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Hiermaier M, Kliewe F, Schinner C, Stüdle C, Maly IP, Wanuske MT, Rötzer V, Endlich N, Vielmuth F, Waschke J, Spindler V. The Actin-Binding Protein α-Adducin Modulates Desmosomal Turnover and Plasticity. J Invest Dermatol 2020; 141:1219-1229.e11. [PMID: 33098828 DOI: 10.1016/j.jid.2020.09.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 01/01/2023]
Abstract
Intercellular adhesion is essential for tissue integrity and homeostasis. Desmosomes are abundant in the epidermis and the myocardium-tissues, which are under constantly changing mechanical stresses. Yet, it is largely unclear whether desmosomal adhesion can be rapidly adapted to changing demands, and the mechanisms underlying desmosome turnover are only partially understood. In this study we show that the loss of the actin-binding protein α-adducin resulted in reduced desmosome numbers and prevented the ability of cultured keratinocytes or murine epidermis to withstand mechanical stress. This effect was not primarily caused by decreased levels or impaired adhesive properties of desmosomal molecules but rather by altered desmosome turnover. Mechanistically, reduced cortical actin density in α-adducin knockout keratinocytes resulted in increased mobility of the desmosomal adhesion molecule desmoglein 3 and impaired interactions with E-cadherin, a crucial step in desmosome formation. Accordingly, the loss of α-adducin prevented increased membrane localization of desmoglein 3 in response to cyclic stretch or shear stress. Our data demonstrate the plasticity of desmosomal molecules in response to mechanical stimuli and unravel a mechanism of how the actin cytoskeleton indirectly shapes intercellular adhesion by restricting the membrane mobility of desmosomal molecules.
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Affiliation(s)
- Matthias Hiermaier
- Department of Biomedicine, University of Basel, Basel, Switzerland; Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Felix Kliewe
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Camilla Schinner
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Chiara Stüdle
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - I Piotr Maly
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marie-Therès Wanuske
- Department of Biomedicine, University of Basel, Basel, Switzerland; Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Vera Rötzer
- Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Franziska Vielmuth
- Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Jens Waschke
- Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Volker Spindler
- Department of Biomedicine, University of Basel, Basel, Switzerland; Faculty of Medicine, Ludwig-Maximilians-Universität Munich, Munich, Germany.
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2
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Nigra AD, Casale CH, Santander VS. Human erythrocytes: cytoskeleton and its origin. Cell Mol Life Sci 2020; 77:1681-1694. [PMID: 31654099 PMCID: PMC11105037 DOI: 10.1007/s00018-019-03346-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/27/2019] [Accepted: 10/16/2019] [Indexed: 01/02/2023]
Abstract
In the last few years, erythrocytes have emerged as the main determinant of blood rheology. In mammals, these cells are devoid of nuclei and are, therefore, unable to divide. Consequently, all circulating erythrocytes come from erythropoiesis, a process in the bone marrow in which several modifications are induced in the expression of membrane and cytoskeletal proteins, and different vertical and horizontal interactions are established between them. Cytoskeleton components play an important role in this process, which explains why they and the interaction between them have been the focus of much recent research. Moreover, in mature erythrocytes, the cytoskeleton integrity is also essential, because the cytoskeleton confers remarkable deformability and stability on the erythrocytes, thus enabling them to undergo deformation in microcirculation. Defects in the cytoskeleton produce changes in erythrocyte deformability and stability, affecting cell viability and rheological properties. Such abnormalities are seen in different pathologies of special interest, such as different types of anemia, hypertension, and diabetes, among others. This review highlights the main findings in mammalian erythrocytes and their progenitors regarding the presence, conformation and function of the three main components of the cytoskeleton: actin, intermediate filaments, and tubulin.
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Affiliation(s)
- Ayelén D Nigra
- Departamento de Biología Molecular, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Químicas, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), UNC-CONICET, Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Cesar H Casale
- Departamento de Biología Molecular, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina
| | - Verónica S Santander
- Departamento de Biología Molecular, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, 5800, Río Cuarto, Córdoba, Argentina.
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3
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Luo C, Wang G, Ying H, Shen J, Gilligan DM. Increased expression of phosphorylated adducin in tumor cells. J Int Med Res 2020; 48:300060520910646. [PMID: 32237935 PMCID: PMC7132819 DOI: 10.1177/0300060520910646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Objective This preclinical research was designed to study the phosphorylation level of adducin in cancer tissues, healthy tissues, and malignant tumor cells to determine the relationship between adducin and cancer. Methods Western blotting was used to detect the expression level of phospho-adducin in tissues and cell lines. Results Phospho-adducin at Ser662 was detected in all tumor cells and cancer tissues. The main type of phospho-adducin at Ser662 was γ-adducin in healthy lung tissue, and α-adducin in both lung cancer tissue and para-lung cancer tissue. Phosphorylation of adducin at Thr445 was observed in healthy lung tissue, adjacent healthy tissue, and cancer tissue, but was not detected in any other malignant cells. Additionally, more phosphorylation of adducin at Thr445 was seen in cancer tissue than in adjacent healthy tissue. Conclusion The abnormal expression of phospho-adducin at Ser662 and Thr445 may be associated with tumorigenesis, suggesting a novel approach for the diagnosis and treatment of tumors.
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Affiliation(s)
- Cong Luo
- Department of Abdominal Oncology, Institute of Cancer Research and Basic Medical Sciences of Chinese Academy of Sciences, Cancer Hospital of University of Chinese Academy of Sciences, Zhejiang Cancer Hospital, Hangzhou, China
| | - Guirong Wang
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Huang Ying
- Department of Pharmacy, The People's Hospital of Yichun City, Yinchun University, Yichun, China
| | - Jiayu Shen
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Diana M Gilligan
- Department of Medicine and Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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4
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A Review of the Epidemiological Evidence for Adducin Family Gene Polymorphisms and Hypertension. Cardiol Res Pract 2019; 2019:7135604. [PMID: 31275642 PMCID: PMC6589276 DOI: 10.1155/2019/7135604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/11/2019] [Accepted: 04/17/2019] [Indexed: 12/31/2022] Open
Abstract
Hypertension is one of the most common cardiovascular diseases that seriously endangers human health and has become a significant public health problem worldwide. In the vast majority of patients, the cause of hypertension is unknown, called essential hypertension (EH), accounting for more than 95% of total hypertension. Epidemiological and genetic studies of humans and animals provide strong evidence of a causal relationship between high salt intake and hypertension. Adducin is one of the important candidate genes for essential hypertension. Adducin is a heterodimeric or heterotetrameric protein that consists of α, β, and γ subunits; the three subunits are encoded by genes (ADD1, ADD2, and ADD3) that map to three different chromosomes. Animal model experiments and clinical studies suggest that changes in single-nucleotide polymorphisms (SNPs) at part of the adducin family gene increase the Na+-K+-ATPase activity of the renal tubular basement membrane and increase the reabsorption of Na+ by renal tubular epithelial cells, which may cause hypertension. This review makes a summary on the structure, function, and mechanism of adducin and the role of adducin on the onset of EH, providing a basis for the early screening, prevention, and treatment of EH.
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Zheng S, Krump NA, McKenna MM, Li YH, Hannemann A, Garrett LJ, Gibson JS, Bodine DM, Low PS. Regulation of erythrocyte Na +/K +/2Cl - cotransport by an oxygen-switched kinase cascade. J Biol Chem 2018; 294:2519-2528. [PMID: 30563844 DOI: 10.1074/jbc.ra118.006393] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/14/2018] [Indexed: 11/06/2022] Open
Abstract
Many erythrocyte processes and pathways, including glycolysis, the pentose phosphate pathway (PPP), KCl cotransport, ATP release, Na+/K+-ATPase activity, ankyrin-band 3 interactions, and nitric oxide (NO) release, are regulated by changes in O2 pressure that occur as a red blood cell (RBC) transits between the lungs and tissues. The O2 dependence of glycolysis, PPP, and ankyrin-band 3 interactions (affecting RBC rheology) are controlled by O2-dependent competition between deoxyhemoglobin (deoxyHb), but not oxyhemoglobin (oxyHb), and other proteins for band 3. We undertook the present study to determine whether the O2 dependence of Na+/K+/2Cl- cotransport (catalyzed by Na+/K+/2Cl- cotransporter 1 [NKCC1]) might similarly originate from competition between deoxyHb and a protein involved in NKCC1 regulation for a common binding site on band 3. Using three transgenic mouse strains having mutated deoxyhemoglobin-binding sites on band 3, we found that docking of deoxyhemoglobin at the N terminus of band 3 displaces the protein with no lysine kinase 1 (WNK1) from its overlapping binding site on band 3. This displacement enabled WNK1 to phosphorylate oxidative stress-responsive kinase 1 (OSR1), which, in turn, phosphorylated and activated NKCC1. Under normal solution conditions, the NKCC1 activation increased RBC volume and thereby induced changes in RBC rheology. Because the deoxyhemoglobin-mediated WNK1 displacement from band 3 in this O2 regulation pathway may also occur in the regulation of other O2-regulated ion transporters, we hypothesize that the NKCC1-mediated regulatory mechanism may represent a general pattern of O2 modulation of ion transporters in erythrocytes.
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Affiliation(s)
- Suilan Zheng
- From the Institute for Drug Discovery and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Nathan A Krump
- the Hematopoiesis Section, National Human Genome Research Institute and
| | - Mary M McKenna
- the Hematopoiesis Section, National Human Genome Research Institute and
| | - Yen-Hsing Li
- From the Institute for Drug Discovery and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Anke Hannemann
- the Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - Lisa J Garrett
- the National Human Genome Research Institute Embryonic Stem Cell and Transgenic Mouse Core Facility, National Institutes of Health, Bethesda, Maryland 20815, and
| | - John S Gibson
- the Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - David M Bodine
- the Hematopoiesis Section, National Human Genome Research Institute and
| | - Philip S Low
- From the Institute for Drug Discovery and Department of Chemistry, Purdue University, West Lafayette, Indiana 47907,
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6
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Hsu WH, Wang WJ, Lin WY, Huang YM, Lai CC, Liao JC, Chen HC. Adducin-1 is essential for spindle pole integrity through its interaction with TPX2. EMBO Rep 2018; 19:embr.201745607. [PMID: 29925526 PMCID: PMC6073210 DOI: 10.15252/embr.201745607] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 05/21/2018] [Accepted: 05/28/2018] [Indexed: 11/25/2022] Open
Abstract
Bipolar spindle assembly is necessary to ensure the proper progression of cell division. Loss of spindle pole integrity leads to multipolar spindles and aberrant chromosomal segregation. However, the mechanism underlying the maintenance of spindle pole integrity remains unclear. In this study, we show that the actin‐binding protein adducin‐1 (ADD1) is phosphorylated at S726 during mitosis. S726‐phosphorylated ADD1 localizes to centrosomes, wherein it organizes into a rosette‐like structure at the pericentriolar material. ADD1 depletion causes centriole splitting and therefore results in multipolar spindles during mitosis, which can be restored by re‐expression of ADD1 and the phosphomimetic S726D mutant but not by the S726A mutant. Moreover, the phosphorylation of ADD1 at S726 is crucial for its interaction with TPX2, which is essential for spindle pole integrity. Together, our findings unveil a novel function of ADD1 in maintaining spindle pole integrity through its interaction with TPX2.
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Affiliation(s)
- Wen-Hsin Hsu
- Ph.D. Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Won-Jing Wang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Wan-Yi Lin
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Min Huang
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Chien-Chen Lai
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Jung-Chi Liao
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | - Hong-Chen Chen
- Ph.D. Program in Tissue Engineering and Regenerative Medicine, National Chung Hsing University, Taichung, Taiwan .,Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.,Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan.,Cancer Progression Research Center, National Yang-Ming University, Taipei, Taiwan
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7
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A Review on Adducin from Functional to Pathological Mechanisms: Future Direction in Cancer. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3465929. [PMID: 29862265 PMCID: PMC5976920 DOI: 10.1155/2018/3465929] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/14/2022]
Abstract
Adducin (ADD) is a family of membrane skeleton proteins including ADD1, ADD2, and ADD3 that are encoded by distinct genes on different chromosomes. Adducin is primarily responsible for the assembly of spectrin-actin network that provides physical support to the plasma membrane and mediates signal transduction in various cellular physiological processes upon regulation by protein kinase C-dependent and calcium/calmodulin-dependent pathways. Abnormal phosphorylation, genetic variations, and alternative splicing of adducin may contribute to alterations in cellular functions involved in pathogenic processes. These alterations are associated with a wide range of diseases including cancer. This paper begins with a discussion on how adducin partakes in the structural formation of membrane skeleton, its regulation, and related functional characteristics, followed by a review on the pathogenesis of hypertension, biliary atresia, and cancer with respect to increased disease susceptibility mediated by adducin polymorphism and/or dysregulation. Given the functional diversity of adducin in different cellular compartments, we aim to provide a knowledge base whereby its pathophysiological roles can be better understood. More importantly, we aim to provide novel insights that may be of significance in turning the adducin model to clinical application.
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8
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Luo C, Shen J. Adducin in tumorigenesis and metastasis. Oncotarget 2018; 8:48453-48459. [PMID: 28476036 PMCID: PMC5564661 DOI: 10.18632/oncotarget.17173] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/28/2017] [Indexed: 12/12/2022] Open
Abstract
Adducin is a membrane-skeletal protein localized at spectrin-actin junctions, involving in the formation of the network of cytoskeleton, cellular signal transduction, ionic transportation, cell motility and cell proliferation. While previous researches focused mainly on the relationship between adducin and hypertension, there are few studies focusing on the role of adducin in tumor. Previous studies showed that adducin played a role in the evolution and progression of neoplasm. This review makes a brief summary on the structure, function and mechanism of adducin and how adducin functions in tumorigenesis and metastasis.
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Affiliation(s)
- Cong Luo
- Zhejiang Cancer Hospital, Department of Abdominal oncology, Hangzhou, Zhejiang, China
| | - Jiayu Shen
- Zhejiang Chinese Medical University, The Second Clinical Medical College, Hangzhou, Zhejiang, China
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9
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Huang YZ, Qian LN, Wang J, Zhang CL, Fang XT, Lei CZ, Lan XY, Ma Y, Bai YY, Lin FP, Chen H. Genetic Variants in ADD1 Gene and their Associations with Growth Traits in Cattle. Anim Biotechnol 2018. [PMID: 29527980 DOI: 10.1080/10495398.2017.1398754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The α-adducin (ADD1) is a subunit of adducin which is a cytoskeleton heterodimeric protein. Adducin participates in oocytes chromosome meiosis of mice, prompting adducin has an effect on embryonic development. Adducin gene mutation has significantly functional change. So the present study was to identify and characterize polymorphisms within the coding region of the bovine ADD1 gene among different cattle breeds. Here, 11 novel single nucleotide polymorphisms (SNPs 1-11) were identified by DNA sequencing and polymerase chain reaction-single stranded conformational polymorphism, there were one synonymous mutation in exon 1 (SNP1); four missense mutations in exons 4, 7, and 8 (SNPs 3-6); and six mutations in introns 4, 12, 13, and 14 (SNPs 2, 7-10). The statistical analyses indicated that the some SNPs are associated with the growth traits (body length, body height, chest circumference, and hucklebone width) in Chinese Jiaxian cattle population. Our results provide evidence that polymorphisms in the ADD1 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.
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Affiliation(s)
- Yong-Zhen Huang
- a Institute of Cellular and Molecular Biology, School of Life Sciences , Jiangsu Normal University , Xuzhou , Jiangsu , China.,b Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi , China
| | - Li-Na Qian
- b Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi , China
| | - Jian Wang
- a Institute of Cellular and Molecular Biology, School of Life Sciences , Jiangsu Normal University , Xuzhou , Jiangsu , China
| | - Chun-Lei Zhang
- b Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi , China
| | - Xing-Tang Fang
- b Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi , China
| | - Chu-Zhao Lei
- a Institute of Cellular and Molecular Biology, School of Life Sciences , Jiangsu Normal University , Xuzhou , Jiangsu , China
| | - Xian-Yong Lan
- a Institute of Cellular and Molecular Biology, School of Life Sciences , Jiangsu Normal University , Xuzhou , Jiangsu , China
| | - Yun Ma
- c College of Life Sciences , Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University , Xinyang , Henan , China
| | - Yue-Yu Bai
- d Animal Health Supervision in Henan Province , Zhengzhou , Henan , China
| | - Feng-Peng Lin
- e Bureau of Animal Husbandry of Biyang County , Biyang , Henan , China
| | - Hong Chen
- a Institute of Cellular and Molecular Biology, School of Life Sciences , Jiangsu Normal University , Xuzhou , Jiangsu , China.,b Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology , Northwest A&F University , Yangling , Shaanxi , China
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10
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Structural organization of the actin-spectrin-based membrane skeleton in dendrites and soma of neurons. Proc Natl Acad Sci U S A 2017; 114:E6678-E6685. [PMID: 28739933 DOI: 10.1073/pnas.1705043114] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Actin, spectrin, and associated molecules form a membrane-associated periodic skeleton (MPS) in neurons. In the MPS, short actin filaments, capped by actin-capping proteins, form ring-like structures that wrap around the circumference of neurites, and these rings are periodically spaced along the neurite by spectrin tetramers, forming a quasi-1D lattice structure. This 1D MPS structure was initially observed in axons and exists extensively in axons, spanning nearly the entire axonal shaft of mature neurons. Such 1D MPS was also observed in dendrites, but the extent to which it exists and how it develops in dendrites remain unclear. It is also unclear whether other structural forms of the membrane skeleton are present in neurons. Here, we investigated the spatial organizations of spectrin, actin, and adducin, an actin-capping protein, in the dendrites and soma of cultured hippocampal neurons at different developmental stages, and compared results with those obtained in axons, using superresolution imaging. We observed that the 1D MPS exists in a substantial fraction of dendritic regions in relatively mature neurons, but this structure develops slower and forms with a lower propensity in dendrites than in axons. In addition, we observed that spectrin, actin, and adducin also form a 2D polygonal lattice structure, resembling the expanded erythrocyte membrane skeleton structure, in the somatodendritic compartment. This 2D lattice structure also develops substantially more slowly in the soma and dendrites than the development of the 1D MPS in axons. These results suggest membrane skeleton structures are differentially regulated across different subcompartments of neurons.
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11
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Radosinska J, Vrbjar N. The role of red blood cell deformability and Na,K-ATPase function in selected risk factors of cardiovascular diseases in humans: focus on hypertension, diabetes mellitus and hypercholesterolemia. Physiol Res 2017; 65 Suppl 1:S43-54. [PMID: 27643939 DOI: 10.33549/physiolres.933402] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Deformability of red blood cells (RBC) is the ability of RBC to change their shape in order to pass through narrow capillaries in circulation. Deterioration in deformability of RBC contributes to alterations in microcirculatory blood flow and delivery of oxygen to tissues. Several factors are responsible for maintenance of RBC deformability. One of them is the Na,K-ATPase known as crucial enzyme in maintenance of intracellular ionic homeostasis affecting thus regulation of cellular volume and consequently RBC deformability. Decreased deformability of RBC has been found to be the marker of adverse outcomes in cardiovascular diseases (CVD) and the presence of cardiovascular risk factors influences rheological properties of the blood. This review summarizes knowledge concerning the RBC deformability in connection with selected risk factors of CVD, including hypertension, hyperlipidemia, and diabetes mellitus, based exclusively on papers from human studies. We attempted to provide an update on important issues regarding the role of Na,K-ATPase in RBC deformability. In patients suffering from hypertension as well as diabetes mellitus the Na,K-ATPase appears to be responsible for the changes leading to alterations in RBC deformability. The triggering factor for changes of RBC deformability during hypercholesterolemia seems to be the increased content of cholesterol in erythrocyte membranes.
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Affiliation(s)
- J Radosinska
- Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, Bratislava, Slovak Republic; Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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12
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Identification of adducin-binding residues on the cytoplasmic domain of erythrocyte membrane protein, band 3. Biochem J 2016; 473:3147-58. [PMID: 27435097 DOI: 10.1042/bcj20160328] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/19/2016] [Indexed: 12/26/2022]
Abstract
Two major complexes form structural bridges that connect the erythrocyte membrane to its underlying spectrin-based cytoskeleton. Although the band 3-ankyrin bridge may account for most of the membrane-to-cytoskeleton interactions, the linkage between the cytoplasmic domain of band 3 (cdb3) and adducin has also been shown to be critical to membrane integrity. In the present paper, we demonstrate that adducin, a major component of the spectrin-actin junctional complex, binds primarily to residues 246-264 of cdb3, and mutation of two exposed glutamic acid residues within this sequence completely abrogates both α- and β-adducin binding. Because these residues are located next to the ankyrin-binding site on cdb3, it seems unlikely that band 3 can bind ankyrin and adducin concurrently, reducing the chances of an association between the ankyrin and junctional complexes that would significantly compromise erythrocyte membrane integrity. We also demonstrate that adducin binds the kidney isoform of cdb3, a spliceoform that lacks the first 65 amino acids of erythrocyte cdb3, including the central strand of a large β-pleated sheet. Because kidney cdb3 is not known to bind any of the common peripheral protein partners of erythrocyte cdb3, including ankyrin, protein 4.1, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and phosphofructokinase, retention of this affinity for adducin was unexpected.
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13
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Akai J, Storey K. Expression of gamma-adducin is associated with regions of morphogenetic cell movement in the chick embryo. Mech Dev 2016; 119 Suppl 1:S191-5. [PMID: 14516684 DOI: 10.1016/s0925-4773(03)00115-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The adducin family of cytoskeletal proteins are known to mediate actin driven cell movements. Here we describe the cloning and expression pattern of a gene encoding gamma-adducin in the chick embryo. Expression of this gene is strikingly restricted to the epithelial cell layer (with a few exceptions including emerging notochord and lateral mesoderm). Gamma-adducin is detected at particularly high levels in cell populations undergoing important morphogenetic movements, such as epiblast approaching the primitive streak, regressing spinal cord primordia and closing neural tube.
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Affiliation(s)
- Jun Akai
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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14
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Khan MAH, Sharma A, Rarick KR, Roman RJ, Harder DR, Imig JD. Elevated Aminopeptidase P Attenuates Cerebral Arterial Responses to Bradykinin in Fawn-Hooded Hypertensive Rats. PLoS One 2015; 10:e0145335. [PMID: 26683993 PMCID: PMC4686180 DOI: 10.1371/journal.pone.0145335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 12/02/2015] [Indexed: 01/30/2023] Open
Abstract
Cerebral arterial myogenic and autoregulatory responses are impaired in Fawn Hooded hypertensive (FHH) rats. Cerebral autoregulatory responses are restored in the congenic rat strain in which a segment of chromosome 1 from the Brown Norway (BN) rat was transferred into the FHH genetic background (FHH.1BN). The impact of this region on cerebral arterial dilator responses remains unknown. Aminopeptidase is a gene that was transferred into the FHH genetic background to generate the FHH.1BN rats and is responsible for degradation of the vasodilator bradykinin. Thus, we hypothesized that FHH rats will have increased aminopeptidase P levels with impaired cerebral arterial responses to bradykinin compared to BN and FHH.1BN rats. We demonstrated higher cerebral arterial expression of aminopeptidase P in FHH compared to BN rats. Accordingly, we demonstrated markedly impaired cerebral arterial dilation to bradykinin in FHH compared to BN rats. Interestingly, aminopeptidase P expression was lower in FHH.1BN compared to FHH rats. Decreased aminopeptidase P levels in FHH.1BN rats were associated with increased cerebral arterial bradykinin-induced dilator responses. Aminopeptidase P inhibition by apstatin improved cerebral arterial bradykinin dilator responses in FHH rats to a level similar to FHH.1BN rats. Unlike bradykinin, cerebral arterial responses to acetylcholine were similar between FHH and FHH.1BN groups. These findings indicate decreased bradykinin bioavailability contributes to impaired cerebral arterial dilation in FHH rats. Overall, these data indicate an important role of aminopeptidase P in the impaired cerebral arterial function in FHH rat.
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Affiliation(s)
- Md Abdul Hye Khan
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Amit Sharma
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Kevin R. Rarick
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Richard J. Roman
- Department of Pharmacology & Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - David R. Harder
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - John D. Imig
- Department of Pharmacology & Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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15
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Brown JW, Bullitt E, Sriswasdi S, Harper S, Speicher DW, McKnight CJ. The Physiological Molecular Shape of Spectrin: A Compact Supercoil Resembling a Chinese Finger Trap. PLoS Comput Biol 2015; 11:e1004302. [PMID: 26067675 PMCID: PMC4466138 DOI: 10.1371/journal.pcbi.1004302] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/27/2015] [Indexed: 01/29/2023] Open
Abstract
The primary, secondary, and tertiary structures of spectrin are reasonably well defined, but the structural basis for the known dramatic molecular shape change, whereby the molecular length can increase three-fold, is not understood. In this study, we combine previously reported biochemical and high-resolution crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the spectrin heterotetramer. In addition to explaining spectrin’s physiological resting length of ~55-65 nm, our model provides a mechanism by which spectrin is able to undergo a seamless three-fold extension while remaining a linear filament, an experimentally observed property. According to the proposed model, spectrin’s quaternary structure and mechanism of extension is similar to a Chinese Finger Trap: at shorter molecular lengths spectrin is a hollow cylinder that extends by increasing the pitch of each spectrin repeat, which decreases the internal diameter. We validated our model with electron microscopy, which demonstrated that, as predicted, spectrin is hollow at its biological resting length of ~55-65 nm. The model is further supported by zero-length chemical crosslink data indicative of an approximately 90 degree bend between adjacent spectrin repeats. The domain-domain interactions in our model are entirely consistent with those present in the prototypical linear antiparallel heterotetramer as well as recently reported inter-strand chemical crosslinks. The model is consistent with all known physical properties of spectrin, and upon full extension our Chinese Finger Trap Model reduces to the ~180-200 nm molecular model currently in common use. Spectrins are cytoskeletal and scaffolding proteins ubiquitously expressed in essentially all cell-types. Despite unequivocal evidence for a short physiological length of ~55–65 nm at rest, spectrin is typically represented as an extended ~200 nm molecule that is implied based on crystallographic structures of a number of tandem repeats. Here, we incorporate previously reported biochemical and crystallographic data with structural mass spectroscopy and electron microscopic data to derive a detailed, experimentally-supported quaternary structure of the physiological compact form of spectrin. In addition to explaining spectrin’s physiological resting length (~55–65 nm), our model provides a mechanism by which spectrin can undergo a seamless three-fold extension, which is an experimentally observed property that is responsible for restoration of cell shape after mechanical deformation.
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Affiliation(s)
- Jeffrey W. Brown
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Internal Medicine Residency Program, University of Pittsburgh Medical Center, UPMC Montefiore Hospital, Pittsburgh, Pennsylvania, United States of America
| | - Esther Bullitt
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Sira Sriswasdi
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sandra Harper
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - David W. Speicher
- Center for Systems and Computational Biology, and Molecular and Cellular Oncogenesis Program, the Wistar Institute, Philadelphia, Pennsylvania, United States of America
- Genomics and Computational Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - C. James McKnight
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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16
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Chan PC, Hsu RYC, Liu CW, Lai CC, Chen HC. Adducin-1 is essential for mitotic spindle assembly through its interaction with myosin-X. ACTA ACUST UNITED AC 2013; 204:19-28. [PMID: 24379415 PMCID: PMC3882790 DOI: 10.1083/jcb.201306083] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The actin-binding protein ADD1 associates with mitotic spindles through Myo10 and is crucial for proper spindle assembly and mitotic progression. Mitotic spindles are microtubule-based structures, but increasing evidence indicates that filamentous actin (F-actin) and F-actin–based motors are components of these structures. ADD1 (adducin-1) is an actin-binding protein that has been shown to play important roles in the stabilization of the membrane cortical cytoskeleton and cell–cell adhesions. In this study, we show that ADD1 associates with mitotic spindles and is crucial for proper spindle assembly and mitotic progression. Phosphorylation of ADD1 at Ser12 and Ser355 by cyclin-dependent kinase 1 enables ADD1 to bind to myosin-X (Myo10) and therefore to associate with mitotic spindles. ADD1 depletion resulted in distorted, elongated, and multipolar spindles, accompanied by aberrant chromosomal alignment. Remarkably, the mitotic defects caused by ADD1 depletion were rescued by reexpression of ADD1 but not of an ADD1 mutant defective in Myo10 binding. Together, our findings unveil a novel function for ADD1 in mitotic spindle assembly through its interaction with Myo10.
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Affiliation(s)
- Po-Chao Chan
- Department of Life Sciences, 2 Graduate Institute of Molecular Biology, 3 Graduate Institute of Biomedical Sciences, 4 Agricultural Biotechnology Center, and 5 Rong-Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 40227, Taiwan
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17
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Machnicka B, Czogalla A, Hryniewicz-Jankowska A, Bogusławska DM, Grochowalska R, Heger E, Sikorski AF. Spectrins: a structural platform for stabilization and activation of membrane channels, receptors and transporters. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:620-34. [PMID: 23673272 DOI: 10.1016/j.bbamem.2013.05.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/25/2013] [Accepted: 05/06/2013] [Indexed: 12/22/2022]
Abstract
This review focuses on structure and functions of spectrin as a major component of the membrane skeleton. Recent advances on spectrin function as an interface for signal transduction mediation and a number of data concerning interaction of spectrin with membrane channels, adhesion molecules, receptors and transporters draw a picture of multifaceted protein. Here, we attempted to show the current depiction of multitask role of spectrin in cell physiology. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- Beata Machnicka
- University of Zielona Góra, Faculty of Biological Sciences, Poland
| | | | | | | | | | - Elżbieta Heger
- University of Zielona Góra, Faculty of Biological Sciences, Poland
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18
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Miyauchi JT, Piermarini PM, Yang JD, Gilligan DM, Beyenbach KW. Roles of PKC and phospho-adducin in transepithelial fluid secretion by Malpighian tubules of the yellow fever mosquito. Tissue Barriers 2013; 1. [PMID: 24062972 PMCID: PMC3779481 DOI: 10.4161/tisb.23120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The diuretic hormone aedeskinin-III is known to increase the paracellular Cl- conductance in Malpighian (renal) tubules of the mosquito Aedes aegypti via a G protein-coupled receptor. The increase serves the blood-meal-initiated diuresis and is associated with elevated levels of Ca2+ and phosphorylated adducin in the cytosol of tubule. In the present study we have cloned adducin in Aedes Malpighian tubules and investigated its physiological roles. Immunolabeling experiments are consistent with the association of adducin with the cortical cytoskeleton, especially near the apical brush border of the tubule. An antibody against phosphorylated adducin revealed the transient phosphorylation of adducin 2 min after stimulating tubules with aedeskinin-III. The PKC inhibitor bisindolylmaleimide-I blocked the phosphorylation of adducin as well as the electrophysiological and diuretic effects of aedeskinin-III. Bisindolylmaleimide-I also inhibited fluid secretion in control tubules. Phorbol 12-myristate 13-acetate increased phosphorylated adducin levels in Malpighian tubules, but it inhibited fluid secretion. Thus, the phosphorylation of adducin by PKC alone is insufficient to trigger diuretic rates of fluid secretion; elevated levels of intracellular Ca2+ may also be required. The above results suggest that the phosphorylation of adducin, which is known to destabilize the cytoskeleton, may (1) facilitate the traffic of transporters into the apical brush border supporting diuretic rates of cation secretion and (2) destabilize proteins in the septate junction thereby enabling paracellular anion (Cl-) secretion at diuretic rates. Moreover, PKC and the phosphorylation of adducin play a central role in control and diuretic tubules, consistent with the dynamic behavior of both transcellular and paracellular transport pathways.
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Affiliation(s)
- Jeremy T Miyauchi
- Department of Biomedical Sciences; College of Veterinary Medicine; Cornell University; Ithaca, NY USA
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19
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Fowler VM. The human erythrocyte plasma membrane: a Rosetta Stone for decoding membrane-cytoskeleton structure. CURRENT TOPICS IN MEMBRANES 2013; 72:39-88. [PMID: 24210427 DOI: 10.1016/b978-0-12-417027-8.00002-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The mammalian erythrocyte, or red blood cell (RBC), is a unique experiment of nature: a cell with no intracellular organelles, nucleus or transcellular cytoskeleton, and a plasma membrane with uniform structure across its entire surface. By virtue of these specialized properties, the RBC membrane has provided a template for discovery of the fundamental actin filament network machine of the membrane skeleton, now known to confer mechanical resilience, anchor membrane proteins, and organize membrane domains in all cells. This chapter provides a historical perspective and critical analysis of the biochemistry, structure, and physiological functions of this actin filament network in RBCs. The core units of this network are nodes of ~35-37 nm-long actin filaments, interconnected by long strands of (α1β1)₂-spectrin tetramers, forming a 2D isotropic lattice with quasi-hexagonal symmetry. Actin filament length and stability is critical for network formation, relying upon filament capping at both ends: tropomodulin-1 at pointed ends and αβ-adducin at barbed ends. Tropomodulin-1 capping is essential for precise filament lengths, and is enhanced by tropomyosin, which binds along the short actin filaments. αβ-adducin capping recruits spectrins to sites near barbed ends, promoting network formation. Accessory proteins, 4.1R and dematin, also promote spectrin binding to actin and, with αβ-adducin, link to membrane proteins, targeting actin nodes to the membrane. Dissection of the molecular organization within the RBC membrane skeleton is one of the paramount achievements of cell biological research in the past century. Future studies will reveal the structure and dynamics of actin filament capping, mechanisms of precise length regulation, and spectrin-actin lattice symmetry.
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Affiliation(s)
- Velia M Fowler
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, USA.
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20
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Burke M, Pabbidi M, Fan F, Ge Y, Liu R, Williams JM, Sarkis A, Lazar J, Jacob HJ, Roman RJ. Genetic basis of the impaired renal myogenic response in FHH rats. Am J Physiol Renal Physiol 2012; 304:F565-77. [PMID: 23220727 DOI: 10.1152/ajprenal.00404.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examined the effect of substitution of a 2.4-megabase pair (Mbp) region of Brown Norway (BN) rat chromosome 1 (RNO1) between 258.8 and 261.2 Mbp onto the genetic background of fawn-hooded hypertensive (FHH) rats on autoregulation of renal blood flow (RBF), myogenic response of renal afferent arterioles (AF-art), K(+) channel activity in renal vascular smooth muscle cells (VSMCs), and development of proteinuria and renal injury. FHH rats exhibited poor autoregulation of RBF, while FHH.1BN congenic strains with the 2.4-Mbp BN region exhibited nearly perfect autoregulation of RBF. The diameter of AF-art from FHH rats increased in response to pressure but decreased in congenic strains containing the 2.4-Mbp BN region. Protein excretion and glomerular and interstitial damage were significantly higher in FHH rats than in congenic strains containing the 2.4-Mbp BN region. K(+) channel current was fivefold greater in VSMCs from renal arterioles of FHH rats than cells obtained from congenic strains containing the 2.4-Mbp region. Sequence analysis of the known and predicted genes in the 2.4-Mbp region of FHH rats revealed amino acid-altering variants in the exons of three genes: Add3, Rbm20, and Soc-2. Quantitative PCR studies indicated that Mxi1 and Rbm20 were differentially expressed in the renal vasculature of FHH and FHH.1BN congenic strain F. These data indicate that transfer of this 2.4-Mbp region from BN to FHH rats restores the myogenic response of AF-art and autoregulation of RBF, decreases K(+) current, and slows the progression of proteinuria and renal injury.
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Affiliation(s)
- Marilyn Burke
- Dept. of Pharmacology and Toxicology, Univ. of Mississippi Medical Center, 2500 North State St. Jackson, MS 39216, USA
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21
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Pabbidi MR, Juncos J, Juncos L, Renic M, Tullos HJ, Lazar J, Jacob HJ, Harder DR, Roman RJ. Identification of a region of rat chromosome 1 that impairs the myogenic response and autoregulation of cerebral blood flow in fawn-hooded hypertensive rats. Am J Physiol Heart Circ Physiol 2012; 304:H311-7. [PMID: 23144316 DOI: 10.1152/ajpheart.00622.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effects of transfer of a 2.4-Mbp region of rat chromosome 1 (RNO1) from Brown Norway (BN) into fawn-hooded hypertensive (FHH) rats on autoregulation (AR) of cerebral blood flow (CBF) and the myogenic response of middle cerebral arteries (MCAs). AR of CBF was poor in FHH and FHH.1(BN) AR(-) congenic strains that excluded the critical 2.4-Mbp region. In contrast, AR was restored in FHH.1(BN) AR(+) congenic strains that included this region. The diameter of MCAs of FHH rats increased from 140 ± 14 to 157 ± 18 μm when transmural pressure was increased from 40 to 140 mmHg, but it decreased from 137 ± 5 to 94 ± 7 μm in FHH.1(BN) AR(+) congenic strains. Transient occlusion of MCAs reduced CBF by 80% in all strains. However, the hyperemic response following ischemia was significantly greater in FHH and AR(-) rats than that seen in AR(+) congenic strains (AR(-), 173 ± 11% vs. AR(+), 124 ± 5%). Infarct size and edema formation were also significantly greater in an AR(-) strain (38.6 ± 2.6 and 12.1 ± 2%) than in AR(+) congenic strains (27.6 ± 1.8 and 6.5 ± 0.9%). These results indicate that there is a gene in the 2.4-Mbp region of RNO1 that alters the development of myogenic tone in cerebral arteries. Transfer of this region from BN to FHH rats restores AR of CBF and vascular reactivity and reduces cerebral injury after transient occlusion and reperfusion of the MCA.
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22
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Structural stabilization of protein 4.1R FERM domain upon binding to apo-calmodulin: novel insights into the biological significance of the calcium-independent binding of calmodulin to protein 4.1R. Biochem J 2012; 440:367-74. [PMID: 21848512 DOI: 10.1042/bj20110676] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In erythrocytes, 4.1R80 (80 kDa isoform of protein 4.1R) binds to the cytoplasmic tail of the transmembrane proteins band 3 and GPC (glycophorin C), and to the membrane-associated protein p55 through the N- (N-terminal), α- (α-helix-rich) and C- (C-terminal) lobes of R30 [N-terminal 30 kDa FERM (4.1/ezrin/radixin/moesin) domain of protein 4.1R] respectively. We have shown previously that R30 binds to CaM (calmodulin) in a Ca2+-independent manner, the equilibrium dissociation constant (Kd) for R30-CaM binding being very similar (in the submicromolar range) in the presence or absence of Ca2+. In the present study, we investigated the consequences of CaM binding on R30's structural stability using resonant mirror detection and FTIR (Fourier-transform IR) spectroscopy. After a 30 min incubation above 40° C, R30 could no longer bind to band 3 or to GPC. In contrast, R30 binding to p55, which could be detected at a temperature as low as 34° C, was maintained up to 44° C in the presence of apo-CaM. Dynamic light scattering measurements indicated that R30, either alone or complexed with apo-CaM, did not aggregate up to 40° C. FTIR spectroscopy revealed that the dramatic variations in the structure of the β-sheet structure of R30 observed at various temperatures were minimized in the presence of apo-CaM. On the basis of Kd values calculated at various temperatures, ΔCp and ΔG° for R30 binding to apo-CaM were determined as -10 kJ · K(-1) · mol-1 and ~ -38 kJ · mol(-1) at 37° C (310.15 K) respectively. These data support the notion that apo-CaM stabilizes R30 through interaction with its β-strand-rich C-lobe and provide a novel function for CaM, i.e. structural stabilization of 4.1R80.
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23
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Chen CL, Lin YP, Lai YC, Chen HC. α-Adducin translocates to the nucleus upon loss of cell-cell adhesions. Traffic 2011; 12:1327-40. [PMID: 21736685 DOI: 10.1111/j.1600-0854.2011.01245.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The F-actin binding protein adducin plays an important role in plasma membrane stability, cell motility and cell-cell junctions. In this study, we demonstrate that α-adducin is mainly localized in the nucleus of sparsely cultured epithelial cells, whereas it is localized at cell-cell junctions when the cells are grown to confluence. Disruption of cell-cell adhesions induces a nuclear translocation of α-adducin. Conversely, α-adducin is redistributed to the cytoplasm and cell-cell junctions in the process of establishing cell-cell adhesions. We identify that α-adducin contains a bipartite nuclear localization signal (NLS) in its COOH-terminal tail domain and a nuclear export signal in its neck region. The phosphorylation of α-adducin at Ser716 that is immediately adjacent to the NLS appears to antagonize the function of the NLS. Moreover, we show that depletion of α-adducin has adverse effects on cell-cell adhesions and, to our surprise, cell proliferation. The impaired cell proliferation is associated with mitotic defects characterized by disorganized mitotic spindles, aberrant chromosomal congregation/segregation and abnormal centrosomes. Taken together, our results not only reveal the mechanism for α-adducin to shuttle between the cytoplasm and nucleus, but also highlight a potential role for α-adducin in mitosis.
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Affiliation(s)
- Chien-Lin Chen
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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24
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Wooden JM, Finney GL, Rynes E, Maccoss MJ, Lambert AJ, Robledo RF, Peters LL, Gilligan DM. Comparative proteomics reveals deficiency of SLC9A1 (sodium/hydrogen exchanger NHE1) in β-adducin null red cells. Br J Haematol 2011; 154:492-501. [PMID: 21689084 DOI: 10.1111/j.1365-2141.2011.08612.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Spherocytosis is one of the most common inherited disorders, yet presents with a wide range of clinical severity. While several genes have been found mutated in patients with spherocytosis, the molecular basis for the variability in severity of haemolytic anaemia is not entirely understood. To identify candidate proteins involved in haemolytic anaemia pathophysiology, we utilized a label-free comparative proteomic approach to detect differences in red blood cells (RBCs) from normal and β-adducin (Add2) knock-out mice. We detected seven proteins that were decreased and 48 proteins that were increased in β-adducin null RBC ghosts. Since haemolytic anaemias are characterized by reticulocytosis, we compared reticulocyte-enriched samples from phenylhydrazine-treated mice with mature RBCs from untreated mice. Among the 48 proteins increased in Add2 knockout RBCs, only 11 were also increased in reticulocytes. Of the proteins decreased in Add2 knockout RBCs, α-adducin showed the greatest intensity difference, followed by SLC9A1, the sodium-hydrogen exchanger previously termed NHE1. We verified these mass spectrometry results by immunoblot. This is the first example of SLC9A1deficiency in haemolytic anaemia and suggests new insights into the mechanisms leading to fragile RBCs.
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25
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Farghaian H, Turnley AM, Sutherland C, Cole AR. Bioinformatic prediction and confirmation of beta-adducin as a novel substrate of glycogen synthase kinase 3. J Biol Chem 2011; 286:25274-83. [PMID: 21606488 DOI: 10.1074/jbc.m111.251629] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
It is important to identify the true substrates of protein kinases because this illuminates the primary function of any kinase. Here, we used bioinformatics and biochemical validation to identify novel brain substrates of the Ser/Thr kinase glycogen synthase kinase 3 (GSK3). Briefly, sequence databases were searched for proteins containing a conserved GSK3 phosphorylation consensus sequence ((S/T)PXX(S/T)P or (S/T)PXXX(S/T)P), as well as other criteria of interest (e.g. brain proteins). Importantly, candidates were highlighted if they had previously been reported to be phosphorylated at these sites by large-scale phosphoproteomic studies. These criteria identified the brain-enriched cytoskeleton-associated protein β-adducin as a likely substrate of GSK3. To confirm this experimentally, it was cloned and subjected to a combination of cell culture and in vitro kinase assays that demonstrated direct phosphorylation by GSK3 in vitro and in cells. Phosphosites were mapped to three separate regions near the C terminus and confirmed using phosphospecific antibodies. Prior priming phosphorylation by Cdk5 enhanced phosphorylation by GSK3. Expression of wild type, but not non-phosphorylatable (GSK3 insensitive), β-adducin increased axon and dendrite elongation in primary cortical neurons. Therefore, phosphorylation of β-adducin by GSK3 promotes efficient neurite outgrowth in neurons.
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Affiliation(s)
- Hovik Farghaian
- Neurosignalling Group, Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia
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26
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Gilligan DM, Finney GL, Rynes E, Maccoss MJ, Lambert AJ, Peters LL, Robledo RF, Wooden JM. Comparative proteomics reveals deficiency of NHE-1 (Slc9a1) in RBCs from the beta-adducin knockout mouse model of hemolytic anemia. Blood Cells Mol Dis 2011; 47:85-94. [PMID: 21592827 DOI: 10.1016/j.bcmd.2011.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/22/2011] [Indexed: 11/29/2022]
Abstract
Hemolytic anemia is one of the most common inherited disorders. To identify candidate proteins involved in hemolytic anemia pathophysiology, we utilized a label-free comparative proteomic approach to detect differences in RBCs from normal and beta-adducin (Add2) knock-out mice. We detected 7 proteins that were decreased and 48 proteins that were increased in the beta-adducin knock-out RBC ghost. Since hemolytic anemias are characterized by reticulocytosis, we compared reticulocyte-enriched samples from phenylhydrazine-treated mice with mature RBCs from untreated mice. Label-free analysis identified 47 proteins that were increased in the reticulocyte-enriched samples and 21 proteins that were decreased. Among the proteins increased in Add2 knockout RBCs, only 11 were also found increased in reticulocytes. Among the proteins decreased in Add2 knockout RBCs, beta- and alpha-adducin showed the greatest intensity difference, followed by NHE-1 (Slc9a1), the sodium-hydrogen exchanger. We verified these mass spectrometry results by immunoblot. This is the first example of a deficiency of NHE-1 in hemolytic anemia and suggests new insights into the mechanisms leading to fragile RBCs. Our use of label-free comparative proteomics to make this discovery demonstrates the usefulness of this approach as opposed to metabolic or chemical isotopic labeling of mice.
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Affiliation(s)
- Diana M Gilligan
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA.
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27
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Morrow JS, Rimm DL, Kennedy SP, Cianci CD, Sinard JH, Weed SA. Of Membrane Stability and Mosaics: The Spectrin Cytoskeleton. Compr Physiol 2011. [DOI: 10.1002/cphy.cp140111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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28
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Baines AJ. The spectrin-ankyrin-4.1-adducin membrane skeleton: adapting eukaryotic cells to the demands of animal life. PROTOPLASMA 2010; 244:99-131. [PMID: 20668894 DOI: 10.1007/s00709-010-0181-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 07/05/2010] [Indexed: 05/29/2023]
Abstract
The cells in animals face unique demands beyond those encountered by their unicellular eukaryotic ancestors. For example, the forces engendered by the movement of animals places stresses on membranes of a different nature than those confronting free-living cells. The integration of cells into tissues, as well as the integration of tissue function into whole animal physiology, requires specialisation of membrane domains and the formation of signalling complexes. With the evolution of mammals, the specialisation of cell types has been taken to an extreme with the advent of the non-nucleated mammalian red blood cell. These and other adaptations to animal life seem to require four proteins--spectrin, ankyrin, 4.1 and adducin--which emerged during eumetazoan evolution. Spectrin, an actin cross-linking protein, was probably the earliest of these, with ankyrin, adducin and 4.1 only appearing as tissues evolved. The interaction of spectrin with ankyrin is probably a prerequisite for the formation of tissues; only with the advent of vertebrates did 4.1 acquires the ability to bind spectrin and actin. The latter activity seems to allow the spectrin complex to regulate the cell surface accumulation of a wide variety of proteins. Functionally, the spectrin-ankyrin-4.1-adducin complex is implicated in the formation of apical and basolateral domains, in aspects of membrane trafficking, in assembly of certain signalling and cell adhesion complexes and in providing stability to otherwise mechanically fragile cell membranes. Defects in this complex are manifest in a variety of hereditary diseases, including deafness, cardiac arrhythmia, spinocerebellar ataxia, as well as hereditary haemolytic anaemias. Some of these proteins also function as tumor suppressors. The spectrin-ankyrin-4.1-adducin complex represents a remarkable system that underpins animal life; it has been adapted to many different functions at different times during animal evolution.
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Affiliation(s)
- Anthony J Baines
- School of Biosciences and Centre for Biomedical Informatics, University of Kent, Canterbury, CT2 7NJ, UK.
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Franco T, Low PS. Erythrocyte adducin: a structural regulator of the red blood cell membrane. Transfus Clin Biol 2010; 17:87-94. [PMID: 20655268 DOI: 10.1016/j.tracli.2010.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 05/30/2010] [Indexed: 10/19/2022]
Abstract
Adducin is an alpha, beta heterotetramer that performs multiple important functions in the human erythrocyte membrane. First, adducin forms a bridge that connects the spectrin-actin junctional complex to band 3, the major membrane-spanning protein in the bilayer. Rupture of this bridge leads to membrane instability and spontaneous fragmentation. Second, adducin caps the fast growing (barbed) end of actin filaments, preventing the tetradecameric protofilaments from elongating into macroscopic F-actin microfilaments. Third, adducin stabilizes the association between actin and spectrin, assuring that the junctional complex remains intact during the mechanical distortions experienced by the circulating cell. And finally, adducin responds to stimuli that may be important in regulating the global properties of the cell, possibly including cation transport, cell morphology and membrane deformability. The text below summarizes the structural properties of adducin, its multiple functions in erythrocytes, and the consequences of engineered deletions of each of adducin subunits in transgenic mice.
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Affiliation(s)
- T Franco
- Department of chemistry, Purdue University, 560, Oval Drive, West Lafayette, IN 47907-2084, USA
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Yurimoto S, Hatano N, Tsuchiya M, Kato K, Fujimoto T, Masaki T, Kobayashi R, Tokumitsu H. Identification and characterization of wolframin, the product of the wolfram syndrome gene (WFS1), as a novel calmodulin-binding protein. Biochemistry 2009; 48:3946-55. [PMID: 19292454 DOI: 10.1021/bi900260y] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To search for calmodulin (CaM) targets, we performed affinity chromatography purification of a rat brain extract using CaM fused with GST as the affinity ligand. Proteomic analysis was then carried out to identify CaM-binding proteins. In addition to identifying 36 known CaM-binding proteins, including CaM kinases, calcineurin, nNOS, the IP(3) receptor, and Ca(2+)-ATPase, we identified an ER transmembrane protein, wolframin [the product of the Wolfram syndrome gene (WFS1)] as interacting. A CaM overlay and an immunoprecipitation assay revealed that wolframin is capable of binding the Ca(2+)/CaM complex in vitro and in transfected cells. Surface plasmon resonance analysis and zero-length cross-linking showed that the N-terminal cytoplasmic domain (residues 2-285) of wolframin binds to an equimolar unit of CaM in a Ca(2+)-dependent manner with a K(D) for CaM of 0.15 muM. Various truncation and deletion mutants showed that the Ca(2+)/CaM binding region in wolframin is located from Glu90 to Trp186. Furthermore, we demonstrated that three mutations (Ala127Thr, Ala134Thr, and Arg178Pro) associated with Wolfram syndrome completely abolished CaM binding of wolframin. This observation may indicate that CaM binding is important for wolframin function and that impairment of this interaction by mutation contributes to the pathology seen in Wolfram syndrome.
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Affiliation(s)
- Saki Yurimoto
- Department of Signal Transduction Sciences, Faculty of Medicine, Kagawa University,Kagawa 761-0793, Japan
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Role of C-Peptide in the regulation of microvascular blood flow. EXPERIMENTAL DIABETES RESEARCH 2008; 2008:176245. [PMID: 18670621 PMCID: PMC2491698 DOI: 10.1155/2008/176245] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Accepted: 06/23/2008] [Indexed: 02/06/2023]
Abstract
During the recent years, the role of C-peptide, released from the pancreatic beta cell, in regulating microvascular blood flow, has received increasing attention. In type 1 diabetic patients, intravenous application of C-peptide in physiological concentrations was shown to increase microvascular blood flow, and to improve microvascular endothelial function and the endothelial release of NO. C-peptide was shown to impact microvascular blood flow by several interactive pathways, like stimulating Na+K+ATPase or the endothelial release of NO. There is increasing evidence, that in patients with declining beta cell function, the lack of C-peptide secretion might play a putative role in the development of microvascular blood flow abnormalities, which go beyond the effects of declining insulin secretion or increased blood glucose levels.
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Abdi KM, Bennett V. Adducin promotes micrometer-scale organization of beta2-spectrin in lateral membranes of bronchial epithelial cells. Mol Biol Cell 2007; 19:536-45. [PMID: 18003973 DOI: 10.1091/mbc.e07-08-0818] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Adducin promotes assembly of spectrin-actin complexes, and is a target for regulation by calmodulin, protein kinase C, and rho kinase. We demonstrate here that adducin is required to stabilize preformed lateral membranes of human bronchial epithelial (HBE) cells through interaction with beta2-spectrin. We use a Tet-on regulated inducible small interfering RNA (siRNA) system to deplete alpha-adducin from confluent HBE cells. Depletion of alpha-adducin resulted in increased detergent solubility of spectrin after normal membrane biogenesis during mitosis. Conversely, depletion of beta2-spectrin resulted in loss of adducin from the lateral membrane. siRNA-resistant alpha-adducin prevented loss of lateral membrane, but only if alpha-adducin retained the MARCKS domain that mediates spectrin-actin interactions. Phospho-mimetic versions of adducin with S/D substitutions at protein kinase C phosphorylation sites in the MARCKS domain were not active in rescue. We find that adducin modulates long-range organization of the lateral membrane based on several criteria. First, the lateral membrane of adducin-depleted cells exhibited reduced height, increased curvature, and expansion into the basal surface. Moreover, E-cadherin-GFP, which normally is restricted in lateral mobility, rapidly diffuses over distances up to 10 microm. We conclude that adducin acting through spectrin provides a novel mechanism to regulate global properties of the lateral membrane of bronchial epithelial cells.
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Affiliation(s)
- Khadar M Abdi
- Howard Hughes Medical Institute and the Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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Chen H, Khan AA, Liu F, Gilligan DM, Peters LL, Messick J, Haschek-Hock WM, Li X, Ostafin AE, Chishti AH. Combined deletion of mouse dematin-headpiece and beta-adducin exerts a novel effect on the spectrin-actin junctions leading to erythrocyte fragility and hemolytic anemia. J Biol Chem 2006; 282:4124-35. [PMID: 17142833 DOI: 10.1074/jbc.m610231200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dematin and adducin are actin-binding proteins of the erythrocyte "junctional complex." Individually, they exert modest effects on erythrocyte shape and membrane stability, and their homologues are expressed widely in non-erythroid cells. Here we report generation and characterization of double knock-out mice lacking beta-adducin and the headpiece domain of dematin. The combined mutations result in altered erythrocyte morphology, increased membrane instability, and severe hemolysis. Peripheral blood analysis shows evidence of severe hemolytic anemia with reduced number of erythrocytes/hematocrit/hemoglobin and an approximately 12-fold increase in the number of circulating reticulocytes. The presence of a variety of misshapen and fragmented erythrocytes correlates with increased osmotic fragility and reduced in vivo life span. Despite the apparently normal protein composition of the mutant erythrocyte membrane, the retention of the spectrin-actin complex in the membrane under low ionic strength conditions is significantly reduced by the double mutation. Atomic force microscopy reveals an increase in grain size and a decrease in filament number of the mutant membrane cytoskeleton, although the volume parameter is similar to wild type erythrocytes. Aggregated, disassembled, and irregular features are visualized in the mutant membrane, consistent with the presence of large protein aggregates. Importantly, purified dematin binds to the stripped inside-out vesicles in a saturable manner, and dematin-membrane binding is abolished upon pretreatment of membrane vesicles with trypsin. Together, these results reveal an essential role of dematin and adducin in the maintenance of erythrocyte shape and membrane stability, and they suggest that the dematin-membrane interaction could link the junctional complex to the plasma membrane in erythroid cells.
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Affiliation(s)
- Huiqing Chen
- Department of Pharmacology/Cancer Center, University of Illinois College of Medicine, Chicago, Illinois 60612, USA
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Kalfa TA, Pushkaran S, Mohandas N, Hartwig JH, Fowler VM, Johnson JF, Joiner CH, Williams DA, Zheng Y. Rac GTPases regulate the morphology and deformability of the erythrocyte cytoskeleton. Blood 2006; 108:3637-45. [PMID: 16882712 PMCID: PMC1895472 DOI: 10.1182/blood-2006-03-005942] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 07/12/2006] [Indexed: 11/20/2022] Open
Abstract
Actin oligomers are a significant structural component of the erythrocyte cytoskeleton. Rac1 and Rac2 GTPases regulate actin structures and have multiple overlapping as well as distinct roles in hematopoietic cells; therefore, we studied their role in red blood cells (RBCs). Conditional gene targeting with a loxP-flanked Rac1 gene allowed Crerecombinase-induced deletion of Rac1 on a Rac2 null genetic background. The Rac1(-/-);Rac2(-/-) mice developed microcytic anemia with a hemoglobin drop of about 20% and significant anisocytosis and poikilocytosis. Reticulocytes increased more than 2-fold. Rac1(-/-);Rac2(-/-) RBCs stained with rhodamine-phalloidin demonstrated F-actin meshwork gaps and aggregates under confocal microscopy. Transmission electron microscopy of the cytoskeleton demonstrated junctional aggregates and pronounced irregularity of the hexagonal spectrin scaffold. Ektacytometry confirmed that these cytoskeletal changes in Rac1(-/-);Rac2(-/-) erythrocytes were associated with significantly decreased cellular deformability. The composition of the cytoskeletal proteins was altered with an increased actin-to-spectrin ratio and increased phosphorylation (Ser724) of adducin, an F-actin capping protein. Actin and phosphorylated adducin of Rac1(-/-);Rac2(-/-) erythrocytes were more easily extractable by Triton X-100, indicating weaker association to the cytoskeleton. Thus, deficiency of Rac1 and Rac2 GTPases in mice alters actin assembly in RBCs and causes microcytic anemia with reticulocytosis, implicating Rac GTPases as dynamic regulators of the erythrocyte cytoskeleton organization.
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Affiliation(s)
- Theodosia A Kalfa
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7015, Cincinnati, OH 45229, USA.
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Gotoh H, Okumura N, Yagi T, Okumura A, Shima T, Nagai K. Fyn-induced phosphorylation of beta-adducin at tyrosine 489 and its role in their subcellular localization. Biochem Biophys Res Commun 2006; 346:600-5. [PMID: 16765915 DOI: 10.1016/j.bbrc.2006.05.167] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Accepted: 05/26/2006] [Indexed: 01/06/2023]
Abstract
Fyn is a Src-family tyrosine kinase involved in neuronal development, transmission, and plasticity in mammalian central nervous system. We have previously reported that Fyn binds to a cytoskeletal protein, beta-adducin, in a phosphorylation-dependent manner. In the present report, we show that Fyn phosphorylates beta-adducin at tyrosine 489 located in its C-terminal tail domain. Phosphorylation of beta-adducin at Y489 was required for its association with the Fyn-SH2 domain. An antibody specific to the phosphorylated form of beta-adducin was raised in rabbits and showed that Y489 of beta-adducin was phosphorylated in wild type, but not in Fyn(-/-) mice, suggesting that Y489 of beta-adducin is phosphorylated downstream of Fyn in vivo. After phosphorylation at Y489, beta-adducin was translocated to the cell periphery, and colocalized with Fyn. These results suggest that Fyn phosphorylates and binds to beta-adducin at Y489, resulting in translocation of beta-adducin to the Fyn-enriched regions in the plasma membrane.
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Affiliation(s)
- Hitoshi Gotoh
- Laboratory of Proteins Involved in Homeostatic Integration, Division of Integrated Protein Functions, Institute for Protein Research, Osaka University, Suita, Japan
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Yenerel MN, Sundell IB, Weese J, Bulger M, Gilligan DM. Expression of adducin genes during erythropoiesis: a novel erythroid promoter for ADD2. Exp Hematol 2005; 33:758-66. [PMID: 15963851 DOI: 10.1016/j.exphem.2005.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 03/17/2005] [Accepted: 03/28/2005] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The first objective of this study was to examine the differences in levels of adducin (ADD1, ADD2, ADD3) mRNA expression during human erythropoiesis. The second objective was to determine whether the rapid induction of ADD2 expression could be attributed to a novel erythroid-specific promoter. METHODS Expression of mRNA was quantified using real-time RT-PCR. Primary erythroid precursors were isolated from normal human bone marrow using fluorescence-activated cell sorting. Two model systems were compared: CD34(+) hematopoietic stem cells induced to differentiate with erythropoietin and HEL cells induced to differentiate with hemin. 5'RACE analysis was performed using primary human erythroblasts as starting material. RESULTS All three adducin genes showed different patterns of expression during erythropoietic differentiation of cultured CD34(+) stem cells. Levels of ADD3 mRNA were higher than levels of ADD2 mRNA at early stages of erythropoiesis. Expression of ADD2 was induced to very high levels (100 times baseline) in erythropoietin-stimulated cultures. 5'RACE analysis identified a novel starting exon and putative erythroid promoter for ADD2. CONCLUSION These results suggest that expression of each adducin gene is regulated in a gene-specific manner during erythropoiesis. The early expression of ADD3 suggests that it may have a role in erythroblasts but is replaced by ADD2 in later stages of erythropoiesis. The very high levels of expression of ADD2 suggest that its promoter may be useful for directing erythroid-specific gene expression.
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Affiliation(s)
- Mustafa N Yenerel
- Puget Sound Blood Center, University of Washington, Seattle, 98104, USA
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Mead PA, Harvey JN, Rutherford PA, Leitch H, Thomas TH. Sodium-lithium countertransport and the Gly460-->Trp alpha-adducin polymorphism in essential hypertension. Clin Sci (Lond) 2005; 108:231-6. [PMID: 15554870 DOI: 10.1042/cs20040267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A polymorphism of the alpha-subunit of adducin, Gly460-->Trp, may affect membrane ion transport and be associated with human EH (essential hypertension). The alpha-adducin Gly460-->Trp polymorphism was determined in 242 NC (normal controls) and 73 patients with EH and was related to the membrane ion transport marker in EH, erythrocyte Na/LiCT (sodium-lithium countertransport), in a subgroup of these subjects. The Km for external sodium was lower in patients with EH than NC. The Km of the Trp allele was lower than with the Gly/Gly genotype [NC, 105+/-6 compared with 88+/-5 mmol Na/l respectively (P=0.05); patients with EH, 76+/-5 compared with 64+/-4 mmol Na/l respectively (P=0.06)]. The Km was lower in patients with EH than NC for any adducin genotype. Thiol alkylation with NEM (N-ethylmaleimide) caused a decrease in Km in NC, but not in patients with EH. With a Trp allele, NEM lowered Km less in NC (-20 compared with -35) and increased it in patients with EH (+24 compared with +3; P=0.007 for genotype effect). Thiol alkylation with NEM caused an increase in Vmax in patients with EH but not in NC. With a Trp allele, NEM increased Vmax substantially in patients with EH (+0.12 compared with +0.03) but did not cause a decrease in NC (+0.02 compared with -0.06; P=0.007 for genotype effect). In conclusion, the Gly460-->Trp polymorphism of alpha-adducin modifies the kinetics of Na/LiCT. The effect of this genotype is different in patients with EH compared with NC and it does not explain the abnormal kinetics in patients with EH. The Trp allele was not associated with disease in the population studied. Several cytoskeletal proteins may interact with adducin in the overall phenotype of EH.
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Affiliation(s)
- Paul A Mead
- Department of Nephrology, Cumberland Infirmary, Carlisle CA2 7HY, UK
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Porro F, Costessi L, Marro ML, Baralle FE, Muro AF. The erythrocyte skeletons of β-adducin deficient mice have altered levels of tropomyosin, tropomodulin and EcapZ. FEBS Lett 2004; 576:36-40. [PMID: 15474006 DOI: 10.1016/j.febslet.2004.08.057] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Revised: 07/23/2004] [Accepted: 08/03/2004] [Indexed: 01/08/2023]
Abstract
The erythrocyte membrane cytoskeleton is organized as a polygonal spectrin network linked to short actin filaments that are capped by adducin at the barbed ends. We have constructed a mouse strain deficient in beta-adducin having abnormal erythrocytes. We show here that the levels of several skeletal proteins from beta-adducin mutant erythrocytes are altered. In fact, CapZ, the main muscle actin-capping protein of the barbed ends that in the erythrocytes is cytoplasmic, is 9-fold upregulated in mutant skeletons of erythrocytes suggesting a compensatory mechanism. We also detected upregulation of tropomodulin and downregulation of alpha-tropomyosin and actin. In addition, purified adducin can be re-incorporated into adducin-deficient ghosts.
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Affiliation(s)
- Fabiola Porro
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I 34012, Trieste, Italy
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Seidenbecher CI, Landwehr M, Smalla KH, Kreutz M, Dieterich DC, Zuschratter W, Reissner C, Hammarback JA, Böckers TM, Gundelfinger ED, Kreutz MR. Caldendrin but not calmodulin binds to light chain 3 of MAP1A/B: an association with the microtubule cytoskeleton highlighting exclusive binding partners for neuronal Ca(2+)-sensor proteins. J Mol Biol 2004; 336:957-70. [PMID: 15095872 DOI: 10.1016/j.jmb.2003.12.054] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Revised: 12/15/2003] [Accepted: 12/18/2003] [Indexed: 11/19/2022]
Abstract
Caldendrin is a neuronal Ca(2+)-sensor protein (NCS), which represents the closest homologue of calmodulin (CaM) in nerve cells. It is tightly associated with the somato-dendritic cytoskeleton of neurons and highly enriched in the postsynaptic cytomatrix. Here, we report that caldendrin specifically associates with the microtubule cytoskeleton via an interaction with light chain 3 (LC3), a microtubule component with sequence homology to the GABAA receptor-associated protein (GABARAP), which is, like LC3, probably involved in cellular transport processes. Interestingly, two binding sites exist in LC3 for caldendrin from which only one exhibits a strict Ca(2+)-dependency for the interaction to take place but both require the presence of the first two EF-hands of caldendrin. CaM, however, is not capable of binding to LC3 at both sites despite its high degree of primary structure similarity with caldendrin. Computer modelling suggests that this might be explained by an altered distribution of surface charges at the first two EF-hands rendering each molecule, in principle, specific for a discrete set of binding partners. These findings provide molecular evidence that NCS can transduce signals to a specific target interaction irrespective of Ca(2+)-concentrations and CaM-levels.
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Affiliation(s)
- Constanze I Seidenbecher
- AG Molecular Mechanisms of Plasticity, Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestr. 6 39118 Magdeburg, Germany
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Citterio L, Tizzoni L, Catalano M, Zerbini G, Bianchi G, Barlassina C. Expression analysis of the human adducin gene family and evidence of ADD2 beta4 multiple splicing variants. Biochem Biophys Res Commun 2003; 309:359-67. [PMID: 12951058 DOI: 10.1016/j.bbrc.2003.08.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Adducin is a cytoskeleton heterodimeric protein. Its subunits are encoded by three related genes (ADD1, ADD2, and ADD3) which show alternative spliced variants. Adducin polymorphisms are involved in blood pressure regulation in humans and rats. We have analyzed mRNA distribution of ADD gene family in human tissues and cells with Real-Time TaqMan RT-PCR. Whereas ADD1 is ubiquitously distributed, ADD3 is more expressed in kidney medulla and cortex than in fetal kidney, while in adult liver it is less abundant than in fetal liver. ADD2 beta1 and beta4 variants show the same pattern of distribution with the highest expression in brain, fetal liver, and kidney. Conventional RT-PCR identified new beta4 variants. Beta4a is characterized by an in-frame insertion of 21 nucleotides upstream exon 15 predicting a 7 amino acids longer protein with a similar C-terminus region. It is coexpressed with beta1 and beta4 in several tissues. Fetal kidney shows further beta4b, beta4c and beta4d variants containing internal exon deletions that enormously modify the predicted NH(2) and central regions. Our findings could help one to understand the functional role of adducin variants in specific tissues and cells.
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Affiliation(s)
- Lorena Citterio
- Division of Nephrology, Dialysis and Hypertension, Università Vita-Salute, San Raffaele Hospital, Milan, Italy.
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Barkalow KL, Italiano JE, Chou DE, Matsuoka Y, Bennett V, Hartwig JH. Alpha-adducin dissociates from F-actin and spectrin during platelet activation. J Cell Biol 2003; 161:557-70. [PMID: 12743105 PMCID: PMC2172952 DOI: 10.1083/jcb.200211122] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Aspectrin-based skeleton uniformly underlies and supports the plasma membrane of the resting platelet, but remodels and centralizes in the activated platelet. alpha-Adducin, a phosphoprotein that forms a ternary complex with F-actin and spectrin, is dephosphorylated and mostly bound to spectrin in the membrane skeleton of the resting platelet at sites where actin filaments attach to the ends of spectrin molecules. Platelets activated through protease-activated receptor 1, FcgammaRIIA, or by treatment with PMA phosphorylate adducin at Ser726. Phosphoadducin releases from the membrane skeleton concomitant with its dissociation from spectrin and actin. Inhibition of PKC blunts adducin phosphorylation and release from spectrin and actin, preventing the centralization of spectrin that normally follows cell activation. We conclude that adducin targets actin filament ends to spectrin to complete the assembly of the resting membrane skeleton. Dissociation of phosphoadducin releases spectrin from actin, facilitating centralization of spectrin, and leads to the exposure of barbed actin filament ends that may then participate in converting the resting platelet's disc shape into its active form.
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Affiliation(s)
- Kurt L Barkalow
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Abstract
The following were investigated: (1) how we became interested in studying adducin genes and what we know about adducin; (2) studies in animals and humans supporting the role of adducin polymorphisms in hypertension, including some methodological problems related to the dissection of the role of a given genetic molecular mechanism in a complex multifactorial polygenic disease like hypertension; (3) biochemical mechanisms underlying the effect of adducin and its interaction with the Na-K pump; and (4) future directions.
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Affiliation(s)
- Giuseppe Bianchi
- Chair and School of Nephrology, Division of Nephrology, Dialysis, and Hypertension, Università Vita e Salute, San Raffaele Hospital, Milan, Italy.
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Gilligan DM, Sarid R, Weese J. Adducin in platelets: activation-induced phosphorylation by PKC and proteolysis by calpain. Blood 2002; 99:2418-26. [PMID: 11895774 DOI: 10.1182/blood.v99.7.2418] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adducins are a family of cytoskeletal proteins encoded by 3 genes (alpha, beta, and gamma). Platelets express alpha and gamma adducins, in contrast to red blood cells that express alpha and beta adducins. During platelet activation with thrombin, calcium ionophore A23187, or phorbol 12-myristate 13-acetate, alpha and gamma adducins were phosphorylated by protein kinase C (PKC) as detected by an antibody specific for a phosphopeptide sequence in the highly conserved carboxy terminus. Platelet activation also led to adducin proteolysis; inhibition by calpeptin suggests that the protease was calpain. The kinase inhibitor staurosporine inhibited PKC phosphorylation of adducin and also inhibited proteolysis of adducin. Experiments with recombinant alpha adducin demonstrated that the PKC-phosphorylated form was proteolyzed at a significantly faster rate than the unphosphorylated form. The concentration of adducin in platelets was estimated at 6 microM, similar to the concentration of capping protein. Fractionation of platelets into high-speed supernatant (cytosol) and pellet (membrane and cytoskeleton) revealed a shift of PKC-phosphorylated adducin to the cytosol during platelet activation. Platelet aggregation detected turbidometrically was decreased in the presence of staurosporine and was completely inhibited by calpeptin. Thrombin-induced changes in morphology were assessed by confocal microscopy with fluorescein phalloidin and were not prevented by staurosporine or calpeptin. Our results suggest that regulation of adducin function by PKC and calpain may play a role in platelet aggregation.
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Affiliation(s)
- Diana M Gilligan
- Department of Internal Medicine (Hematology), Yale University School of Medicine, New Haven, CT, USA.
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Feldner JC, Brandt BH. Cancer cell motility--on the road from c-erbB-2 receptor steered signaling to actin reorganization. Exp Cell Res 2002; 272:93-108. [PMID: 11777334 DOI: 10.1006/excr.2001.5385] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cell migration depends mainly on actin polymerization and intracellular organization, which are influenced by a vast variety of actin binding proteins (ABPs). Regulation of ABP activity is mediated by second messengers such as phosphoinositides and calcium. Signaling via these second messengers is initiated and regulated by membrane receptors, e.g., receptor tyrosine kinases (RTKs), and by adhesion molecule interactions (e.g., integrins and selectins) and focal adhesion kinases. A major role in steering second-messenger signaling and thus in actin cytoskeleton reorganization and motility of cancer cells is played by the RTK c-erbB-2. This occurs through a number of signaling pathways which involve mainly enzymes, e.g., phospholipase Cgamma1 and GTPases, which modify signaling molecules. Furthermore large multiprotein complexes including actin-related protein 2/3, Wiskott-Aldrich syndrome protein, profilin, and capping protein among others play an important role in regulating actin reorganization. The complex picture of the mode of actin reorganization, which is involved in tumor cell migration, is slowly emerging from the mists of cellular signaling pathways, but this is still by no means a clear view.
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Affiliation(s)
- Julia C Feldner
- Institut für Klinische Chemie und Laboratoriumsmedizin, Westfälische Wilhelms-Universität, Münster, Albert-Schweitzer-Strasse 33, Münster, 48149, Germany
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Shima T, Okumura N, Takao T, Satomi Y, Yagi T, Okada M, Nagai K. Interaction of the SH2 domain of Fyn with a cytoskeletal protein, beta-adducin. J Biol Chem 2001; 276:42233-40. [PMID: 11526103 DOI: 10.1074/jbc.m102699200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Fyn is a Src family tyrosine kinase expressed abundantly in neurons and believed to have specific functions in the brain. To understand the function of Fyn tyrosine kinase, we attempted to identify Fyn Src homology 2 (SH2) domain-binding proteins from a Nonidet P-40-insoluble fraction of the mouse brain. beta-Adducin, an actin filament-associated cytoskeletal protein, was isolated by two-dimensional gel electrophoresis and identified by tandem mass spectrometry. beta-Adducin was tyrosine phosphorylated by coexpression with wild type but not with a kinase-negative form of Fyn in COS-7 cells. Cell staining analysis showed that coexpression of beta-adducin with Fyn induced translocation of beta-adducin from the cytoplasm to the periphery of the cells where it was colocalized with actin filaments and Fyn. These findings suggest that tyrosine-phosphorylated beta-adducin associates with the SH2 domain of Fyn and colocalizes under plasma membranes.
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Affiliation(s)
- T Shima
- Divisions of Protein Metabolism and Organic Chemistry, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
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Bennett V, Baines AJ. Spectrin and ankyrin-based pathways: metazoan inventions for integrating cells into tissues. Physiol Rev 2001; 81:1353-92. [PMID: 11427698 DOI: 10.1152/physrev.2001.81.3.1353] [Citation(s) in RCA: 714] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The spectrin-based membrane skeleton of the humble mammalian erythrocyte has provided biologists with a set of interacting proteins with diverse roles in organization and survival of cells in metazoan organisms. This review deals with the molecular physiology of spectrin, ankyrin, which links spectrin to the anion exchanger, and two spectrin-associated proteins that promote spectrin interactions with actin: adducin and protein 4.1. The lack of essential functions for these proteins in generic cells grown in culture and the absence of their genes in the yeast genome have, until recently, limited advances in understanding their roles outside of erythrocytes. However, completion of the genomes of simple metazoans and application of homologous recombination in mice now are providing the first glimpses of the full scope of physiological roles for spectrin, ankyrin, and their associated proteins. These functions now include targeting of ion channels and cell adhesion molecules to specialized compartments within the plasma membrane and endoplasmic reticulum of striated muscle and the nervous system, mechanical stabilization at the tissue level based on transcellular protein assemblies, participation in epithelial morphogenesis, and orientation of mitotic spindles in asymmetric cell divisions. These studies, in addition to stretching the erythrocyte paradigm beyond recognition, also are revealing novel cellular pathways essential for metazoan life. Examples are ankyrin-dependent targeting of proteins to excitable membrane domains in the plasma membrane and the Ca(2+) homeostasis compartment of the endoplasmic reticulum. Exciting questions for the future relate to the molecular basis for these pathways and their roles in a clinical context, either as the basis for disease or more positively as therapeutic targets.
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Affiliation(s)
- V Bennett
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Ghassemi F, Dib-Hajj SD, Waxman SG. Beta1 adducin gene expression in DRG is developmentally regulated and is upregulated by glial-derived neurotrophic factor and nerve growth factor. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 90:118-24. [PMID: 11406290 DOI: 10.1016/s0169-328x(01)00091-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Differential display technique has proven to be effective in identifying differentially regulated genes under a variety of experimental conditions. We identified beta1 adducin as a target in primary rat dorsal root ganglia (DRG) cultures that is upregulated by exposure to nerve growth factor (NGF) and glial-derived neurotrophic factor (GDNF). We used real-time reverse-transcription polymerase chain reaction (RT-PCR) for quantitative measurement of beta1 adducin gene expression both in DRG cultures and in vivo. Significant increase in beta1 adducin expression level was observed in DRG cultures treated with either GDNF or NGF, compared to untreated cultures. The expression of beta1 adducin in rat tissues was highest in the brain and high in the cerebellum, superior cervical ganglion and DRG tissues. By contrast, low expression levels of beta1 adducin are detected in sciatic nerve and in non-neural tissues. Our study also showed that expression of beta1 adducin gene is developmentally regulated in rat DRG and trigeminal ganglia, with a peak around P0 and significant attenuation by P21. The level of expression of beta1 adducin in adult rat DRG and trigeminal ganglia may be maintained by the action of neurotrophic factors that are produced in innervated targets like skin and muscle.
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Affiliation(s)
- F Ghassemi
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
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Abstract
Dendritic spines undergo several types of transformations, ranging from growth to collapse, and from elongation to shortening, and they experience dynamic morphological activity on a rapid time scale. Changes in spine number and morphology occur under pathological conditions like excitotoxicity, but also during normal central nervous system development, during hormonal fluctuations, and in response to neural activity under physiological circumstances. We briefly review evidence for various types of alterations in spines, and discuss the possible molecular basis for changes in spine stability. Filamentous actin appears to be the most important cytoskeletal component of spines, and a growing list of actin-associated and actin-regulatory proteins has been reported to reside within spines. We conclude that spines contain two distinct pools of actin filaments (one stable, the other unstable) that provide the spine with both a stable core structure and a dynamic, complex shape. Finally, we review the current state of knowledge of actin filament regulation, based on studies in nonneuronal cells.
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Affiliation(s)
- F M Smart
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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Abstract
Remarkable progress has been made in understanding effector molecules of small GTPase Rho, especially Rho-associated kinase (Rho-kinase/ROK/ROCK), in the past 5 years. Rho-associated kinase appears to mediate a large proportion of the signals from Rho and regulate dynamic reorganization of cytoskeletal proteins, such as stress fiber and focal adhesion formation. Several substrates of Rho-associated kinase have been reported and their cellular functions unraveled. In this review, we focus on the regulation and cellular functions of Rho-associated kinase.
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Affiliation(s)
- M Amano
- Division of Signal Transduction, Nara Institute of Science and Technology, Ikoma, 630-0101, Japan
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Marro ML, Scremin OU, Jordan MC, Huynh L, Porro F, Roos KP, Gajovic S, Baralle FE, Muro AF. Hypertension in beta-adducin-deficient mice. Hypertension 2000; 36:449-53. [PMID: 10988280 DOI: 10.1161/01.hyp.36.3.449] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Polymorphic variants of the cytoskeletal protein adducin have been associated with hypertension in humans and rats. However, the direct role of this protein in modulating arterial blood pressure has never been demonstrated. To assess the effect of beta-adducin on blood pressure, a beta-adducin-deficient mouse strain (-/-) was studied and compared with wild-type controls (+/+). Aortic blood pressure was measured in nonanesthetized, freely moving animals with the use of telemetry implants. It is important to note that these mice have at least 98% of C57Bl/6 genetic background, with the only difference from wild-type animals being the beta-adducin mutation. We found statistically significant higher levels of systolic blood pressure (mm Hg) (mean+/-SE values: -/-: 126.94+/-1.14, n=5; +/+: 108.06+/-2. 34, n=6; P:</=0.0001), diastolic blood pressure (-/-: 83.54+/-1.07; +/+: 74.87+/-2.23; P:</=0.005), and pulse blood pressure (-/-: 43. 32+/-1.10; +/+: 33.19+/-1.96; P:</=0.001) in beta-adducin-deficient mice. Western blot analysis showed that as a result of the introduced genetic modification, beta-adducin was not present in heart protein extracts from -/- mice. Consequently, this deficiency produced a sharp decrease of alpha-adducin and a lesser reduction in gamma-adducin levels. However, we found neither cardiac remodeling nor modification of the heart function in these animals. This is the first report showing direct evidence that hypertension is triggered by a mutation in the adducin gene family.
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Affiliation(s)
- M L Marro
- International Center for Genetic Engineering and Biotechnology, Trieste, Italy
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