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Abrams CK. Mechanisms of Diseases Associated with Mutation in GJC2/Connexin 47. Biomolecules 2023; 13:biom13040712. [PMID: 37189458 DOI: 10.3390/biom13040712] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/17/2023] Open
Abstract
Connexins are members of a family of integral membrane proteins that provide a pathway for both electrical and metabolic coupling between cells. Astroglia express connexin 30 (Cx30)-GJB6 and Cx43-GJA1, while oligodendroglia express Cx29/Cx31.3-GJC3, Cx32-GJB1, and Cx47-GJC2. Connexins organize into hexameric hemichannels (homomeric if all subunits are identical or heteromeric if one or more differs). Hemichannels from one cell then form cell-cell channels with a hemichannel from an apposed cell. (These are termed homotypic if the hemichannels are identical and heterotypic if the hemichannels differ). Oligodendrocytes couple to each other through Cx32/Cx32 or Cx47/Cx47 homotypic channels and they couple to astrocytes via Cx32/Cx30 or Cx47/Cx43 heterotypic channels. Astrocytes couple via Cx30/Cx30 and Cx43/Cx43 homotypic channels. Though Cx32 and Cx47 may be expressed in the same cells, all available data suggest that Cx32 and Cx47 cannot interact heteromerically. Animal models wherein one or in some cases two different CNS glial connexins have been deleted have helped to clarify the role of these molecules in CNS function. Mutations in a number of different CNS glial connexin genes cause human disease. Mutations in GJC2 lead to three distinct phenotypes, Pelizaeus Merzbacher like disease, hereditary spastic paraparesis (SPG44) and subclinical leukodystrophy.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
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2
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Rathjen FG, Jüttner R. The IgSF Cell Adhesion Protein CLMP and Congenital Short Bowel Syndrome (CSBS). Int J Mol Sci 2023; 24:ijms24065719. [PMID: 36982793 PMCID: PMC10056934 DOI: 10.3390/ijms24065719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/09/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
The immunoglobulin-like cell adhesion molecule CLMP is a member of the CAR family of cell adhesion proteins and is implicated in human congenital short-bowel syndrome (CSBS). CSBS is a rare but very severe disease for which no cure is currently available. In this review, we compare data from human CSBS patients and a mouse knockout model. These data indicate that CSBS is characterized by a defect in intestinal elongation during embryonic development and impaired peristalsis. The latter is driven by uncoordinated calcium signaling via gap junctions, which is linked to a reduction in connexin43 and 45 levels in the circumferential smooth muscle layer of the intestine. Furthermore, we discuss how mutations in the CLMP gene affect other organs and tissues, including the ureter. Here, the absence of CLMP produces a severe bilateral hydronephrosis—also caused by a reduced level of connexin43 and associated uncoordinated calcium signaling via gap junctions.
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Activation of the unfolded protein response by Connexin47 mutations associated with Pelizaeus-Merzbacher-like disease. Mol Cell Neurosci 2022; 120:103716. [PMID: 35276347 DOI: 10.1016/j.mcn.2022.103716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 11/23/2022] Open
Abstract
Pelizaeus-Merzbacher-like disease type 1 (PMLD1) is a hypomyelinating disorder arising in patients with mutations in GJC2, encoding Connexin47 (Cx47). PMLD1 causes nystagmus, cerebellar ataxia, spasticity and changes in CNS white matter detected by MRI. At least one mutation (p.I33M) yields a much milder phenotype, spastic paraplegia type 44 (SPG44). Cx47 contributes to gap junction communication channels between oligodendrocytes (OLs), the myelinating cells in the central nervous system (CNS), and between OLs and astrocytes. Prior studies in cell lines have shown that PMLD1 mutants such as p.P87S display defective protein trafficking, intracellular retention in the ER and loss-of-function. Here we show that when expressed in primary OLs, three PMLD1 associated mutants (p.P87S, p.Y269D and p.M283T) show ER retention of Cx47 and evidence of activation of the cellular stress (unfolded protein response, UPR) and apoptotic pathways. On the other hand, the milder SPG44 associated mutation p.I33M shows a wild-type-like subcellular distribution and no activation of the UPR or apoptotic pathways. These studies provide new insight into a potential element of toxic gain of function underlying the mechanism of PMLD1 that should help guide future therapeutic approaches.
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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5
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Rathjen FG. The CAR group of Ig cell adhesion proteins–Regulators of gap junctions? Bioessays 2020; 42:e2000031. [DOI: 10.1002/bies.202000031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 09/01/2020] [Indexed: 12/29/2022]
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6
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Luo M, Zhang L, Yang H, Luo K, Qing C. Long non‑coding RNA NEAT1 promotes ovarian cancer cell invasion and migration by interacting with miR‑1321 and regulating tight junction protein 3 expression. Mol Med Rep 2020; 22:3429-3439. [PMID: 32945443 PMCID: PMC7453588 DOI: 10.3892/mmr.2020.11428] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
Previous studies have reported that long non‑coding RNAs (lncRNAs) have a significant role in the metastasis of tumors, including ovarian cancer (OC). The aim of the present study was to demonstrate the function and working mechanism of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in OC. The expressions of NEAT1 in OC were measured by reverse transcription‑quantitativePCR (RT‑qPCR). The effects of NEAT1 on cell proliferation, invasion, migration and epithelial‑mesenchymal transition (EMT) were detected by Cell Counting Kit‑8, transwell and wound healing assays, and western blotting. Dual‑luciferase reporter assays were performed to confirm the correlated between NEAT and miR‑1321, miR‑1321 and TJP3. The effect of NEAT1 on miR‑1321 and TJP3 was confirmed by RT‑qPCR and western blotting. Elevated expression of NEAT1 was observed in OC cell lines, and NEAT1 expression was found to be positively related to the expression of tight junction protein 3 (TJP3), which is important in cancer development. Moreover, the present results indicated that NEAT1 and TJP3 expression levels were negatively correlated with microRNA (miR)‑1321 expression in OC. Knockdown of NEAT1 attenuated the migration and invasion of OC cells, as well as increased miR‑1321 expression and in turn led to the reduction of TJP3. Thus, the present study demonstrated that NEAT1 regulates TJP3 expression by sponging miR‑1321 and enhances the epithelial‑mesenchymal transition, invasion and migration of OC cells. Overall, the present study identified the function and mechanism of NEAT1 in OC, suggesting that NEAT1 may be a promising therapeutic target for OC metastasis.
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Affiliation(s)
- Min Luo
- School of Medicine, Yunnan University, Kunming, Yunnan 650091, P.R. China
- School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
- Yunnan Key Laboratory of Quality Standards for Traditional Chinese Medicine and National Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan 650500, P.R. China
| | - Lei Zhang
- Department of Gynecology, Yunnan Tumor Hospital & The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, P.R. China
| | - Hongying Yang
- Department of Gynecology, Yunnan Tumor Hospital & The Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118, P.R. China
| | - Kaili Luo
- School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
| | - Chen Qing
- School of Pharmaceutical Sciences and Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, Yunnan 650500, P.R. China
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7
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Rouaud F, Sluysmans S, Flinois A, Shah J, Vasileva E, Citi S. Scaffolding proteins of vertebrate apical junctions: structure, functions and biophysics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183399. [DOI: 10.1016/j.bbamem.2020.183399] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
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8
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Dai W, Nadadur RD, Brennan JA, Smith HL, Shen KM, Gadek M, Laforest B, Wang M, Gemel J, Li Y, Zhang J, Ziman BD, Yan J, Ai X, Beyer EC, Lakata EG, Kasthuri N, Efimov IR, Broman MT, Moskowitz IP, Shen L, Weber CR. ZO-1 Regulates Intercalated Disc Composition and Atrioventricular Node Conduction. Circ Res 2020; 127:e28-e43. [PMID: 32347164 PMCID: PMC7334106 DOI: 10.1161/circresaha.119.316415] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
RATIONALE ZO-1 (Zona occludens 1), encoded by the tight junction protein 1 (TJP1) gene, is a regulator of paracellular permeability in epithelia and endothelia. ZO-1 interacts with the actin cytoskeleton, gap, and adherens junction proteins and localizes to intercalated discs in cardiomyocytes. However, the contribution of ZO-1 to cardiac physiology remains poorly defined. OBJECTIVE We aim to determine the role of ZO-1 in cardiac function. METHODS AND RESULTS Inducible cardiomyocyte-specific Tjp1 deletion mice (Tjp1fl/fl; Myh6Cre/Esr1*) were generated by crossing the Tjp1 floxed mice and Myh6Cre/Esr1* transgenic mice. Tamoxifen-induced loss of ZO-1 led to atrioventricular (AV) block without changes in heart rate, as measured by ECG and ex vivo optical mapping. Mice with tamoxifen-induced conduction system-specific deletion of Tjp1 (Tjp1fl/fl; Hcn4CreERt2) developed AV block while tamoxifen-induced conduction system deletion of Tjp1 distal to the AV node (Tjp1fl/fl; Kcne1CreERt2) did not demonstrate conduction defects. Western blot and immunostaining analyses of AV nodes showed that ZO-1 loss decreased Cx (connexin) 40 expression and intercalated disc localization. Consistent with the mouse model study, immunohistochemical staining showed that ZO-1 is abundantly expressed in the human AV node and colocalizes with Cx40. Ventricular conduction was not altered despite decreased localization of ZO-1 and Cx43 at the ventricular intercalated disc and modestly decreased left ventricular ejection fraction, suggesting ZO-1 is differentially required for AV node and ventricular conduction. CONCLUSIONS ZO-1 is a key protein responsible for maintaining appropriate AV node conduction through maintaining gap junction protein localization.
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Affiliation(s)
- Wenli Dai
- Pathology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Rangarajan D. Nadadur
- Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Jaclyn A. Brennan
- Department of Biomedical Engineering, The George Washington University, 800 22nd St NW, Washington, DC 20052
| | - Heather L. Smith
- Pathology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Kaitlyn M. Shen
- Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Margaret Gadek
- Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Brigitte Laforest
- Medicine, Section of Cardiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Mingyi Wang
- Laboratory of Cardiovascular Science, National Institution on Aging-NIH, BRC-9B0127 251 Bayview Blvd, Baltimore, MD 21224
| | - Joanna Gemel
- Pediatrics, University of Chicago, Chicago, IL 60637, USA
| | - Ye Li
- Pathology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Jing Zhang
- Laboratory of Cardiovascular Science, National Institution on Aging-NIH, BRC-9B0127 251 Bayview Blvd, Baltimore, MD 21224
| | - Bruce D. Ziman
- Laboratory of Cardiovascular Science, National Institution on Aging-NIH, BRC-9B0127 251 Bayview Blvd, Baltimore, MD 21224
| | - Jiajie Yan
- Physiology and Biophysics, Rush University, 1750 West Harrison St., Chicago, IL 60612
| | - Xun Ai
- Physiology and Biophysics, Rush University, 1750 West Harrison St., Chicago, IL 60612
| | - Eric C. Beyer
- Pediatrics, University of Chicago, Chicago, IL 60637, USA
| | - Edward G. Lakata
- Laboratory of Cardiovascular Science, National Institution on Aging-NIH, BRC-9B0127 251 Bayview Blvd, Baltimore, MD 21224
| | - Narayanan Kasthuri
- Neurobiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Igor R. Efimov
- Department of Biomedical Engineering, The George Washington University, 800 22nd St NW, Washington, DC 20052
| | - Michael T. Broman
- Medicine, Section of Cardiology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
| | - Ivan P. Moskowitz
- Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, IL 60637, USA
| | - Le Shen
- Pathology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
- Section of Neurosurgery, Department of Surgery, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637
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9
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Zhang J, Vincent KP, Peter AK, Klos M, Cheng H, Huang SM, Towne JK, Ferng D, Gu Y, Dalton ND, Chan Y, Li R, Peterson KL, Chen J, McCulloch AD, Knowlton KU, Ross RS. Cardiomyocyte Expression of ZO-1 Is Essential for Normal Atrioventricular Conduction but Does Not Alter Ventricular Function. Circ Res 2020; 127:284-297. [PMID: 32345129 DOI: 10.1161/circresaha.119.315539] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE ZO-1 (Zonula occludens-1), a plasma membrane-associated scaffolding protein regulates signal transduction, transcription, and cellular communication. Global deletion of ZO-1 in the mouse is lethal by embryonic day 11.5. The function of ZO-1 in cardiac myocytes (CM) is largely unknown. OBJECTIVE To determine the function of CM ZO-1 in the intact heart, given its binding to other CM proteins that have been shown instrumental in normal cardiac conduction and function. METHODS AND RESULTS We generated ZO-1 CM-specific knockout (KO) mice using α-Myosin Heavy Chain-nuclear Cre (ZO-1cKO) and investigated physiological and electrophysiological function by echocardiography, surface ECG and conscious telemetry, intracardiac electrograms and pacing, and optical mapping studies. ZO-1cKO mice were viable, had normal Mendelian ratios, and had a normal lifespan. Ventricular morphometry and function were not significantly different between the ZO-1cKO versus control (CTL) mice, basally in young or aged mice, or even when hearts were subjected to hemodynamic loading. Atrial mass was increased in ZO-1cKO. Electrophysiological and optical mapping studies indicated high-grade atrioventricular (A-V) block in ZO-1cKO comparing to CTL hearts. While ZO-1-associated proteins such as vinculin, connexin 43, N-cadherin, and α-catenin showed no significant change with the loss of ZO-1, Connexin-45 and Coxsackie-adenovirus (CAR) proteins were reduced in atria of ZO-1cKO. Further, with loss of ZO-1, ZO-2 protein was increased significantly in ventricular CM in a presumed compensatory manner but was still not detected in the AV nodal myocytes. Importantly, the expression of the sodium channel protein NaV1.5 was altered in AV nodal cells of the ZO-1cKO versus CTL. CONCLUSIONS ZO-1 protein has a unique physiological role in cardiac nodal tissue. This is in alignment with its known interaction with CAR and Cx45, and a new function in regulating the expression of NaV1.5 in AV node. Uniquely, ZO-1 is dispensable for function of the working myocardium.
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Affiliation(s)
- Jianlin Zhang
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Kevin P Vincent
- Department of Bioengineering (K.P.V., A.D.M.), University of California San Diego, La Jolla, CA
| | - Angela K Peter
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Matthew Klos
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Hongqiang Cheng
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Selina M Huang
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Jordan K Towne
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Debbie Ferng
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Yusu Gu
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Nancy D Dalton
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Yunghang Chan
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Ruixia Li
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Kirk L Peterson
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Ju Chen
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
| | - Andrew D McCulloch
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
- Department of Bioengineering (K.P.V., A.D.M.), University of California San Diego, La Jolla, CA
| | | | - Robert S Ross
- From the Department of Medicine (J.Z., A.K.P., M.K., H.C., S.M.H., J.K.T., D.F., Y.G., N.D.D., Y.C., J.K.T., D.F., Y.G., N.D.D., Y.C., R.L., K.L.P., J.C., A.D.M., R.S.R.), University of California San Diego, La Jolla, CA
- Veterans Administration Healthcare, Cardiology Section, San Diego, CA (R.S.R.)
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González-Mariscal L, Miranda J, Gallego-Gutiérrez H, Cano-Cortina M, Amaya E. Relationship between apical junction proteins, gene expression and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183278. [PMID: 32240623 DOI: 10.1016/j.bbamem.2020.183278] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/09/2020] [Accepted: 03/06/2020] [Indexed: 12/11/2022]
Abstract
The apical junctional complex (AJC) is a cell-cell adhesion system present at the upper portion of the lateral membrane of epithelial cells integrated by the tight junction (TJ) and the adherens junction (AJ). This complex is crucial to initiate and stabilize cell-cell adhesion, to regulate the paracellular transit of ions and molecules and to maintain cell polarity. Moreover, we now consider the AJC as a hub of signal transduction that regulates cell-cell adhesion, gene transcription and cell proliferation and differentiation. The molecular components of the AJC are multiple and diverse and depending on the cellular context some of the proteins in this complex act as tumor suppressors or as promoters of cell transformation, migration and metastasis outgrowth. Here, we describe these new roles played by TJ and AJ proteins and their potential use in cancer diagnostics and as targets for therapeutic intervention.
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Affiliation(s)
- Lorenza González-Mariscal
- Department of Physiology, Biophysics and Neuroscience, Center of Research and Advanced Studies (Cinvestav), Mexico City, Mexico.
| | - Jael Miranda
- Department of Physiology, Biophysics and Neuroscience, Center of Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Helios Gallego-Gutiérrez
- Department of Physiology, Biophysics and Neuroscience, Center of Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Misael Cano-Cortina
- Department of Physiology, Biophysics and Neuroscience, Center of Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Elida Amaya
- Department of Physiology, Biophysics and Neuroscience, Center of Research and Advanced Studies (Cinvestav), Mexico City, Mexico
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11
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Abrams CK, Peinado A, Mahmoud R, Bocarsly M, Zhang H, Chang P, Botello-Smith WM, Freidin MM, Luo Y. Alterations at Arg 76 of human connexin 46, a residue associated with cataract formation, cause loss of gap junction formation but preserve hemichannel function. Am J Physiol Cell Physiol 2018; 315:C623-C635. [PMID: 30044662 DOI: 10.1152/ajpcell.00157.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The connexins are members of a family of integral membrane proteins that form gap junction channels between apposed cells and/or hemichannels across the plasma membranes. The importance of the arginine at position 76 (Arg76) in the structure and/or function of connexin 46 (Cx46) is highlighted by its conservation across the entire connexin family and the occurrence of pathogenic mutations at this (or the corresponding homologous) residue in a number of human diseases. Two mutations at Arg76 in Cx46 are associated with cataracts in humans, highlighting the importance of this residue. We examined the expression levels and macroscopic and single-channel properties of human Cx46 and compared them with those for two pathogenic mutants, namely R76H and R76G. To gain further insight into the role of charge at this position, we generated two additional nonnaturally occurring mutants, R76K (charge conserving) and R76E (charge inverting). We found that, when expressed exogenously in Neuro2a cells, all four mutants formed membrane hemichannels, inducing membrane permeability at levels comparable to those recorded in cells expressing the wild-type Cx46. In contrast, the number of gap-junction plaques and the magnitude of junctional coupling were reduced by all four mutations. To gain further insight into the role of Arg76 in the function of Cx46, we performed homology modeling of Cx46 and in silico mutagenesis of Arg76 to Gly, His, or Glu. Our studies suggest that the loss of interprotomeric interactions has a significant effect on the extracellular domain conformation and dynamics, thus affecting the hemichannel docking required for formation of cell-cell channels.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Alejandro Peinado
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
| | - Rola Mahmoud
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Matan Bocarsly
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Han Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Paul Chang
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Wesley M Botello-Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine , Chicago, Illinois
- Department of Neurology State University of New York Downstate Medical Center , Brooklyn New York
| | - Yun Luo
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences , Pomona, California
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Alaei SR, Abrams CK, Bulinski JC, Hertzberg EL, Freidin MM. Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32. BMC Cell Biol 2018; 19:22. [PMID: 30268116 PMCID: PMC6162937 DOI: 10.1186/s12860-018-0173-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 09/17/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The gap junction protein, Connexin32 (Cx32), is expressed in various tissues including liver, exocrine pancreas, gastrointestinal epithelium, and the glia of the central and peripheral nervous system. Gap junction-mediated cell-cell communication and channel-independent processes of Cx32 contribute to the regulation of physiological and cellular activities such as glial differentiation, survival, and proliferation; maintenance of the hepatic epithelium; and axonal myelination. Mutations in Cx32 cause X-linked Charcot-Marie-Tooth disease (CMT1X), an inherited peripheral neuropathy. Several CMT1X causing mutations are found in the cytoplasmic domains of Cx32, a region implicated in the regulation of gap junction assembly, turnover and function. Here we investigate the roles of acetylation and ubiquitination in the C-terminus on Cx32 protein function. Cx32 protein turnover, ubiquitination, and response to deacetylase inhibitors were determined for wild-type and C-terminus lysine mutants using transiently transfected Neuro2A (N2a) cells. RESULTS We report here that Cx32 is acetylated in transfected N2a cells and that inhibition of the histone deacetylase, HDAC6, results in an accumulation of Cx32. We identified five lysine acetylation targets in the C-terminus. Mutational analysis demonstrates that these lysines are involved in the regulation of Cx32 ubiquitination and turnover. While these lysines are not required for functional Cx32 mediated cell-cell communication, BrdU incorporation studies demonstrate that their relative acetylation state plays a channel-independent role in Cx32-mediated control of cell proliferation. CONCLUSION Taken together these results highlight the role of post translational modifications and lysines in the C-terminal tail of Cx32 in the fine-tuning of Cx32 protein stability and channel-independent functions.
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Affiliation(s)
- Sarah R. Alaei
- Department of Molecular Genetics & Microbiology, Stony Brook University, Stony Brook, NY 11794 USA
| | - Charles K. Abrams
- Department of Neurology & Rehabilitation, University of Illinois at Chicago, Chicago, IL 60612 USA
| | - J. Chloë Bulinski
- Department of Cell & Molecular Biology, Columbia University, New York, NY 10032 USA
| | - Elliot L. Hertzberg
- Department of Cell & Molecular Biology, Columbia University, New York, NY 10032 USA
| | - Mona M. Freidin
- Department of Neurology & Rehabilitation, University of Illinois at Chicago, Chicago, IL 60612 USA
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A Cell Junctional Protein Network Associated with Connexin-26. Int J Mol Sci 2018; 19:ijms19092535. [PMID: 30150563 PMCID: PMC6163694 DOI: 10.3390/ijms19092535] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 02/06/2023] Open
Abstract
GJB2 mutations are the leading cause of non-syndromic inherited hearing loss. GJB2 encodes connexin-26 (CX26), which is a connexin (CX) family protein expressed in cochlea, skin, liver, and brain, displaying short cytoplasmic N-termini and C-termini. We searched for CX26 C-terminus binding partners by affinity capture and identified 12 unique proteins associated with cell junctions or cytoskeleton (CGN, DAAM1, FLNB, GAPDH, HOMER2, MAP7, MAPRE2 (EB2), JUP, PTK2B, RAI14, TJP1, and VCL) by using mass spectrometry. We show that, similar to other CX family members, CX26 co-fractionates with TJP1, VCL, and EB2 (EB1 paralogue) as well as the membrane-associated protein ASS1. The adaptor protein CGN (cingulin) co-immuno-precipitates with CX26, ASS1, and TJP1. In addition, CGN co-immunoprecipitation with CX30, CX31, and CX43 indicates that CX association is independent on the CX C-terminus length or sequence. CX26, CGN, FLNB, and DAMM1 were shown to distribute to the organ of Corti and hepatocyte plasma membrane. In the mouse liver, CX26 and TJP1 co-localized at the plasma membrane. In conclusion, CX26 associates with components of other membrane junctions that integrate with the cytoskeleton.
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Langhorst H, Jüttner R, Groneberg D, Mohtashamdolatshahi A, Pelz L, Purfürst B, Schmidt-Ott KM, Friebe A, Rathjen FG. The IgCAM CLMP regulates expression of Connexin43 and Connexin45 in intestinal and ureteral smooth muscle contraction in mice. Dis Model Mech 2018; 11:dmm.032128. [PMID: 29361518 PMCID: PMC5894946 DOI: 10.1242/dmm.032128] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 01/09/2018] [Indexed: 11/25/2022] Open
Abstract
CAR-like membrane protein (CLMP), an immunoglobulin cell adhesion molecule (IgCAM), has been implicated in congenital short-bowel syndrome in humans, a condition with high mortality for which there is currently no cure. We therefore studied the function of CLMP in a Clmp-deficient mouse model. Although we found that the levels of mRNAs encoding Connexin43 or Connexin45 were not or were only marginally affected, respectively, by Clmp deficiency, the absence of CLMP caused a severe reduction of both proteins in smooth muscle cells of the intestine and of Connexin43 in the ureter. Analysis of calcium signaling revealed a disordered cell-cell communication between smooth muscle cells, which in turn induced an impaired and uncoordinated motility of the intestine and the ureter. Consequently, insufficient transport of chyme and urine caused a fatal delay to thrive, a high rate of mortality, and provoked a severe hydronephrosis in CLMP knockouts. Neurotransmission and the capability of smooth muscle cells to contract in ring preparations of the intestine were not altered. Physical obstructions were not detectable and an overall normal histology in the intestine as well as in the ureter was observed, except for a slight hypertrophy of smooth muscle layers. Deletion of Clmp did not lead to a reduced length of the intestine as shown for the human CLMP gene but resulted in gut malrotations. In sum, the absence of CLMP caused functional obstructions in the intestinal tract and ureter by impaired peristaltic contractions most likely due to a lack of gap-junctional communication between smooth muscle cells. Summary: The function of the immunoglobulin cell adhesion molecule CLMP was investigated in a mouse model. CLMP is essential for intestinal and ureteral peristalsis, and for expression of Connexin43 and 45 in smooth muscle cells.
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Affiliation(s)
- Hanna Langhorst
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - René Jüttner
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Dieter Groneberg
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, DE-97070 Würzburg, Germany
| | | | - Laura Pelz
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Bettina Purfürst
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
| | - Kai M Schmidt-Ott
- Charité-Universitätsmedizin Berlin, Department of Nephrology, Charitéplatz 1, DE-10117 Berlin, Germany
| | - Andreas Friebe
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, DE-97070 Würzburg, Germany
| | - Fritz G Rathjen
- Max-Delbrück-Center for Molecular Medicine, DE-13092 Berlin, Germany
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15
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Ock S, Lee WS, Kim HM, Park KS, Kim YK, Kook H, Park WJ, Lee TJ, Abel ED, Kim J. Connexin43 and zonula occludens-1 are targets of Akt in cardiomyocytes that correlate with cardiac contractile dysfunction in Akt deficient hearts. Biochim Biophys Acta Mol Basis Dis 2018; 1864:1183-1191. [PMID: 29378301 DOI: 10.1016/j.bbadis.2018.01.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/12/2018] [Accepted: 01/23/2018] [Indexed: 01/05/2023]
Abstract
While deletion of Akt1 results in a smaller heart size and Akt2-/- mice are mildly insulin resistant, Akt1-/-/Akt2-/- mice exhibit perinatal lethality, indicating a large degree of functional overlap between the isoforms of the serine/threonine kinase Akt. The present study aimed to determine the cooperative contribution of Akt1 and Akt2 on the structure and contractile function of adult hearts. To generate an inducible, cardiomyocyte-restricted Akt2 knockout (KO) model, Akt2flox/flox mice were crossed with tamoxifen-inducible MerCreMer transgenic (MCM) mice and germline Akt1-/- mice to generate the following genotypes:Akt1+/+; Akt2flox/flox (WT), Akt2flox/flox; α-MHC-MCM (iAkt2 KO), Akt1-/-, and Akt1-/-; Akt2flox/flox; α-MHC-MCM mice (Akt1-/-/iAkt2 KO). At 28 days after the first tamoxifen injection, Akt1-/-/iAkt2 KO mice developed contractile dysfunction paralleling increased atrial and brain natriuretic peptide (ANP and BNP) levels, and repressed mitochondrial gene expression. Neither cardiac fibrosis nor apoptosis were detected in Akt1-/-/iAkt2 KO hearts. To explore potential molecular mechanisms for contractile dysfunction, we investigated myocardial microstructure before the onset of heart failure. At 3 days after the first tamoxifen injection, Akt1-/-/iAkt2 KO hearts showed decreased expression of connexin43 (Cx43) and connexin-interacting protein zonula occludens-1 (ZO-1). Furthermore, Akt1/2 silencing significantly decreased both Cx43 and ZO-1 expression in cultured neonatal rat cardiomyocytes in concert with reduced beating frequency. Akt1 and Akt2 are required to maintain cardiac contraction. Loss of Akt signaling disrupts gap junction protein, which might precipitate early contractile dysfunction prior to heart failure in the absence of myocardial remodeling, such as hypertrophy, fibrosis, or cell death.
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Affiliation(s)
- Sangmi Ock
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Wang Soo Lee
- Division of Cardiology, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Hyun Min Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - Kyu-Sang Park
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonjoo, Republic of Korea
| | - Young-Kook Kim
- Department of Biochemistry, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Hyun Kook
- Department of Pharmacology, Medical Research Center for Gene Regulation, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Woo Jin Park
- Department of Life Science, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Tae Jin Lee
- Department of Pathology, College of Medicine, Chung-Ang University, Seoul, Republic of Korea
| | - E D Abel
- Fraternal Order of Eagles Diabetes Research Center, Division of Endocrinology and Metabolism, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
| | - Jaetaek Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Republic of Korea.
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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: 171] [Impact Index Per Article: 24.4] [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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Papadopoulos D, Scheiner-Bobis G. Dehydroepiandrosterone sulfate augments blood-brain barrier and tight junction protein expression in brain endothelial cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1382-1392. [DOI: 10.1016/j.bbamcr.2017.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 12/15/2022]
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18
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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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19
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Raya-Sandino A, Castillo-Kauil A, Domínguez-Calderón A, Alarcón L, Flores-Benitez D, Cuellar-Perez F, López-Bayghen B, Chávez-Munguía B, Vázquez-Prado J, González-Mariscal L. Zonula occludens-2 regulates Rho proteins activity and the development of epithelial cytoarchitecture and barrier function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1714-1733. [PMID: 28554775 DOI: 10.1016/j.bbamcr.2017.05.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 05/18/2017] [Accepted: 05/24/2017] [Indexed: 12/11/2022]
Abstract
Silencing Zonula occludens 2 (ZO-2), a tight junctions (TJ) scaffold protein, in epithelial cells (MDCK ZO-2 KD) triggers: 1) Decreased cell to substratum attachment, accompanied by reduced expression of claudin-7 and integrin β1, and increased vinculin recruitment to focal adhesions and stress fibers formation; 2) Lowered cell-cell aggregation and appearance of wider intercellular spaces; 3) Increased RhoA/ROCK activity, mediated by GEF-HI recruitment to cell borders by cingulin; 4) Increased Cdc42 activity, mitotic spindle disorientation and the appearance of cysts with multiple lumens; 5) Increased Rac and cofilin activity, multiple lamellipodia formation and random cell migration but increased wound closure; 6) Diminished cingulin phosphorylation and disappearance of planar network of microtubules at the TJ region; and 7) Increased transepithelial electrical resistance at steady state, coupled to an increased expression of ZO-1 and claudin-4 and a decreased expression of claudin-2 and paracingulin. Hence, ZO-2 is a crucial regulator of Rho proteins activity and the development of epithelial cytoarchitecture and barrier function.
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Affiliation(s)
- Arturo Raya-Sandino
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Alejandro Castillo-Kauil
- Department of Cell Biology, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Alaide Domínguez-Calderón
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Lourdes Alarcón
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - David Flores-Benitez
- Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Francisco Cuellar-Perez
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Bruno López-Bayghen
- Department of Toxicology, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Bibiana Chávez-Munguía
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - José Vázquez-Prado
- Department of Pharmacology, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico
| | - Lorenza González-Mariscal
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), México D.F. 07360, Mexico.
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20
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Yao F, Kausalya JP, Sia YY, Teo ASM, Lee WH, Ong AGM, Zhang Z, Tan JHJ, Li G, Bertrand D, Liu X, Poh HM, Guan P, Zhu F, Pathiraja TN, Ariyaratne PN, Rao J, Woo XY, Cai S, Mulawadi FH, Poh WT, Veeravalli L, Chan CS, Lim SS, Leong ST, Neo SC, Choi PSD, Chew EGY, Nagarajan N, Jacques PÉ, So JBY, Ruan X, Yeoh KG, Tan P, Sung WK, Hunziker W, Ruan Y, Hillmer AM. Recurrent Fusion Genes in Gastric Cancer: CLDN18-ARHGAP26 Induces Loss of Epithelial Integrity. Cell Rep 2015; 12:272-85. [PMID: 26146084 DOI: 10.1016/j.celrep.2015.06.020] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 04/21/2015] [Accepted: 06/06/2015] [Indexed: 12/21/2022] Open
Abstract
Genome rearrangements, a hallmark of cancer, can result in gene fusions with oncogenic properties. Using DNA paired-end-tag (DNA-PET) whole-genome sequencing, we analyzed 15 gastric cancers (GCs) from Southeast Asians. Rearrangements were enriched in open chromatin and shaped by chromatin structure. We identified seven rearrangement hot spots and 136 gene fusions. In three out of 100 GC cases, we found recurrent fusions between CLDN18, a tight junction gene, and ARHGAP26, a gene encoding a RHOA inhibitor. Epithelial cell lines expressing CLDN18-ARHGAP26 displayed a dramatic loss of epithelial phenotype and long protrusions indicative of epithelial-mesenchymal transition (EMT). Fusion-positive cell lines showed impaired barrier properties, reduced cell-cell and cell-extracellular matrix adhesion, retarded wound healing, and inhibition of RHOA. Gain of invasion was seen in cancer cell lines expressing the fusion. Thus, CLDN18-ARHGAP26 mediates epithelial disintegration, possibly leading to stomach H(+) leakage, and the fusion might contribute to invasiveness once a cell is transformed.
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Affiliation(s)
- Fei Yao
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore
| | - Jaya P Kausalya
- Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Yee Yen Sia
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore
| | - Audrey S M Teo
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore
| | - Wah Heng Lee
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Alicia G M Ong
- Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, Singapore 138673, Singapore
| | - Zhenshui Zhang
- Human Genetics, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Joanna H J Tan
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Guoliang Li
- National Key Laboratory of Crop Genetic Improvement, Center for Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Denis Bertrand
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Xingliang Liu
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Huay Mei Poh
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Peiyong Guan
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore; School of Computing, National University of Singapore, Singapore 117417, Singapore
| | - Feng Zhu
- The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Thushangi Nadeera Pathiraja
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore
| | - Pramila N Ariyaratne
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Jaideepraj Rao
- Department of General Surgery, Tan Tock Seng Hospital, Singapore 308433, Singapore
| | - Xing Yi Woo
- Personal Genomic Solutions, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Shaojiang Cai
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Fabianus H Mulawadi
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Wan Ting Poh
- Personal Genomic Solutions, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Lavanya Veeravalli
- Research Computing, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Chee Seng Chan
- Research Computing, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Seong Soo Lim
- Human Genetics, Genome Institute of Singapore, Singapore 138672, Singapore
| | - See Ting Leong
- Genome Technology and Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Say Chuan Neo
- Genome Technology and Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Poh Sum D Choi
- Genome Technology and Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Elaine G Y Chew
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Niranjan Nagarajan
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | | | - Jimmy B Y So
- The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore; Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; National University Health System, Singapore 119228, Singapore
| | - Xiaoan Ruan
- Personal Genomic Solutions, Genome Institute of Singapore, Singapore 138672, Singapore; Genome Technology and Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Khay Guan Yeoh
- The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; National University Health System, Singapore 119228, Singapore
| | - Patrick Tan
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore; Duke-NUS Graduate Medical School, Singapore 169857, Singapore; Cancer Science Institute of Singapore, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117599, Singapore
| | - Wing-Kin Sung
- Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore; School of Computing, National University of Singapore, Singapore 117417, Singapore
| | - Walter Hunziker
- Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, Singapore 138673, Singapore; Department of Physiology, National University of Singapore, Singapore 117597, Singapore.
| | - Yijun Ruan
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA.
| | - Axel M Hillmer
- Cancer Therapeutics and Stratified Oncology, Genome Institute of Singapore, Singapore 138672, Singapore; The Singapore Gastric Cancer Consortium, National University of Singapore, Singapore 119228, Singapore.
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21
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Kopanic JL, Al-mugotir MH, Kieken F, Zach S, Trease AJ, Sorgen PL. Characterization of the connexin45 carboxyl-terminal domain structure and interactions with molecular partners. Biophys J 2014; 106:2184-95. [PMID: 24853747 PMCID: PMC4052358 DOI: 10.1016/j.bpj.2014.03.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 03/19/2014] [Accepted: 03/31/2014] [Indexed: 02/02/2023] Open
Abstract
Mechanisms underlying the initiation and persistence of lethal cardiac rhythms are of significant clinical and scientific interests. Gap junctions are principally involved in forming the electrical connections between myocytes, and changes in distribution, density, and properties are consistent characteristics in arrhythmic heart disease. Therefore, understanding the structure and function of gap junctions during normal and abnormal impulse propagation are essential in the control of arrhythmias. For example, Cx45 is predominately expressed in the specialized myocytes of the impulse generation and conduction system. In both ventricular and atrial human working myocytes, Cx45 is present in very low quantities. However, a reduction in Cx43 coupled with an increased Cx45 protein levels within the ventricles have been observed after myocardial infarction and end-stage heart failure. Cx45 may influence electrical and/or metabolic coupling as a result of pathophysiological overexpression. Our goal was to identify mechanisms that could cause cellular coupling to be different between the cardiac connexins. Based upon the conserved transmembrane and extracellular loop segments, our focus was on identifying features within the divergent cytoplasmic portions. Here, we biophysically characterize the carboxyl-terminal domain of Cx45 (Cx45CT). Purification revealed the possibility of oligomeric species, which was confirmed by analytical ultracentrifugation experiments. Sedimentation equilibrium and circular dichroism studies of different Cx45CT constructs identified one region of α-helical structure (A333-N361) that mediates CT dimerization through hydrophobic contacts. Interestingly, the binding affinity of Cx45CT dimerization is 1000-fold stronger than Cx43CT dimerization. Cx45CT resonance assignments were also used to identify the binding sites and affinities of molecular partners involved in the Cx45 regulation; although none disrupted dimerization, many of these proteins interacted within one intrinsically disordered region (P278-P285). This domain has similarities with other cardiac connexins, and we propose they constitute a master regulatory domain, which contains overlapping molecular partner binding, cis-trans proline isomerization, and phosphorylation sites.
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Affiliation(s)
- Jennifer L Kopanic
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Mona H Al-mugotir
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Fabien Kieken
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Sydney Zach
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska.
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22
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Billaud M, Lohman AW, Johnstone SR, Biwer LA, Mutchler S, Isakson BE. Regulation of cellular communication by signaling microdomains in the blood vessel wall. Pharmacol Rev 2014; 66:513-69. [PMID: 24671377 DOI: 10.1124/pr.112.007351] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It has become increasingly clear that the accumulation of proteins in specific regions of the plasma membrane can facilitate cellular communication. These regions, termed signaling microdomains, are found throughout the blood vessel wall where cellular communication, both within and between cell types, must be tightly regulated to maintain proper vascular function. We will define a cellular signaling microdomain and apply this definition to the plethora of means by which cellular communication has been hypothesized to occur in the blood vessel wall. To that end, we make a case for three broad areas of cellular communication where signaling microdomains could play an important role: 1) paracrine release of free radicals and gaseous molecules such as nitric oxide and reactive oxygen species; 2) role of ion channels including gap junctions and potassium channels, especially those associated with the endothelium-derived hyperpolarization mediated signaling, and lastly, 3) mechanism of exocytosis that has considerable oversight by signaling microdomains, especially those associated with the release of von Willebrand factor. When summed, we believe that it is clear that the organization and regulation of signaling microdomains is an essential component to vessel wall function.
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Affiliation(s)
- Marie Billaud
- Dept. of Molecular Physiology and Biophysics, University of Virginia School of Medicine, PO Box 801394, Charlottesville, VA 22902.
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23
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Kurtenbach S, Kurtenbach S, Zoidl G. Gap junction modulation and its implications for heart function. Front Physiol 2014; 5:82. [PMID: 24578694 PMCID: PMC3936571 DOI: 10.3389/fphys.2014.00082] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/10/2014] [Indexed: 01/04/2023] Open
Abstract
Gap junction communication (GJC) mediated by connexins is critical for heart function. To gain insight into the causal relationship of molecular mechanisms of disease pathology, it is important to understand which mechanisms contribute to impairment of gap junctional communication. Here, we present an update on the known modulators of connexins, including various interaction partners, kinases, and signaling cascades. This gap junction network (GJN) can serve as a blueprint for data mining approaches exploring the growing number of publicly available data sets from experimental and clinical studies.
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Affiliation(s)
- Stefan Kurtenbach
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada
| | - Sarah Kurtenbach
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada
| | - Georg Zoidl
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada ; Department of Biology, Faculty of Science, York University Toronto, ON, Canada ; Center for Vision Research, York University Toronto, ON, Canada
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24
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Hervé JC, Derangeon M, Sarrouilhe D, Bourmeyster N. Influence of the scaffolding protein Zonula Occludens (ZOs) on membrane channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:595-604. [DOI: 10.1016/j.bbamem.2013.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 01/20/2023]
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25
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Thévenin AF, Kowal TJ, Fong JT, Kells RM, Fisher CG, Falk MM. Proteins and mechanisms regulating gap-junction assembly, internalization, and degradation. Physiology (Bethesda) 2014; 28:93-116. [PMID: 23455769 DOI: 10.1152/physiol.00038.2012] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Gap junctions (GJs) are the only known cellular structures that allow a direct cell-to-cell transfer of signaling molecules by forming densely packed arrays or "plaques" of hydrophilic channels that bridge the apposing membranes of neighboring cells. The crucial role of GJ-mediated intercellular communication (GJIC) for all aspects of multicellular life, including coordination of development, tissue function, and cell homeostasis, has been well documented. Assembly and degradation of these membrane channels is a complex process that includes biosynthesis of the connexin (Cx) subunit proteins (innexins in invertebrates) on endoplasmic reticulum (ER) membranes, oligomerization of compatible subunits into hexameric hemichannels (connexons), delivery of the connexons to the plasma membrane (PM), head-on docking of compatible connexons in the extracellular space at distinct locations, arrangement of channels into dynamic spatially and temporally organized GJ channel plaques, as well as internalization of GJs into the cytoplasm followed by their degradation. Clearly, precise modulation of GJIC, biosynthesis, and degradation are crucial for accurate function, and much research currently addresses how these fundamental processes are regulated. Here, we review posttranslational protein modifications (e.g., phosphorylation and ubiquitination) and the binding of protein partners (e.g., the scaffolding protein ZO-1) known to regulate GJ biosynthesis, internalization, and degradation. We also look closely at the atomic resolution structure of a GJ channel, since the structure harbors vital cues relevant to GJ biosynthesis and turnover.
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Affiliation(s)
- Anastasia F Thévenin
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
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26
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You H, Lei P, Andreadis ST. JNK is a novel regulator of intercellular adhesion. Tissue Barriers 2013; 1:e26845. [PMID: 24868495 PMCID: PMC3942331 DOI: 10.4161/tisb.26845] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/16/2013] [Accepted: 10/16/2013] [Indexed: 12/11/2022] Open
Abstract
c-Jun N-terminal Kinase (JNK) is a family of protein kinases, which are activated by stress stimuli such as inflammation, heat stress and osmotic stress, and regulate diverse cellular processes including proliferation, survival and apoptosis. In this review, we focus on a recently discovered function of JNK as a regulator of intercellular adhesion. We summarize the existing knowledge regarding the role of JNK during the formation of cell-cell junctions. The potential mechanisms and implications for processes requiring dynamic formation and dissolution of cell-cell junctions including wound healing, migration, cancer metastasis and stem cell differentiation are also discussed.
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Affiliation(s)
- Hui You
- Bioengineering Laboratory; Department of Chemical and Biological Engineering; University at Buffalo; The State University of New York; Amherst, NY USA
| | - Pedro Lei
- Bioengineering Laboratory; Department of Chemical and Biological Engineering; University at Buffalo; The State University of New York; Amherst, NY USA
| | - Stelios T Andreadis
- Bioengineering Laboratory; Department of Chemical and Biological Engineering; University at Buffalo; The State University of New York; Amherst, NY USA ; Department of Biomedical Engineering; University at Buffalo; The State University of New York; Amherst, NY USA ; Center for Excellence in Bioinformatics and Life Sciences; University at Buffalo; The State University of New York; Amherst, NY USA
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27
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Bazzoun D, Lelièvre S, Talhouk R. Polarity proteins as regulators of cell junction complexes: implications for breast cancer. Pharmacol Ther 2013; 138:418-27. [PMID: 23458609 PMCID: PMC3648792 DOI: 10.1016/j.pharmthera.2013.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 02/07/2013] [Indexed: 12/19/2022]
Abstract
The epithelium of multicellular organisms possesses a well-defined architecture, referred to as polarity that coordinates the regulation of essential cell features. Polarity proteins are intimately linked to the protein complexes that make the tight, adherens and gap junctions; they contribute to the proper localization and assembly of these cell-cell junctions within cells and consequently to functional tissue organization. The establishment of cell-cell junctions and polarity are both implicated in the regulation of epithelial modifications in normal and cancer situations. Uncovering the mechanisms through which cell-cell junctions and epithelial polarization are established and how their interaction with the microenvironment directs cell and tissue organization has opened new venues for the development of cancer therapies. In this review, we focus on the breast epithelium to highlight how polarity and cell-cell junction proteins interact together in normal and cancerous contexts to regulate major cellular mechanisms such as migration. The impact of these proteins on epigenetic mechanisms responsible for resetting cells toward oncogenesis is discussed in light of increasing evidence that tissue polarity modulates chromatin function. Finally, we give an overview of recent breast cancer therapies that target proteins involved in cell-cell junctions.
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Affiliation(s)
- Dana Bazzoun
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut (AUB), Beirut, Lebanon
| | - Sophie Lelièvre
- Department of Basic Medical Sciences and Center for Cancer Research, Purdue University, IN, U.S.A
| | - Rabih Talhouk
- Department of Biology, Faculty of Arts and Sciences, American University of Beirut (AUB), Beirut, Lebanon
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28
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Li D, Sekhon P, Barr KJ, Márquez-Rosado L, Lampe PD, Kidder GM. Connexins and steroidogenesis in mouse Leydig cells. Can J Physiol Pharmacol 2013; 91:157-64. [PMID: 23458200 PMCID: PMC3624991 DOI: 10.1139/cjpp-2012-0385] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Connexin43 has been recognized as forming gap junctions in Leydig cells. However, previous work has shown that mouse Leydig cells lacking this connexin do not suffer any limitation of their ability to produce testosterone when stimulated with luteinizing hormone. The objective of this study was to identify additional connexins in mouse Leydig cells that could be required for steroidogenesis. A reverse transcription - polymerase chain reaction screen involving isolated adult Leydig cells identified connexin36 and connexin45 as expressed along with connexin43. Treatment of dissociated testes with carbenoxolone, a nonspecific blocker of gap junctional coupling, significantly reduced testosterone output as did treatment with quinine, which disrupts coupling provided by connexin36 and connexin45 gap junctions but not those composed of connexin43, indicating that either or both of connexins 36 and 45 could be involved in supporting Leydig cell steroidogenesis. Immunolabeling of adult mouse testis sections confirmed the localization of connexin36 along with connexin43 in Leydig cell gap junctions but not connexin45, which is distributed throughout the cells. It was concluded that connexin36, connexin43, and connexin45 are coexpressed in Leydig cells with connexins 36 and 43 contributing to gap junctions. The role of connexin45 remains to be elucidated.
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Affiliation(s)
- Dan Li
- Depart of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1
- Children’s Health Research Institute, 800 Commissioners Road East, London, ON N6C 2V5
| | - Poonam Sekhon
- Depart of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1
| | - Kevin J. Barr
- Depart of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1
- Children’s Health Research Institute, 800 Commissioners Road East, London, ON N6C 2V5
| | - Lucrecia Márquez-Rosado
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M5-C129, Seattle, WA 98109
| | - Paul D. Lampe
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M5-C129, Seattle, WA 98109
| | - Gerald M. Kidder
- Depart of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1
- Children’s Health Research Institute, 800 Commissioners Road East, London, ON N6C 2V5
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29
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Xu J, Lim SBH, Ng MY, Ali SM, Kausalya JP, Limviphuvadh V, Maurer-Stroh S, Hunziker W. ZO-1 regulates Erk, Smad1/5/8, Smad2, and RhoA activities to modulate self-renewal and differentiation of mouse embryonic stem cells. Stem Cells 2013; 30:1885-900. [PMID: 22782886 DOI: 10.1002/stem.1172] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
ZO-1/Tjp1 is a cytosolic adaptor that links tight junction (TJ) transmembrane proteins to the actin cytoskeleton and has also been implicated in regulating cell proliferation and differentiation by interacting with transcriptional regulators and signaling proteins. To explore possible roles for ZO-1 in mouse embryonic stem cells (mESCs), we inactivated the ZO-1 locus by homologous recombination. The lack of ZO-1 was found to affect mESC self-renewal and differentiation in the presence of leukemia-inhibiting factor (LIF) and Bmp4 or following removal of the growth factors. Our data suggest that ZO-1 suppresses Stat3 and Smad1/5/8 activities and sustains extracellular-signal-regulated kinase (Erk) activity to promote mESC differentiation. Interestingly, Smad2, critical for human but not mESC self-renewal, was hyperactivated in ZO-1(-/-) mESCs and RhoA protein levels were concomitantly enhanced, suggesting attenuation of the noncanonical transforming growth factor β (Tgfβ)/Activin/Nodal pathway that mediates ubiquitination and degradation of RhoA via the TJ proteins Occludin, Par6, and Smurf1 and activation of the canonical Smad2-dependent pathway. Furthermore, Bmp4-induced differentiation of mESCs in the absence of LIF was suppressed in ZO-1(-/-) mESCs, but differentiation down the neural or cardiac lineages was not disturbed. These findings reveal novel roles for ZO-1 in mESC self-renewal, pluripotency, and differentiation by influencing several signaling networks that regulate these processes. Possible implications for the differing relevance of Smad2 in mESC and human ESC self-renewal and how ZO-1 may connect to the different pathways are discussed.
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Affiliation(s)
- Jianliang Xu
- Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, Singapore
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Campbell M, Humphries P. The Blood-Retina Barrier. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-4711-5_3] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Frank M, Wirth A, Andrié RP, Kreuzberg MM, Dobrowolski R, Seifert G, Offermanns S, Nickenig G, Willecke K, Schrickel JW. Connexin45 Provides Optimal Atrioventricular Nodal Conduction in the Adult Mouse Heart. Circ Res 2012; 111:1528-38. [DOI: 10.1161/circresaha.112.270561] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rationale:
The gap junctional protein connexin (Cx) 45 is strongly expressed in the early embryonic myocardium. In the adult hearts of mice and humans, the expression mainly is restricted to the cardiac conduction system. Cx45 plays an essential role for development and function of the embryonic heart because general and cardiomyocyte-directed deficiencies of Cx45 in mice lead to embryonic lethality attributable to morphological and functional cardiovascular defects. The function of Cx45 in the adult mouse has not yet been cleared.
Objective:
To clarify the function of Cx45 in the adult mouse heart.
Methods and Results:
To circumvent the embryonic lethality resulting from Cx45 deficiency, mice were generated in which deletion of Cx45 specifically was induced in cardiomyocytes of adult mice. These Cx45-deficient mice were viable but showed a decrease in atrioventricular nodal conductivity. In addition, the Cx30.2 protein that is coexpressed with Cx45 in the cardiac conduction system was posttranscriptionally reduced by 70% in mutant hearts. Furthermore, deletion of both Cx45 and Cx30.2 resulted in viable mice that, however, showed stronger impairment of atrioventricular nodal conduction than the single Cx45-deficient mice.
Conclusions:
Cx45 is required for optimal impulse propagation in the atrioventricular node and stabilizes the level of the coexpressed Cx30.2 protein in the adult mouse heart. In contrast to the embryo, Cx45 is not essential for the viability of adult mice.
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Affiliation(s)
- Marina Frank
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Angela Wirth
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - René P. Andrié
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Maria M. Kreuzberg
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Radoslaw Dobrowolski
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Gerald Seifert
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Stefan Offermanns
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Georg Nickenig
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Klaus Willecke
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
| | - Jan W. Schrickel
- From the LIMES-Institute, Molecular Genetics (M.F., M.M.K., R.D., K.W.) and Institute of Cellular Neurosciences (G.S.), University of Bonn, Bonn, Germany; Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany (A.W., S.O.); and Department of Medicine-Cardiology, University Hospital Bonn, Bonn, Germany (R.P.A., G.N., J.W.S.)
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A functional interaction between the MAGUK protein hDlg and the gap junction protein connexin 43 in cervical tumour cells. Biochem J 2012; 446:9-21. [PMID: 22657348 DOI: 10.1042/bj20111144] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Gap junctions, composed of Cxs (connexins), allow direct intercellular communication. Gap junctions are often lost during the development of malignancy, although the processes behind this are not fully understood. Cx43 is a widely expressed Cx with a long cytoplasmic C-terminal tail that contains several potential protein-interaction domains. Previously, in a model of cervical carcinogenesis, we showed that the loss of gap junctional communication correlated with relocalization of Cx43 to the cytoplasm late in tumorigenesis. In the present study, we demonstrate a similar pattern of altered expression for the hDlg (human discs large) MAGUK (membrane-associated guanylate kinase) family tumour suppressor protein in cervical tumour cells, with partial co-localization of Cx43 and hDlg in an endosomal/lysosomal compartment. Relocalization of these proteins is not due to a general disruption of cell membrane integrity or Cx targeting. Cx43 (via its C-terminus) and hDlg interact directly in vitro and can form a complex in cells. This novel interaction requires the N- and C-termini of hDlg. hDlg is not required for Cx43 internalization in W12GPXY cells. Instead, hDlg appears to have a role in maintaining a cytoplasmic pool of Cx43. These results demonstrate that hDlg is a physiologically relevant regulator of Cx43 in transformed epithelial cells.
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Abstract
Cell polarization is an evolutionarily conserved process that facilitates asymmetric distribution of organelles and proteins and that is modified dynamically during physiological processes such as cell division, migration, and morphogenesis. The plasticity with which cells change their behavior and phenotype in response to cell intrinsic and extrinsic cues is an essential feature of normal physiology. In disease states such as cancer, cells lose their ability to behave normally in response to physiological cues. A molecular understanding of mechanisms that alter the behavior of cancer cells is limited. Cell polarity proteins are a recognized class of molecules that can receive and interpret both intrinsic and extrinsic signals to modulate cell behavior. In this review, we discuss how cell polarity proteins regulate a diverse array of biological processes and how they can contribute to alterations in the behavior of cancer cells.
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Affiliation(s)
- Senthil K Muthuswamy
- Ontario Cancer Institute, Campbell Family Institute for Breast Cancer Research, University of Toronto, Toronto M5G 2M9, Canada.
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Abrams CK, Scherer SS. Gap junctions in inherited human disorders of the central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1818:2030-47. [PMID: 21871435 PMCID: PMC3771870 DOI: 10.1016/j.bbamem.2011.08.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/04/2011] [Accepted: 08/10/2011] [Indexed: 12/15/2022]
Abstract
CNS glia and neurons express connexins, the proteins that form gap junctions in vertebrates. We review the connexins expressed by oligodendrocytes and astrocytes, and discuss their proposed physiologic roles. Of the 21 members of the human connexin family, mutations in three are associated with significant central nervous system manifestations. For each, we review the phenotype and discuss possible mechanisms of disease. Mutations in GJB1, the gene for connexin 32 (Cx32) cause the second most common form of Charcot-Marie-Tooth disease (CMT1X). Though the only consistent phenotype in CMT1X patients is a peripheral demyelinating neuropathy, CNS signs and symptoms have been found in some patients. Recessive mutations in GJC2, the gene for Cx47, are one cause of Pelizaeus-Merzbacher-like disease (PMLD), which is characterized by nystagmus within the first 6 months of life, cerebellar ataxia by 4 years, and spasticity by 6 years of age. MRI imaging shows abnormal myelination. A different recessive GJC2 mutation causes a form of hereditary spastic paraparesis, which is a milder phenotype than PMLD. Dominant mutations in GJA1, the gene for Cx43, cause oculodentodigital dysplasia (ODDD), a pleitropic disorder characterized by oculo-facial abnormalities including micropthalmia, microcornia and hypoplastic nares, syndactyly of the fourth to fifth fingers and dental abnormalities. Neurologic manifestations, including spasticity and gait difficulties, are often but not universally seen. Recessive GJA1 mutations cause Hallermann-Streiff syndrome, a disorder showing substantial overlap with ODDD. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and functions.
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Affiliation(s)
- Charles K. Abrams
- Department of Neurology and Physiology & Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, 1-718-270-1270 Phone, 1-718-270-8944 Fax,
| | - Steven S. Scherer
- Department of Neurology, The University of Pennsylvania School of Medicine, Room 450 Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA 19104-6077, 215-573-3198,
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Daoud J, Asami K, Rosenberg L, Tabrizian M. Dielectric spectroscopy for non-invasive monitoring of epithelial cell differentiation within three-dimensional scaffolds. Phys Med Biol 2012; 57:5097-112. [DOI: 10.1088/0031-9155/57/16/5097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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36
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Lupo J, Conti A, Sueur C, Coly PA, Couté Y, Hunziker W, Burmeister WP, Germi R, Manet E, Gruffat H, Morand P, Boyer V. Identification of new interacting partners of the shuttling protein ubinuclein (Ubn-1). Exp Cell Res 2012; 318:509-20. [PMID: 22245583 DOI: 10.1016/j.yexcr.2011.12.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/21/2011] [Accepted: 12/24/2011] [Indexed: 10/14/2022]
Abstract
We have previously characterized ubinuclein (Ubn-1) as a NACos (Nuclear and Adherent junction Complex components) protein which interacts with viral or cellular transcription factors and the tight junction (TJ) protein ZO-1. The purpose of the present study was to get more insights on the binding partners of Ubn-1, notably those present in the epithelial junctions. Using an in vivo assay of fluorescent protein-complementation assay (PCA), we demonstrated that the N-terminal domains of the Ubn-1 and ZO-1 proteins triggered a functional interaction inside the cell. Indeed, expression of both complementary fragments of venus fused to the N-terminal parts of Ubn-1 and ZO-1 was able to reconstitute a fluorescent venus protein. Furthermore, nuclear expression of the chimeric Ubn-1 triggered nuclear localization of the chimeric ZO-1. We could localize this interaction to the PDZ2 domain of ZO-1 using an in vitro pull-down assay. More precisely, a 184-amino acid region (from amino acids 39 to 223) at the N-terminal region of Ubn-1 was responsible for the interaction with the PDZ2 domain of ZO-1. Co-imunoprecipitation and confocal microscopy experiments also revealed the tight junction protein cingulin as a new interacting partner of Ubn-1. A proteomic approach based on mass spectrometry analysis (MS) was then undertaken to identify further binding partners of GST-Ubn-1 fusion protein in different subcellular fractions of human epithelial HT29 cells. LYRIC (Lysine-rich CEACAM1-associated protein) and RACK-1 (receptor for activated C-kinase) proteins were validated as bona fide interacting partners of Ubn-1. Altogether, these results suggest that Ubn-1 is a scaffold protein influencing protein subcellular localization and is involved in several processes such as cell-cell contact signalling or modulation of gene activity.
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Affiliation(s)
- Julien Lupo
- Unit of Virus Host Cell Interactions, UMI 3265 UJF-EMBL-CNRS, 6 rue Jules Horowitz, BP 181, F-38042 Grenoble Cedex 9, France
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Hervé JC, Derangeon M, Sarrouilhe D, Giepmans BNG, Bourmeyster N. Gap junctional channels are parts of multiprotein complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1844-65. [PMID: 22197781 DOI: 10.1016/j.bbamem.2011.12.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 11/28/2011] [Accepted: 12/06/2011] [Indexed: 12/16/2022]
Abstract
Gap junctional channels are a class of membrane channels composed of transmembrane channel-forming integral membrane proteins termed connexins, innexins or pannexins that mediate direct cell-to-cell or cell-to extracellular medium communication in almost all animal tissues. The activity of these channels is tightly regulated, particularly by intramolecular modifications as phosphorylations of proteins and via the formation of multiprotein complexes where pore-forming subunits bind to auxiliary channel subunits and associate with scaffolding proteins that play essential roles in channel localization and activity. Scaffolding proteins link signaling enzymes, substrates, and potential effectors (such as channels) into multiprotein signaling complexes that may be anchored to the cytoskeleton. Protein-protein interactions play essential roles in channel localization and activity and, besides their cell-to-cell channel-forming functions, gap junctional proteins now appear involved in different cellular functions (e.g. transcriptional and cytoskeletal regulations). The present review summarizes the recent progress regarding the proteins capable of interacting with junctional proteins and highlights the function of these protein-protein interactions in cell physiology and aberrant function in diseases. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and functions.
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Affiliation(s)
- Jean-Claude Hervé
- Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, CNRS, Poitiers, France.
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Chai Z, Goodenough DA, Paul DL. Cx50 requires an intact PDZ-binding motif and ZO-1 for the formation of functional intercellular channels. Mol Biol Cell 2011; 22:4503-12. [PMID: 21965293 PMCID: PMC3226470 DOI: 10.1091/mbc.e11-05-0438] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 09/09/2011] [Accepted: 09/21/2011] [Indexed: 11/20/2022] Open
Abstract
The three connexins expressed in the ocular lens each contain PDZ domain-binding motifs directing a physical association with the scaffolding protein ZO-1, but the significance of the interaction is unknown. We found that Cx50 with PDZ-binding motif mutations did not form gap junction plaques or induce cell-cell communication in HeLa cells, whereas the addition of a seven-amino acid PDZ-binding motif restored normal function to Cx50 lacking its entire C-terminal cytoplasmic domain. C-Terminal deletion had a similar although weaker effect on Cx46 but little if any effect on targeting and function of Cx43. Furthermore, small interfering RNA knockdown of ZO-1 completely inhibited the formation of gap junctions by wild-type Cx50 in HeLa cells. Thus both a PDZ-binding motif and ZO-1 are necessary for Cx50 intercellular channel formation in HeLa cells. Knock-in mice expressing Cx50 with a PDZ-binding motif mutation phenocopied Cx50 knockouts. Furthermore, differentiating lens fibers in the knock-in displayed extensive intracellular Cx50, whereas plaques in mature fibers contained only Cx46. Thus normal Cx50 function in vivo also requires an intact PDZ domain-binding motif. This is the first demonstration of a connexin-specific requirement for a connexin-interacting protein in gap junction assembly.
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Affiliation(s)
- Zhifang Chai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | | | - David L. Paul
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
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González-Mariscal L, Quirós M, Díaz-Coránguez M. ZO proteins and redox-dependent processes. Antioxid Redox Signal 2011; 15:1235-53. [PMID: 21294657 DOI: 10.1089/ars.2011.3913] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
SIGNIFICANCE ZO-1, ZO-2, and ZO-3 are scaffold proteins of the tight junction (TJ) that belong to the MAGUK protein family characterized for exhibiting PDZ, SH3, and GuK domains. ZO proteins are present only in multicellular organisms, being the placozoa the first to have them. ZO proteins associate among themselves and with other integral and adaptor proteins of the TJ, of the ZA and of gap junctions, as with numerous signaling proteins and the actin cytoskeleton. ZO proteins are also present at the nucleus of proliferating cells. RECENT ADVANCES Oxidative stress disassembles the TJs of endothelial and epithelial cells. CRITICAL ISSUES Oxidative stress alters ZO proteins expression and localization, in conditions like hypoxia, bacterial and viral infections, vitamin deficiencies, age-related diseases, diabetes and inflammation, alcohol and tobacco consumption. FUTURE DIRECTIONS Molecules present in the signaling pathways triggered by oxidative stress can be targets for therapeutic intervention.
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Affiliation(s)
- Lorenza González-Mariscal
- Department of Physiology, Biophysics and Neuroscience, Center for Research and Advanced Studies (Cinvestav), Mexico DF, México.
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Palatinus JA, Rhett JM, Gourdie RG. The connexin43 carboxyl terminus and cardiac gap junction organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1831-43. [PMID: 21856279 DOI: 10.1016/j.bbamem.2011.08.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/25/2011] [Accepted: 08/03/2011] [Indexed: 12/09/2022]
Abstract
The precise spatial order of gap junctions at intercalated disks in adult ventricular myocardium is thought vital for maintaining cardiac synchrony. Breakdown or remodeling of this order is a hallmark of arrhythmic disease of the heart. The principal component of gap junction channels between ventricular cardiomyocytes is connexin43 (Cx43). Protein-protein interactions and modifications of the carboxyl-terminus of Cx43 are key determinants of gap junction function, size, distribution and organization during normal development and in disease processes. Here, we review data on the role of proteins interacting with the Cx43 carboxyl-terminus in the regulation of cardiac gap junction organization, with particular emphasis on Zonula Occludens-1. The rapid progress in this area suggests that in coming years we are likely to develop a fuller understanding of the molecular mechanisms causing pathologic remodeling of gap junctions. With these advances come the promise of novel approach to the treatment of arrhythmia and the prevention of sudden cardiac death. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Affiliation(s)
- Joseph A Palatinus
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
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Gilleron J, Carette D, Fiorini C, Benkdane M, Segretain D, Pointis G. Connexin 43 gap junction plaque endocytosis implies molecular remodelling of ZO-1 and c-Src partners. Commun Integr Biol 2011; 2:104-6. [PMID: 19704902 DOI: 10.4161/cib.7626] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 12/11/2008] [Indexed: 11/19/2022] Open
Abstract
Gap junctions, through their constitutive proteins, connexins (Cx), are involved in several processes including regulation of cellular proliferation, tissue differentiation, homeostasis and neoplasic transformation. Internalization of the gap junction plaque to form annular gap junction is a dynamic process, which present similarities with endocytosis, and participates in the control of gap junction coupling. Cx43 exhibits dynamic trafficking that needs sequential implication of a large number of protein partners. We have recently shown that ZO-1 localized in both sides of the gap junction plaque was restricted to one side during internalization. The dissociation between ZO-1 and Cx43 particularly occurred on the face where c-Src specifically associated with Cx43 and was abnormally accelerated in response to a carcinogen. In this addendum we summarize and further discuss these results.
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Petitprez S, Zmoos AF, Ogrodnik J, Balse E, Raad N, El-Haou S, Albesa M, Bittihn P, Luther S, Lehnart SE, Hatem SN, Coulombe A, Abriel H. SAP97 and dystrophin macromolecular complexes determine two pools of cardiac sodium channels Nav1.5 in cardiomyocytes. Circ Res 2010; 108:294-304. [PMID: 21164104 DOI: 10.1161/circresaha.110.228312] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE The cardiac sodium channel Na(v)1.5 plays a key role in excitability and conduction. The 3 last residues of Na(v)1.5 (Ser-Ile-Val) constitute a PDZ-domain binding motif that interacts with the syntrophin-dystrophin complex. As dystrophin is absent at the intercalated discs, Na(v)1.5 could potentially interact with other, yet unknown, proteins at this site. OBJECTIVE The aim of this study was to determine whether Na(v)1.5 is part of distinct regulatory complexes at lateral membranes and intercalated discs. METHODS AND RESULTS Immunostaining experiments demonstrated that Na(v)1.5 localizes at lateral membranes of cardiomyocytes with dystrophin and syntrophin. Optical measurements on isolated dystrophin-deficient mdx hearts revealed significantly reduced conduction velocity, accompanied by strong reduction of Na(v)1.5 at lateral membranes of mdx cardiomyocytes. Pull-down experiments revealed that the MAGUK protein SAP97 also interacts with the SIV motif of Na(v)1.5, an interaction specific for SAP97 as no pull-down could be detected with other cardiac MAGUK proteins (PSD95 or ZO-1). Furthermore, immunostainings showed that Na(v)1.5 and SAP97 are both localized at intercalated discs. Silencing of SAP97 expression in HEK293 and rat cardiomyocytes resulted in reduced sodium current (I(Na)) measured by patch-clamp. The I(Na) generated by Na(v)1.5 channels lacking the SIV motif was also reduced. Finally, surface expression of Na(v)1.5 was decreased in silenced cells, as well as in cells transfected with SIV-truncated channels. CONCLUSIONS These data support a model with at least 2 coexisting pools of Na(v)1.5 channels in cardiomyocytes: one targeted at lateral membranes by the syntrophin-dystrophin complex, and one at intercalated discs by SAP97.
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Affiliation(s)
- Séverine Petitprez
- University of Bern, Department of Clinical Research, Murtenstrasse, 35, 3010 Bern, Switzerland
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New aspects of the molecular constituents of tissue barriers. J Neural Transm (Vienna) 2010; 118:7-21. [PMID: 20865434 DOI: 10.1007/s00702-010-0484-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 08/30/2010] [Indexed: 01/24/2023]
Abstract
Epithelial and endothelial tissue barriers are based on tight intercellular contacts (Tight Junctions, TJs) between neighbouring cells. TJs are multimeric complexes, located at the most apical border of the lateral membrane. So far, a plethora of proteins locating at tight intercellular contacts have been discovered, the role of which has just partly been unraveled. Yet, there is convincing evidence that many TJ proteins exert a dual role: They act as structural components at the junctional site and they are involved in signalling pathways leading to alterations of gene expression and cell behaviour (migration, proliferation). This review will shortly summarize the classical functions of TJs and TJ-related proteins and will introduce a new category, termed the "non-classical" functions of junctional proteins. A particular focus will be directed towards the nuclear targeting of junctional proteins and the downstream effects elicited by their intranuclear activities.
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Campbell M, Ozaki E, Humphries P. Systemic delivery of therapeutics to neuronal tissues: a barrier modulation approach. Expert Opin Drug Deliv 2010; 7:859-69. [DOI: 10.1517/17425247.2010.490554] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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45
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Olk S, Zoidl G, Dermietzel R. Connexins, cell motility, and the cytoskeleton. ACTA ACUST UNITED AC 2010; 66:1000-16. [PMID: 19544403 DOI: 10.1002/cm.20404] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Connexins (Cx) comprise a family of transmembrane proteins, which form intercellular channels between plasma membranes of two adjoining cells, commonly known as gap junctions. Recent reports revealed that Cx proteins interact with diverse cellular components to form a multiprotein complex, which has been termed "Nexus". Potential interaction partners include proteins such as cytoskeletal proteins, scaffolding proteins, protein kinases and phosphatases. These interactions allow correct subcellular localization of Cxs and functional regulation of gap junction-mediated intercellular communication. Evidence is accruing that Cxs might have channel-independent functions, which potentially include regulation of cell migration, cell polarization and growth control. In the current review, we summarize recent knowledge on Cx interactions with cytoskeletal proteins and highlight some aspects of their role in cellular motility.
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Affiliation(s)
- Stephan Olk
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, Bochum, Germany
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46
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The dual role of zonula occludens (ZO) proteins. J Biomed Biotechnol 2010; 2010:402593. [PMID: 20224657 PMCID: PMC2836178 DOI: 10.1155/2010/402593] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 01/06/2010] [Indexed: 02/07/2023] Open
Abstract
ZO (zonula occludens) proteins are scaffolding proteins providing the structural basis for the assembly of multiprotein complexes at the cytoplasmic surface of intercellular junctions. In addition, they provide a link between the integral membrane proteins and the filamentous cytoskeleton. ZO proteins belong to the large family of membrane-associated guanylate kinase (MAGUK)-like proteins comprising a number of subfamilies based on domain content and sequence similarity. Besides their structural function at cell-cell contacts, ZO proteins appear to participate in the regulation of cell growth and proliferation. Detailed molecular studies have shown that ZO proteins exhibit conserved functional nuclear localization and nuclear export motifs within their amino acid sequence. Further, ZO proteins interact with dual residency proteins localizing to the plasma membrane and the nucleus. Although the nuclear targeting of ZO proteins has well been described, many questions concerning the biological significance of this process have remained open. This review focuses on the dual role of ZO proteins, being indispensable structural components at the junctional site and functioning in signal transduction pathways related to gene expression and cell behavior.
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47
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Li Q, Zhou XD, Xu XY, Yang J. Recombinant human elafin protects airway epithelium integrity during inflammation. Mol Biol Rep 2009; 37:2981-8. [DOI: 10.1007/s11033-009-9865-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Accepted: 09/29/2009] [Indexed: 10/20/2022]
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48
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Franke WW. Discovering the molecular components of intercellular junctions--a historical view. Cold Spring Harb Perspect Biol 2009; 1:a003061. [PMID: 20066111 PMCID: PMC2773636 DOI: 10.1101/cshperspect.a003061] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The organization of metazoa is based on the formation of tissues and on tissue-typical functions and these in turn are based on cell-cell connecting structures. In vertebrates, four major forms of cell junctions have been classified and the molecular composition of which has been elucidated in the past three decades: Desmosomes, which connect epithelial and some other cell types, and the almost ubiquitous adherens junctions are based on closely cis-packed glycoproteins, cadherins, which are associated head-to-head with those of the hemi-junction domain of an adjacent cell, whereas their cytoplasmic regions assemble sizable plaques of special proteins anchoring cytoskeletal filaments. In contrast, the tight junctions (TJs) and gap junctions (GJs) are formed by tetraspan proteins (claudins and occludins, or connexins) arranged head-to-head as TJ seal bands or as paracrystalline connexin channels, allowing intercellular exchange of small molecules. The by and large parallel discoveries of the junction protein families are reported.
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Affiliation(s)
- Werner W Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
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Xu J, Anuar F, Ali SM, Ng MY, Phua DCY, Hunziker W. Zona occludens-2 is critical for blood-testis barrier integrity and male fertility. Mol Biol Cell 2009; 20:4268-77. [PMID: 19692573 DOI: 10.1091/mbc.e08-12-1236] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Tight junction integral membrane proteins such as claudins and occludin are tethered to the actin cytoskeleton by adaptor proteins, notably the closely related zonula occludens (ZO) proteins ZO-1, ZO-2, and ZO-3. All three ZO proteins have recently been inactivated in mice. Although ZO-3 knockout mice lack an obvious phenotype, animals deficient in ZO-1 or ZO-2 show early embryonic lethality. Here, we rescue the embryonic lethality of ZO-2 knockout mice by injecting ZO-2(-/-) embryonic stem (ES) cells into wild-type blastocysts to generate viable ZO-2 chimera. ZO-2(-/-) ES cells contribute extensively to different tissues of the chimera, consistent with an extraembryonic requirement for ZO-2 rather than a critical role in epiblast development. Adult chimera present a set of phenotypes in different organs. In particular, male ZO-2 chimeras show reduced fertility and pathological changes in the testis. Lanthanum tracer experiments show a compromised blood-testis barrier. Expression levels of ZO-1, ZO-3, claudin-11, and occludin are not apparently affected. ZO-1 and occludin still localize to the blood-testis barrier region, but claudin-11 is less well restricted and the localization of connexin-43 is perturbed. The critical role of ZO-2 for male fertility and blood-testis barrier integrity thus provides a first example for a nonredundant role of an individual ZO protein in adult mice.
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Affiliation(s)
- Jianliang Xu
- Epithelial Cell Biology Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore 138673
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Bunse S, Haghika A, Zoidl G, Dermietzel R. Identification of a Potential Regulator of the Gap Junction Protein Pannexin1. ACTA ACUST UNITED AC 2009; 12:231-6. [PMID: 16531318 DOI: 10.1080/15419060500511834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Recent studies have revealed a second class of gap-junction-forming proteins in vertebrates. These genes are termed pannexins, and it has been suggested that they perform similar functions as connexins. Pannexin1 is expressed in diverse tissues including the central nervous system and seems to form gap junction channels in the Xenopus oocyte expression system. Since protein interacting partners have frequently been described for connexins, the most prominent family of gap junction forming proteins, we thus started to search for candidate genes of pannexin interacting partners. Kvbeta3, a protein belonging to the family of regulatory beta-subunits of the voltage-dependent potassium channels, was identified as a binding partner of pannexin1 in an E. coli two-hybrid system. This result was verified by confocal laser scanning microscopy using double transfected Neuro2A cells. The colocalization of both proteins at the plasma membrane is suggestive of functional interaction.
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Affiliation(s)
- Stefanie Bunse
- The Graduate School (GRK 736) of Ruhr-University Bochum, Bochum, Germany
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