1
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Totland MZ, Knudsen LM, Rasmussen NL, Omori Y, Sørensen V, Elster VCW, Stenersen JM, Larsen M, Jensen CL, Zickfeldt Lade AA, Bruusgaard E, Basing S, Kryeziu K, Brech A, Aasen T, Lothe RA, Leithe E. The E3 ubiquitin ligase ITCH negatively regulates intercellular communication via gap junctions by targeting connexin43 for lysosomal degradation. Cell Mol Life Sci 2024; 81:171. [PMID: 38597989 PMCID: PMC11006747 DOI: 10.1007/s00018-024-05165-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 01/27/2024] [Accepted: 02/05/2024] [Indexed: 04/11/2024]
Abstract
Intercellular communication via gap junctions has a fundamental role in regulating cell growth and tissue homeostasis, and its dysregulation may be involved in cancer development and radio- and chemotherapy resistance. Connexin43 (Cx43) is the most ubiquitously expressed gap junction channel protein in human tissues. Emerging evidence indicates that dysregulation of the sorting of Cx43 to lysosomes is important in mediating the loss of Cx43-based gap junctions in cancer cells. However, the molecular basis underlying this process is currently poorly understood. Here, we identified the E3 ubiquitin ligase ITCH as a novel regulator of intercellular communication via gap junctions. We demonstrate that ITCH promotes loss of gap junctions in cervical cancer cells, which is associated with increased degradation of Cx43 in lysosomes. The data further indicate that ITCH interacts with and regulates Cx43 ubiquitination and that the ITCH-induced loss of Cx43-based gap junctions requires its catalytic HECT (homologous to E6-AP C-terminus) domain. The data also suggest that the ability of ITCH to efficiently promote loss of Cx43-based gap junctions and degradation of Cx43 depends on a functional PY (PPXY) motif in the C-terminal tail of Cx43. Together, these data provide new insights into the molecular basis underlying the degradation of Cx43 and have implications for the understanding of how intercellular communication via gap junctions is lost during cancer development.
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Affiliation(s)
- Max Zachrisson Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Lars Mørland Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Nikoline Lander Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Centre for Molecular Medicine Norway, Faculty of Medicine, Oslo, Norway
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita, 010-8543, Japan
| | - Vigdis Sørensen
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, 0379, Norway
| | - Vilde C Wivestad Elster
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Jakob Mørkved Stenersen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Mathias Larsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Caroline Lunder Jensen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Anna A Zickfeldt Lade
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Emilie Bruusgaard
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Sebastian Basing
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Kushtrim Kryeziu
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
| | - Andreas Brech
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, 0379, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, Oslo, 0316, Norway
| | - Trond Aasen
- Patologia Molecular Translacional, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain
| | - Ragnhild A Lothe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, Oslo, 0316, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, 0317, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, NO-0424, Norway
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2
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Yang F, Zhang XL, Liu HH, Qian LL, Wang RX. Post translational modifications of connexin 43 in ventricular arrhythmias after myocardial infarction. Mol Biol Rep 2024; 51:329. [PMID: 38393658 DOI: 10.1007/s11033-024-09290-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
Ventricular arrhythmias are the leading cause of sudden cardiac death in patients after myocardial infarction (MI). Connexin43 (Cx43) is the most important gap junction channel-forming protein in cardiomyocytes. Dysfunction of Cx43 contributes to impaired myocardial conduction and the development of ventricular arrhythmias. Following an MI, Cx43 undergoes structural remodeling, including expression abnormalities, and redistribution. These alterations detrimentally affect intercellular communication and electrical conduction within the myocardium, thereby increasing the susceptibility to post-infarction ventricular arrhythmias. Emerging evidence suggests that post-translational modifications play essential roles in Cx43 regulation after MI. Therefore, Cx43-targeted management has the potential to be a promising protective strategy for the prevention and treatment of post infarction ventricular arrhythmias. In this article, we primarily reviewed the regulatory mechanisms of Cx43 mediated post-translational modifications on post-infarction ventricular arrhythmias. Furthermore, Cx43-targeted therapy have also been discussed, providing insights into an innovative treatment strategy for ventricular arrhythmias after MI.
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Affiliation(s)
- Fan Yang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Xiao-Lu Zhang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Huan-Huan Liu
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
- Wuxi School of Medicine, Jiangnan University, Wuxi, China.
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3
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Huang Y, Wei C, Li P, Shao Y, Wang M, Wang F, Niu G, Sun K, Zhang Q, Gou Z, Yan X. FGF21 protects against doxorubicin-induced cardiotoxicity by inhibiting connexin 43 ubiquitination. Free Radic Biol Med 2023; 208:748-758. [PMID: 37774805 DOI: 10.1016/j.freeradbiomed.2023.09.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 10/01/2023]
Abstract
BACKGROUND Fibroblast growth factor 21 (FGF21) regulates glycolipid metabolism and insulin homeostasis and acts as a cardioprotective factor by protecting against myocardial ischemia/reperfusion injury, hypertension, and vascular dysfunction. FGF21 has been reported to prevent Doxorubicin (Dox)-induced cardiotoxicity, and the related signaling pathway is worthy of further study. Connexin43 (Cx43) protein was reduced by Dox treatment, especially low phosphorylated form of Cx43. Thus the aim of study is to explore the protection effect of FGF21 on Dox induced cardiotoxicity by improving the expression of Cx43 and the involved signaling pathway. METHODS AND RESULTS FGF21 inhibited apoptosis in Dox-treated mice and cardiomyocytes. FGF21 increased the levels of connexin43 phosphorylated at serine (S) 282 (p-Cx43 S282) and total Cx43 to inhibit Dox-induced apoptosis. By RNA sequencing, we found that deubiquitinase monocyte chemoattractant protein-induced protein 1 (MCPIP1) expression was increased by FGF21. We further found that FGF21 induced the phosphorylation of fibroblast growth factor receptor 1 (FGFR1), extracellular signal-regulated kinase 1 and 2 (Erk1/2), and Elk. Phosphorylated Elk translocated to the nucleus and increased the expression of MCPIP1. Then, MCPIP1 bound neural precursor cell expressed developmentally downregulated protein 4 (Nedd4), an E3 ubiquitination ligase, as shown by co-immunoprecipitation (Co-IP), and suppressed Cx43 ubiquitination and degradation, competitively inhibiting the binding of Cx43 with Nedd4. Thus Nedd4 could not bind and ubiquitinate Cx43, leading to the up-regulation of Cx43 and phosphorylation of Cx43 at S282. CONCLUSIONS FGF21 inhibited the effects of Dox on cardiomyocytes by elevating the phosphorylation of Cx43 at S282 and total Cx43 expression. This study suggests a previously unknown mechanism for the FGF21-mediated enhancement of cardiomyocyte survival and provides an effective approach to protect against the adverse cardiac effects of Dox.
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Affiliation(s)
- Ying Huang
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Chenchen Wei
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Ping Li
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Yaqing Shao
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Min Wang
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Feng Wang
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China; Department of Pharmacology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Guanghao Niu
- Department of Cardiovascular Surgery of the First Affiliated Hospital & Institute for Cardiovascular Science, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Protection, Medical College, Soochow University, Suzhou, Jiangsu, 215000, PR China
| | - Kangyun Sun
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China
| | - Qian Zhang
- Department of Pharmacology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China.
| | - Zhongshan Gou
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China.
| | - Xinxin Yan
- Center for Cardiovascular Disease, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China; Department of Pharmacology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu, 215008, PR China.
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4
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Fisher CG, Falk MM. Endocytosis and Endocytic Motifs across the Connexin Gene Family. Int J Mol Sci 2023; 24:12851. [PMID: 37629031 PMCID: PMC10454166 DOI: 10.3390/ijms241612851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
Proteins fated to be internalized by clathrin-mediated endocytosis require an endocytic motif, where AP-2 or another adaptor protein can bind and recruit clathrin. Tyrosine and di-leucine-based sorting signals are such canonical motifs. Connexin 43 (Cx43) has three canonical tyrosine-based endocytic motifs, two of which have been previously shown to recruit clathrin and mediate its endocytosis. In addition, di-leucine-based motifs have been characterized in the Cx32 C-terminal domain and shown to mediate its endocytosis. Here, we examined the amino acid sequences of all 21 human connexins to identify endocytic motifs across the connexin gene family. We find that although there is limited conservation of endocytic motifs between connexins, 14 of the 21 human connexins contain one or more canonical tyrosine or di-leucine-based endocytic motif in their C-terminal or intracellular loop domain. Three connexins contain non-canonical (modified) di-leucine motifs. However, four connexins (Cx25, Cx26, Cx31, and Cx40.1) do not harbor any recognizable endocytic motif. Interestingly, live cell time-lapse imaging of different GFP-tagged connexins that either contain or do not contain recognizable endocytic motifs readily undergo endocytosis, forming clearly identifiable annular gap junctions when expressed in HeLa cells. How connexins without defined endocytic motifs are endocytosed is currently not known. Our results demonstrate that an array of endocytic motifs exists in the connexin gene family. Further analysis will establish whether the sites we identified in this in silico analysis are legitimate endocytic motifs.
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Affiliation(s)
| | - Matthias M. Falk
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Bethlehem, PA 18015, USA
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5
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Totland MZ, Omori Y, Sørensen V, Kryeziu K, Aasen T, Brech A, Leithe E. Endocytic trafficking of connexins in cancer pathogenesis. Biochim Biophys Acta Mol Basis Dis 2023:166812. [PMID: 37454772 DOI: 10.1016/j.bbadis.2023.166812] [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: 02/06/2023] [Revised: 06/26/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Gap junctions are specialized regions of the plasma membrane containing clusters of channels that provide for the diffusion of ions and small molecules between adjacent cells. A fundamental role of gap junctions is to coordinate the functions of cells in tissues. Cancer pathogenesis is usually associated with loss of intercellular communication mediated by gap junctions, which may affect tumor growth and the response to radio- and chemotherapy. Gap junction channels consist of integral membrane proteins termed connexins. In addition to their canonical roles in cell-cell communication, connexins modulate a range of signal transduction pathways via interactions with proteins such as β-catenin, c-Src, and PTEN. Consequently, connexins can regulate cellular processes such as cell growth, migration, and differentiation through both channel-dependent and independent mechanisms. Gap junctions are dynamic plasma membrane entities, and by modulating the rate at which connexins undergo endocytosis and sorting to lysosomes for degradation, cells rapidly adjust the level of gap junctions in response to alterations in the intracellular or extracellular milieu. Current experimental evidence indicates that aberrant trafficking of connexins in the endocytic system is intrinsically involved in mediating the loss of gap junctions during carcinogenesis. This review highlights the role played by the endocytic system in controlling connexin degradation, and consequently gap junction levels, and discusses how dysregulation of these processes contributes to the loss of gap junctions during cancer development. We also discuss the therapeutic implications of aberrant endocytic trafficking of connexins in cancer cells.
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Affiliation(s)
| | - Yasufumi Omori
- Department of Molecular and Tumour Pathology, Akita University Graduate School of Medicine, Akita, Japan
| | | | | | - Trond Aasen
- Patologia Molecular Translacional, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron, Barcelona, Spain
| | - Andreas Brech
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway; Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway; Section for Physiology and Cell Biology, Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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6
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Nielsen MS, van Opbergen CJM, van Veen TAB, Delmar M. The intercalated disc: a unique organelle for electromechanical synchrony in cardiomyocytes. Physiol Rev 2023; 103:2271-2319. [PMID: 36731030 PMCID: PMC10191137 DOI: 10.1152/physrev.00021.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
The intercalated disc (ID) is a highly specialized structure that connects cardiomyocytes via mechanical and electrical junctions. Although described in some detail by light microscopy in the 19th century, it was in 1966 that electron microscopy images showed that the ID represented apposing cell borders and provided detailed insight into the complex ID nanostructure. Since then, much has been learned about the ID and its molecular composition, and it has become evident that a large number of proteins, not all of them involved in direct cell-to-cell coupling via mechanical or gap junctions, reside at the ID. Furthermore, an increasing number of functional interactions between ID components are emerging, leading to the concept that the ID is not the sum of isolated molecular silos but an interacting molecular complex, an "organelle" where components work in concert to bring about electrical and mechanical synchrony. The aim of the present review is to give a short historical account of the ID's discovery and an updated overview of its composition and organization, followed by a discussion of the physiological implications of the ID architecture and the local intermolecular interactions. The latter will focus on both the importance of normal conduction of cardiac action potentials as well as the impact on the pathophysiology of arrhythmias.
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Affiliation(s)
- Morten S Nielsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Chantal J M van Opbergen
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
| | - Toon A B van Veen
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mario Delmar
- The Leon Charney Division of Cardiology, New York University Grossmann School of Medicine, New York, New York, United States
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7
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Zhang M, Wang ZZ, Chen NH. Connexin 43 Phosphorylation: Implications in Multiple Diseases. Molecules 2023; 28:4914. [PMID: 37446576 DOI: 10.3390/molecules28134914] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Connexin 43 (Cx43) is most widely distributed in mammals, especially in the cardiovascular and nervous systems. Its phosphorylation state has been found to be regulated by the action of more than ten kinases and phosphatases, including mitogen-activated protein kinase/extracellular signaling and regulating kinase signaling. In addition, the phosphorylation status of different phosphorylation sites affects its own synthesis and assembly and the function of the gap junctions (GJs) to varying degrees. The phosphorylation of Cx43 can affect the permeability, electrical conductivity, and gating properties of GJs, thereby having various effects on intercellular communication and affecting physiological or pathological processes in vitro and in vivo. Therefore, clarifying the relationship between Cx43 phosphorylation and specific disease processes will help us better understand the disease. Based on the above clinical and preclinical findings, we present in this review the functional significance of Cx43 phosphorylation in multiple diseases and discuss the potential of Cx43 as a drug target in Cx43-related disease pathophysiology, with an emphasis on the importance of connexin 43 as an emerging therapeutic target in cardiac and neuroprotection.
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Affiliation(s)
- Meng Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
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8
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Huang SN, Pan YT, Zhou YP, Wang XZ, Mei MJ, Yang B, Li D, Zeng WB, Cheng S, Sun JY, Cheng H, Zhao F, Luo MH. Human Cytomegalovirus IE1 Impairs Neuronal Migration by Downregulating Connexin 43. J Virol 2023; 97:e0031323. [PMID: 37097169 PMCID: PMC10231247 DOI: 10.1128/jvi.00313-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/07/2023] [Indexed: 04/26/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a leading cause of congenital birth defects. Though the underlying mechanisms remain poorly characterized, mouse models of congenital CMV infection have demonstrated that the neuronal migration process is damaged. In this study, we evaluated the effects of HCMV infection on connexin 43 (Cx43), a crucial adhesion molecule mediating neuronal migration. We show in multiple cellular models that HCMV infection downregulated Cx43 posttranslationally. Further analysis identified the immediate early protein IE1 as the viral protein responsible for the reduction of Cx43. IE1 was found to bind the Cx43 C terminus and promote Cx43 degradation through the ubiquitin-proteasome pathway. Deletion of the Cx43-binding site in IE1 rendered it incapable of inducing Cx43 degradation. We validated the IE1-induced loss of Cx43 in vivo by introducing IE1 into the fetal mouse brain. Noteworthily, ectopic IE1 expression induced cortical atrophy and neuronal migration defects. Several lines of evidence suggest that these damages result from decreased Cx43, and restoration of Cx43 levels partially rescued IE1-induced interruption of neuronal migration. Taken together, the results of our investigation reveal a novel mechanism of HCMV-induced neural maldevelopment and identify a potential intervention target. IMPORTANCE Congenital CMV (cCMV) infection causes neurological sequelae in newborns. Recent studies of cCMV pathogenesis in animal models reveal ventriculomegaly and cortical atrophy associated with impaired neural progenitor cell (NPC) proliferation and migration. In this study, we investigated the mechanisms underlying these NPC abnormalities. We show that Cx43, a critical adhesion molecule mediating NPC migration, is downregulated by HCMV infection in vitro and HCMV-IE1 in vivo. We provide evidence that IE1 interacts with the C terminus of Cx43 to promote its ubiquitination and consequent degradation through the proteasome. Moreover, we demonstrate that introducing IE1 into mouse fetal brains led to neuronal migration defects, which was associated with Cx43 reduction. Deletion of the Cx43-binding region in IE1 or ectopic expression of Cx43 rescued the IE1-induced migration defects in vivo. Our study provides insight into how cCMV infection impairs neuronal migration and reveals a target for therapeutic interventions.
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Affiliation(s)
- Sheng-Nan Huang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu-Ting Pan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yue-Peng Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy of Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Xian-Zhang Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Meng-Jie Mei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bo Yang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- The Joint Center of Translational Precision Medicine, Guangzhou Institute of Pediatrics, Guangzhou Women and Children Medical Center, Guangzhou, China
| | - Dong Li
- Chinese Institute for Brain Research, Beijing, China
- School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wen-Bo Zeng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Shuang Cheng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jin-Yan Sun
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Han Cheng
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Fei Zhao
- Chinese Institute for Brain Research, Beijing, China
- School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Min-Hua Luo
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy of Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
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9
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Basu I, Li H, Trease AJ, Sorgen PL. Regulation of Cx43 Gap Junction Intercellular Communication by Bruton's Tyrosine Kinase and Interleukin-2-Inducible T-Cell Kinase. Biomolecules 2023; 13:biom13040660. [PMID: 37189407 DOI: 10.3390/biom13040660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/17/2023] Open
Abstract
T and B cell receptor signaling involves the activation of Akt, MAPKs, and PKC as well as an increase in intracellular Ca2+ and calmodulin activation. While these coordinate the rapid turnover of gap junctions, also implicated in this process is Src, which is not activated as part of T and B cell receptor signaling. An in vitro kinase screen identified that Bruton's tyrosine kinase (BTK) and interleukin-2-inducible T-cell kinase (ITK) phosphorylate Cx43. Mass spectroscopy revealed that BTK and ITK phosphorylate Cx43 residues Y247, Y265, and Y313, which are identical to the residues phosphorylated by Src. Overexpression of BTK or ITK in the HEK-293T cells led to increased Cx43 tyrosine phosphorylation as well as decreased gap junction intercellular communication (GJIC) and Cx43 membrane localization. In the lymphocytes, activation of the B cell receptor (Daudi cells) or T cell receptor (Jurkat cells) increased the BTK and ITK activity, respectively. While this led to increased tyrosine phosphorylation of Cx43 and decreased GJIC, the cellular localization of Cx43 changed little. We have previously identified that Pyk2 and Tyk2 also phosphorylate Cx43 at residues Y247, Y265, and Y313 with a similar cellular fate to that of Src. With phosphorylation critical to Cx43 assembly and turnover, and kinase expression varying between different cell types, there would be a need for different kinases to achieve the same regulation of Cx43. The work presented herein suggests that in the immune system, ITK and BTK have the capacity for the tyrosine phosphorylation of Cx43 to alter the gap junction function in a similar manner as Pyk2, Tyk2, and Src.
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Affiliation(s)
- Ishika Basu
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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10
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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11
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Interrogation of Carboxy-Terminus Localized GJA1 Variants Associated with Erythrokeratodermia Variabilis et Progressiva. Int J Mol Sci 2022; 23:ijms23010486. [PMID: 35008913 PMCID: PMC8745721 DOI: 10.3390/ijms23010486] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/17/2021] [Accepted: 12/24/2021] [Indexed: 02/04/2023] Open
Abstract
Although inherited GJA1 (encoding Cx43) gene mutations most often lead to oculodentodigital dysplasia and related disorders, four variants have been linked to erythrokeratodermia variabilis et progressiva (EKVP), a skin disorder characterized by erythematous and hyperkeratotic lesions. While two autosomal-dominant EKVP-linked GJA1 mutations have been shown to lead to augmented hemichannels, the consequence(s) of keratinocytes harboring a de novo P283L variant alone or in combination with a de novo T290N variant remain unknown. Interestingly, these variants reside within or adjacent to a carboxy terminus polypeptide motif that has been shown to be important in regulating the internalization and degradation of Cx43. Cx43-rich rat epidermal keratinocytes (REKs) or Cx43-ablated REKs engineered to express fluorescent protein-tagged P283L and/or T290N variants formed prototypical gap junctions at cell-cell interfaces similar to wildtype Cx43. Dye coupling and dye uptake studies further revealed that each variant or a combination of both variants formed functional gap junction channels, with no evidence of augmented hemichannel function or induction of cell death. Tracking the fate of EKVP-associated variants in the presence of the protein secretion blocker brefeldin A, or an inhibitor of protein synthesis cycloheximide, revealed that P283L or the combination of P283L and T290N variants either significantly extended Cx43 residency on the cell surface of keratinocytes or delayed its degradation. However, caution is needed in concluding that this modest change in the Cx43 life cycle is sufficient to cause EKVP, or whether an additional underlying mechanism or another unidentified gene mutation is contributing to the pathogenesis found in patients. This question will be resolved if further patients are identified where whole exome sequencing reveals a Cx43 P283L variant alone or, in combination with a T290N variant, co-segregates with EKVP across several family generations.
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12
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Sun XH, Xiao HM, Zhang M, Lin ZY, Yang Y, Chen R, Liu PQ, Huang KP, Huang HQ. USP9X deubiquitinates connexin43 to prevent high glucose-induced epithelial-to-mesenchymal transition in NRK-52E cells. Biochem Pharmacol 2021; 188:114562. [PMID: 33857489 DOI: 10.1016/j.bcp.2021.114562] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 01/24/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) plays an important role in diabetic nephropathy (DN). Ubiquitin-specific protease 9X (USP9X/FAM) is closely linked to TGF-β and fibrosis signaling pathway. However, it remains unknown whether USP9X is involved in the process of EMT in DN. Our previous study has shown that connexin 43 (Cx43) activation attenuated the development of diabetic renal tubulointerstitial fibrosis (RIF). Here, we showed that USP9X is a novel negative regulator of EMT and the potential mechanism is related to the deubiquitination and degradation of Cx43. To explore the potential regulatory mechanism of USP9X, the expression and activity of USP9X were studied by CRISPR/Cas9-based synergistic activation mediator (SAM) system, short hairpin RNAs, and selective inhibitor. The following findings were observed: (1) Expression of USP9X was down-regulated in the kidney tissue of db/db diabetic mice; (2) overexpression of USP9X suppressed high glucose (HG)-induced expressions of EMT markers and extra cellular matrix (ECM) in NRK-52E cells; (3) depletion of USP9X further aggravated EMT process and ECM production in NRK-52E cells; (4) USP9X deubiquitinated Cx43 and suppressed its degradation to regulate EMT process; (5) USP9X deubiquitinated Cx43 by directly binding to the C-terminal Tyr286 of Cx43. The current study determined the protective role of USP9X in the process of EMT and the molecular mechanism clarified that the protective effects of USP9X on DN were associated with the deubiquitination of Cx43.
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Affiliation(s)
- Xiao-Hong Sun
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Hai-Ming Xiao
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Meng Zhang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Ze-Yuan Lin
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Yan Yang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Rui Chen
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Pei-Qing Liu
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Kai-Peng Huang
- Phase I Clinical Trial Center, Guangzhou Eighth People's Hospital, Guangzhou Medical University, Guangzhou 510060, China.
| | - He-Qing Huang
- Laboratory of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China.
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13
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Li D, Li L, Chen X, Zhou C, Hao B, Cao Y. Dysregulation of lncRNA-CCRR contributes to brain metastasis of breast cancer by intercellular coupling via regulating connexin 43 expression. J Cell Mol Med 2021; 25:4826-4834. [PMID: 33793070 PMCID: PMC8107087 DOI: 10.1111/jcmm.16455] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/19/2021] [Accepted: 03/01/2021] [Indexed: 01/05/2023] Open
Abstract
Cardiac conduction regulatory RNA (CCRR) is down‐regulated in the pathogenesis of heart failure (HF), which accordingly suppresses cardiac conduction while promoting arrhythmogenicity. Meanwhile, CX43 was reported to play a role in the pathogenesis of metastatic breast cancer and melanoma brain colonization. In this study, we studied the role of long non‐coding RNA CCRR and its interaction with CX43 in brain metastasis of breast cancer. Breast cancer patients were grouped according to the metastasis status. Real‐time PCR and IHC assay were used to measure the expression of lncRNA‐CCRR and CX43 in patients. Western blot was conducted to observe the effect of lncRNA‐CCRR on the expression of CX43 in MDA‐MB‐231BR and BT‐474BR cells. Compared with the non‐metastasis group, the mRNA expression of tissue lncRNA‐CCRR, cerebrospinal fluid (CSF) lncRNA‐CCRR, tissue CX43 and tissue protein expression of CX43 were both evidently up‐regulated in metastasis patients, especially in patients with brain metastasis. The expression of lncRNA‐CCRR was positively correlated with the up‐regulated expression of CX43. Moreover, CX43 expression was significantly lower in MDA‐MB‐231WT cells compared with that in MDA‐MB‐231BR cells. Also, the overexpression of lncRNA‐CCRR evidently increased dye transfer rate from astrocytes to MDA‐MB‐231BR/BT‐474BR cells but reduced lncRNA‐CCRR expression and suppressed the transmigration of MDA‐MB‐231BR/BT‐474BR cells in a blood‐brain barrier (BBB) model. In this study, we demonstrated that the presence of lncRNA‐CCRR could up‐regulate the expression of CX43, which promoted gap junction formation in brain metastasis of breast cancer. Accordingly, the communication between breast cancer cells and astrocytes was also promoted.
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Affiliation(s)
- Deheng Li
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Liangdong Li
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xin Chen
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Changshuai Zhou
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Bin Hao
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yiqun Cao
- Department of Neurosurgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
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14
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Solan JL, Lampe PD. Src Regulation of Cx43 Phosphorylation and Gap Junction Turnover. Biomolecules 2020; 10:biom10121596. [PMID: 33255329 PMCID: PMC7759836 DOI: 10.3390/biom10121596] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/19/2020] [Accepted: 11/22/2020] [Indexed: 12/18/2022] Open
Abstract
The gap junction protein Connexin43 (Cx43) is highly regulated by phosphorylation at over a dozen sites by probably at least as many kinases. This Cx43 “kinome” plays an important role in gap junction assembly and turnover. We sought to gain a better understanding of the interrelationship of these phosphorylation events particularly related to src activation and Cx43 turnover. Using state-of-the-art live imaging methods, specific inhibitors and many phosphorylation-status specific antibodies, we found phospho-specific domains in gap junction plaques and show evidence that multiple pathways of disassembly exist and can be regulated at the cellular and subcellular level. We found Src activation promotes formation of connexisomes (internalized gap junctions) in a process involving ERK-mediated phosphorylation of S279/282. Proteasome inhibition dramatically and rapidly restored gap junctions in the presence of Src and led to dramatic changes in the Cx43 phospho-profile including to increased Y247, Y265, S279/282, S365, and S373 phosphorylation. Lysosomal inhibition, on the other hand, nearly eliminated phosphorylation on Y247 and Y265 and reduced S368 and S373 while increasing S279/282 phosphorylation levels. We present a model of gap junction disassembly where multiple modes of disassembly are regulated by phosphorylation and can have differential effects on cellular signaling.
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Affiliation(s)
- Joell L. Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Department of Global Health, Pathobiology Program, University of Washington, Seattle, WA 98109, USA
- Correspondence:
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15
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Zheng L, Trease AJ, Katsurada K, Spagnol G, Li H, Shi W, Duan B, Patel KP, Sorgen PL. Inhibition of Pyk2 and Src activity improves Cx43 gap junction intercellular communication. J Mol Cell Cardiol 2020; 149:27-40. [PMID: 32956670 DOI: 10.1016/j.yjmcc.2020.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 11/24/2022]
Abstract
Identification of proteins that interact with Cx43 has been instrumental in the understanding of gap junction (GJ) regulation. An in vitro phosphorylation screen identified that Protein tyrosine kinase 2 beta (Pyk2) phosphorylated purified Cx43CT and this led us to characterize the impact of this phosphorylation on Cx43 function. Mass spectrometry identified Pyk2 phosphorylates Cx43 residues Y247, Y265, Y267, and Y313. Western blot and immunofluorescence staining using HeLaCx43 cells, HEK 293 T cells, and neonatal rat ventricular myocytes (NRVMs) revealed Pyk2 can be activated by Src and active Pyk2 interacts with Cx43 at the plasma membrane. Overexpression of Pyk2 increases Cx43 phosphorylation and knock-down of Pyk2 decreases Cx43 phosphorylation, without affecting the level of active Src. In HeLaCx43 cells treated with PMA to activate Pyk2, a decrease in Cx43 GJ intercellular communication (GJIC) was observed when assayed by dye transfer. Moreover, PMA activation of Pyk2 could be inhibited by the small molecule PF4618433. This partially restored GJIC, and when paired with a Src inhibitor, returned GJIC to the no PMA control-level. The ability of Pyk2 and Src inhibitors to restore Cx43 function in the presence of PMA was also observed in NRVMs. Additionally, an animal model of myocardial infarction induced heart failure showed a higher level of active Pyk2 activity and increased interaction with Cx43 in ventricular myocytes. Src inhibitors have been used to reverse Cx43 remodeling and improve heart function after myocardial infarction; however, they alone could not fully restore proper Cx43 function. Our data suggest that Pyk2 may need to be inhibited, in addition to Src, to further (if not completely) reverse Cx43 remodeling and improve intercellular communication.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kenichi Katsurada
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wen Shi
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bin Duan
- Division of Cardiology, Department of Internal Medicine/Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kaushik P Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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16
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Wang X, Feng L, Xin M, Hao Y, Wang X, Shang P, Zhao M, Hou S, Zhang Y, Xiao Y, Ma D, Feng J. Mechanisms underlying astrocytic connexin-43 autophagy degradation during cerebral ischemia injury and the effect on neuroinflammation and cell apoptosis. Biomed Pharmacother 2020; 127:110125. [PMID: 32361163 DOI: 10.1016/j.biopha.2020.110125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/18/2020] [Accepted: 03/27/2020] [Indexed: 12/26/2022] Open
Abstract
Connexin-43 (Cx43) is the most abundant gap junction protein in the nervous system. It enables cell communication and has important physiological roles including ion transport and substrate exchange, all of which have been implicated in cerebral ischemia injury. Our previous in vitro and in vivo studies have demonstrated that Cx43 is internalized and degraded during ischemia stress. However, the significance of ischemia-induced degradation of Cx43 remains unclear. Herein, we demonstrated that Cx43 degradation during ischemia injury is mediated by selective autophagy; additionally, we identified two related autophagy receptors-OPTN and NDP52. Cx43 degradation during ischemia requires its phosphorylation and ubiquitination, which are mediated by PKC, Src kinases, and ubiquitin kinase PINK1. Using point mutagenesis, we identified three phosphorylation sites underlying Cx43 autophagy degradation under ischemic stress. Cx43 degradation inhibition promoted the transition of astrocytes from a pro-inflammatory to an anti-inflammatory status, based on the levels of IL-10 and TNF in ischemia. Knockdown or accelerated degradation of Cx43 protected astrocytes from apoptosis under ischemic stress. These findings elucidate the underlying mechanism of astrocytic Cx43 autophagic degradation during ischemia. The study has identified potentially novel therapeutic strategies against ischemic stroke and evidence of crosstalk between autophagic degradation of Cx43, astrocytic apoptosis, and neuroinflammation.
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Affiliation(s)
- Xinyu Wang
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Liangshu Feng
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Meiying Xin
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Yulei Hao
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Xu Wang
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Pei Shang
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Mingming Zhao
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Shuai Hou
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China
| | - Yunhai Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, No. 88 Keling Street, Suzhou 215163, China
| | - Yun Xiao
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, No. 88 Keling Street, Suzhou 215163, China
| | - Di Ma
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China.
| | - Jiachun Feng
- Department of Neurology, The First Hospital of Jilin University, Changchun 130021, China.
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17
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Catarino S, Ribeiro-Rodrigues TM, Sá Ferreira R, Ramalho J, Abert C, Martens S, Girão H. A Conserved LIR Motif in Connexins Mediates Ubiquitin-Independent Binding to LC3/GABARAP Proteins. Cells 2020; 9:E902. [PMID: 32272685 PMCID: PMC7226732 DOI: 10.3390/cells9040902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/20/2020] [Accepted: 04/03/2020] [Indexed: 01/05/2023] Open
Abstract
Gap junctions (GJ) are specialized cell-cell contacts formed by connexins (Cxs), which provide direct communication between adjacent cells. Cx43 ubiquitination has been suggested to induce the internalization of GJs, as well as the recruitment of the autophagy receptor p62 to mediate binding to LC3B and degradation by macroautophagy. In this report, we describe a functional LC3 interacting region (LIR), present in the amino terminal of most Cx protein family members, which can mediate the autophagy degradation of Cx43 without the need of ubiquitin. Mutation of the LIR motif on Cx37, Cx43, Cx46 and Cx50 impairs interaction with LC3B and GABARAP without compromising protein ubiquitination. Through in vitro protein-protein interaction assays, we demonstrate that this LIR motif is required for the binding of Cx43 to LC3B and GABARAP. Overall, our findings describe an alternative mechanism whereby Cxs interact with LC3/GABARAP proteins, envisioning a new model for the autophagy degradation of connexins.
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Affiliation(s)
- Steve Catarino
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (S.C.); (T.M.R.-R.); (R.S.F.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Teresa M Ribeiro-Rodrigues
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (S.C.); (T.M.R.-R.); (R.S.F.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Rita Sá Ferreira
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (S.C.); (T.M.R.-R.); (R.S.F.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - José Ramalho
- CEDOC, Chronic Diseases Research Centre, NOVA Medical School|Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal;
| | - Christine Abert
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria; (C.A.); (S.M.)
| | - Sascha Martens
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, 1030 Vienna, Austria; (C.A.); (S.M.)
| | - Henrique Girão
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (S.C.); (T.M.R.-R.); (R.S.F.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), University of Coimbra, 3000-548 Coimbra, Portugal
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18
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Huang S, Hsu L, Chang N. Functional role of WW domain-containing proteins in tumor biology and diseases: Insight into the role in ubiquitin-proteasome system. FASEB Bioadv 2020; 2:234-253. [PMID: 32259050 PMCID: PMC7133736 DOI: 10.1096/fba.2019-00060] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 07/23/2019] [Accepted: 01/31/2020] [Indexed: 01/10/2023] Open
Abstract
The ubiquitin-proteasome system (UPS) governs the protein degradation process and balances proteostasis and cellular homeostasis. It is a well-controlled mechanism, in which removal of the damaged or excessive proteins is essential in driving signal pathways for cell survival or death. Accumulation of damaged proteins and failure in removal may contribute to disease initiation such as in cancers and neurodegenerative diseases. In this notion, specific protein-protein interaction is essential for the recognition of targeted proteins in UPS. WW domain plays an indispensable role in the protein-protein interactions during signaling. Among the 51 WW domain-containing proteins in the human proteomics, near one-quarter of them are involved in the UPS, suggesting that WW domains are crucial modules for driving the protein-protein binding and subsequent ubiquitination and degradation. In this review, we detail a broad spectrum of WW domains in protein-protein recognition, signal transduction, and relevance to diseases. New perspectives in dissecting the molecular interactions are provided.
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Affiliation(s)
- Shenq‐Shyang Huang
- Graduate Program of Biotechnology in MedicineInstitute of Molecular and Cellular BiologyNational Tsing Hua UniversityHsinchuTaiwan, ROC
| | - Li‐Jin Hsu
- Department of Medical Laboratory Science and BiotechnologyNational Cheng Kung University College of MedicineTainanTaiwan, ROC
| | - Nan‐Shan Chang
- Institute of Molecular MedicineNational Cheng Kung University College of MedicineTainanTaiwan, ROC
- Department of NeurochemistryNew York State Institute for Basic Research in Developmental DisabilitiesStaten IslandNYUSA
- Graduate Institute of Biomedical SciencesCollege of MedicineChina Medical UniversityTaichungTaiwan, ROC
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19
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Pournia F, Dang-Lawson M, Choi K, Mo V, Lampe PD, Matsuuchi L. Identification of serine residues in the connexin43 carboxyl tail important for BCR-mediated spreading of B-lymphocytes. J Cell Sci 2020; 133:jcs237925. [PMID: 31964709 PMCID: PMC10682646 DOI: 10.1242/jcs.237925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/20/2019] [Indexed: 11/20/2022] Open
Abstract
B-lymphocytes recognize antigen via B-cell antigen receptors (BCRs). This binding induces signaling, leading to B-cell activation, proliferation and differentiation. Early events of BCR signaling include reorganization of actin and membrane spreading, which facilitates increased antigen gathering. We have previously shown that the gap junction protein connexin43 (Cx43; also known as GJA1) is phosphorylated upon BCR signaling, and its carboxyl tail (CT) is important for BCR-mediated spreading. Here, specific serine residues in the Cx43 CT that are phosphorylated following BCR stimulation were identified. A chimeric protein containing the extracellular and transmembrane domains of CD8 fused to the Cx43 CT was sufficient to support cell spreading. Cx43 CT truncations showed that the region between amino acids 246-307 is necessary for B-cell spreading. Site-specific serine-to-alanine mutations (S255A, S262A, S279A and S282A) resulted in differential effects on both BCR signaling and BCR-mediated spreading. These serine residues can serve as potential binding sites for actin remodeling mediators and/or BCR signaling effectors; therefore, our results may reflect unique roles for each of these serines in terms of linking the Cx43 CT to actin remodeling.
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Affiliation(s)
- Farnaz Pournia
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - May Dang-Lawson
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Kate Choi
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Victor Mo
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Paul D Lampe
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109-1024, USA
| | - Linda Matsuuchi
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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20
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Totland MZ, Rasmussen NL, Knudsen LM, Leithe E. Regulation of gap junction intercellular communication by connexin ubiquitination: physiological and pathophysiological implications. Cell Mol Life Sci 2020; 77:573-591. [PMID: 31501970 PMCID: PMC7040059 DOI: 10.1007/s00018-019-03285-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/10/2019] [Accepted: 08/16/2019] [Indexed: 12/15/2022]
Abstract
Gap junctions consist of arrays of intercellular channels that enable adjacent cells to communicate both electrically and metabolically. Gap junctions have a wide diversity of physiological functions, playing critical roles in both excitable and non-excitable tissues. Gap junction channels are formed by integral membrane proteins called connexins. Inherited or acquired alterations in connexins are associated with numerous diseases, including heart failure, neuropathologies, deafness, skin disorders, cataracts and cancer. Gap junctions are highly dynamic structures and by modulating the turnover rate of connexins, cells can rapidly alter the number of gap junction channels at the plasma membrane in response to extracellular or intracellular cues. Increasing evidence suggests that ubiquitination has important roles in the regulation of endoplasmic reticulum-associated degradation of connexins as well as in the modulation of gap junction endocytosis and post-endocytic sorting of connexins to lysosomes. In recent years, researchers have also started to provide insights into the physiological roles of connexin ubiquitination in specific tissue types. This review provides an overview of the advances made in understanding the roles of connexin ubiquitination in the regulation of gap junction intercellular communication and discusses the emerging physiological and pathophysiological implications of these processes.
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Affiliation(s)
- Max Zachrisson Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Nikoline Lander Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
- Department of Medical Biology, University of Tromsø, Tromsø, Norway
| | - Lars Mørland Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, 0424, Oslo, Norway.
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway.
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21
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Cotter ML, Boitano S, Lampe PD, Solan JL, Vagner J, Ek-Vitorin JF, Burt JM. The lipidated connexin mimetic peptide SRPTEKT- Hdc is a potent inhibitor of Cx43 channels with specificity for the pS368 phospho-isoform. Am J Physiol Cell Physiol 2019; 317:C825-C842. [PMID: 31365296 PMCID: PMC6850999 DOI: 10.1152/ajpcell.00160.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/16/2019] [Accepted: 07/19/2019] [Indexed: 11/22/2022]
Abstract
Connexin (Cx) mimetic peptides derived from extracellular loop II sequences (e.g., Gap27: SRPTEKTIFII; Peptide5: VDCFLSRPTEKT) have been used as reversible, Cx-specific blockers of hemichannel (HCh) and gap junction channel (GJCh) function. These blockers typically require high concentrations (~5 µM, <1 h for HCh; ~100 µM, >1 h for GJCh) to achieve inhibition. We have shown that addition of a hexadecyl (Hdc) lipid tail to the conserved SRPTEKT peptide sequence (SRPTEKT-Hdc) results in a novel, highly efficacious, and potent inhibitor of mechanically induced Ca2+-wave propagation (IC50 64.8 pM) and HCh-mediated dye uptake (IC50 45.0 pM) in Madin-Darby canine kidney cells expressing rat Cx43 (MDCK43). The lack of similar effect on dye coupling (NBD-MTMA) suggested channel conformation-specific inhibition. Here we report that SRPTEKT-Hdc inhibition of Ca2+-wave propagation, dye coupling, and dye uptake depended on the functional configuration of Cx43 as determined by phosphorylation at serine 368 (S368). Ca2+-wave propagation was enhanced in MDCK cells expressing single-site mutants of Cx43 that mimicked (MDCK43-S368D) or favored (MDCK43-S365A) phosphorylation at S368. Furthermore, SRPTEKT-Hdc potently inhibited GJCh-mediated Ca2+-wave propagation (IC50 230.4 pM), dye coupling, and HCh-mediated dye uptake in MDCK43-S368D and -S365A cells. In contrast, Ca2+-wave propagation, dye coupling, and dye uptake were largely unaffected (IC50 12.3 μM) by SRPTEKT-Hdc in MDCK43-S368A and -S365D cells, mutations that mimic or favor dephosphorylation at S368. Together, these data indicate that SRPTEKT-Hdc is a potent inhibitor of physiological Ca2+-wave signaling mediated specifically by the pS368 phosphorylated form of Cx43.
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Affiliation(s)
- Maura L Cotter
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Scott Boitano
- Department of Physiology, University of Arizona, Tucson, Arizona
- Asthma and Airway Disease Research Center, University of Arizona, Tucson, Arizona
- Bio5 Institute, University of Arizona, Tucson, Arizona
| | - Paul D Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Joell L Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Josef Vagner
- Bio5 Institute, University of Arizona, Tucson, Arizona
- Department of Pharmacology, University of Arizona, Tucson, Arizona
| | | | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, Arizona
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22
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Trease AJ, Li H, Spagnol G, Zheng L, Stauch KL, Sorgen PL. Regulation of Connexin32 by ephrin receptors and T-cell protein-tyrosine phosphatase. J Biol Chem 2019; 294:341-350. [PMID: 30401746 PMCID: PMC6322898 DOI: 10.1074/jbc.ra118.003883] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 10/25/2018] [Indexed: 11/06/2022] Open
Abstract
Gap junctions are intercellular conduits that permit the passage of ions, small metabolites, and signaling molecules between cells. Connexin32 (Cx32) is a major gap junction protein in the liver and brain. Phosphorylation is integral to regulating connexin assembly, degradation, and electrical and metabolic coupling, as well as to interactions with molecular partners. Cx32 contains two intracellular tyrosine residues, and tyrosine phosphorylation of Cx32 has been detected after activation of the epidermal growth factor receptor; however, the specific tyrosine residue and the functional implication of this phosphorylation remain unknown. To address the limited available information on Cx32 regulation by tyrosine kinases, here we used the Cx32 C-terminal (CT) domain in an in vitro kinase-screening assay, which identified ephrin (Eph) receptor family members as tyrosine kinases that phosphorylate Cx32. We found that EphB1 and EphA1 phosphorylate the Cx32CT domain residue Tyr243 Unlike for Cx43, the tyrosine phosphorylation of the Cx32CT increased gap junction intercellular communication. We also demonstrated that T-cell protein-tyrosine phosphatase dephosphorylates pTyr243 The data presented above along with additional examples throughout the literature of gap junction regulation by kinases, indicate that one cannot extrapolate the effect of a kinase on one connexin to another.
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Affiliation(s)
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | | | - Li Zheng
- Department of Biochemistry and Molecular Biology
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23
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Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
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Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
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24
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Zheng L, Li H, Cannon A, Trease AJ, Spagnol G, Zheng H, Radio S, Patel K, Batra S, Sorgen PL. Phosphorylation of Cx43 residue Y313 by Src contributes to blocking the interaction with Drebrin and disassembling gap junctions. J Mol Cell Cardiol 2018; 126:36-49. [PMID: 30448479 DOI: 10.1016/j.yjmcc.2018.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 10/26/2018] [Accepted: 11/13/2018] [Indexed: 01/21/2023]
Abstract
Phosphorylation regulates connexin43 (Cx43) function from assembly/disassembly to coupling at the plaque. Src is a tyrosine kinase known to both phosphorylate Cx43 (residues Y247 and Y265) and affect gap junction intercellular communication. However, the Cx43 carboxyl-terminal (CT) domain contains additional tyrosine residues and proteomic discovery mass spectrometry data identified Y313 as a potential phosphorylation target. Based upon the study of Lin et al. (2001) J. Cell Biol., which still observed tyrosine phosphorylation by Src when using a Cx43 Y247/Y265F mutant, we addressed the possibility of Y313 phosphorylation (pY313) by Src. In vitro Src phosphorylation of purified Cx43CT followed by mass spectroscopy revealed that Src also phosphorylates Y313. This observation was confirmed by repeating the in vitro phosphorylation using different combinations of Cx43CT Y → F mutants and a general anti-pTyr antibody. Next, a phospho-specific antibody was generated to help characterize the importance of pY313. We established an in cyto experimental system by stably expressing Cx43 WT and mutants (Y247F, Y265F, Y313F, Y247/265F, Y247/313F, Y265/313F, or Y247/265/313F) in Cx43-deficient HeLa cells. Cx43 WT and mutants, in the absence of v-Src, localized to the plasma membrane and formed gap junctions. When v-Src was over-expressed, Cx43 WT localized intracellularly, while all of the single and double mutants remained able to form plaques and transfer dye, albeit variable in number and amount, respectively. Complete Src-resistance was only achieved with the Cx43 Y247/265/313F mutant. Furthermore, Cx43 Y265F inhibited the ability of v-Src to phosphorylate Y247 and Y313 as well as phosphorylation at both Y265 and Y313 was necessary to inhibit the Cx43 interaction with Drebrin. Finally, we observed in diseased cardiac tissue, in which Src is active, an increase in intercalated disc and intracellular localized Cx43 pY313.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hanjun Li
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew Cannon
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Hong Zheng
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Stanley Radio
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kaushik Patel
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Surinder Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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25
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Lynn BD, Li X, Hormuzdi SG, Griffiths EK, McGlade CJ, Nagy JI. E3 ubiquitin ligases LNX1 and LNX2 localize at neuronal gap junctions formed by connexin36 in rodent brain and molecularly interact with connexin36. Eur J Neurosci 2018; 48:3062-3081. [PMID: 30295974 DOI: 10.1111/ejn.14198] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 08/31/2018] [Accepted: 09/25/2018] [Indexed: 12/31/2022]
Abstract
Electrical synapses in the mammalian central nervous system (CNS) are increasingly recognized as highly complex structures for mediation of neuronal communication, both with respect to their capacity for dynamic short- and long-term modification in efficacy of synaptic transmission and their multimolecular regulatory and structural components. These two characteristics are inextricably linked, such that understanding of mechanisms that contribute to electrical synaptic plasticity requires knowledge of the molecular composition of electrical synapses and the functions of proteins associated with these synapses. Here, we provide evidence that the key component of gap junctions that form the majority of electrical synapses in the mammalian CNS, namely connexin36 (Cx36), directly interacts with the related E3 ubiquitin ligase proteins Ligand of NUMB protein X1 (LNX1) and Ligand of NUMB protein X2 (LNX2). This is based on immunofluorescence colocalization of LNX1 and LNX2 with Cx36-containing gap junctions in adult mouse brain versus lack of such coassociation in LNX null mice, coimmunoprecipitation of LNX proteins with Cx36, and pull-down of Cx36 with the second PDZ domain of LNX1 and LNX2. Furthermore, cotransfection of cultured cells with Cx36 and E3 ubiquitin ligase-competent LNX1 and LNX2 isoforms led to loss of Cx36-containing gap junctions between cells, whereas these junctions persisted following transfection with isoforms of these proteins that lack ligase activity. Our results suggest that a LNX protein mediates ubiquitination of Cx36 at neuronal gap junctions, with consequent Cx36 internalization, and may thereby contribute to intracellular mechanisms that govern the recently identified modifiability of synaptic transmission at electrical synapses.
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Affiliation(s)
- Bruce D Lynn
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Xinbo Li
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon
| | - Sheriar G Hormuzdi
- D'Arcy Thompson Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Emily K Griffiths
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - C Jane McGlade
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- The Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | - James I Nagy
- Department of Physiology and Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Science, University of Manitoba, Winnipeg, Manitoba, Canada
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26
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Kells-Andrews RM, Margraf RA, Fisher CG, Falk MM. Connexin-43 K63-polyubiquitylation on lysines 264 and 303 regulates gap junction internalization. J Cell Sci 2018; 131:jcs.204321. [PMID: 30054380 DOI: 10.1242/jcs.204321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/22/2018] [Indexed: 12/20/2022] Open
Abstract
Gap junctions (GJs) assembled from connexin (Cx) proteins allow direct cell-cell communication. While phosphorylation is known to regulate multiple GJ functions, much less is known about the role of ubiquitin in these processes. Using ubiquitylation-type-specific antibodies and Cx43 lysine-to-arginine mutants we show that ∼8% of a GJ, localized in central plaque domains, is K63-polyubiquitylated on K264 and K303. Levels and localization of ubiquitylation correlated well with: (1) the short turnover rate of Cxs and GJs; (2) removal of older channels from the plaque center; and (3) the fact that not all Cxs in an internalizing GJ channel need to be ubiquitylated. Connexins mutated at these two sites assembled significantly larger GJs, exhibited much longer protein half-lives and were internalization impaired. Interestingly, these ubiquitin-deficient Cx43 mutants accumulated as hyper-phosphorylated polypeptides in the plasma membrane, suggesting that K63-polyubiquitylation is triggered by phosphorylation. Phospho-specific anti-Cx43 antibodies revealed that upregulated phosphorylation affected serines 368, 279/282 and 255, which are well-known regulatory PKC and MAPK sites. Together, these novel findings suggest that the internalizing portion of channels in a GJ is K63-polyubiquitylated, ubiquitylation is critical for GJ internalization and that phosphorylation induces Cx K63-polyubiquitylation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Rachael M Kells-Andrews
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Rachel A Margraf
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Charles G Fisher
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Matthias M Falk
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
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27
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Basheer WA, Shaw RM. Connexin 43 and CaV1.2 Ion Channel Trafficking in Healthy and Diseased Myocardium. Circ Arrhythm Electrophysiol 2018; 9:e001357. [PMID: 27266274 DOI: 10.1161/circep.115.001357] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/29/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Wassim A Basheer
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.)
| | - Robin M Shaw
- From the Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA (W.A.B., R.M.S.); and Department of Medicine, University of California Los Angeles (R.M.S.).
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28
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Manring HR, Dorn LE, Ex-Willey A, Accornero F, Ackermann MA. At the heart of inter- and intracellular signaling: the intercalated disc. Biophys Rev 2018; 10:961-971. [PMID: 29876873 DOI: 10.1007/s12551-018-0430-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 05/22/2018] [Indexed: 12/17/2022] Open
Abstract
Proper cardiac function requires the synchronous mechanical and electrical coupling of individual cardiomyocytes. The intercalated disc (ID) mediates coupling of neighboring myocytes through intercellular signaling. Intercellular communication is highly regulated via intracellular signaling, and signaling pathways originating from the ID control cardiomyocyte remodeling and function. Herein, we present an overview of the inter- and intracellular signaling that occurs at and originates from the intercalated disc in normal physiology and pathophysiology. This review highlights the importance of the intercalated disc as an integrator of signaling events regulating homeostasis and stress responses in the heart and the center of several pathophysiological processes mediating the development of cardiomyopathies.
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Affiliation(s)
- Heather R Manring
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Lisa E Dorn
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Aidan Ex-Willey
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Federica Accornero
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
| | - Maegen A Ackermann
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
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29
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Spagnol G, Trease AJ, Zheng L, Gutierrez M, Basu I, Sarmiento C, Moore G, Cervantes M, Sorgen PL. Connexin43 Carboxyl-Terminal Domain Directly Interacts with β-Catenin. Int J Mol Sci 2018; 19:ijms19061562. [PMID: 29882937 PMCID: PMC6032326 DOI: 10.3390/ijms19061562] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 12/13/2022] Open
Abstract
Activation of Wnt signaling induces Connexin43 (Cx43) expression via the transcriptional activity of β-catenin, and results in the enhanced accumulation of the Cx43 protein and the formation of gap junction channels. In response to Wnt signaling, β-catenin co-localizes with the Cx43 protein itself as part of a complex at the gap junction plaque. Work from several labs have also shown indirect evidence of this interaction via reciprocal co-immunoprecipitation. Our goal for the current study was to identify whether β-catenin directly interacts with Cx43, and if so, the location of that direct interaction. Identifying residues involved in direct protein⁻protein interaction is of importance when they are correlated to the phosphorylation of Cx43, as phosphorylation can modify the binding affinities of Cx43 regulatory protein partners. Therefore, combining the location of a protein partner interaction on Cx43 along with the phosphorylation pattern under different homeostatic and pathological conditions will be crucial information for any potential therapeutic intervention. Here, we identified that β-catenin directly interacts with the Cx43 carboxyl-terminal domain, and that this interaction would be inhibited by the Src phosphorylation of Cx43CT residues Y265 and Y313.
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Affiliation(s)
- Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Mirtha Gutierrez
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Ishika Basu
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Cleofes Sarmiento
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Gabriella Moore
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Matthew Cervantes
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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Sorgen PL, Trease AJ, Spagnol G, Delmar M, Nielsen MS. Protein⁻Protein Interactions with Connexin 43: Regulation and Function. Int J Mol Sci 2018; 19:E1428. [PMID: 29748463 PMCID: PMC5983787 DOI: 10.3390/ijms19051428] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/11/2022] Open
Abstract
Connexins are integral membrane building blocks that form gap junctions, enabling direct cytoplasmic exchange of ions and low-molecular-mass metabolites between adjacent cells. In the heart, gap junctions mediate the propagation of cardiac action potentials and the maintenance of a regular beating rhythm. A number of connexin interacting proteins have been described and are known gap junction regulators either through direct effects (e.g., kinases) or the formation of larger multifunctional complexes (e.g., cytoskeleton scaffold proteins). Most connexin partners can be categorized as either proteins promoting coupling by stimulating forward trafficking and channel opening or inhibiting coupling by inducing channel closure, internalization, and degradation. While some interactions have only been implied through co-localization using immunohistochemistry, others have been confirmed by biophysical methods that allow detection of a direct interaction. Our understanding of these interactions is, by far, most well developed for connexin 43 (Cx43) and the scope of this review is to summarize our current knowledge of their functional and regulatory roles. The significance of these interactions is further exemplified by demonstrating their importance at the intercalated disc, a major hub for Cx43 regulation and Cx43 mediated effects.
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Affiliation(s)
- Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Mario Delmar
- Leon H Charney Division of Cardiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Morten S Nielsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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31
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Ribeiro-Rodrigues TM, Martins-Marques T, Morel S, Kwak BR, Girão H. Role of connexin 43 in different forms of intercellular communication - gap junctions, extracellular vesicles and tunnelling nanotubes. J Cell Sci 2017; 130:3619-3630. [PMID: 29025971 DOI: 10.1242/jcs.200667] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Communication is important to ensure the correct and efficient flow of information, which is required to sustain active social networks. A fine-tuned communication between cells is vital to maintain the homeostasis and function of multicellular or unicellular organisms in a community environment. Although there are different levels of complexity, intercellular communication, in prokaryotes to mammalians, can occur through secreted molecules (either soluble or encapsulated in vesicles), tubular structures connecting close cells or intercellular channels that link the cytoplasm of adjacent cells. In mammals, these different types of communication serve different purposes, may involve distinct factors and are mediated by extracellular vesicles, tunnelling nanotubes or gap junctions. Recent studies have shown that connexin 43 (Cx43, also known as GJA1), a transmembrane protein initially described as a gap junction protein, participates in all these forms of communication; this emphasizes the concept of adopting strategies to maximize the potential of available resources by reutilizing the same factor in different scenarios. In this Review, we provide an overview of the most recent advances regarding the role of Cx43 in intercellular communication mediated by extracellular vesicles, tunnelling nanotubes and gap junctions.
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Affiliation(s)
- Teresa M Ribeiro-Rodrigues
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Sta Comba, 3000-548 Coimbra, Portugal.,CNC.IBILI, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Tânia Martins-Marques
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Sta Comba, 3000-548 Coimbra, Portugal.,CNC.IBILI, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Sandrine Morel
- Dept. of Pathology and Immunology, and Dept. of Medical Specialties - Cardiology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Brenda R Kwak
- Dept. of Pathology and Immunology, and Dept. of Medical Specialties - Cardiology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Henrique Girão
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Azinhaga de Sta Comba, 3000-548 Coimbra, Portugal .,CNC.IBILI, University of Coimbra, 3000-548 Coimbra, Portugal
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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Trease AJ, Capuccino JMV, Contreras J, Harris AL, Sorgen PL. Intramolecular signaling in a cardiac connexin: Role of cytoplasmic domain dimerization. J Mol Cell Cardiol 2017; 111:69-80. [PMID: 28754342 DOI: 10.1016/j.yjmcc.2017.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 06/06/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
Abstract
Gap junctions, composed of connexins, mediate electrical coupling and impulse propagation in the working myocardium. In the human heart, the spatio-temporal regulation and distinct functional properties of the three dominant connexins (Cx43, Cx45, and Cx40) suggests non-redundant physiological roles for each isoform. There are substantial differences in gating properties, expression, and trafficking among these isoforms, however, little is known about the determinants of these different phenotypes. To gain insight regarding these determinants, we focused on the carboxyl-terminal (CT) domain because of its importance in channel regulation and large degree of sequence divergence among connexin family members. Using in vitro biophysical experiments, we identified a structural feature unique to Cx45: high affinity (KD~100nM) dimerization between CT domains. In this study, we sought to determine if this dimerization occurs in cells and to identify the biological significance of the dimerization. Using a bimolecular fluorescence complementation assay, we demonstrate that the CT domains dimerize at the plasma membrane. By inhibiting CT dimerization with a mutant construct, we show that CT dimerization is necessary for proper Cx45 membrane localization, turnover, phosphorylation status, and binding to protein partners. Furthermore, CT dimerization is needed for normal intercellular communication and hemichannel activity. Altogether, our results demonstrate that CT dimerization is a structural feature important for correct Cx45 function. This study is significant because discovery of how interactions mediated by the CT domains can be modulated would open the door to strategies to ameliorate the pathological effects of altered connexin regulation in the failing heart.
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Affiliation(s)
- Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Juan M V Capuccino
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Jorge Contreras
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Andrew L Harris
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, NJ 07103, USA
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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34
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Mesnil M, Aasen T, Boucher J, Chépied A, Cronier L, Defamie N, Kameritsch P, Laird DW, Lampe PD, Lathia JD, Leithe E, Mehta PP, Monvoisin A, Pogoda K, Sin WC, Tabernero A, Yamasaki H, Yeh ES, Dagli MLZ, Naus CC. An update on minding the gap in cancer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:237-243. [PMID: 28655619 DOI: 10.1016/j.bbamem.2017.06.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 01/08/2023]
Abstract
This article is a report of the "International Colloquium on Gap junctions: 50Years of Impact on Cancer" that was held 8-9 September 2016, at the Amphitheater "Pôle Biologie Santé" of the University of Poitiers (Poitiers, France). The colloquium was organized by M Mesnil (Université de Poitiers, Poitiers, France) and C Naus (University of British Columbia, Vancouver, Canada) to celebrate the 50th anniversary of the seminal work published in 1966 by Loewenstein and Kanno [Intercellular communication and the control of tissue growth: lack of communication between cancer cells, Nature, 116 (1966) 1248-1249] which initiated studies on the involvement of gap junctions in carcinogenesis. During the colloquium, 15 participants presented reviews or research updates in the field which are summarized below.
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Affiliation(s)
- Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France.
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain
| | - Jonathan Boucher
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Amandine Chépied
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Laurent Cronier
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Norah Defamie
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Petra Kameritsch
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario N6A 5C1, Canada
| | - Paul D Lampe
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Justin D Lathia
- Cleveland Clinic, Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, and Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Parmender P Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska, Medical Center, Omaha, NE 68198, USA
| | - Arnaud Monvoisin
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, cedex 09, France
| | - Kristin Pogoda
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, München, Germany
| | - Wun-Chey Sin
- Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Arantxa Tabernero
- Departamento de Bioquímica y Biología Molecular, Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca 37007, Spain
| | | | - Elizabeth S Yeh
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC 29412, USA
| | - Maria Lucia Zaidan Dagli
- Laboratory of Experimental and Comparative Oncology, School of Veterinary Medicine and Animal Science of the University of São Paulo, São Paulo, SP CEP 05508-900, Brazil
| | - Christian C Naus
- Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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Epifantseva I, Shaw RM. Intracellular trafficking pathways of Cx43 gap junction channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:40-47. [PMID: 28576298 DOI: 10.1016/j.bbamem.2017.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/11/2022]
Abstract
Gap Junction (GJ) channels, including the most common Connexin 43 (Cx43), have fundamental roles in excitable tissues by facilitating rapid transmission of action potentials between adjacent cells. For instance, synchronization during each heartbeat is regulated by these ion channels at the cardiomyocyte cell-cell border. Cx43 protein has a short half-life, and rapid synthesis and timely delivery of those proteins to particular subdomains are crucial for the cellular organization of gap junctions and maintenance of intracellular coupling. Impairment in gap junction trafficking contributes to dangerous complications in diseased hearts such as the arrhythmias of sudden cardiac death. Of recent interest are the protein-protein interactions with the Cx43 carboxy-terminus. These interactions have significant impact on the full length Cx43 lifecycle and also contribute to trafficking of Cx43 as well as possibly other functions. We are learning that many of the known non-canonical roles of Cx43 can be attributed to the recently identified six endogenous Cx43 truncated isoforms which are produced by internal translation. In general, alternative translation is a new leading edge for proteome expansion and therapeutic drug development. This review highlights recent mechanisms identified in the trafficking of gap junction channels, involvement of other proteins contributing to the delivery of channels to the cell-cell border, and understanding of possible roles of the newly discovered alternatively translated isoforms in Cx43 biology. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Irina Epifantseva
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.; Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA..
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36
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Leithe E, Mesnil M, Aasen T. The connexin 43 C-terminus: A tail of many tales. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:48-64. [PMID: 28526583 DOI: 10.1016/j.bbamem.2017.05.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
Abstract
Connexins are chordate gap junction channel proteins that, by enabling direct communication between the cytosols of adjacent cells, create a unique cell signalling network. Gap junctional intercellular communication (GJIC) has important roles in controlling cell growth and differentiation and in tissue development and homeostasis. Moreover, several non-canonical connexin functions unrelated to GJIC have been discovered. Of the 21 members of the human connexin family, connexin 43 (Cx43) is the most widely expressed and studied. The long cytosolic C-terminus (CT) of Cx43 is subject to extensive post-translational modifications that modulate its intracellular trafficking and gap junction channel gating. Moreover, the Cx43 CT contains multiple domains involved in protein interactions that permit crosstalk between Cx43 and cytoskeletal and regulatory proteins. These domains endow Cx43 with the capacity to affect cell growth and differentiation independently of GJIC. Here, we review the current understanding of the regulation and unique functions of the Cx43 CT, both as an essential component of full-length Cx43 and as an independent signalling hub. We highlight the complex regulatory and signalling networks controlled by the Cx43 CT, including the extensive protein interactome that underlies both gap junction channel-dependent and -independent functions. We discuss these data in relation to the recent discovery of the direct translation of specific truncated forms of Cx43. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, University of Oslo, NO-0424 Oslo, Norway; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, NO-0424 Oslo, Norway
| | - Marc Mesnil
- STIM Laboratory ERL 7368 CNRS - Faculté des Sciences Fondamentales et Appliquées, Université de Poitiers, Poitiers 86073, France
| | - Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
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37
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Roy N, Pacini G, Berlioz-Torrent C, Janvier K. Characterization of E3 ligases involved in lysosomal sorting of the HIV-1 restriction factor BST2. J Cell Sci 2017; 130:1596-1611. [PMID: 28320822 PMCID: PMC5450231 DOI: 10.1242/jcs.195412] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/17/2017] [Indexed: 12/17/2022] Open
Abstract
The cellular protein BST2 (also known as tetherin) acts as a major intrinsic antiviral protein that prevents the release of enveloped viruses by trapping nascent viral particles at the surface of infected cells. Viruses have evolved specific strategies to displace BST2 from viral budding sites in order to promote virus egress. In HIV-1, the accessory protein Vpu counters BST2 antiviral activity and promotes sorting of BST2 for lysosomal degradation. Vpu increases polyubiquitylation of BST2, a post-translation modification required for Vpu-induced BST2 downregulation, through recruitment of the E3 ligase complex SCF adaptors β-TrCP1 and β-TrCP2 (two isoforms encoded by BTRC and FBXW11, respectively). Herein, we further investigate the role of the ubiquitylation machinery in the lysosomal sorting of BST2. Using a small siRNA screen, we highlighted two additional regulators of BST2 constitutive ubiquitylation and sorting to the lysosomes: the E3 ubiquitin ligases NEDD4 and MARCH8. Interestingly, Vpu does not hijack the cellular machinery that is constitutively involved in BST2 ubiquitylation to sort BST2 for degradation in the lysosomes but instead promotes the recognition of BST2 by β-TrCP proteins. Altogether, our results provide further understanding of the mechanisms underlying BST2 turnover in cells. Highlighted Article: We identify two E3 ubiquitin ligases, NEDD4 and MARCH8, as regulators of BST2 (tetherin) – a protein that restricts viral release; we thus provide further understanding of the mechanisms underlying BST2 turnover in cells.
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Affiliation(s)
- Nicolas Roy
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Grégory Pacini
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Clarisse Berlioz-Torrent
- Inserm, U1016, Institut Cochin, Paris, France.,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Katy Janvier
- Inserm, U1016, Institut Cochin, Paris, France .,CNRS, UMR8104, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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38
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Totland MZ, Bergsland CH, Fykerud TA, Knudsen LM, Rasmussen NL, Eide PW, Yohannes Z, Sørensen V, Brech A, Lothe RA, Leithe E. E3 ubiquitin ligase NEDD4 induces endocytosis and lysosomal sorting of connexin43 to promote loss of gap junctions. J Cell Sci 2017; 130:2867-2882. [DOI: 10.1242/jcs.202408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 07/12/2017] [Indexed: 01/07/2023] Open
Abstract
Intercellular communication via gap junctions has an important role in controlling cell growth and in maintaining tissue homeostasis. Connexin43 is the most abundantly expressed gap junction channel protein in humans and acts as a tumor suppressor in multiple tissue types. Connexin43 is often dysregulated at the post-translational level during cancer development, resulting in loss of gap junctions. However, the molecular basis underlying the aberrant regulation of connexin43 in cancer cells has remained elusive. Here, we demonstrate that the oncogenic E3 ubiquitin ligase NEDD4 regulates the connexin43 protein level in HeLa cells, both under basal conditions and in response to protein kinase C activation. Furthermore, overexpression of NEDD4, but not a catalytically inactive form of NEDD4, was found to result in nearly complete loss of gap junctions and increased lysosomal degradation of connexin43 in both HeLa and C33A cervical carcinoma cells. Collectively, the data provide new insights into the molecular basis underlying the regulation of gap junction size and represent the first evidence that an oncogenic E3 ubiquitin ligase promotes loss of gap junctions and connexin43 degradation in human carcinoma cells.
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Affiliation(s)
- Max Z. Totland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Christian H. Bergsland
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Tone A. Fykerud
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Lars M. Knudsen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Nikoline L. Rasmussen
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Peter W. Eide
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Zeremariam Yohannes
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Vigdis Sørensen
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Andreas Brech
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Ragnhild A. Lothe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Institute for Biosciences, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
| | - Edward Leithe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway
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Ehrlichia chaffeensis TRP32 is a Nucleomodulin that Directly Regulates Expression of Host Genes Governing Differentiation and Proliferation. Infect Immun 2016; 84:3182-3194. [PMID: 27572329 DOI: 10.1128/iai.00657-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ehrlichia chaffeensis is an obligately intracellular bacterium that reprograms the mononuclear phagocyte through diverse effector-host interactions to modulate numerous host cell processes, including transcription. In a previous study, we reported that E. chaffeensis TRP32, a type 1 secreted effector, interacts with multiple host nucleus-associated proteins and also auto-activates reporter gene expression in yeast. In this study, we demonstrate that TRP32 is a nucleomodulin that binds host DNA and alters host gene transcription. TRP32 enters the host cell nucleus via a noncanonical translocation mechanism that involves phosphorylation of Y179 located in a C-terminal tri-tyrosine motif. Both genistein and mutation of Y179 inhibited TRP32 nuclear entry. An electromobility shift assay (EMSA) demonstrated TRP32 host DNA binding via its tandem repeat domain. TRP32 DNA binding and motif preference were further confirmed by supershift assays, as well as competition and mutant probe analyses. Using ChIP-Seq, we determined that TRP32 binds a G-rich motif primarily within ±500 bp of the gene transcription start site. An ontology analysis identified genes involved in processes such as immune cell differentiation, chromatin remodeling, and RNA transcription and processing, as primary TRP32 targets. TRP32 bound genes (n=1223) were distributed on all chromosomes and included several global regulators of proliferation and inflammation such as FOS and JUN, AKT3 and NRAS, and non-coding RNA genes, miRNA 21 and miRNA 142. TRP32 target genes were differentially regulated during infection, the majority of which were repressed, and direct repression/activation of these genes by TRP32 was confirmed in vitro with a cellular luciferase reporter assay.
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Li H, Spagnol G, Zheng L, Stauch KL, Sorgen PL. Regulation of Connexin43 Function and Expression by Tyrosine Kinase 2. J Biol Chem 2016; 291:15867-80. [PMID: 27235399 DOI: 10.1074/jbc.m116.727008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Indexed: 11/06/2022] Open
Abstract
Connexin43 (Cx43) assembly and degradation, the regulation of electrical and metabolic coupling, as well as modulating the interaction with other proteins, involve phosphorylation. Here, we identified and characterized the biological significance of a novel tyrosine kinase that phosphorylates Cx43, tyrosine kinase 2 (Tyk2). Activation of Tyk2 led to a decrease in Cx43 gap junction communication by increasing the turnover rate of Cx43 from the plasma membrane. Tyk2 directly phosphorylated Cx43 residues Tyr-247 and Tyr-265, leading to indirect phosphorylation on residues Ser-279/Ser-282 (MAPK) and Ser-368 (PKC). Although this phosphorylation pattern is similar to what has been observed following Src activation, the response caused by Tyk2 occurred when Src was inactive in NRK cells. Knockdown of Tyk2 at the permissive temperature (active v-Src) in LA-25 cells decreased Cx43 phosphorylation, indicating that although activation of Tyk2 and v-Src leads to phosphorylation of the same Cx43CT residues, they are not identical in level at each site. Additionally, angiotensin II activation of Tyk2 increased the intracellular protein level of Cx43 via STAT3. These findings indicate that, like Src, Tyk2 can also inhibit gap junction communication by phosphorylating Cx43.
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Affiliation(s)
- Hanjun Li
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Gaelle Spagnol
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Li Zheng
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Kelly L Stauch
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Paul L Sorgen
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
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Iyyathurai J, Decuypere JP, Leybaert L, D'hondt C, Bultynck G. Connexins: substrates and regulators of autophagy. BMC Cell Biol 2016; 17 Suppl 1:20. [PMID: 27229147 PMCID: PMC4896244 DOI: 10.1186/s12860-016-0093-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Connexins mediate intercellular communication by assembling into hexameric channel complexes that act as hemichannels and gap junction channels. Most connexins are characterized by a very rapid turn-over in a variety of cell systems. The regulation of connexin turn-over by phosphorylation and ubiquitination events has been well documented. Moreover, different pathways have been implicated in connexin degradation, including proteasomal and lysosomal-based pathways. Only recently, autophagy emerged as an important connexin-degradation pathway for different connexin isoforms. As such, conditions well known to induce autophagy have an immediate impact on the connexin-expression levels. This is not only limited to experimental conditions but also several pathophysiological conditions associated with autophagy (dys)function affect connexin levels and their presence at the cell surface as gap junctions. Finally, connexins are not only substrates of autophagy but also emerge as regulators of the autophagy process. In particular, several connexin isoforms appear to recruit pre-autophagosomal autophagy-related proteins, including Atg16 and PI3K-complex components, to the plasma membrane, thereby limiting their availability and capacity for regulating autophagy.
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Affiliation(s)
- Jegan Iyyathurai
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Jean-Paul Decuypere
- KU Leuven, Laboratory for Membrane Trafficking, Department of Human Genetics, and VIB-Center for the Biology of Disease, Campus Gasthuisberg, O/N-IV, 7.159, Herestraat 49, 3000, Leuven, Belgium
| | - Luc Leybaert
- Ghent University, Physiology Group, Department of Basic Medical Sciences, 9000, Ghent, Belgium
| | - Catheleyne D'hondt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000, Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, B-3000, Leuven, Belgium.
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42
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Intestinal knockout of Nedd4 enhances growth of Apc min tumors. Oncogene 2016; 35:5839-5849. [PMID: 27086928 DOI: 10.1038/onc.2016.125] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 12/24/2022]
Abstract
Nedd4 (Nedd4-1) is an E3 ubiquitin ligase that belongs to the HECT family and comprises a C2-WW(n)-HECT domain architecture. Although it has been reported to regulate growth factor receptors and cellular signaling, its role in cancer development has been controversial, with some studies proposing that it promotes cancer while others suggest it inhibits tumor growth. Here, we tested the effect of Nedd4 on intestinal tumor formation and growth using Nedd4-knockout mice (Nedd4 floxed (fl) mice crossed to villin-Cre mice). Although we find that knockout of Nedd4 on its own does not cause tumor growth, its knockout in the context of Apc+/min-derived colorectal tumors leads to augmentation of tumor growth, suggesting that Nedd4 normally suppresses intestinal WNT signaling and growth of colonic tumors. WNT signaling microarray, immunoblotting and immunohistochemistry analyses of tumors derived from the Villin-Cre;Nedd4fl/fl;Apc+/min colons demonstrated elevated expression of the WNT upstream effectors LEF1 (full length) and YY1 in these tumors relative to control (Apc+/min alone) tumors. Together, these results suggest that Nedd4 suppresses colonic WNT signaling and tumor growth, at least in part, by suppressing the transcription factors LEF1 and YY1.
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Leithe E. Regulation of connexins by the ubiquitin system: Implications for intercellular communication and cancer. Biochim Biophys Acta Rev Cancer 2016; 1865:133-46. [DOI: 10.1016/j.bbcan.2016.02.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/15/2016] [Accepted: 02/04/2016] [Indexed: 12/31/2022]
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Spagnol G, Kieken F, Kopanic JL, Li H, Zach S, Stauch KL, Grosely R, Sorgen PL. Structural Studies of the Nedd4 WW Domains and Their Selectivity for the Connexin43 (Cx43) Carboxyl Terminus. J Biol Chem 2016; 291:7637-50. [PMID: 26841867 DOI: 10.1074/jbc.m115.701417] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 12/13/2022] Open
Abstract
Neuronal precursor cell-expressed developmentally down-regulated 4 (Nedd4) was the first ubiquitin protein ligase identified to interact with connexin43 (Cx43), and its suppressed expression results in accumulation of gap junction plaques at the plasma membrane. Nedd4-mediated ubiquitination of Cx43 is required to recruit Eps15 and target Cx43 to the endocytic pathway. Although the Cx43 residues that undergo ubiquitination are still unknown, in this study we address other unresolved questions pertaining to the molecular mechanisms mediating the direct interaction between Nedd4 (WW1-3 domains) and Cx43 (carboxyl terminus (CT)). All three WW domains display a similar three antiparallel β-strand structure and interact with the same Cx43CT(283)PPXY(286)sequence. Although Tyr(286)is essential for the interaction, MAPK phosphorylation of the preceding serine residues (Ser(P)(279)and Ser(P)(282)) increases the binding affinity by 2-fold for the WW domains (WW2 > WW3 ≫ WW1). The structure of the WW2·Cx43CT(276-289)(Ser(P)(279), Ser(P)(282)) complex reveals that coordination of Ser(P)(282)with the end of β-strand 3 enables Ser(P)(279)to interact with the back face of β-strand 3 (Tyr(286)is on the front face) and loop 2, forming a horseshoe-shaped arrangement. The close sequence identity of WW2 with WW1 and WW3 residues that interact with the Cx43CT PPXY motif and Ser(P)(279)/Ser(P)(282)strongly suggests that the significantly lower binding affinity of WW1 is the result of a more rigid structure. This study presents the first structure illustrating how phosphorylation of the Cx43CT domain helps mediate the interaction with a molecular partner involved in gap junction regulation.
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Affiliation(s)
- Gaelle Spagnol
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Fabien Kieken
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | | | - Hanjun Li
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Sydney Zach
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Kelly L Stauch
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Rosslyn Grosely
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
| | - Paul L Sorgen
- From the University of Nebraska Medical Center, Omaha, Nebraska 68105
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Chapter Five - Ubiquitination of Ion Channels and Transporters. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:161-223. [DOI: 10.1016/bs.pmbts.2016.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Fang WL, Lai SY, Lai WA, Lee MT, Liao CF, Ke FC, Hwang JJ. CRTC2 and Nedd4 ligase involvement in FSH and TGFβ1 upregulation of connexin43 gap junction. J Mol Endocrinol 2015; 55:263-75. [PMID: 26508620 DOI: 10.1530/jme-15-0076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The major mission of the ovarian follicle is the timely production of the mature fertilizable oocyte, and this is achieved by gonadotropin-regulated, gap junction-mediated cell-cell communication between the oocyte and surrounding nurturing granulosa cells. We have demonstrated that FSH and transforming growth factor beta 1 (TGFβ1) stimulate Gja1 gene-encoded connexin43 (Cx43) gap junction formation/function in rat ovarian granulosa cells is important for their induction of steroidogenesis; additionally, cAMP-protein kinase A (PKA)- and calcium-calcineurin-sensitive cAMP response element-binding (CREB) coactivator CRTC2 plays a crucial role during steroidogenesis. This study was to explore the potential molecular mechanism whereby FSH and TGFβ1 regulate Cx43 synthesis and degradation, particularly the involvement of CRTC2 and ubiquitin ligase Nedd4. Primary culture of granulosa cells from ovarian antral follicles of gonadotropin-primed immature rats was used. At 48 h post-treatment, FSH plus TGFβ1 increased Cx43 level and gap junction function in a PKA- and calcineurin-dependent manner, and TGFβ1 acting through its type I receptor modulated FSH action. Chromatin-immunoprecipitation analysis reveals FSH induced an early-phase (45 min) and FSH+TGFβ1 further elicited a late-phase (24 h) increase in CRTC2, CREB and CBP binding to the Gja1 promoter. Additionally, FSH+TGFβ1 increased the half-life of hyper-phosphorylated Cx43 (Cx43-P2). Also, the proteasome inhibitor MG132 prevented the brefeldin A (blocker of protein transport through Golgi)-reduced Cx43-P2 level and membrane Cx43 gap junction plaque. This is associated with FSH+TGFβ1-attenuated Cx43 interaction with Nedd4 and Cx43 ubiquitination. In all, this study uncovers that FSH and TGFβ1 upregulation of Cx43 gap junctions in ovarian granulosa cells critically involves enhancing CRTC2/CREB/CBP-mediated Cx43 expression and attenuating ubiquitin ligase Nedd4-mediated proteosomal degradation of Cx43 protein.
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Affiliation(s)
- Wei-Ling Fang
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Si-Yi Lai
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Wei-An Lai
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ming-Ting Lee
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ching-Fong Liao
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Ferng-Chun Ke
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
| | - Jiuan-Jiuan Hwang
- School of MedicineInstitute of Physiology, National Yang-Ming University, 155 Linong Street, Section 2, Taipei 112, TaiwanDepartment of NursingHsin-Sheng College of Medical Care and Management, Taoyuan, TaiwanInstitute of Biological ChemistryInstitute of Cellular and Organismic BiologyAcademia Sinica, Taipei, TaiwanCollege of Life ScienceInstitute of Molecular and Cellular Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
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Basheer W, Shaw R. The "tail" of Connexin43: An unexpected journey from alternative translation to trafficking. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1848-56. [PMID: 26526689 DOI: 10.1016/j.bbamcr.2015.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022]
Abstract
With each heartbeat, Connexin43 (Cx43) cell-cell communication gap junctions are needed to rapidly spread and coordinate excitation signals for an effective heart contraction. The correct formation and delivery of channels to their respective membrane subdomain is referred to as protein trafficking. Altered Cx43 trafficking is a dangerous complication of diseased myocardium which contributes to the arrhythmias of sudden cardiac death. Cx43 has also been found to regulate many other cellular processes that cannot be explained by cell-cell communication. We recently identified the existence of up to six endogenous internally translated Cx43 N-terminal truncated isoforms from the same full-length mRNA molecule. This is the first evidence that alternative translation is possible for human ion channels and in human heart. Interestingly, we found that these internally translated isoforms, more specifically the 20 kDa isoform (GJA1-20k), is important for delivery of Cx43 to its respective membrane subdomain. This review covers recent advances in Cx43 trafficking and potential importance of alternatively translated Cx43 truncated isoforms. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Wassim Basheer
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Robin Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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48
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Basheer WA, Harris BS, Mentrup HL, Abreha M, Thames EL, Lea JB, Swing DA, Copeland NG, Jenkins NA, Price RL, Matesic LE. Cardiomyocyte-specific overexpression of the ubiquitin ligase Wwp1 contributes to reduction in Connexin 43 and arrhythmogenesis. J Mol Cell Cardiol 2015; 88:1-13. [PMID: 26386426 DOI: 10.1016/j.yjmcc.2015.09.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/30/2015] [Accepted: 09/14/2015] [Indexed: 12/12/2022]
Abstract
Gap junctions (GJ) are intercellular channels composed of connexin subunits that play a critical role in a diverse number of cellular processes in all tissue types. In the heart, GJs mediate electrical coupling between cardiomyocytes and display mislocalization and/or downregulation in cardiac disease (a process known as GJ remodeling), producing an arrhythmogenic substrate. The main constituent of GJs in the ventricular myocardium is Connexin 43 (Cx43), an integral membrane protein that is rapidly turned over and shows decreased expression or function with age. We hypothesized that Wwp1, an ubiquitin ligase whose expression in known to increase in aging-related pathologies, may regulate Cx43 in vivo by targeting it for ubiquitylation and degradation and yield tissue-specific Cx43 loss of function phenotypes. When Wwp1 was globally overexpressed in mice under the control of a β-actin promoter, the highest induction of Wwp1 expression was observed in the heart which was associated with a 90% reduction in cardiac Cx43 protein levels, left ventricular hypertrophy (LVH), and the development of lethal ventricular arrhythmias around 8weeks of age. This phenotype was completely penetrant in two independent founder lines. Cardiomyocyte-specific overexpression of Wwp1 confirmed that this phenotype was cell autonomous and delineated Cx43-dependent and -independent roles for Wwp1 in arrhythmogenesis and LVH, respectively. Using a cell-based system, it was determined that Wwp1 co-immunoprecipitates with and ubiquitylates Cx43, causing a decrease in the steady state levels of Cx43 protein. These findings offer new mechanistic insights into the regulation of Cx43 which may be exploitable in various gap junctionopathies.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Connexin 43/genetics
- Connexin 43/metabolism
- Disease Models, Animal
- Female
- Gap Junctions/metabolism
- Gap Junctions/pathology
- Gene Expression Regulation
- Heart Ventricles/metabolism
- Heart Ventricles/pathology
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/pathology
- Male
- Mice
- Mice, Transgenic
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Phenotype
- Promoter Regions, Genetic
- Proteasome Endopeptidase Complex/metabolism
- Protein Stability
- Proteolysis
- Signal Transduction
- Ubiquitin-Protein Ligases/genetics
- Ubiquitin-Protein Ligases/metabolism
- Ubiquitination
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Affiliation(s)
- Wassim A Basheer
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Brett S Harris
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Heather L Mentrup
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Measho Abreha
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Elizabeth L Thames
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Jessica B Lea
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Deborah A Swing
- Mouse Cancer Genetics Program, The National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Neal G Copeland
- Mouse Cancer Genetics Program, The National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Nancy A Jenkins
- Mouse Cancer Genetics Program, The National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Robert L Price
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29209, USA
| | - Lydia E Matesic
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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49
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Connexin 43 ubiquitination determines the fate of gap junctions: restrict to survive. Biochem Soc Trans 2015; 43:471-5. [DOI: 10.1042/bst20150036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Connexins (Cxs) are transmembrane proteins that form channels which allow direct intercellular communication (IC) between neighbouring cells via gap junctions. Mechanisms that modulate the amount of channels at the plasma membrane have emerged as important regulators of IC and their de-regulation has been associated with various diseases. Although Cx-mediated IC can be modulated by different mechanisms, ubiquitination has been described as one of the major post-translational modifications involved in Cx regulation and consequently IC. In this review, we focus on the role of ubiquitin and its effect on gap junction intercellular communication.
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50
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Heart ischemia results in connexin43 ubiquitination localized at the intercalated discs. Biochimie 2015; 112:196-201. [DOI: 10.1016/j.biochi.2015.02.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 02/23/2015] [Indexed: 12/18/2022]
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