1
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Manifestations of Intellectual Disability, Dystonia, and Parkinson's Disease in an Adult Patient with ARX Gene Mutation c.558_560dup p.(Pro187dup). Case Rep Genet 2023; 2023:3636748. [PMID: 36816814 PMCID: PMC9935879 DOI: 10.1155/2023/3636748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 02/11/2023] Open
Abstract
We describe a 38-year-old male patient with intellectual disability and progressive motor symptoms who lacked an etiological diagnosis for many years. Finally, clinical exome sequencing showed a likely pathogenic variant of the ARX gene suggesting Partington syndrome. His main symptoms were mild intellectual disability, severe kinetic apraxia, resting and action tremor, dysarthria, tonic pupils, constant dystonia of one upper limb, and focal dystonia in different parts of the body, axial rigidity, spasticity, epilepsy, and poor sleep. Another likely pathogenic gene variant was observed in the PKP2 gene and is in accordance with the observed early cardiomyopathy. Single-photon emission computed tomography imaging of dopamine transporters showed a reduced signal in the basal ganglia consistent with Parkinson's disease. Therapies with a variable number of drugs, including antiparkinsonian medications, have yielded poor responses. Our case report extends the picture of the adult phenotype of Partington syndrome.
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2
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Arrhythmogenic Cardiomyopathy: Molecular Insights for Improved Therapeutic Design. J Cardiovasc Dev Dis 2020; 7:jcdd7020021. [PMID: 32466575 PMCID: PMC7345706 DOI: 10.3390/jcdd7020021] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/17/2020] [Accepted: 05/20/2020] [Indexed: 02/07/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited disorder characterized by structural and electrical cardiac abnormalities, including myocardial fibro-fatty replacement. Its pathological ventricular substrate predisposes subjects to an increased risk of sudden cardiac death (SCD). ACM is a notorious cause of SCD in young athletes, and exercise has been documented to accelerate its progression. Although the genetic culprits are not exclusively limited to the intercalated disc, the majority of ACM-linked variants reside within desmosomal genes and are transmitted via Mendelian inheritance patterns; however, penetrance is highly variable. Its natural history features an initial “concealed phase” that results in patients being vulnerable to malignant arrhythmias prior to the onset of structural changes. Lack of effective therapies that target its pathophysiology renders management of patients challenging due to its progressive nature, and has highlighted a critical need to improve our understanding of its underlying mechanistic basis. In vitro and in vivo studies have begun to unravel the molecular consequences associated with disease causing variants, including altered Wnt/β-catenin signaling. Characterization of ACM mouse models has facilitated the evaluation of new therapeutic approaches. Improved molecular insight into the condition promises to usher in novel forms of therapy that will lead to improved care at the clinical bedside.
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3
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Martewicz S, Luni C, Serena E, Pavan P, Chen HSV, Rampazzo A, Elvassore N. Transcriptomic Characterization of a Human In Vitro Model of Arrhythmogenic Cardiomyopathy Under Topological and Mechanical Stimuli. Ann Biomed Eng 2018; 47:852-865. [DOI: 10.1007/s10439-018-02134-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 09/15/2018] [Indexed: 12/11/2022]
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4
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Genetics of and pathogenic mechanisms in arrhythmogenic right ventricular cardiomyopathy. Biophys Rev 2018; 10:973-982. [PMID: 29995277 DOI: 10.1007/s12551-018-0437-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 06/28/2018] [Indexed: 02/06/2023] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease, associated with a high risk of sudden cardiac death. ARVC has been termed a 'disease of the desmosome' based on the fact that in many cases, it is caused by mutations in genes encoding desmosomal proteins at the specialised intercellular junctions between cardiomyocytes, the intercalated discs. Desmosomes maintain the structural integrity of the ventricular myocardium and are also implicated in signal transduction pathways. Mutated desmosomal proteins are thought to cause detachment of cardiac myocytes by the loss of cellular adhesions and also affect signalling pathways, leading to cell death and substitution by fibrofatty adipocytic tissue. However, mutations in desmosomal proteins are not the sole cause for ARVC as mutations in non-desmosomal genes were also implicated in its pathogenesis. This review will consider the pathology, genetic basis and mechanisms of pathogenesis for ARVC.
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5
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Garcia MA, Nelson WJ, Chavez N. Cell-Cell Junctions Organize Structural and Signaling Networks. Cold Spring Harb Perspect Biol 2018; 10:a029181. [PMID: 28600395 PMCID: PMC5773398 DOI: 10.1101/cshperspect.a029181] [Citation(s) in RCA: 273] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cell-cell junctions link cells to each other in tissues, and regulate tissue homeostasis in critical cell processes that include tissue barrier function, cell proliferation, and migration. Defects in cell-cell junctions give rise to a wide range of tissue abnormalities that disrupt homeostasis and are common in genetic abnormalities and cancers. Here, we discuss the organization and function of cell-cell junctions primarily involved in adhesion (tight junction, adherens junction, and desmosomes) in two different epithelial tissues: a simple epithelium (intestine) and a stratified epithelium (epidermis). Studies in these tissues reveal similarities and differences in the organization and functions of different cell-cell junctions that meet the requirements for the specialized functions of each tissue. We discuss cell-cell junction responses to genetic and environmental perturbations that provide further insights into their roles in maintaining tissue homeostasis.
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Affiliation(s)
- Miguel A Garcia
- Department of Biology, Stanford University, Stanford, California 94305
| | - W James Nelson
- Department of Biology, Stanford University, Stanford, California 94305
- Departments of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305
| | - Natalie Chavez
- Department of Biology, Stanford University, Stanford, California 94305
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6
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Wang L, Liu S, Zhang H, Hu S, Wei Y. Arrhythmogenic cardiomyopathy: Identification of desmosomal gene variations and desmosomal protein expression in variation carriers. Exp Ther Med 2018; 15:2255-2262. [PMID: 29456632 PMCID: PMC5795771 DOI: 10.3892/etm.2018.5694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/16/2016] [Indexed: 01/26/2023] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is an inherited disorder that is predominantly present in the right ventricular myocardium. Mutations in the genes encoding the desmosomal protein are thought to underlie the pathogenesis of AC. Since AC is genetically heterogeneous and phenotypically diverse, modifier genes and environmental factors have an important role in disease expression. The aim of the present study was to identify AC-associated desmosomal gene variations, and examine the expression levels of intercalated disc proteins in AC patients who carry the variations (DSG2 p.Leu797Gln, PKP2 p.Ser249Thr and p.E808fsX30). The results of the present investigation provided information on the search for modifier genes and desmosomal gene mutations, and improved our understanding of the mechanism underlying these AC mutations. Genetic screening of five desmosomal genes (DSG2, DSC2, JUP, PKP2, and DSP) in 23 patients with AC who underwent heart transplantation was performed and the expression levels and localizations of intercalated disc proteins were assessed using western blotting and immunohistochemistry, respectively. The results enabled the identification of three desmosomal gene variations (DSG2 L797Q, PKP2 S249T, and E808fsX30), two of which are reported for the first time. DSG2 L797Q was identified in one patient. The protein expression levels of DSG2 in the L797Q carrier were unchanged compared with the healthy controls, and the expression levels of the other proteins (JUP and Cx43) in the intercalated disc were also similar between the healthy controls, the variation carrier and the case controls. Two variations (S249T and E808fsX30) in PKP2 were identified in one patient, the protein expression levels of PKP2 in this patient were significantly decreased, and the expression levels of the other proteins in the intercalated disc was also decreased. The data suggest that there may be modifier genes and other AC-associated mutations requiring identification, in order to further our understanding of the disease mechanism induced by these mutations.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China.,First College of Clinical Medical Science, China Three Gorges University, Yichang Central People's Hospital, Yichang, Hubei 443000, P.R. China
| | - Shenghua Liu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Hongliang Zhang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Shengshou Hu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
| | - Yingjie Wei
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, P.R. China
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7
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Dueker ND, Guo S, Beecham A, Wang L, Blanton SH, Di Tullio MR, Rundek T, Sacco RL. Sequencing of Linkage Region on Chromosome 12p11 Identifies PKP2 as a Candidate Gene for Left Ventricular Mass in Dominican Families. G3 (BETHESDA, MD.) 2018; 8:659-668. [PMID: 29288195 PMCID: PMC5919734 DOI: 10.1534/g3.117.300358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/10/2017] [Indexed: 12/16/2022]
Abstract
Increased left ventricular mass (LVM) is an intermediate phenotype for cardiovascular disease (CVD) and a predictor of stroke. Using families from the Dominican Republic, we have previously shown LVM to be heritable and found evidence for linkage to chromosome 12p11. Our current study aimed to further characterize the QTL by sequencing the 1 LOD unit down region in 10 families from the Dominican Republic with evidence for linkage to LVM. Within this region, we tested 5477 common variants [CVs; minor allele frequency (MAF) ≥5%] using the Quantitative Transmission-Disequilibrium Test (QTDT). Gene-based analyses were performed to test rare variants (RVs; MAF < 5%) in 181 genes using the family-based sequence kernel association test. A sample of 618 unrelated Dominicans from the Northern Manhattan Study (NOMAS) and 12 Dominican families with Exome Array data were used for replication analyses. The most strongly associated CV with evidence for replication was rs1046116 (Discovery families P = 9.0 × 10-4; NOMAS P = 0.03; replication families P = 0.46), a missense variant in PKP2 In nonsynonymous RV analyses, PKP2 was one of the most strongly associated genes (P = 0.05) with suggestive evidence for replication in NOMAS (P = 0.05). PKP2 encodes the plakophilin 2 protein and is a desmosomal gene implicated in arrythmogenic right ventricular cardiomyopathy and recently in arrhythmogenic left ventricular cardiomyopathy, which makes PKP2 an excellent candidate gene for LVM. In conclusion, sequencing of our previously reported QTL identified common and rare variants within PKP2 to be associated with LVM. Future studies are necessary to elucidate the role these variants play in influencing LVM.
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Affiliation(s)
- Nicole D Dueker
- John P. Hussman Institute for Human Genomics, University of Miami, Florida 33136
| | - Shengru Guo
- John P. Hussman Institute for Human Genomics, University of Miami, Florida 33136
| | - Ashley Beecham
- John P. Hussman Institute for Human Genomics, University of Miami, Florida 33136
| | - Liyong Wang
- John P. Hussman Institute for Human Genomics, University of Miami, Florida 33136
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Florida 33136
| | - Susan H Blanton
- John P. Hussman Institute for Human Genomics, University of Miami, Florida 33136
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Florida 33136
| | - Marco R Di Tullio
- Department of Medicine, Columbia University, New York, New York 10032
| | - Tatjana Rundek
- Department of Neurology, Miller School of Medicine, University of Miami, Florida 33136
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Florida 33136
| | - Ralph L Sacco
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Florida 33136
- Department of Neurology, Miller School of Medicine, University of Miami, Florida 33136
- Department of Public Health Sciences, Miller School of Medicine, University of Miami, Florida 33136
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8
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High proportion of genetic cases in patients with advanced cardiomyopathy including a novel homozygous Plakophilin 2-gene mutation. PLoS One 2017; 12:e0189489. [PMID: 29253866 PMCID: PMC5734774 DOI: 10.1371/journal.pone.0189489] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/27/2017] [Indexed: 11/19/2022] Open
Abstract
Cardiomyopathies might lead to end-stage heart disease with the requirement of drastic treatments like bridging up to transplant or heart transplantation. A not precisely known proportion of these diseases are genetically determined. We genotyped 43 index-patients (30 DCM, 10 ARVC, 3 RCM) with advanced or end stage cardiomyopathy using a gene panel which covered 46 known cardiomyopathy disease genes. Fifty-three variants with possible impact on disease in 33 patients were identified. Of these 27 (51%) were classified as likely pathogenic or pathogenic in the MYH7, MYL2, MYL3, NEXN, TNNC1, TNNI3, DES, LMNA, PKP2, PLN, RBM20, TTN, and CRYAB genes. Fifty-six percent (n = 24) of index-patients carried a likely pathogenic or pathogenic mutation. Of these 75% (n = 18) were familial and 25% (n = 6) sporadic cases. However, severe cardiomyopathy seemed to be not characterized by a specific mutation profile. Remarkably, we identified a novel homozygous PKP2-missense variant in a large consanguineous family with sudden death in early childhood and several members with heart transplantation in adolescent age.
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9
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Roberts BJ, Johnson KE, McGuinn KP, Saowapa J, Svoboda RA, Mahoney MG, Johnson KR, Wahl JK. Palmitoylation of plakophilin is required for desmosome assembly. J Cell Sci 2014; 127:3782-93. [PMID: 25002405 DOI: 10.1242/jcs.149849] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Desmosomes are prominent adhesive junctions found in various epithelial tissues. The cytoplasmic domains of desmosomal cadherins interact with a host of desmosomal plaque proteins, including plakophilins, plakoglobin and desmoplakin, which, in turn, recruit the intermediate filament cytoskeleton to sites of cell-cell contact. Although the individual components of the desmosome are known, mechanisms regulating the assembly of this junction are poorly understood. Protein palmitoylation is a posttranslational lipid modification that plays an important role in protein trafficking and function. Here, we demonstrate that multiple desmosomal components are palmitoylated in vivo. Pharmacologic inhibition of palmitoylation disrupts desmosome assembly at cell-cell borders. We mapped the site of plakophilin palmitoylation to a conserved cysteine residue present in the armadillo repeat domain. Mutation of this single cysteine residue prevents palmitoylation, disrupts plakophilin incorporation into the desmosomal plaque and prevents plakophilin-dependent desmosome assembly. Finally, plakophilin mutants unable to become palmitoylated act in a dominant-negative manner to disrupt proper localization of endogenous desmosome components and decrease desmosomal adhesion. Taken together, these data demonstrate that palmitoylation of desmosomal components is important for desmosome assembly and adhesion.
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Affiliation(s)
- Brett J Roberts
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Kristen E Johnson
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Kathleen P McGuinn
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Jintana Saowapa
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - Robert A Svoboda
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
| | - My G Mahoney
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Keith R Johnson
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA Eppley Institute for Research in Cancer and Allied Diseases, Omaha, NE 68198, USA
| | - James K Wahl
- The University of Nebraska Medical Center, College of Dentistry, Department of Oral Biology, Lincoln, NE 68583, USA
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10
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Rasmussen TB, Nissen PH, Palmfeldt J, Gehmlich K, Dalager S, Jensen UB, Kim WY, Heickendorff L, Mølgaard H, Jensen HK, Baandrup UT, Bross P, Mogensen J. Truncating Plakophilin-2 Mutations in Arrhythmogenic Cardiomyopathy Are Associated With Protein Haploinsufficiency in Both Myocardium and Epidermis. ACTA ACUST UNITED AC 2014; 7:230-40. [DOI: 10.1161/circgenetics.113.000338] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac condition associated with ventricular arrhythmias, heart failure, and sudden death. The disease is most often caused by mutations in the desmosomal gene for plakophilin-2 (
PKP2
), which is expressed in both myocardial and epidermal tissue. This study aimed to investigate protein expression in myocardial tissue of patients with AC carrying
PKP2
mutations and elucidate whether keratinocytes of the same individuals exhibited a similar pattern of protein expression.
Methods and Results—
Direct sequencing of 5 AC genes in 71 unrelated patients with AC identified 10 different
PKP2
mutations in 12 index patients. One patient, heterozygous for a
PKP2
nonsense mutation, developed severe heart failure and underwent cardiac transplantation. Western blotting and immunohistochemistry of the explanted heart showed a significant decrease in PKP2 protein expression without detectable amounts of truncated PKP2 protein. Cultured keratinocytes of the patient showed a similar reduction in PKP2 protein expression. Nine additional
PKP2
mutations were investigated in both cultured keratinocytes and endomyocardial biopsies from affected individuals. It was evident that
PKP2
mutations introducing a premature termination codon in the reading frame were associated with PKP2 transcript and protein levels reduced to ≈50%, whereas a missense variant did not seem to affect the amount of PKP2 protein.
Conclusions—
The results of this study showed that truncating
PKP2
mutations in AC are associated with low expression of the mutant allele and that the myocardial protein expression of PKP2 is mirrored in keratinocytes. These findings indicate that
PKP2
haploinsufficiency contributes to pathogenesis in AC.
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Affiliation(s)
- Torsten B. Rasmussen
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Peter H. Nissen
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Johan Palmfeldt
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Katja Gehmlich
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Søren Dalager
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Uffe B. Jensen
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Won Y. Kim
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Lene Heickendorff
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Henning Mølgaard
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Henrik K. Jensen
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Ulrik T. Baandrup
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Peter Bross
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
| | - Jens Mogensen
- From the Department of Cardiology (T.B.R., W.Y.K., H.M., H.K.J., J.M.), Research Unit for Molecular Medicine (T.B.R., J.P., P.B.), Department of Clinical Biochemistry (P.H.N., L.H.), Institute of Pathology (S.D.), Department of Clinical Genetics (U.B.J.), and MR Centre (W.Y.K.), Aarhus University Hospital, Aarhus, Denmark; Clinical Research Center, Vendsyssel Hospital, Aalborg University, Hjørring, Denmark (U.T.B.); Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of
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11
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Munoz WA, Lee M, Miller RK, Ahmed Z, Ji H, Link TM, Lee GR, Kloc M, Ladbury JE, McCrea PD. Plakophilin-3 catenin associates with the ETV1/ER81 transcription factor to positively modulate gene activity. PLoS One 2014; 9:e86784. [PMID: 24475179 PMCID: PMC3903613 DOI: 10.1371/journal.pone.0086784] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/13/2013] [Indexed: 12/31/2022] Open
Abstract
Members of the plakophilin-catenin sub-family (Pkp-1, -2, and -3) facilitate the linkage of desmosome junctional components to each other (e.g. desmosomal cadherins to desmoplakin) and the intermediate-filament cytoskeleton. Pkps also contribute to desmosomal stabilization and the trafficking of its components. The functions of Pkps outside of the desmosome are less well studied, despite evidence suggesting their roles in mRNA regulation, small-GTPase modulation (e.g. mid-body scission) during cell division, and cell survival following DNA damage. Pkp-catenins are further believed to have roles in the nucleus given their nuclear localization in some contexts and the known nuclear roles of structurally related catenins, such as beta-catenin and p120-catenin. Further, Pkp-catenin activities in the nuclear compartment have become of increased interest with the identification of interactions between Pkp2-catenin and RNA Pol III and Pkp1 with single-stranded DNA. Consistent with earlier reports suggesting possible nuclear roles in development, we previously demonstrated prominent nuclear localization of Pkp3 in Xenopus naïve ectoderm (“animal cap”) cells and recently resolved a similar localization in mouse embryonic stem cells. Here, we report the association and positive functional interaction of Pkp3 with a transcription factor, Ets variant gene 1 (ETV1), which has critical roles in neural development and prominent roles in human genetic disease. Our results are the first to report the interaction of a sequence-specific transcription factor with any Pkp. Using Xenopus laevis embryos and mammalian cells, we provide evidence for the Pkp3:ETV1 complex on both biochemical and functional levels.
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Affiliation(s)
- William A. Munoz
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes & Development, The University of Texas Graduate School of Biomedical Science - Houston, Texas, United States of America
| | - Moonsup Lee
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes & Development, The University of Texas Graduate School of Biomedical Science - Houston, Texas, United States of America
| | - Rachel K. Miller
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Zamal Ahmed
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Center for Biomolecular Structure and Function, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Hong Ji
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Todd M. Link
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Center for Biomolecular Structure and Function, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Gilbert R. Lee
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Center for Biomolecular Structure and Function, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Malgorzata Kloc
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Department of Surgery, Houston Methodist, Houston Methodist Research Institute, Houston, Texas, United States of America
| | - John E. Ladbury
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes & Development, The University of Texas Graduate School of Biomedical Science - Houston, Texas, United States of America
- Center for Biomolecular Structure and Function, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Pierre D. McCrea
- Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes & Development, The University of Texas Graduate School of Biomedical Science - Houston, Texas, United States of America
- * E-mail:
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12
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Al-Jassar C, Bikker H, Overduin M, Chidgey M. Mechanistic basis of desmosome-targeted diseases. J Mol Biol 2013; 425:4006-22. [PMID: 23911551 PMCID: PMC3807649 DOI: 10.1016/j.jmb.2013.07.035] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 11/21/2022]
Abstract
Desmosomes are dynamic junctions between cells that maintain the structural integrity of skin and heart tissues by withstanding shear forces. Mutations in component genes cause life-threatening conditions including arrhythmogenic right ventricular cardiomyopathy, and desmosomal proteins are targeted by pathogenic autoantibodies in skin blistering diseases such as pemphigus. Here, we review a set of newly discovered pathogenic alterations and discuss the structural repercussions of debilitating mutations on desmosomal proteins. The architectures of native desmosomal assemblies have been visualized by cryo-electron microscopy and cryo-electron tomography, and the network of protein domain interactions is becoming apparent. Plakophilin and desmoplakin mutations have been discovered to alter binding interfaces, structures, and stabilities of folded domains that have been resolved by X-ray crystallography and NMR spectroscopy. The flexibility within desmoplakin has been revealed by small-angle X-ray scattering and fluorescence assays, explaining how mechanical stresses are accommodated. These studies have shown that the structural and functional consequences of desmosomal mutations can now begin to be understood at multiple levels of spatial and temporal resolution. This review discusses the recent structural insights and raises the possibility of using modeling for mechanism-based diagnosis of how deleterious mutations alter the integrity of solid tissues.
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Affiliation(s)
- Caezar Al-Jassar
- School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, UK
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13
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Lahtinen AM, Havulinna AS, Noseworthy PA, Jula A, Karhunen PJ, Perola M, Newton-Cheh C, Salomaa V, Kontula K. Prevalence of arrhythmia-associated gene mutations and risk of sudden cardiac death in the Finnish population. Ann Med 2013; 45:328-35. [PMID: 23651034 PMCID: PMC3778376 DOI: 10.3109/07853890.2013.783995] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Sudden cardiac death (SCD) remains a major cause of death in Western countries. It has a heritable component, but previous molecular studies have mainly focused on common genetic variants. We studied the prevalence, clinical phenotypes, and risk of SCD presented by ten rare mutations previously associated with arrhythmogenic right ventricular cardiomyopathy, long QT syndrome, or catecholaminergic polymorphic ventricular tachycardia. METHODS The occurrence of ten arrhythmia-associated mutations was determined in four large prospective population cohorts (FINRISK 1992, 1997, 2002, and Health 2000, n = 28,465) and two series of forensic autopsies (The Helsinki Sudden Death Study and The Tampere Autopsy Study, n = 825). Follow-up data were collected from national registries. RESULTS The ten mutations showed a combined prevalence of 79 per 10,000 individuals in Finland, and six of them showed remarkable geographic clustering. Of a total of 715 SCD cases, seven (1.0%) carried one of the ten mutations assayed: three carried KCNH2 R176W, one KCNH2 L552S, two PKP2 Q59L, and one RYR2 R3570W. CONCLUSIONS Arrhythmia-associated mutations are prevalent in the general Finnish population but do not seem to present a major risk factor for SCD, at least during a mean of 10-year follow-up of a random adult population sample.
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Affiliation(s)
- Annukka M. Lahtinen
- Research Programs Unit, Molecular Medicine and Department of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Peter A. Noseworthy
- Cardiovascular Research Center and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Antti Jula
- National Institute for Health and Welfare, Turku, Finland
| | - Pekka J. Karhunen
- School of Medicine, University of Tampere and Centre for Laboratory Medicine, Tampere University Hospital, Tampere, Finland
| | - Markus Perola
- National Institute for Health and Welfare, Helsinki, Finland
- Institute of Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - Christopher Newton-Cheh
- Cardiovascular Research Center and Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - Veikko Salomaa
- National Institute for Health and Welfare, Helsinki, Finland
| | - Kimmo Kontula
- Research Programs Unit, Molecular Medicine and Department of Medicine, University of Helsinki, Helsinki, Finland
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14
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Kirchner F, Schuetz A, Boldt LH, Martens K, Dittmar G, Haverkamp W, Thierfelder L, Heinemann U, Gerull B. Molecular insights into arrhythmogenic right ventricular cardiomyopathy caused by plakophilin-2 missense mutations. ACTA ACUST UNITED AC 2012; 5:400-11. [PMID: 22781308 DOI: 10.1161/circgenetics.111.961854] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder mainly caused by dominant mutations in several components of the cardiac desmosome including plakophilin-2 (PKP2), the most prevalent disease gene. Little is known about the underlying genetic and molecular mechanisms of missense mutations located in the armadillo (ARM) domains of PKP2, as well as their consequences on human cardiac pathology. METHODS AND RESULTS We focused on in vivo and in vitro studies of the PKP2 founder mutation c.2386T>C (p.C796R), and demonstrated in cardiac tissue from 2 related mutation carriers a patchy expression pattern ranging from unchanged to totally absent immunoreactive signals of PKP2 and other desmosomal proteins. In vitro expression analysis of mutant PKP2 in cardiac derived HL-1 cells revealed unstable proteins that fail to interact with desmoplakin and are targeted by degradation involving calpain proteases. Bacterial expression, crystallization, and structural modeling of mutated proteins impacting different ARM domains and helices of PKP2 confirmed their instability and degradation, resulting in the same remaining protein fragment that was crystallized and used to model the entire ARM domain of PKP2. CONCLUSIONS The p.C796R and other ARVC-related PKP2 mutations indicate loss of function effects by intrinsic instability and calpain proteases mediated degradation in in vitro model systems, suggesting haploinsufficiency as the most likely cause for the genesis of dominant ARVC due to mutations in PKP2.
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15
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Rickelt S. Plakophilin-2: a cell-cell adhesion plaque molecule of selective and fundamental importance in cardiac functions and tumor cell growth. Cell Tissue Res 2012; 348:281-94. [PMID: 22281687 PMCID: PMC3349858 DOI: 10.1007/s00441-011-1314-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 12/16/2011] [Indexed: 01/23/2023]
Abstract
Within the characteristic ensemble of desmosomal plaque proteins, the armadillo protein plakophilin-2 (Pkp2) is known as a particularly important regulatory component in the cytoplasmic plaques of various other cell-cell junctions, such as the composite junctions (areae compositae) of the myocardiac intercalated disks and in the variously-sized and -shaped complex junctions of permanent cell culture lines derived therefrom. In addition, Pkp2 has been detected in certain protein complexes in the nucleoplasm of diverse kinds of cells. Using a novel set of highly sensitive and specific antibodies, both kinds of Pkp2, the junctional plaque-bound and the nuclear ones, can also be localized to the cytoplasmic plaques of diverse non-desmosomal cell-cell junction structures. These are not only the puncta adhaerentia and the fasciae adhaerentes connecting various types of highly proliferative non-epithelial cells growing in culture but also some very proliferative states of cardiac interstitial cells and cardiac myxomata, including tumors growing in situ as well as fetal stages of heart development and cultures of valvular interstitial cells. Possible functions and assembly mechanisms of such Pkp2-positive cell-cell junctions as well as medical consequences are discussed.
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Affiliation(s)
- Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center, Heidelberg, Germany.
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16
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Rickelt S, Pieperhoff S. Mutations with pathogenic potential in proteins located in or at the composite junctions of the intercalated disk connecting mammalian cardiomyocytes: a reference thesaurus for arrhythmogenic cardiomyopathies and for Naxos and Carvajal diseases. Cell Tissue Res 2012; 348:325-33. [PMID: 22450909 PMCID: PMC3349860 DOI: 10.1007/s00441-012-1365-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 02/03/2012] [Indexed: 01/30/2023]
Abstract
In the past decade, an avalanche of findings and reports has correlated arrhythmogenic ventricular cardiomyopathies (ARVC) and Naxos and Carvajal diseases with certain mutations in protein constituents of the special junctions connecting the polar regions (intercalated disks) of mature mammalian cardiomyocytes. These molecules, apparently together with some specific cytoskeletal proteins, are components of (or interact with) composite junctions. Composite junctions contain the amalgamated fusion products of the molecules that, in other cell types and tissues, occur in distinct separate junctions, i.e. desmosomes and adherens junctions. As the pertinent literature is still in an expanding phase and is obviously becoming important for various groups of researchers in basic cell and molecular biology, developmental biology, histology, physiology, cardiology, pathology and genetics, the relevant references so far recognized have been collected and are presented here in the following order: desmocollin-2 (Dsc2, DSC2), desmoglein-2 (Dsg2, DSG2), desmoplakin (DP, DSP), plakoglobin (PG, JUP), plakophilin-2 (Pkp2, PKP2) and some non-desmosomal proteins such as transmembrane protein 43 (TMEM43), ryanodine receptor 2 (RYR2), desmin, lamins A and C, striatin, titin and transforming growth factor-β3 (TGFβ3), followed by a collection of animal models and of reviews, commentaries, collections and comparative studies.
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Affiliation(s)
- Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, Building TP4, 69120 Heidelberg, Germany
- Progen Biotechnik, Heidelberg, Germany
| | - Sebastian Pieperhoff
- BHF Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, EH164TJ Edinburgh, Scotland UK
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17
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Zhang M, Tavora F, Oliveira JB, Li L, Franco M, Fowler D, Zhao Z, Burke A. PKP2 mutations in sudden death from arrhythmogenic right ventricular cardiomyopathy (ARVC) and sudden unexpected death with negative autopsy (SUDNA). Circ J 2011; 76:189-94. [PMID: 22019812 DOI: 10.1253/circj.cj-11-0747] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Plakophilin2 (PKP2) is a desmosome-related protein with numerous armadillo repeats and has been linked to arrhythmogenic right ventricular cardiomyopathy (ARVC). Fatal arrhythmias resulting in sudden death also occur in the absence of morphologic cardiac abnormalities at autopsy, and have been linked to ion channel mutations in a subset of cases, but so far not to PKP2. METHODS AND RESULTS We sequenced all 14 exons of PKP2 in DNA extracted from postmortem heart tissues of 25 patients dying from ARVC and 25 from sudden unexpected death with negative autopsy (SUDNA). The primers were designed using the Primer Express 3.0 software. Direct sequencing for both sense and antisense strands was performed with a BigDye Terminator DNA sequencing kit on a 3130XL Genetic Analyzer. Mutation damage prediction was made using Mutation Taster, Polyphen and SIFT software. In 6 of the 25 ARVC samples, 6 PKP2 mutations were identified, 4 of which were likely significant, and 3 of which were novel (p.N641del, p.L64PfsX22, p.G269R). In 6 of the 25 cases of SUDNA samples, 6 PKP2 mutations were identified, 3 of which were likely significant, and 4 of which were not previously described (p.P665S, p.Y217TfsX45, p.E540, p.S615T). CONCLUSIONS PKP2 mutations are not specific for ARVC and may result in SUDNA. The link between ARVC and desmosomal mutations may not be causal but related to an association between defective desmosomal proteins and arrhythmias.
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Affiliation(s)
- Mingchang Zhang
- Department of Forensic Medicine, Shanghai Medical College, Fudan University, Shanghai, China
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18
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Lahtinen AM, Lehtonen E, Marjamaa A, Kaartinen M, Heliö T, Porthan K, Oikarinen L, Toivonen L, Swan H, Jula A, Peltonen L, Palotie A, Salomaa V, Kontula K. Population-prevalent desmosomal mutations predisposing to arrhythmogenic right ventricular cardiomyopathy. Heart Rhythm 2011; 8:1214-21. [PMID: 21397041 DOI: 10.1016/j.hrthm.2011.03.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 03/03/2011] [Indexed: 01/16/2023]
Abstract
BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive myocardial disorder caused by mutations of desmosomal cell adhesion proteins. The prevalence of these variants in the general population is unknown. OBJECTIVE This study examined the spectrum and population prevalence of desmosomal mutations predisposing to ARVC in Finland. METHODS We screened 29 Finnish ARVC probands for mutations in the DSP, DSG2, and DSC2 genes. All Finnish-type ARVC-associated mutations, including those 3 previously identified in PKP2 in the same patient group, were analyzed in the population-based Health 2000 cohort of 6,334 individuals and tested for association with electrocardiographic variables. RESULTS We detected 2 novel mutations: DSG2 3059_3062delAGAG and DSP T1373A. DSG2 3059_3062delAGAG was present in a family with 5 mutation carriers. The endomyocardial samples of the DSG2 deletion carrier showed reduced immunoreactive signal for desmoglein-2, plakophilin-2, plakoglobin, and desmoplakin. DSP T1373A was found in 1 proband with typical right ventricular disease and exercise-related ventricular tachycardia. In the population sample, the collective prevalence of all 5 mutations identified in the 29 ARVC patients (PKP2 Q62K, Q59L, N613K, DSG2 3059_3062delAGAG, and DSP T1373A) was 31 of 6,334 individuals, or 0.5%. The apparent founder mutation PKP2 Q59L is present in 0.3% of Finns and was previously shown to have an approximately 20% disease penetrance. CONCLUSION One of 200 Finns carries a desmosomal mutation that may predispose to ARVC and its clinical sequelae. ARVC-associated mutations may thus be more prevalent in the population than expected based on the published ARVC prevalence data.
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Affiliation(s)
- Annukka M Lahtinen
- Research Program for Molecular Medicine, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
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A novel kind of tumor type-characteristic junction: plakophilin-2 as a major protein of adherens junctions in cardiac myxomata. Mod Pathol 2010; 23:1429-37. [PMID: 20693980 DOI: 10.1038/modpathol.2010.138] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Using novel antibodies of high avidity to--and specificity for--the constitutive desmosomal plaque protein, plakophilin-2 (Pkp2), in a systematic study of the molecular composition of junctions connecting the cells of soft tissue tumors, we have discovered with immunocytochemical, biochemical and electron microscopical methods, a novel type of adherens junctions in all 32 cardiac myxomata examined. These junctions contain cadherin-11 as their major transmembrane glycoprotein, which we could repeatedly show in colocalization with N-cadherin, anchored in a cytoplasmic plaque formed by α- and β-catenin, together with the further armadillo-type proteins plakoglobin, p120, p0071 and ARVCF. Surprisingly, all adherens junctions of these tumors contained, in addition, another major armadillo protein Pkp2, hitherto known as an obligatory and characteristic constituent of desmosomes in epithelium-derived tumors. We have not detected Pkp2 in a series of noncardiac myxomata studied in parallel. Therefore, we conclude that this acquisition of Pkp2, which we have recently also observed in some mesenchymally derived cells growing in culture, can also occur in tumorigenic transformations in situ. We propose to examine the marker value of Pkp2 in clinical diagnoses of cardiac myxomata and to develop Pkp2-targeted therapeutic reagents.
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Abstract
Desmosomes are intercellular junctions whose primary function is strong intercellular adhesion, known as hyperadhesion. In the present review, we discuss how their structure appears to support this function as well as how they are assembled and down-regulated. Desmosomal components also have signalling functions that are important in tissue development and remodelling. Their adhesive and signalling functions are both compromised in genetic and autoimmune diseases that affect the heart, skin and mucous membranes. We conclude that much work is required on structure–function relationships within desmosomes in vivo and on how they participate in signalling processes to enhance our knowledge of tissue homoeostasis and human disease.
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Pieperhoff S, Barth M, Rickelt S, Franke WW. Desmosomal molecules in and out of adhering junctions: normal and diseased States of epidermal, cardiac and mesenchymally derived cells. Dermatol Res Pract 2010; 2010:139167. [PMID: 20671973 PMCID: PMC2909724 DOI: 10.1155/2010/139167] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/23/2010] [Indexed: 11/18/2022] Open
Abstract
Current cell biology textbooks mention only two kinds of cell-to-cell adhering junctions coated with the cytoplasmic plaques: the desmosomes (maculae adhaerentes), anchoring intermediate-sized filaments (IFs), and the actin microfilament-anchoring adherens junctions (AJs), including both punctate (puncta adhaerentia) and elongate (fasciae adhaerentes) structures. In addition, however, a series of other junction types has been identified and characterized which contain desmosomal molecules but do not fit the definition of desmosomes. Of these special cell-cell junctions containing desmosomal glycoproteins or proteins we review the composite junctions (areae compositae) connecting the cardiomyocytes of mature mammalian hearts and their importance in relation to human arrhythmogenic cardiomyopathies. We also emphasize the various plakophilin-2-positive plaques in AJs (coniunctiones adhaerentes) connecting proliferatively active mesenchymally-derived cells, including interstitial cells of the heart and several soft tissue tumor cell types. Moreover, desmoplakin has also been recognized as a constituent of the plaques of the complexus adhaerentes connecting certain lymphatic endothelial cells. Finally, we emphasize the occurrence of the desmosomal transmembrane glycoprotein, desmoglein Dsg2, out of the context of any junction as dispersed cell surface molecules in certain types of melanoma cells and melanocytes. This broadening of our knowledge on the diversity of AJ structures indicates that it may still be too premature to close the textbook chapters on cell-cell junctions.
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Affiliation(s)
- Sebastian Pieperhoff
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Mareike Barth
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Werner W. Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- Progen Biotechnik GmbH, Maaßstraße 30, 69123 Heidelberg, Germany
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The area composita of adhering junctions connecting heart muscle cells of vertebrates. VII. The different types of lateral junctions between the special cardiomyocytes of the conduction system of ovine and bovine hearts. Eur J Cell Biol 2010; 89:365-78. [DOI: 10.1016/j.ejcb.2009.11.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/29/2009] [Accepted: 11/09/2009] [Indexed: 11/19/2022] Open
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