, Mobbs CV, Neubert TA, Coetzee WA. Comparative proteomic analysis of the ATP-sensitive K+ channel complex in different tissue types. Proteomics 2013. [PMID: 23197389 DOI: 10.1002/pmic.201200324] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ATP-sensitive K(+) (K(ATP)) channels are expressed ubiquitously, but have diverse roles in various organs and cells. Their diversity can partly be explained by distinct tissue-specific compositions of four copies of the pore-forming inward rectifier potassium channel subunits (Kir6.1 and/or Kir6.2) and four regulatory sulfonylurea receptor subunits (SUR1 and/or SUR2). Channel function and/or subcellular localization also can be modified by the proteins with which they transiently or permanently interact to generate even more diversity. We performed a quantitative proteomic analysis of K(ATP) channel complexes in the heart, endothelium, insulin-secreting min6 cells (pancreatic β-cell like), and the hypothalamus to identify proteins with which they interact in different tissues. Glycolysis is an overrepresented pathway in identified proteins of the heart, min6 cells, and the endothelium. Proteins with other energy metabolic functions were identified in the hypothalamic samples. These data suggest that the metabolo-electrical coupling conferred by K(ATP) channels is conferred partly by proteins with which they interact. A large number of identified cytoskeletal and trafficking proteins suggests endocytic recycling may help control K(ATP) channel surface density and/or subcellular localization. Overall, our data demonstrate that K(ATP) channels in different tissues may assemble with proteins having common functions, but that tissue-specific complex organization also occurs.
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21
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Neuroprotective role of ATP-sensitive potassium channels in cerebral ischemia. Acta Pharmacol Sin 2013; 34:24-32. [PMID: 23123646 DOI: 10.1038/aps.2012.138] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are weak, inward rectifiers that couple metabolic status to cell membrane electrical activity, thus modulating many cellular functions. An increase in the ADP/ATP ratio opens K(ATP) channels, leading to membrane hyperpolarization. K(ATP) channels are ubiquitously expressed in neurons located in different regions of the brain, including the hippocampus and cortex. Brief hypoxia triggers membrane hyperpolarization in these central neurons. In vivo animal studies confirmed that knocking out the Kir6.2 subunit of the K(ATP) channels increases ischemic infarction, and overexpression of the Kir6.2 subunit reduces neuronal injury from ischemic insults. These findings provide the basis for a practical strategy whereby activation of endogenous K(ATP) channels reduces cellular damage resulting from cerebral ischemic stroke. K(ATP) channel modulators may prove to be clinically useful as part of a combination therapy for stroke management in the future.
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22
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Martens MA, Seyfer DL, Andridge RR, Foster JEA, Chowdhury M, McClure KE, Coury DL. Parent report of antidepressant, anxiolytic, and antipsychotic medication use in individuals with Williams syndrome: effectiveness and adverse effects. RESEARCH IN DEVELOPMENTAL DISABILITIES 2012; 33:2106-2121. [PMID: 22776821 DOI: 10.1016/j.ridd.2012.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/11/2012] [Accepted: 06/11/2012] [Indexed: 06/01/2023]
Abstract
Williams syndrome (WS) is a neurodevelopmental genetic disorder characterized in part by anxiety and behavioral difficulties. We examine the effectiveness and adverse effects of antidepressant, anxiolytic, and antipsychotic medications in individuals with WS. A total of 513 parents/caregivers completed a survey of psychotropic medication usage regarding their child or adult with WS. Twenty-four percent (24%) of the individuals had been prescribed an SSRI medication, while 12% had been prescribed another type of antidepressant or anxiolytic. Overall, 81% of respondents indicated that SSRI medications were either "Helpful" or "Somewhat Helpful", with paroxetine reported to be the least helpful. Sixty-four percent (64%) of survey participants reported that non-SSRI antidepressants and anxiolytics were either "Helpful" or "Somewhat Helpful" in treating symptoms of anxiety. Side effects for the antidepressants and anxiolytics were typically neurological in nature. Ten percent (10%) of the survey participants reported taking an antipsychotic medication, with risperidone and quetiapine described as more helpful than aripiprazole. Medication effectiveness may be related to the impact on serotonin levels. These findings call for further studies of medication usage in WS in order to improve their quality of life.
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Affiliation(s)
- Marilee A Martens
- The Nisonger Center, The Ohio State University, Columbus, OH 43210, USA.
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23
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Wang F, Olson EM, Shyng SL. Role of Derlin-1 protein in proteostasis regulation of ATP-sensitive potassium channels. J Biol Chem 2012; 287:10482-10493. [PMID: 22311976 DOI: 10.1074/jbc.m111.312223] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels composed of sulfonylurea receptor 1 (SUR1) and Kir6.2 regulate insulin secretion by linking glucose metabolism with membrane potential. The number of K(ATP) channels in the plasma membrane affects the sensitivity of β-cells to glucose. Aberrant surface channel expression leads to insulin secretion disease. Previously, we have shown that K(ATP) channel proteins undergo endoplasmic reticulum (ER)-associated degradation (ERAD) via the ubiquitin-proteasome pathway, and inhibition of proteasome function results in an increase in channel surface expression. Here, we investigated whether Derlin-1, a protein involved in retrotranslocation of misfolded or misassembled proteins across the ER membrane for degradation by cytosolic proteasomes, plays a role in ERAD and, in turn, biogenesis efficiency of K(ATP) channels. We show that both SUR1 and Kir6.2 form a complex with Derlin-1 and an associated AAA-ATPase, p97. Overexpression of Derlin-1 led to a decrease in the biogenesis efficiency and surface expression of K(ATP) channels. Conversely, knockdown of Derlin-1 by RNA interference resulted in increased processing of SUR1 and a corresponding increase in surface expression of K(ATP) channels. Importantly, knockdown of Derlin-1 increased the abundance of disease-causing misfolded SUR1 or Kir6.2 proteins and even partially rescued surface expression in a mutant channel. We conclude that Derlin-1, by being involved in ERAD of SUR1 and Kir6.2, has a role in modulating the biogenesis efficiency and surface expression of K(ATP) channels. The results suggest that physiological or pathological changes in Derlin-1 expression levels may affect glucose-stimulated insulin secretion by altering surface expression of K(ATP) channels.
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Affiliation(s)
- Fang Wang
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Erik M Olson
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239.
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Kefaloyianni E, Bao L, Rindler MJ, Hong M, Patel T, Taskin E, Coetzee WA. Measuring and evaluating the role of ATP-sensitive K+ channels in cardiac muscle. J Mol Cell Cardiol 2012; 52:596-607. [PMID: 22245446 DOI: 10.1016/j.yjmcc.2011.12.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 12/06/2011] [Accepted: 12/23/2011] [Indexed: 11/27/2022]
Abstract
Since ion channels move electrical charge during their activity, they have traditionally been studied using electrophysiological approaches. This was sometimes combined with mathematical models, for example with the description of the ionic mechanisms underlying the initiation and propagation of action potentials in the squid giant axon by Hodgkin and Huxley. The methods for studying ion channels also have strong roots in protein chemistry (limited proteolysis, the use of antibodies, etc.). The advent of the molecular cloning and the identification of genes coding for specific ion channel subunits in the late 1980s introduced a multitude of new techniques with which to study ion channels and the field has been rapidly expanding ever since (e.g. antibody development against specific peptide sequences, mutagenesis, the use of gene targeting in animal models, determination of their protein structures) and new methods are still in development. This review focuses on techniques commonly employed to examine ion channel function in an electrophysiological laboratory. The focus is on the K(ATP) channel, but many of the techniques described are also used to study other ion channels.
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Quan Y, Barszczyk A, Feng ZP, Sun HS. Current understanding of K ATP channels in neonatal diseases: focus on insulin secretion disorders. Acta Pharmacol Sin 2011; 32:765-80. [PMID: 21602835 PMCID: PMC4009965 DOI: 10.1038/aps.2011.57] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/13/2011] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are cell metabolic sensors that couple cell metabolic status to electric activity, thus regulating many cellular functions. In pancreatic beta cells, K(ATP) channels modulate insulin secretion in response to fluctuations in plasma glucose level, and play an important role in glucose homeostasis. Recent studies show that gain-of-function and loss-of-function mutations in K(ATP) channel subunits cause neonatal diabetes mellitus and congenital hyperinsulinism respectively. These findings lead to significant changes in the diagnosis and treatment for neonatal insulin secretion disorders. This review describes the physiological and pathophysiological functions of K(ATP) channels in glucose homeostasis, their specific roles in neonatal diabetes mellitus and congenital hyperinsulinism, as well as future perspectives of K(ATP) channels in neonatal diseases.
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Affiliation(s)
- Yi Quan
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Andrew Barszczyk
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Zhong-ping Feng
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Hong-shuo Sun
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Surgery, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
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