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Müller L, Keil R, Glaß M, Hatzfeld M. Plakophilin 4 controls the spatio-temporal activity of RhoA at adherens junctions to promote cortical actin ring formation and tissue tension. Cell Mol Life Sci 2024; 81:291. [PMID: 38970683 PMCID: PMC11335210 DOI: 10.1007/s00018-024-05329-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/17/2024] [Accepted: 06/18/2024] [Indexed: 07/08/2024]
Abstract
Plakophilin 4 (PKP4) is a component of cell-cell junctions that regulates intercellular adhesion and Rho-signaling during cytokinesis with an unknown function during epidermal differentiation. Here we show that keratinocytes lacking PKP4 fail to develop a cortical actin ring, preventing adherens junction maturation and generation of tissue tension. Instead, PKP4-depleted cells display increased stress fibers. PKP4-dependent RhoA localization at AJs was required to activate a RhoA-ROCK2-MLCK-MLC2 axis and organize actin into a cortical ring. AJ-associated PKP4 provided a scaffold for the Rho activator ARHGEF2 and the RhoA effectors MLCK and MLC2, facilitating the spatio-temporal activation of RhoA signaling at cell junctions to allow cortical ring formation and actomyosin contraction. In contrast, association of PKP4 with the Rho suppressor ARHGAP23 reduced ARHGAP23 binding to RhoA which prevented RhoA activation in the cytoplasm and stress fiber formation. These data identify PKP4 as an AJ component that transduces mechanical signals into cytoskeletal organization.
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Affiliation(s)
- Lisa Müller
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Research Center, Kurt-Mothes-Str. 3A, 06120, Halle, Germany.
| | - René Keil
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Research Center, Kurt-Mothes-Str. 3A, 06120, Halle, Germany
| | - Markus Glaß
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Research Center, Kurt-Mothes-Str. 3A, 06120, Halle, Germany
| | - Mechthild Hatzfeld
- Institute of Molecular Medicine, Martin Luther University Halle-Wittenberg, Charles Tanford Protein Research Center, Kurt-Mothes-Str. 3A, 06120, Halle, Germany
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2
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Donta MS, Srivastava Y, Di Mauro CM, Paulucci-Holthauzen A, Waxham MN, McCrea PD. p120-catenin subfamily members have distinct as well as shared effects on dendrite morphology during neuron development in vitro. Front Cell Neurosci 2023; 17:1151249. [PMID: 37082208 PMCID: PMC10112520 DOI: 10.3389/fncel.2023.1151249] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 03/21/2023] [Indexed: 04/22/2023] Open
Abstract
Dendritic arborization is essential for proper neuronal connectivity and function. Conversely, abnormal dendrite morphology is associated with several neurological pathologies like Alzheimer's disease and schizophrenia. Among major intrinsic mechanisms that determine the extent of the dendritic arbor is cytoskeletal remodeling. Here, we characterize and compare the impact of the four proteins involved in cytoskeletal remodeling-vertebrate members of the p120-catenin subfamily-on neuronal dendrite morphology. In relation to each of their own distributions, we find that p120-catenin and delta-catenin are expressed at relatively higher proportions in growth cones compared to ARVCF-catenin and p0071-catenin; ARVCF-catenin is expressed at relatively high proportions in the nucleus; and all catenins are expressed in dendritic processes and the soma. Through altering the expression of each p120-subfamily catenin in neurons, we find that exogenous expression of either p120-catenin or delta-catenin correlates with increased dendritic length and branching, whereas their respective depletion decreases dendritic length and branching. While increasing ARVCF-catenin expression also increases dendritic length and branching, decreasing expression has no grossly observable morphological effect. Finally, increasing p0071-catenin expression increases dendritic branching, but not length, while decreasing expression decreases dendritic length and branching. These distinct localization patterns and morphological effects during neuron development suggest that these catenins have both shared and distinct roles in the context of dendrite morphogenesis.
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Affiliation(s)
- Maxsam S. Donta
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Program in Genetics and Epigenetics, Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Yogesh Srivastava
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Christina M. Di Mauro
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | | | - M. Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Pierre D. McCrea
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Program in Genetics and Epigenetics, Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, TX, United States
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3
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Wei J, Beebe-Dimmer J, Shi Z, Sample C, Yan G, Rifkin AS, Sadeghpour A, Gielzak M, Choi S, Moon D, Zheng SL, Helfand BT, Walsh PC, Xu J, Cooney KA, Isaacs WB. Association of rare, recurrent nonsynonymous variants in the germline of prostate cancer patients of African ancestry. Prostate 2023; 83:454-461. [PMID: 36567534 DOI: 10.1002/pros.24477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Although men of African ancestry (AA) have the highest mortality rate from prostate cancer (PCa), relatively little is known about the germline variants that are associated with PCa risk in AA men. The goal of this study is to systematically evaluate rare, recurrent nonsynonymous variants across the exome for their association with PCa in AA men. METHODS Whole exome sequencing (WES) of germline DNA in two AA PCa patient cohorts of Johns Hopkins Hospital (N = 960) and Wayne State University (N = 747) was performed. All nonsynonymous variants present in both case cohorts, with a carrier rate between 0.5% and 1%, were identified. Their carrier rates were compared with rates from 8128 African/African American (AFR) control subjects from The Genome Aggregation Database (gnomAD) using Fisher's exact test. Significant variants, defined as false discovery rate (FDR) adjusted p-value ≤ 0.05, were further evaluated in AA PCa cases (N = 132) and controls (N = 1184) from the UK Biobank (UKB). RESULTS Two variants reached a pre-specified statistical significance level. The first was p.R14Q in GPRC5C (found in 0.47% of PCa cases and 0.01% of population controls); odds ratio (OR) for PCa was 37.46 (95% confidence interval CI 4.68-299.72), pexact = 7.01E-06, FDR-adjusted p-value = 0.05. The second was p.R511Q in IGF1R (found in 0.53% of PCa cases and 0.01% of population controls); OR for PCa was 21.54 (95%CI 4.65-99.76), pexact = 5.51E-06, FDR-adjusted p-value = 0.05. The mean percentage of African ancestry was similar between variant carriers and noncarriers of each variant, p > 0.05. In the UKB AA men, GPRC5C R14Q was 0.76% and 0.08% in cases and controls, respectively, OR for PCa was 9.00 (95%CI 0.56-145.23), pexact = 0.19. However, IGF1R R511Q was not found in cases or controls. CONCLUSIONS This WES study identified two rare, recurrent nonsynonymous PCa risk-associated variants in AA. Confirmation in additional large populations of AA PCa cases and controls is required.
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Affiliation(s)
- Jun Wei
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
| | - Jennifer Beebe-Dimmer
- Barabara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Zhuqing Shi
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
| | - Christopher Sample
- Department of Medicine, Duke University School of Medicine and Duke Cancer Institute, Durham, North Carolina, USA
| | - Guifang Yan
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Andrew S Rifkin
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
| | - Azita Sadeghpour
- Department of Medicine, Duke University School of Medicine and Duke Cancer Institute, Durham, North Carolina, USA
| | - Marta Gielzak
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Sodam Choi
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - David Moon
- Department of Medicine, Duke University School of Medicine and Duke Cancer Institute, Durham, North Carolina, USA
| | - S Lilly Zheng
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
| | - Brian T Helfand
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
- Department of Surgery, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA
| | - Patrick C Walsh
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Jianfeng Xu
- Program for Personalized Cancer Care, NorthShore University Health System, Evanston, Illinois, USA
| | - Kathleen A Cooney
- Department of Medicine, Duke University School of Medicine and Duke Cancer Institute, Durham, North Carolina, USA
| | - William B Isaacs
- Department of Urology, The Brady Urological Institute, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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4
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Kunduri G, Acharya U, Acharya JK. Lipid Polarization during Cytokinesis. Cells 2022; 11:3977. [PMID: 36552741 PMCID: PMC9776629 DOI: 10.3390/cells11243977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
The plasma membrane of eukaryotic cells is composed of a large number of lipid species that are laterally segregated into functional domains as well as asymmetrically distributed between the outer and inner leaflets. Additionally, the spatial distribution and organization of these lipids dramatically change in response to various cellular states, such as cell division, differentiation, and apoptosis. Division of one cell into two daughter cells is one of the most fundamental requirements for the sustenance of growth in all living organisms. The successful completion of cytokinesis, the final stage of cell division, is critically dependent on the spatial distribution and organization of specific lipids. In this review, we discuss the properties of various lipid species associated with cytokinesis and the mechanisms involved in their polarization, including forward trafficking, endocytic recycling, local synthesis, and cortical flow models. The differences in lipid species requirements and distribution in mitotic vs. male meiotic cells will be discussed. We will concentrate on sphingolipids and phosphatidylinositols because their transbilayer organization and movement may be linked via the cytoskeleton and thus critically regulate various steps of cytokinesis.
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Affiliation(s)
- Govind Kunduri
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA
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5
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Li M, Nopparat J, Aguilar BJ, Chen YH, Zhang J, Du J, Ai X, Luo Y, Jiang Y, Boykin C, Lu Q. Intratumor δ-catenin heterogeneity driven by genomic rearrangement dictates growth factor dependent prostate cancer progression. Oncogene 2020; 39:4358-4374. [PMID: 32313227 PMCID: PMC10493073 DOI: 10.1038/s41388-020-1281-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 11/09/2022]
Abstract
Only a small number of genes are bona fide oncogenes and tumor suppressors such as Ras, Myc, β-catenin, p53, and APC. However, targeting these cancer drivers frequently fail to demonstrate sustained cancer remission. Tumor heterogeneity and evolution contribute to cancer resistance and pose challenges for cancer therapy due to differential genomic rearrangement and expression driving distinct tumor responses to treatments. Here we report that intratumor heterogeneity of Wnt/β-catenin modulator δ-catenin controls individual cell behavior to promote cancer. The differential intratumor subcellular localization of δ-catenin mirrors its compartmentalization in prostate cancer xenograft cultures as result of mutation-rendered δ-catenin truncations. Wild-type and δ-catenin mutants displayed distinct protein interactomes that highlight rewiring of signal networks. Localization specific δ-catenin mutants influenced p120ctn-dependent Rho GTPase phosphorylation and shifted cells towards differential bFGF-responsive growth and motility, a known signal to bypass androgen receptor dependence. Mutant δ-catenin promoted Myc-induced prostate tumorigenesis while increasing bFGF-p38 MAP kinase signaling, β-catenin-HIF-1α expression, and the nuclear size. Therefore, intratumor δ-catenin heterogeneity originated from genetic remodeling promotes prostate cancer expansion towards androgen independent signaling, supporting a neomorphism model paradigm for targeting tumor progression.
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Affiliation(s)
- Mingchuan Li
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
- Department of Urological Surgery, Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | - Jongdee Nopparat
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
- Department of Anatomy, Prince of Songkla University, Songkhla, Thailand
| | - Byron J. Aguilar
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
| | - Yan-hua Chen
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
| | - Jiao Zhang
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
| | - Jie Du
- Beijing Institute of Heart, Lung, and Blood Vessel Diseases, Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | - Xin Ai
- Dept. of Urology, PLA Army General Hospital, Beijing, China
| | - Yong Luo
- Department of Urological Surgery, Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | - Yongguang Jiang
- Department of Urological Surgery, Beijing An Zhen Hospital, Capital Medical University, Beijing, China
| | - Christi Boykin
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
| | - Qun Lu
- Department of Anatomy and Cell Biology, The Brody school of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
- Department of Urological Surgery, Beijing An Zhen Hospital, Capital Medical University, Beijing, China
- The Harriet and John Wooten Laboratory for Alzheimer’s and Neurodegenerative Diseases Research, The Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA 27834
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6
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Müller L, Rietscher K, Keil R, Neuholz M, Hatzfeld M. Plakophilin 3 phosphorylation by ribosomal S6 kinases supports desmosome assembly. J Cell Sci 2020; 133:jcs238295. [PMID: 32122945 DOI: 10.1242/jcs.238295] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/20/2020] [Indexed: 01/06/2023] Open
Abstract
Desmosome remodeling is crucial for epidermal regeneration, differentiation and wound healing. It is mediated by adapting the composition, and by post-translational modifications, of constituent proteins. We have previously demonstrated in mouse suprabasal keratinocytes that plakophilin (PKP) 1 mediates strong adhesion, which is negatively regulated by insulin-like growth factor 1 (IGF1) signaling. The importance of PKP3 for epidermal adhesion is incompletely understood. Here, we identify a major role of epidermal growth factor (EGF), but not IGF1, signaling in PKP3 recruitment to the plasma membrane to facilitate desmosome assembly. We find that ribosomal S6 kinases (RSKs) associate with and phosphorylate PKP3, which promotes PKP3 association with desmosomes downstream of the EGF receptor. Knockdown of RSKs as well as mutation of an RSK phosphorylation site in PKP3 interfered with desmosome formation, maturation and adhesion. Our findings implicate a coordinate action of distinct growth factors in the control of adhesive properties of desmosomes through modulation of PKPs in a context-dependent manner.
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Affiliation(s)
- Lisa Müller
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Katrin Rietscher
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Marvin Neuholz
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
| | - Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany
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7
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Jacquet K, Banerjee SL, Chartier FJM, Elowe S, Bisson N. Proteomic Analysis of NCK1/2 Adaptors Uncovers Paralog-specific Interactions That Reveal a New Role for NCK2 in Cell Abscission During Cytokinesis. Mol Cell Proteomics 2018; 17:1979-1990. [PMID: 30002203 DOI: 10.1074/mcp.ra118.000689] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 07/11/2018] [Indexed: 12/31/2022] Open
Abstract
Signals from cell surface receptors are often relayed via adaptor proteins. NCK1 and NCK2 are Src-Homology (SH) 2 and 3 domain adaptors that regulate processes requiring a remodeling of the actin cytoskeleton. Evidence from gene inactivation in mouse suggests that NCK1 and NCK2 are functionally redundant, although recent reports support the idea of unique functions for NCK1 and NCK2. We sought to examine this question further by delineating NCK1- and NCK2-specific signaling networks. We used both affinity purification-mass spectrometry and BioID proximity labeling to identify NCK1/2 signaling networks comprised of 98 proteins. Strikingly, we found 30 proteins restricted to NCK1 and 28 proteins specifically associated with NCK2, suggesting differences in their function. We report that Nck2 -/-, but not Nck1 -/- mouse embryo fibroblasts (MEFs) are multinucleated and display extended protrusions reminiscent of intercellular bridges, which correlate with an extended time spent in cytokinesis as well as a failure of a significant proportion of cells to complete abscission. Our data also show that the midbody of NCK2-deficient cells is not only increased in length, but also altered in composition, as judged by the mislocalization of AURKB, PLK1 and ECT2. Finally, we show that NCK2 function during cytokinesis requires its SH2 domain. Taken together, our data delineate the first high-confidence interactome for NCK1/2 adaptors and highlight several proteins specifically associated with either protein. Thus, contrary to what is generally accepted, we demonstrate that NCK1 and NCK2 are not completely redundant, and shed light on a previously uncharacterized function for the NCK2 adaptor protein in cell division.
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Affiliation(s)
- Kévin Jacquet
- From the ‡Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Axe Oncologie, Québec G1R 2J6, QC, Canada.,§Centre de recherche sur le cancer de l'Université Laval, Québec G1R 2J6, QC, Canada.,¶PROTEO-Quebec Network for Research on Protein Function, Engineering, and Applications, Québec G1V 0A6, QC, Canada
| | - Sara L Banerjee
- From the ‡Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Axe Oncologie, Québec G1R 2J6, QC, Canada.,§Centre de recherche sur le cancer de l'Université Laval, Québec G1R 2J6, QC, Canada.,¶PROTEO-Quebec Network for Research on Protein Function, Engineering, and Applications, Québec G1V 0A6, QC, Canada
| | - François J M Chartier
- From the ‡Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Axe Oncologie, Québec G1R 2J6, QC, Canada.,§Centre de recherche sur le cancer de l'Université Laval, Québec G1R 2J6, QC, Canada.,¶PROTEO-Quebec Network for Research on Protein Function, Engineering, and Applications, Québec G1V 0A6, QC, Canada
| | - Sabine Elowe
- §Centre de recherche sur le cancer de l'Université Laval, Québec G1R 2J6, QC, Canada.,¶PROTEO-Quebec Network for Research on Protein Function, Engineering, and Applications, Québec G1V 0A6, QC, Canada.,‖Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Axe Reproduction, santé de la mère et de l'enfant, Québec G1V 4G2, QC, Canada.,**Department of Pediatrics, Université Laval, Québec, QC, Canada
| | - Nicolas Bisson
- From the ‡Centre de recherche du Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Axe Oncologie, Québec G1R 2J6, QC, Canada; .,§Centre de recherche sur le cancer de l'Université Laval, Québec G1R 2J6, QC, Canada.,¶PROTEO-Quebec Network for Research on Protein Function, Engineering, and Applications, Québec G1V 0A6, QC, Canada.,‡‡Department of Molecular Biology, Medical Biochemistry and Pathology, Université Laval, Québec G1V 0A6, QC, Canada
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8
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Pal M, Bhattacharya S, Kalyan G, Hazra S. Cadherin profiling for therapeutic interventions in Epithelial Mesenchymal Transition (EMT) and tumorigenesis. Exp Cell Res 2018; 368:137-146. [DOI: 10.1016/j.yexcr.2018.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 12/14/2022]
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9
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Abstract
Cells depend on hugely diverse lipidomes for many functions. The actions and structural integrity of the plasma membrane and most organelles also critically depend on membranes and their lipid components. Despite the biological importance of lipids, our understanding of lipid engagement, especially the roles of lipid hydrophobic alkyl side chains, in key cellular processes is still developing. Emerging research has begun to dissect the importance of lipids in intricate events such as cell division. This review discusses how these structurally diverse biomolecules are spatially and temporally regulated during cell division, with a focus on cytokinesis. We analyze how lipids facilitate changes in cellular morphology during division and how they participate in key signaling events. We identify which cytokinesis proteins are associated with membranes, suggesting lipid interactions. More broadly, we highlight key unaddressed questions in lipid cell biology and techniques, including mass spectrometry, advanced imaging, and chemical biology, which will help us gain insights into the functional roles of lipids.
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Affiliation(s)
- Elisabeth M Storck
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, United Kingdom;
| | - Cagakan Özbalci
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, United Kingdom;
| | - Ulrike S Eggert
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, United Kingdom; .,Department of Chemistry, King's College London, London SE1 1DB, United Kingdom
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10
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Derksen PWB, van de Ven RAH. Shared mechanisms regulate spatiotemporal RhoA-dependent actomyosin contractility during adhesion and cell division. Small GTPases 2018; 11:113-121. [PMID: 29291271 DOI: 10.1080/21541248.2017.1366966] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Local modulation of the actin cytoskeleton is essential for the initiation and maintenance of strong homotypic adhesive interfaces between neighboring cells. The epithelial adherens junction (AJ) fulfils a central role in this process by mediating E-cadherin interactions and functioning as a signaling scaffold to control the activity of the small GTPase RhoA and subsequent actomyosin contractility. Interestingly, a number of regulatory proteins that modulate RhoA activity at the AJ also control RhoA during cytokinesis, an actomyosin-dependent process that divides the cytoplasm to generate two daughter cells at the final stages of mitosis. Recent insights have revealed that the central player in AJ stability, p120-catenin (p120), interacts with and modulates essential regulators of actomyosin contraction during cytokinesis. In cancer, loss of this modulation is a common event during tumor progression that can induce chromosomal instability and tumor progression.In this review, we will highlight the functional differences and similarities of the different RhoA-associated factors that have been linked to both the regulation of cell-cell adhesion and cytokinesis.
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Affiliation(s)
- Patrick W B Derksen
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan CX Utrecht, the Netherlands
| | - Robert A H van de Ven
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA, USA
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11
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Rietscher K, Keil R, Jordan A, Hatzfeld M. 14-3-3 proteins regulate desmosomal adhesion via plakophilins. J Cell Sci 2018; 131:jcs.212191. [DOI: 10.1242/jcs.212191] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/11/2018] [Indexed: 12/11/2022] Open
Abstract
Desmosomes are essential for strong intercellular adhesion and are abundant in tissues exposed to mechanical strain. At the same time, desmosomes need to be dynamic to allow for remodeling of epithelia during differentiation or wound healing. Phosphorylation of desmosomal plaque proteins appears essential for desmosome dynamics. However, the mechanisms how context-dependent post-translational modifications regulate desmosome formation, dynamics or stability are incompletely understood. Here, we show that growth factor signaling regulates the phosphorylation-dependent association of plakophilins 1 and 3 with 14-3-3 protein isoforms and uncover unique and partially antagonistic functions of members of the 14-3-3 family in the regulation of desmosomes. 14-3-3γ associated primarily with cytoplasmic plakophilin 1 phosphorylated at S155 and destabilized intercellular cohesion of keratinocytes by reducing its incorporation into desmosomes. In contrast, stratifin/14-3-3σ interacted preferentially with S285-phosphorylated plakophilin 3 to promote its accumulation at tricellular contact sites, leading to stable desmosomes. Taken together, our study identifies a new layer of regulation of intercellular adhesion by 14-3-3 proteins.
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Affiliation(s)
- Katrin Rietscher
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Annemarie Jordan
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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12
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Abreu Velez AM, Howard MS, Velazquez-Velez JE. Cardiac rhythm and pacemaking abnormalities in patients affected by endemic pemphigus in Colombia may be the result of deposition of autoantibodies, complement, fibrinogen, and other molecules. Heart Rhythm 2017; 15:725-731. [PMID: 29277685 DOI: 10.1016/j.hrthm.2017.12.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 02/03/2023]
Abstract
BACKGROUND We previously showed that one-third of patients affected by endemic pemphigus foliaceus in El Bagre, Colombia (El Bagre-EPF), display autoreactivity to the heart. OBJECTIVE The purpose of this study was to investigate rhythm disturbances with the presence of autoantibodies and correlate them with ECG changes in these patients. METHODS We performed a study comparing 30 patients and 30 controls from the endemic area, matched by demographics, including age, sex, weight, work activities, and comorbidities. ECG as well as direct and indirect immunofluorescence, immunohistochemistry, and confocal microscopic studies focusing on cardiac node abnormalities were performed. Autopsies of 7 patients also were reviewed. RESULTS The main ECG abnormalities seen in the El Bagre-EPF patients were sinus bradycardia (in one-half), followed by left bundle branch block, left posterior fascicular block, and left anterior fascicular block compared with the controls. One-third of the patients displayed polyclonal autoantibodies against the sinoatrial and/or AV nodes and the His bundle correlating with rhythm anomalies and delays in the cardiac conduction system (P <.01). The patient antibodies colocalized with commercial antibodies to desmoplakins I and II, p0071, armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), and myocardium-enriched zonula occludens-1-associated protein (MYZAP; Progen Biotechnik) (P <.01). CONCLUSION One-third of the patients affected by El Bagre-EPF have rhythm abnormalities that slow the conduction of impulses in cardiac nodes and the cardiac conduction system. These abnormalities likely occur as a result of deposition of autoantibodies, complement, and other inflammatory molecules. We show for the first time that MYZAP is present in cardiac nodes.
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13
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Zhao H, Zhang D, Yang L, Wang E. p0071 interacts with E-cadherin in the cytoplasm so as to promote the invasion and metastasis of non-small cell lung cancer. Mol Carcinog 2017; 57:89-96. [PMID: 28898462 DOI: 10.1002/mc.22734] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 08/21/2017] [Accepted: 09/05/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Huanyu Zhao
- Department of Pathology; First Affiliated Hospital and College of Basic Medical Sciences of China Medical University; Shenyang China
| | - Di Zhang
- Department of Pathology; First Affiliated Hospital and College of Basic Medical Sciences of China Medical University; Shenyang China
| | - Lianhe Yang
- Department of Pathology; First Affiliated Hospital and College of Basic Medical Sciences of China Medical University; Shenyang China
| | - Enhua Wang
- Department of Pathology; First Affiliated Hospital and College of Basic Medical Sciences of China Medical University; Shenyang China
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14
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Becher A, Eiseler T, Porzner M, Walther P, Keil R, Bobrovich S, Hatzfeld M, Seufferlein T. The armadillo protein p0071 controls KIF3 motor transport. J Cell Sci 2017; 130:3374-3387. [PMID: 28808088 DOI: 10.1242/jcs.200170] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 08/02/2017] [Indexed: 01/17/2023] Open
Abstract
We here report a novel function of the armadillo protein p0071 (also known as PKP4) during transport mediated by the KIF3 transport complex. Secretion of chromogranin A and matrix metallopeptidase 9 from pancreatic neuroendocrine tumor cells or pancreatic cancer cells, respectively, was substantially reduced following knockdown of p0071. Vesicle tracking indicated that there was impaired directional persistence of vesicle movement upon p0071 depletion. This suggests a disturbed balance between plus- and minus-end directed microtubule transport in cells lacking p0071. p0071 directly interacts with the KIF3 motor subunit KIF3B. Our data indicate that p0071 also interacts with the kinesin cargo adaptor protein KAP3 (also known as KIFAP3) acting as a stabilizing linker between KIF3B and its KAP3 cargo-binding entity. Thus, p0071 is required for directional vesicle movement and secretion of different KIF3-transported carriers, thereby regulating the transport of intracellular membrane vesicles along microtubules.
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Affiliation(s)
- Alexander Becher
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Tim Eiseler
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Marc Porzner
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University of Halle-Wittenberg, D-06114 Halle, Germany
| | - Susanne Bobrovich
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University of Halle-Wittenberg, D-06114 Halle, Germany
| | - Thomas Seufferlein
- Department of Internal Medicine I, Ulm University, Albert-Einstein-Allee 23, 89081 Ulm, Germany
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15
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Yuan L, Arikkath J. Functional roles of p120ctn family of proteins in central neurons. Semin Cell Dev Biol 2017; 69:70-82. [PMID: 28603076 DOI: 10.1016/j.semcdb.2017.05.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/16/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023]
Abstract
The cadherin-catenin complex in central neurons is associated with a variety of cytosolic partners, collectively called catenins. The p120ctn members are a family of catenins that are distinct from the more ubiquitously expressed α- and β-catenins. It is becoming increasingly clear that the functional roles of the p120ctn family of catenins in central neurons extend well beyond their functional roles in non-neuronal cells in partnering with cadherin to regulate adhesion. In this review, we will provide an overview of the p120ctn family in neurons and their varied functional roles in central neurons. Finally, we will examine the emerging roles of this family of proteins in neurodevelopmental disorders.
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Affiliation(s)
- Li Yuan
- Department of Pharmacology and Experimental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, NE 68198, United States; Developmental Neuroscience, Munroe-Meyer Institute, Durham Research Center II, Room 3031, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE 68198-5960, United States.
| | - Jyothi Arikkath
- Developmental Neuroscience, Munroe-Meyer Institute, Durham Research Center II, Room 3031, University of Nebraska Medical Center, 985960 Nebraska Medical Center, Omaha, NE 68198-5960, United States.
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16
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Guo X, Koff JL, Moffitt AB, Cinar M, Ramachandiran S, Chen Z, Switchenko JM, Mosunjac M, Neill SG, Mann KP, Bagirov M, Du Y, Natkunam Y, Khoury HJ, Rossi MR, Harris W, Flowers CR, Lossos IS, Boise LH, Dave SS, Kowalski J, Bernal-Mizrachi L. Molecular impact of selective NFKB1 and NFKB2 signaling on DLBCL phenotype. Oncogene 2017; 36:4224-4232. [PMID: 28368397 DOI: 10.1038/onc.2017.90] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 02/15/2017] [Accepted: 02/26/2017] [Indexed: 12/15/2022]
Abstract
Diffuse large B-cell lymphoma (DLBCL) has been categorized into two molecular subtypes that have prognostic significance, namely germinal center B-cell like (GCB) and activated B-cell like (ABC). Although ABC-DLBCL has been associated with NF-κB activation, the relationships between activation of specific NF-κB signals and DLBCL phenotype remain unclear. Application of novel gene expression classifiers identified two new DLBCL categories characterized by selective p100 (NF-κB2) and p105 (NF-κB1) signaling. Interestingly, our molecular studies showed that p105 signaling is predominantly associated with GCB subtype and histone mutations. Conversely, most tumors with p100 signaling displayed ABC phenotype and harbored ABC-associated mutations in genes such as MYD88 and PIM1. In vitro, MYD88 L265P mutation promoted p100 signaling through TAK1/IKKα and GSK3/Fbxw7a pathways, suggesting a novel role for this protein as an upstream regulator of p100. p100 signaling was engaged during activation of normal B cells, suggesting p100's role in ABC phenotype development. Additionally, silencing p100 in ABC-DLBCL cells resulted in a GCB-like phenotype, with suppression of Blimp, IRF4 and XBP1 and upregulation of BCL6, whereas introduction of p52 or p100 into GC cells resulted in differentiation toward an ABC-like phenotype. Together, these findings identify specific roles for p100 and p105 signaling in defining DLBCL molecular subtypes and posit MYD88/p100 signaling as a regulator for B-cell activation.
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Affiliation(s)
- X Guo
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - J L Koff
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - A B Moffitt
- Duke Institute for Genome Sciences and Policy, Department of Medicine, Duke University, Durham, NC, USA
| | - M Cinar
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - S Ramachandiran
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - Z Chen
- Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - J M Switchenko
- Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - M Mosunjac
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - S G Neill
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - K P Mann
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - M Bagirov
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA
| | - Y Du
- Department of Pharmacology, Emory University, Atlanta, GA, USA
| | - Y Natkunam
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - H J Khoury
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - M R Rossi
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA
| | - W Harris
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - C R Flowers
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - I S Lossos
- Division of Hematology Oncology and Molecular and Cellular Pharmacology, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL, USA
| | - L H Boise
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - S S Dave
- Duke Institute for Genome Sciences and Policy, Department of Medicine, Duke University, Durham, NC, USA
| | - J Kowalski
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA.,Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - L Bernal-Mizrachi
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, USA
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17
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Zhao Z, Ma X, Sung D, Li M, Kosti A, Lin G, Chen Y, Pertsemlidis A, Hsiao TH, Du L. microRNA-449a functions as a tumor suppressor in neuroblastoma through inducing cell differentiation and cell cycle arrest. RNA Biol 2016; 12:538-54. [PMID: 25760387 DOI: 10.1080/15476286.2015.1023495] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
microRNA-449a (miR-449a) has been identified to function as a tumor suppressor in several types of cancers. However, the role of miR-449a in neuroblastoma has not been intensively investigated. We recently found that the overexpression of miR-449a significantly induces neuroblastoma cell differentiation, suggesting its potential tumor suppressor function in neuroblastoma. In this study, we further investigated the mechanisms underlying the tumor suppressive function of miR-449a in neuroblastoma. We observed that miR-449a inhibits neuroblastoma cell survival and growth through 2 mechanisms--inducing cell differentiation and cell cycle arrest. Our comprehensive investigations on the dissection of the target genes of miR-449a revealed that 3 novel targets- MFAP4, PKP4 and TSEN15 -play important roles in mediating its differentiation-inducing function. In addition, we further found that its function in inducing cell cycle arrest involves down-regulating its direct targets CDK6 and LEF1. To determine the clinical significance of the miR-449a-mediated tumor suppressive mechanism, we examined the correlation between the expression of these 5 target genes in neuroblastoma tumor specimens and the survival of neuroblastoma patients. Remarkably, we noted that high tumor expression levels of all the 3 miR-449a target genes involved in regulating cell differentiation, but not the target genes involved in regulating cell cycle, are significantly correlated with poor survival of neuroblastoma patients. These results suggest the critical role of the differentiation-inducing function of miR-449a in determining neuroblastoma progression. Overall, our study provides the first comprehensive characterization of the tumor-suppressive function of miR-449a in neuroblastoma, and reveals the potential clinical significance of the miR-449a-mediated tumor suppressive pathway in neuroblastoma prognosis.
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Affiliation(s)
- Zhenze Zhao
- a Greehey Children's Cancer Research Institute; The University of Texas Health Science Center at San Antonio ; San Antonio , TX USA
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18
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Abstract
Birt-Hogg-Dubé (BHD) syndrome is an inherited renal cancer syndrome in which affected individuals are at risk of developing benign cutaneous fibrofolliculomas, bilateral pulmonary cysts and spontaneous pneumothoraces, and kidney tumours. Bilateral multifocal renal tumours that develop in BHD syndrome are most frequently hybrid oncocytic tumours and chromophobe renal carcinoma, but can present with other histologies. Germline mutations in the FLCN gene on chromosome 17 are responsible for BHD syndrome--BHD-associated renal tumours display inactivation of the wild-type FLCN allele by somatic mutation or chromosomal loss, confirming that FLCN is a tumour suppressor gene that fits the classic two-hit model. FLCN interacts with two novel proteins, FNIP1 and FNIP2, and with AMPK, a negative regulator of mTOR. Studies with FLCN-deficient cell and animal models support a role for FLCN in modulating the AKT-mTOR pathway. Emerging evidence links FLCN with a number of other molecular pathways and cellular processes important for cell homeostasis that are frequently deregulated in cancer, including regulation of TFE3 and/or TFEB transcriptional activity, amino-acid-dependent mTOR activation through Rag GTPases, TGFβ signalling, PGC1α-driven mitochondrial biogenesis, and autophagy. Currently, surgical intervention is the only therapy available for BHD-associated renal tumours, but improved understanding of the FLCN pathway will hopefully lead to the development of effective forms of targeted systemic therapy for this disease.
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Affiliation(s)
- Laura S. Schmidt
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, CRC, Room 1-5940, Bethesda, MD 20892-1107 USA
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702 USA
| | - W. Marston Linehan
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg 10, CRC, Room 1-5940, Bethesda, MD 20892-1107 USA
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19
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Nopparat J, Zhang J, Lu JP, Chen YH, Zheng D, Neufer PD, Fan JM, Hong H, Boykin C, Lu Q. δ-Catenin, a Wnt/β-catenin modulator, reveals inducible mutagenesis promoting cancer cell survival adaptation and metabolic reprogramming. Oncogene 2015; 34:1542-52. [PMID: 24727894 PMCID: PMC4197123 DOI: 10.1038/onc.2014.89] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 01/16/2014] [Accepted: 02/17/2014] [Indexed: 02/06/2023]
Abstract
Mutations of Wnt/β-catenin signaling pathway has essential roles in development and cancer. Although β-catenin and adenomatous polyposis coli (APC) gene mutations are well established and are known to drive tumorigenesis, discoveries of mutations in other components of the pathway lagged, which hinders the understanding of cancer mechanisms. Here we report that δ-catenin (gene designation: CTNND2), a primarily neural member of the β-catenin superfamily that promotes canonical Wnt/β-catenin/LEF-1-mediated transcription, displays exonic mutations in human prostate cancer and promotes cancer cell survival adaptation and metabolic reprogramming. When overexpressed in cells derived from prostate tumor xenografts, δ-catenin gene invariably gives rise to mutations, leading to sequence disruptions predicting functional alterations. Ectopic δ-catenin gene integrating into host chromosomes is locus nonselective. δ-Catenin mutations promote tumor development in mouse prostate with probasin promoter (ARR2PB)-driven, prostate-specific expression of Myc oncogene, whereas mutant cells empower survival advantage upon overgrowth and glucose deprivation. Reprogramming energy utilization accompanies the downregulation of glucose transporter-1 and poly (ADP-ribose) polymerase cleavage while preserving tumor type 2 pyruvate kinase expression. δ-Catenin mutations increase β-catenin translocation to the nucleus and hypoxia-inducible factor 1α (HIF-1α) expression. Therefore, introducing δ-catenin mutations is an important milestone in prostate cancer metabolic adaptation by modulating β-catenin and HIF-1α signaling under glucose shortage to amplify its tumor-promoting potential.
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Affiliation(s)
- J Nopparat
- Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - J Zhang
- Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - J-P Lu
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Y-H Chen
- 1] Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA [2] Leo Jenkins Cancer Center, The Brody School of Medicine, East Carolina University, Greenville, NC, USA [3] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - D Zheng
- 1] Department of Kinesiology, East Carolina University, Greenville, NC, USA [2] East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA
| | - P D Neufer
- 1] Department of Kinesiology, East Carolina University, Greenville, NC, USA [2] East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA [3] Department of Physiology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - J M Fan
- Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - H Hong
- Department of Pathology and Laboratory Medicine, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - C Boykin
- Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Q Lu
- 1] Department of Anatomy and Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA [2] Leo Jenkins Cancer Center, The Brody School of Medicine, East Carolina University, Greenville, NC, USA [3] Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
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20
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Galic M, Tsai FC, Collins SR, Matis M, Bandara S, Meyer T. Dynamic recruitment of the curvature-sensitive protein ArhGAP44 to nanoscale membrane deformations limits exploratory filopodia initiation in neurons. eLife 2014; 3:e03116. [PMID: 25498153 PMCID: PMC4381785 DOI: 10.7554/elife.03116] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 11/13/2014] [Indexed: 12/14/2022] Open
Abstract
In the vertebrate central nervous system, exploratory filopodia transiently form on
dendritic branches to sample the neuronal environment and initiate new trans-neuronal
contacts. While much is known about the molecules that control filopodia extension
and subsequent maturation into functional synapses, the mechanisms that regulate
initiation of these dynamic, actin-rich structures have remained elusive. Here, we
find that filopodia initiation is suppressed by recruitment of ArhGAP44 to
actin-patches that seed filopodia. Recruitment is mediated by binding of a membrane
curvature-sensing ArhGAP44 N-BAR domain to plasma membrane sections that were
deformed inward by acto-myosin mediated contractile forces. A GAP domain in ArhGAP44
triggers local Rac-GTP hydrolysis, thus reducing actin polymerization required for
filopodia formation. Additionally, ArhGAP44 expression increases during neuronal
development, concurrent with a decrease in the rate of filopodia formation. Together,
our data reveals a local auto-regulatory mechanism that limits initiation of
filopodia via protein recruitment to nanoscale membrane deformations. DOI:http://dx.doi.org/10.7554/eLife.03116.001 Our brains contain a vast network of many billions of cells that communicate with,
and are connected to, each other. Each brain cell, or neuron, can form connections
with as many as 10,000 other neurons—and signals pass from one neuron to the
next at sites known as synapses. A neuron's surface has numerous finger-like protrusions known as filopodia that are
important for sensing the environment around the cells. Filopodia are highly
changeable and constantly extend and retract as the filaments that support
them—which are made up of a protein called actin—grow and shrink back.
Neurons use their filopodia to explore and seek out other neurons in the brain, and
when they make contact with the right neuron, it leads to the formation of a synapse.
However, how filopodial extensions begin to grow—and what stops a neuron from
forming too many filopodia—is not fully understood. Galic et al. now show that a protein called ArhGAP44 limits the formation of new
filopodia in neurons. The ArhGAP44 protein is recruited to patches of the surface
membrane that have a lot of actin and that curve inwards. ArhGAP44 then locally
inhibits other proteins that are normally required to extend the actin filaments and
drive the growth of filopodia out from the surface of the cell. Galic et al. also show that more ArhGAP44 is produced with age—levels are low
in embryos and high in adults—and this increase in the amount of protein
correlates with a decrease in the number of filopodia formed. When Galic et al.
engineered rat neurons to produce more of the ArhGAP44 protein, fewer filopodia
formed on the surface of the neurons. Decreasing the amount of this protein had the
opposite effect. Moreover, ArhGAP44 was shown to mainly stop new filopodia from
forming and had little effect on existing filopodia. Together, these findings suggest
that ArhGAP44 may help neurons transition from a dynamic exploratory mode to a
mature, more static, state; this is a characteristic of the development of the
nervous system. DOI:http://dx.doi.org/10.7554/eLife.03116.002
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Affiliation(s)
- Milos Galic
- Department of Chemical and Systems Biology, Stanford University, Stanford, United States
| | - Feng-Chiao Tsai
- Department of Chemical and Systems Biology, Stanford University, Stanford, United States
| | - Sean R Collins
- Department of Chemical and Systems Biology, Stanford University, Stanford, United States
| | - Maja Matis
- Department of Pathology, Stanford University, Stanford, United States
| | - Samuel Bandara
- Department of Chemical and Systems Biology, Stanford University, Stanford, United States
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University, Stanford, United States
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21
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Chircop M. Rho GTPases as regulators of mitosis and cytokinesis in mammalian cells. Small GTPases 2014; 5:29770. [PMID: 24988197 DOI: 10.4161/sgtp.29770] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases regulate a diverse range of cellular functions primarily through their ability to modulate microtubule dynamics and the actin-myosin cytoskeleton. Both of these cytoskeletal structures are crucial for a mitotic cell division. Specifically, their assembly and disassembly is tightly regulated in a temporal manner to ensure that each mitotic stage occurs in the correct sequential order and not prematurely until the previous stage is completed. Thus, it is not surprising that the Rho GTPases, RhoA, and Cdc42, have reported roles in several stages of mitosis: cell cortex stiffening during cell rounding, mitotic spindle formation, and bi-orient attachment of the spindle microtubules to the kinetochore and during cytokinesis play multiple roles in establishing the division plane, assembly, and activation of the contractile ring, membrane ingression, and abscission. Here, I review the molecular mechanisms regulating the spatial and temporal activation of RhoA and Cdc42 during mitosis, and how this is critical for mitotic progression and completion.
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Affiliation(s)
- Megan Chircop
- Children's Medical Research Institute; The University of Sydney; Westmead, Australia
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22
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Hatzfeld M, Wolf A, Keil R. Plakophilins in Desmosomal Adhesion and Signaling. ACTA ACUST UNITED AC 2014; 21:25-42. [DOI: 10.3109/15419061.2013.876017] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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23
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p120 catenin: an essential regulator of cadherin stability, adhesion-induced signaling, and cancer progression. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 116:409-32. [PMID: 23481205 DOI: 10.1016/b978-0-12-394311-8.00018-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
p120 catenin is the best studied member of a subfamily of proteins that associate with the cadherin juxtamembrane domain to suppress cadherin endocytosis. p120 also recruits the minus ends of microtubules to the cadherin complex, leading to junction maturation. In addition, p120 regulates the activity of Rho family GTPases through multiple interactions with Rho GEFs, GAPs, Rho GTPases, and their effectors. Nuclear signaling is affected by the interaction of p120 with Kaiso, a transcription factor regulating Wnt-responsive genes as well as transcriptionally repressing methylated promoters. Multiple alternatively spliced p120 isoforms and complex phosphorylation events affect these p120 functions. In cancer, reduced p120 expression correlates with reduced E-cadherin function and with tumor progression. In contrast, in tumor cells that have lost E-cadherin expression, p120 promotes cell invasion and anchorage-independent growth. Furthermore, p120 is required for Src-induced oncogenic transformation and provides a potential target for future therapeutic interventions.
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24
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Nolze A, Schneider J, Keil R, Lederer M, Hüttelmaier S, Kessels MM, Qualmann B, Hatzfeld M. FMRP regulates actin filament organization via the armadillo protein p0071. RNA (NEW YORK, N.Y.) 2013; 19:1483-96. [PMID: 24062571 PMCID: PMC3851716 DOI: 10.1261/rna.037945.112] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Loss of fragile X mental retardation protein (FMRP) causes synaptic dysfunction and intellectual disability. FMRP is an RNA-binding protein that controls the translation or turnover of a subset of mRNAs. Identifying these target transcripts is an important step toward understanding the pathology of the disease. Here, we show that FMRP regulates actin organization and neurite outgrowth via the armadillo protein p0071. In mouse embryonic fibroblasts (MEFs) lacking FMRP (Fmr1-), the actin cytoskeleton was markedly reorganized with reduced stress fibers and F-actin/G-actin ratios compared to fibroblasts re-expressing the protein. FMRP interfered with the translation of the p0071 mRNA in a 3'-UTR-dependent manner. Accordingly, FMRP-depleted cells revealed elevated levels of p0071 protein. The knockdown of p0071 in Fmr1- fibroblasts restored stress fibers and an elongated cell shape, thus rescuing the Fmr1- phenotype, whereas overexpression of p0071 in Fmr1+ cells mimicked the Fmr1- phenotype. Moreover, p0071 and FMRP regulated neurite outgrowth and branching in a diametrically opposed way in agreement with the negative regulation of p0071 by FMRP. These results identify p0071 as an important and novel FMRP target and strongly suggest that impaired actin cytoskeletal functions mediated by an excess of p0071 are key aspects underlying the fragile X syndrome.
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Affiliation(s)
- Alexander Nolze
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University of Halle, 06114 Halle, Germany
| | - Jacqueline Schneider
- Institute for Biochemistry I, Jena University Hospital–Friedrich Schiller University Jena, 07743 Jena, Germany
| | - René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University of Halle, 06114 Halle, Germany
| | - Marcell Lederer
- Institute of Molecular Medicine, Division of Cell Biology, Martin-Luther-University of Halle, 06120 Halle, Germany
| | - Stefan Hüttelmaier
- Institute of Molecular Medicine, Division of Cell Biology, Martin-Luther-University of Halle, 06120 Halle, Germany
| | - Michael M. Kessels
- Institute for Biochemistry I, Jena University Hospital–Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital–Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Mechthild Hatzfeld
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University of Halle, 06114 Halle, Germany
- Corresponding authorE-mail
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Keil R, Hatzfeld M. The armadillo protein p0071 is involved in Rab11-dependent recycling. J Cell Sci 2013; 127:60-71. [PMID: 24163434 DOI: 10.1242/jcs.132266] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
p0071 is an intercellular junction protein of the p120 catenin family. We have identified Rab11a as a novel interaction partner of p0071. p0071 interacted preferentially with active Rab11a. Knockdown experiments revealed an interdependent regulation of both proteins. On the one hand, p0071 depletion induced a perinuclear accumulation of Rab11, suggesting a role of p0071 in the anterograde transport of Rab11 from the pericentrosomal region to the plasma membrane but not in retrograde transport. p0071 as well as Rab11 depletion increased transferrin receptor recycling indicating that p0071-induced Rab11 mislocalization interfered with Rab11 function and shifted recycling from the slow Rab11-dependent pathway to the fast Rab4-dependent pathway. When p0071 or Rab11 depletion was combined with a Rab4 knockdown the effect was reversed. On the other hand, Rab11a depletion increased p0071 recycling to cell contacts thereby identifying p0071 as a Rab11 cargo protein. This correlated with increased intercellular adhesion. Thus, we propose that p0071 has a key role in regulating recycling through the Rab11-dependent perinuclear recycling compartment, and links the regulation of adherens junctions to recycling to allow dynamic modulation of intercellular adhesion.
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Affiliation(s)
- René Keil
- Institute of Molecular Medicine, Division of Pathobiochemistry, Martin-Luther-University Halle, Hollystrasse 1, 06114 Halle, Germany
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Direct RNA sequencing mediated identification of mRNA localized in protrusions of human MDA-MB-231 metastatic breast cancer cells. J Mol Signal 2013; 8:9. [PMID: 24004954 PMCID: PMC3844448 DOI: 10.1186/1750-2187-8-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 08/20/2013] [Indexed: 01/13/2023] Open
Abstract
Background Protrusions of cancer cells conferrers a vital function for cell migration and metastasis. Protein and RNA localization mechanisms have been extensively examined and shown to play pivotal roles for the functional presence of specific protein components in cancer cell protrusions. Methods To describe genome wide RNA localized in protrusions of the metastatic human breast cancer cell line MDA-MB-231 we used Boyden chamber based methodology followed by direct mRNA sequencing. Results In the hereby identified group of protrusion localized mRNA some previously were described to be localized exemplified by mRNA for Ras-Related protein 13 (RAB13) and p0071 (Plakophilin-4/PKP4). For other transcripts, exemplified by mRNA for SH3PXD2A/TKS5 and PPFIA1/Liprin-α1, only the corresponding proteins previously were described to have protrusion localization. Finally, a cohort of MDA-MB-231 protrusion localized transcripts represents novel candidates to mediate cancer cell subcellular region specific functions through mRNA direction to protrusions. We included a further characterization of p0071, an armadillo repeat protein of adherence junctions and desmosomes, in MDA-MB-231 and non-metastatic MCF7 cells including analysis of novel identified alternative spliced p0071 mRNA isoforms. The results showed isoform and cell type specific p0071 mRNA localization. Conclusions Altogether, the presented data represents a genome wide and gene specific descriptive and functional analyses of RNA localization in protrusions of MDA-MB-231 metastatic cancer cells.
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Folliculin, the product of the Birt-Hogg-Dube tumor suppressor gene, interacts with the adherens junction protein p0071 to regulate cell-cell adhesion. PLoS One 2012; 7:e47842. [PMID: 23139756 PMCID: PMC3490959 DOI: 10.1371/journal.pone.0047842] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 09/21/2012] [Indexed: 01/04/2023] Open
Abstract
Birt-Hogg-Dube (BHD) is a tumor suppressor gene syndrome associated with fibrofolliculomas, cystic lung disease, and chromophobe renal cell carcinoma. In seeking to elucidate the pathogenesis of BHD, we discovered a physical interaction between folliculin (FLCN), the protein product of the BHD gene, and p0071, an armadillo repeat containing protein that localizes to the cytoplasm and to adherens junctions. Adherens junctions are one of the three cell-cell junctions that are essential to the establishment and maintenance of the cellular architecture of all epithelial tissues. Surprisingly, we found that downregulation of FLCN leads to increased cell-cell adhesion in functional cell-based assays and disruption of cell polarity in a three-dimensional lumen-forming assay, both of which are phenocopied by downregulation of p0071. These data indicate that the FLCN-p0071 protein complex is a negative regulator of cell-cell adhesion. We also found that FLCN positively regulates RhoA activity and Rho-associated kinase activity, consistent with the only known function of p0071. Finally, to examine the role of Flcn loss on cell-cell adhesion in vivo, we utilized keratin-14 cre-recombinase (K14-cre) to inactivate Flcn in the mouse epidermis. The K14-Cre-Bhd(flox/flox) mice have striking delays in eyelid opening, wavy fur, hair loss, and epidermal hyperplasia with increased levels of mammalian target of rapamycin complex 1 (mTORC1) activity. These data support a model in which dysregulation of the FLCN-p0071 interaction leads to alterations in cell adhesion, cell polarity, and RhoA signaling, with broad implications for the role of cell-cell adhesion molecules in the pathogenesis of human disease, including emphysema and renal cell carcinoma.
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Nahorski MS, Seabra L, Straatman-Iwanowska A, Wingenfeld A, Reiman A, Lu X, Klomp JA, Teh BT, Hatzfeld M, Gissen P, Maher ER. Folliculin interacts with p0071 (plakophilin-4) and deficiency is associated with disordered RhoA signalling, epithelial polarization and cytokinesis. Hum Mol Genet 2012; 21:5268-79. [PMID: 22965878 DOI: 10.1093/hmg/dds378] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Inherited mutations in the folliculin (FLCN) gene cause the Birt-Hogg-Dubé syndrome of familial hair follicle tumours (fibrofolliculomas), lung cysts and kidney tumours. Though folliculin has features of a tumour suppressor, the precise function of the FLCN gene product is not well characterized. We identified plakophilin-4 (p0071) as a potential novel folliculin interacting protein by yeast two-hybrid analysis. We confirmed the interaction of folliculin with p0071 by co-immunoprecipitation studies and, in view of previous studies linking p0071 to the regulation of rho-signalling, cytokinesis and intercellular junction formation, we investigated the effect of cell folliculin status on p0071-related functions. Folliculin and p0071 partially co-localized at cell junctions and in mitotic cells, at the midbody during cytokinesis. Previously, p0071 has been reported to regulate RhoA signalling during cytokinesis and we found that folliculin deficiency was associated with increased expression and activity of RhoA and evidence of disordered cytokinesis. Treatment of folliculin-deficient cells with a downstream inhibitor of RhoA signalling (the ROCK inhibitor Y-27632) reversed the increased cell migration phenotype observed in folliculin-deficient cells. Deficiency of folliculin and of p0071 resulted in tight junction defects and mislocalization of E-cadherin in mouse inner medullary collecting duct-3 renal tubular cells. These findings suggest that aspects of folliculin tumour suppressor function are linked to interaction with p0071 and the regulation of RhoA signalling.
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Affiliation(s)
- Michael S Nahorski
- Department of Medical and Molecular Genetics, Centre for Rare Diseases and Personalized Medicine, School of Clinical and Experimental Medicine, University of Birmingham College of Medical and Dental Sciences, Edgbaston, Birmingham, UK
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Munoz WA, Kloc M, Cho K, Lee M, Hofmann I, Sater A, Vleminckx K, McCrea PD. Plakophilin-3 is required for late embryonic amphibian development, exhibiting roles in ectodermal and neural tissues. PLoS One 2012; 7:e34342. [PMID: 22496792 PMCID: PMC3320641 DOI: 10.1371/journal.pone.0034342] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 02/27/2012] [Indexed: 12/31/2022] Open
Abstract
The p120-catenin family has undergone a significant expansion during the evolution of vertebrates, resulting in varied functions that have yet to be discerned or fully characterized. Likewise, members of the plakophilins, a related catenin subfamily, are found throughout the cell with little known about their functions outside the desmosomal plaque. While the plakophilin-3 (Pkp3) knockout mouse resulted in skin defects, we find larger, including lethal effects following its depletion in Xenopus. Pkp3, unlike some other characterized catenins in amphibians, does not have significant maternal deposits of mRNA. However, during embryogenesis, two Pkp3 protein products whose temporal expression is partially complimentary become expressed. Only the smaller of these products is found in adult Xenopus tissues, with an expression pattern exhibiting distinctions as well as overlaps with those observed in mammalian studies. We determined that Xenopus Pkp3 depletion causes a skin fragility phenotype in keeping with the mouse knockout, but more novel, Xenopus tailbud embryos are hyposensitive to touch even in embryos lacking outward discernable phenotypes, and we additionally resolved disruptions in certain peripheral neural structures, altered establishment and migration of neural crest, and defects in ectodermal multiciliated cells. The use of two distinct morpholinos, as well as rescue approaches, indicated the specificity of these effects. Our results point to the requirement of Pkp3 in amphibian embryogenesis, with functional roles in a number of tissue types.
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Affiliation(s)
- William A. Munoz
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes and Development, University of Texas Graduate School of Biomedical Science, Houston, Texas, United States of America
| | - Malgorzata Kloc
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Department of Surgery, The Methodist Hospital Research Institute, Houston, Texas, United States of America
| | - Kyucheol Cho
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes and Development, University of Texas Graduate School of Biomedical Science, Houston, Texas, United States of America
| | - Moonsup Lee
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes and Development, University of Texas Graduate School of Biomedical Science, Houston, Texas, United States of America
| | - Ilse Hofmann
- Joint Research Division Vascular Biology of the Medical Faculty Mannheim, University of Heidelberg- DKFZ, Mannheim, Germany
| | - Amy Sater
- Biology and Biochemistry Department, University of Houston, Houston, Texas, United States of America
| | - Kris Vleminckx
- Department for Molecular Biomedical Research, Flanders Institute for Biotechnology VIB, Ghent, Belgium
| | - Pierre D. McCrea
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, United States of America
- Program in Genes and Development, University of Texas Graduate School of Biomedical Science, Houston, Texas, United States of America
- * E-mail:
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Weidemann W, Reinhardt A, Thate A, Horstkorte R. Biochemical characterization of the M712T-mutation of the UDP-N-acetylglucosamine 2-epimerase/N-acetyl-mannosaminekinase in hereditary inclusion body myopathy. Neuromuscul Disord 2011; 21:824-31. [PMID: 21873062 DOI: 10.1016/j.nmd.2011.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/08/2011] [Accepted: 06/10/2011] [Indexed: 01/01/2023]
Abstract
Hereditary inclusion body myopathy is a neuromuscular disorder characterized by muscle weakness with a late onset and slow progression. It is caused by mutations of the gene encoding UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE). One of the most frequent mutations is an exchange of methionine to threonine at position 712 (M712T). Here we analyzed wildtype (wt) and M712T-mutated (M712T) GNE. We identified threonine 712 as an additional possible phosphorylation site and found by two-dimensional gel-electrophoresis a lower isoelectric point compared to wt-GNE. This lower isoelectric point could be partially reversed back to the wildtype isoelectric point after treatment with protein phosphatase. Furthermore, in contrast to wt-GNE, a significant fraction of M712T-GNE was in the insoluble fraction. Finally, by using bimolecular fluorescence complementation we demonstrate that the M712T mutation does not disrupt the formation of GNE-oligomers.
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Affiliation(s)
- Wenke Weidemann
- Institute of Physiological Chemistry, Martin-Luther University of Halle-Wittenberg, Hollystr. 1, D-06114 Halle, Germany
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31
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Hong JY, Park JI, Cho K, Gu D, Ji H, Artandi SE, McCrea PD. Shared molecular mechanisms regulate multiple catenin proteins: canonical Wnt signals and components modulate p120-catenin isoform-1 and additional p120 subfamily members. J Cell Sci 2010; 123:4351-65. [PMID: 21098636 DOI: 10.1242/jcs.067199] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Wnt signaling pathways have fundamental roles in animal development and tumor progression. Here, employing Xenopus embryos and mammalian cell lines, we report that the degradation machinery of the canonical Wnt pathway modulates p120-catenin protein stability through mechanisms shared with those regulating β-catenin. For example, in common with β-catenin, exogenous expression of destruction complex components, such as GSK3β and axin, promotes degradation of p120-catenin. Again in parallel with β-catenin, reduction of canonical Wnt signals upon depletion of LRP5 and LRP6 results in p120-catenin degradation. At the primary sequence level, we resolved conserved GSK3β phosphorylation sites in the amino-terminal region of p120-catenin present exclusively in isoform-1. Point-mutagenesis of these residues inhibited the association of destruction complex components, such as those involved in ubiquitylation, resulting in stabilization of p120-catenin. Functionally, in line with predictions, p120 stabilization increased its signaling activity in the context of the p120-Kaiso pathway. Importantly, we found that two additional p120-catenin family members, ARVCF-catenin and δ-catenin, associate with axin and are degraded in its presence. Thus, as supported using gain- and loss-of-function approaches in embryo and cell line systems, canonical Wnt signals appear poised to have an impact upon a breadth of catenin biology in vertebrate development and, possibly, human cancers.
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Affiliation(s)
- Ji Yeon Hong
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
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32
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McCrea PD, Gu D, Balda MS. Junctional music that the nucleus hears: cell-cell contact signaling and the modulation of gene activity. Cold Spring Harb Perspect Biol 2010; 1:a002923. [PMID: 20066098 DOI: 10.1101/cshperspect.a002923] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell-cell junctions continue to capture the interest of cell and developmental biologists, with an emerging area being the molecular means by which junctional signals relate to gene activity in the nucleus. Although complexities often arise in determining the direct versus indirect nature of such signal transduction, it is clear that such pathways are essential for the function of tissues and that alterations may contribute to many pathological outcomes. This review assesses a variety of cell-cell junction-to-nuclear signaling pathways, and outlines interesting areas for further study.
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Affiliation(s)
- Pierre D McCrea
- Department of Biochemistry and Molecular Biology, University of Texas MD Anderson Cancer Center, Program in Genes and Development, University of Texas Graduate School of Biomedical Sciences, Houston, Texas 77030, USA.
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Mutations in mouse Aspm (abnormal spindle-like microcephaly associated) cause not only microcephaly but also major defects in the germline. Proc Natl Acad Sci U S A 2010; 107:16595-600. [PMID: 20823249 DOI: 10.1073/pnas.1010494107] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in ASPM (abnormal spindle-like microcephaly associated) cause primary microcephaly in humans, a disorder characterized by a major reduction in brain size in the apparent absence of nonneurological anomalies. The function of the Aspm protein in neural progenitor cell expansion, as well as its localization to the mitotic spindle and midbody, suggest that it regulates brain development by a cell division-related mechanism. Furthermore, evidence that positive selection affected ASPM during primate evolution has led to suggestions that such a function changed during primate evolution. Here, we report that in Aspm mutant mice, truncated Aspm proteins similar to those causing microcephaly in humans fail to localize to the midbody during M-phase and cause mild microcephaly. A human ASPM transgene rescues this phenotype but, interestingly, does not cause a gain of function. Strikingly, truncated Aspm proteins also cause a massive loss of germ cells, resulting in a severe reduction in testis and ovary size accompanied by reduced fertility. These germline effects, too, are fully rescued by the human ASPM transgene, indicating that ASPM is functionally similar in mice and humans. Our findings broaden the spectrum of phenotypic effects of ASPM mutations and raise the possibility that positive selection of ASPM during primate evolution reflects its function in the germline.
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Kanai M, Crowe MS, Zheng Y, Vande Woude GF, Fukasawa K. RhoA and RhoC are both required for the ROCK II-dependent promotion of centrosome duplication. Oncogene 2010; 29:6040-50. [PMID: 20697357 PMCID: PMC2978787 DOI: 10.1038/onc.2010.328] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
CDK2-cyclin E triggers centrosome duplication, and nucleophosmin (NPM/B23) is found to be one of its targets. NPM/B23 phosphorylated by CDK2-cyclin E acquires a high binding affinity to Rho-associated kinase (ROCK II), and physically associates with ROCK II. The NPM/B23-binding results in super-activation of ROCK II, which is a critical event for initiation of centrosome duplication. The activation of ROCK II also requires the binding of Rho small GTPase to the auto-inhibitory region; hence the availability of the active Rho protein is an important aspect of the centrosomally localized ROCK II to properly initiate centrosome duplication. There are three isoforms of Rho (RhoA, B, and C), all of which are capable of binding to and priming the activation of ROCK II. Here, we investigated which Rho isoform(s) are involved in the activation of ROCK II in respect to the initiation of centrosome duplication. We found that both RhoA and RhoC, but not RhoB, were required for initiation of centrosome duplication, and over-activation of RhoA as well as RhoC, but not RhoB, promoted centrosome duplication and centrosome amplification.
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Affiliation(s)
- M Kanai
- Molecular Oncology Program, H Lee Moffitt Cancer Center & Research Institute, Tampa, FL 33612, USA
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35
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Cytokinesis and cancer: Polo loves ROCK'n' Rho(A). J Genet Genomics 2010; 37:159-72. [PMID: 20347825 DOI: 10.1016/s1673-8527(09)60034-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 12/11/2022]
Abstract
Cytokinesis is the last step of the M (mitosis) phase, yet it is crucial for the faithful division of one cell into two. Cytokinesis failure is often associated with cancer. Cytokinesis can be morphologically divided into four steps: cleavage furrow initiation, cleavage furrow ingression, midbody formation and abscission. Molecular studies have revealed that RhoA as well as its regulators and effectors are important players to ensure a successful cytokinesis. At the same time, Polo-like kinase 1 (Plk1) is an important kinase that can target many substrates and carry out different functions during mitosis, including cytokinesis. Recent studies are beginning to unveil a closer tie between Plk1 and RhoA networks. More specifically, Plk1 phosphorylates the centralspindlin complex Cyk4 and MKLP1/CHO1, thus recruiting RhoA guanine nucleotide-exchange factor (GEF) Ect2 through its phosphopeptide-binding BRCT domains. Ect2 itself can be phosphorylated by Plk1 in vitro. Plk1 can also phosphorylate another GEF MyoGEF to regulate RhoA activity. Once activated, RhoA-GTP will activate downstream effectors, including ROCK1 and ROCK2. ROCK2 is among the proteins that associate with Plk1 Polo-binding domain (PBD) in a large proteomic screen, and Plk1 can phosphorylate ROCK2 in vitro. We review current understandings of the interplay between Plk1, RhoA proteins and other proteins (e.g., NudC, MKLP2, PRC1, CEP55) involved in cytokinesis, with particular emphasis of its clinical implications in cancer.
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Affiliation(s)
- Pierre D McCrea
- Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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37
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Kosel D, Heiker JT, Juhl C, Wottawah CM, Blüher M, Mörl K, Beck-Sickinger AG. Dimerization of adiponectin receptor 1 is inhibited by adiponectin. J Cell Sci 2010; 123:1320-8. [PMID: 20332107 DOI: 10.1242/jcs.057919] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AdipoR1 and AdipoR2 are newly discovered members of the huge family of seven-transmembrane receptors, but both receptors are structurally and functionally different from G-protein-coupled receptors. Little is known about the oligomerization of the AdipoRs. Here, we show the presence of endogenous AdipoR1 dimers in various cell lines and human muscle tissue. To directly follow and localize the dimerization, we applied bimolecular fluorescence complementation (BiFC) in combination with flow cytometry. We visualized and quantified AdipoR1 homodimers in HEK293 cells. Moreover, we identified a GxxxG dimerization motif in the fifth transmembrane domain of the AdipoR1. By mutating both glycine residues to phenylalanine or glutamic acid, we were able to modulate the dimerization of AdipoR1, implicating a role for the GxxxG motif in AdipoR1 dimerization. Furthermore, we tested whether the AdipoR1 ligand adiponectin had any influence on receptor dimerization. Interestingly, we found that adiponectin decreases the receptor dimerization in a concentration-dependent manner. This effect is mainly mediated by segments of the collagen-like domain of full-length adiponectin. Accordingly, this is the first direct read-out signal of adiponectin at the AdipoR1 receptor, which revealed the involvement of specific amino acids of both the receptor and the ligand to modulate the quaternary structure of the AdipoR1.
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Affiliation(s)
- David Kosel
- Faculty of Biosciences, Institute of Biochemistry, Leipzig University, Brüderstr 34, 04103 Leipzig, Germany
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Wolf A, Krause-Gruszczynska M, Birkenmeier O, Ostareck-Lederer A, Hüttelmaier S, Hatzfeld M. Plakophilin 1 stimulates translation by promoting eIF4A1 activity. ACTA ACUST UNITED AC 2010; 188:463-71. [PMID: 20156963 PMCID: PMC2828926 DOI: 10.1083/jcb.200908135] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
p120 armadillo protein plakophilin 1 binds to eukaryotic translation factor eIF4A1, recruiting it into cap-binding complexes and stimulating translation. Plakophilins 1–3 (PKP1–3) are desmosomal proteins of the p120ctn family of armadillo-related proteins that are essential for organizing the desmosomal plaque. Recent findings identified PKPs in stress granules, suggesting an association with the translational machinery. However, a role of PKPs in controlling translation remained elusive so far. In this study, we show a direct association of PKP1 with the eukaryotic translation initiation factor 4A1 (eIF4A1). PKP1 stimulated eIF4A1-dependent translation via messenger RNA cap and encephalomyocarditis virus internal ribosomal entry site (IRES) structures, whereas eIF4A1-independent translation via hepatitis C virus IRES was not affected. PKP1 copurified with eIF4A1 in the cap complex, and its overexpression stimulated eIF4A1 recruitment into cap-binding complexes. At the molecular level, PKP1 directly promoted eIF4A1 adenosine triphosphatase activity. The stimulation of translation upon PKP1 overexpression correlated with the up-regulation of proliferation and cell size. In conclusion, these findings identify PKP1 as a regulator of translation and proliferation via modulation of eIF4A1 activity and suggest that PKP1 controls cell growth in physiological and pathological conditions.
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Affiliation(s)
- Annika Wolf
- Division of Pathobiochemistry, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany
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Abstract
Cytokinesis is the final step in cell division. The process begins during chromosome segregation, when the ingressing cleavage furrow begins to partition the cytoplasm between the nascent daughter cells. The process is not completed until much later, however, when the final cytoplasmic bridge connecting the two daughter cells is severed. Cytokinesis is a highly ordered process, requiring an intricate interplay between cytoskeletal, chromosomal and cell cycle regulatory pathways. A surprisingly broad range of additional cellular processes are also important for cytokinesis, including protein and membrane trafficking, lipid metabolism, protein synthesis and signaling pathways. As a highly regulated, complex process, it is not surprising that cytokinesis can sometimes fail. Cytokinesis failure leads to both centrosome amplification and production of tetraploid cells, which may set the stage for the development of tumor cells. However, tetraploid cells are abundant components of some normal tissues including liver and heart, indicating that cytokinesis is physiologically regulated. In this chapter, we summarize our current understanding of the mechanisms of cytokinesis, emphasizing steps in the pathway that may be regulated or prone to failure. Our discussion emphasizes findings in vertebrate cells although we have attempted to highlight important contributions from other model systems.
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Walter B, Krebs U, Berger I, Hofmann I. Protein p0071, an armadillo plaque protein of adherens junctions, is predominantly expressed in distal renal tubules. Histochem Cell Biol 2009; 133:69-83. [PMID: 19830446 DOI: 10.1007/s00418-009-0645-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2009] [Indexed: 01/27/2023]
Abstract
Protein p0071 is a member of the p120-subfamily of armadillo proteins and is well known as a junctional plaque component involved in cell-cell adhesion, especially in adherens junctions. By systematic immunohistochemical analysis of mouse and human kidney tissues, p0071 was prominently detected in distinct kidney tubules. Upon double-labeling immunolocalization experiments with segment-specific markers, p0071 was predominantly localized in distal straight and convoluted tubules and to a lesser extent in proximal tubules, in the ascending thin limb of loop of Henle and in the collecting ducts. In capillaries of the kidney, p0071 co-localized with VE-cadherin an endothelium-specific cadherin. Protein p0071 was also detected in both, renal cell carcinomas derived from distal tubules and in maturing nephrons of early mouse developmental stages. Immunoblotting of total extracts of cultured cells of renal origin showed that p0071 was detected in all human and murine cells analyzed. Upon immunolocalization, p0071 was observed in adherens junctions but also in distinct cytoplasmic structures at the cell periphery of cultured cells. Possible structural and functional roles of p0071 are suggested by its preferential occurrence in distinct tubule segments, and its potential use as a cytodiagnostic cell type marker in renal pathology is discussed.
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Affiliation(s)
- Britta Walter
- Joint Research Division Vascular Biology of the Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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Stenzel N, Fetzer CP, Heumann R, Erdmann KS. PDZ-domain-directed basolateral targeting of the peripheral membrane protein FRMPD2 in epithelial cells. J Cell Sci 2009; 122:3374-84. [PMID: 19706687 DOI: 10.1242/jcs.046854] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Multi-PDZ (PSD-95/Discs large/Zonula-occludens-1) domain proteins play a crucial role in the establishment and maintenance of cell polarization. The novel multi-PDZ domain protein FRMPD2 is a potential scaffolding protein consisting of an N-terminal KIND domain, a FERM domain and three PDZ domains. Here we show that FRMPD2 is localized in a polarized fashion in epithelial cells at the basolateral membrane and partially colocalizes with the tight-junction marker protein Zonula-occludens-1. Downregulation of FRMPD2 protein in Caco-2 cells is associated with an impairment of tight junction formation. We find that the FERM domain of FRMPD2 binds phosphatidylinositols and is sufficient for membrane localization. Moreover, we demonstrate that recruitment of FRMPD2 to cell-cell junctions is strictly E-cadherin-dependent, which is in line with our identification of catenin family proteins as binding partners for FRMPD2. We demonstrate that the FERM domain and binding of the PDZ2 domain to the armadillo protein p0071 are required for basolateral restriction of FRMPD2. Moreover, the PDZ2 domain of FRMPD2 is sufficient to partially redirect an apically localized protein to the basolateral membrane. Our results provide novel insights into the molecular function of FRMPD2 and into the targeting mechanism of peripheral membrane proteins in polarized epithelial cells.
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Affiliation(s)
- Nina Stenzel
- Department of Biochemistry II, Ruhr-University Bochum, 44780 Bochum, Germany
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Bass-Zubek AE, Godsel LM, Delmar M, Green KJ. Plakophilins: multifunctional scaffolds for adhesion and signaling. Curr Opin Cell Biol 2009; 21:708-16. [PMID: 19674883 DOI: 10.1016/j.ceb.2009.07.002] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/28/2009] [Accepted: 07/06/2009] [Indexed: 11/26/2022]
Abstract
Armadillo family proteins known as plakophilins have been characterized as structural components of desmosomes that stabilize and strengthen adhesion by enhancing attachments with the intermediate filament cytoskeleton. However, plakophilins and their close relatives are emerging as versatile scaffolds for multiple signaling and metabolic processes that not only facilitate junction dynamics but also more globally regulate diverse cellular activities. While perturbation of plakophilin functions contribute to inherited diseases and cancer pathogenesis, the functional significance of the multiple PKP isoforms and the mechanisms by which their behaviors are regulated remain to be elucidated.
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Affiliation(s)
- Amanda E Bass-Zubek
- Department of Pathology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL 60611, USA
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Keil R, Kiessling C, Hatzfeld M. Targeting of p0071 to the midbody depends on KIF3. J Cell Sci 2009; 122:1174-83. [PMID: 19339549 DOI: 10.1242/jcs.045377] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
P0071 (plakophilin-4) is a member of the p120ctn subfamily of armadillo proteins that are essential for cell contact formation. Additionally, p0071 plays a role in cytokinesis, in which it regulates local activation of RhoA together with Ect2. Because spatiotemporal regulation is required for progression through cytokinesis, we analyzed when and how p0071 is targeted to the midbody to induce RhoA activation. We show that Ect2 precedes p0071 accumulation at the midbody and that targeting is mediated by different motor proteins. p0071 interacted with the kinesin-II family member KIF3b, and knockdown of KIF3b interfered with p0071 midbody recruitment whereas Ect2 or RhoA localization was not affected in these cells. Moreover, knockdown of KIF3b induced a similar phenotype as the p0071 knockdown, with reduced actin and phospho-myosin-light-chain accumulation at the midbody and decreased levels of active RhoA during cytokinesis. The lack of RhoA activation in KIF3b-deficient cells was not rescued by overexpression of wild-type p0071 but was substantially ameliorated by a p0071-MKLP1-motor-domain fusion protein that was targeted to the furrow independently of KIF3. These data indicate that p0071 and Ect2 are transported via distinct motors and identify a novel pathway implicating KIF3 in the regulation of actin organization during cytokinesis.
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Affiliation(s)
- René Keil
- Institute for Pathophysiology, Division of Pathobiochemistry, Martin-Luther-University Halle, 06114 Halle, Germany
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Hofmann I, Kuhn C, Franke WW. Protein p0071, a major plaque protein of non-desmosomal adhering junctions, is a selective cell-type marker. Cell Tissue Res 2008; 334:381-99. [PMID: 19005682 DOI: 10.1007/s00441-008-0725-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 10/14/2008] [Indexed: 12/01/2022]
Abstract
Protein p0071, which originally was introduced as a member of the p120-subfamily of armadillo proteins, common to desmosomes and adhaerens junctions (AJs) and to several other cell structures (centrosomes, midbodies), has been localized by using a series of novel mono- and polyclonal antibodies generated against various domains of the molecule. By protein analysis and immunolocalization techniques, protein p0071 has been localized as a plaque protein in AJs of diverse epithelia and certain vascular endothelia, in the composite junctions (areal compositae) of the intercalated disks of cardiomyocytes, and in the punctate or more extended AJs of the vast majority of cell culture types examined, including mitotic states. Using these antibodies, we have also shown that this AJ protein occurs only rarely or is even absent in tissues such as skeletal and smooth muscles, in a series of mesenchymal tissue cells, and in specific desmosome-rich cells such as those of the upper layers of the epidermis and certain other stratified epithelia and Hassall corpuscles of the thymus. We have also demonstrated that p0071 is absent from desmosomes. The occurrence of two major subtypes of lymphatic endothelial cells, one with AJs containing p0071 and one without detectable p0071, is emphasized. Possible structural and functional roles of p0071 are discussed in light of these new findings regarding its localization, and the addition of p0071 to the armamentarium of cytodiagnostic cell-type markers is recommended.
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Affiliation(s)
- Ilse Hofmann
- Joint Research Division Vascular Biology of the Medical Faculty Mannheim, University of Heidelberg, German Cancer Research Center (DKFZ) at Mannheim, CBTM, Ludolf-Krehl-Strasse 13-17, 68167 Mannheim, Germany.
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Asiedu M, Wu D, Matsumura F, Wei Q. Phosphorylation of MyoGEF on Thr-574 by Plk1 promotes MyoGEF localization to the central spindle. J Biol Chem 2008; 283:28392-400. [PMID: 18694934 PMCID: PMC2568926 DOI: 10.1074/jbc.m801801200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 08/05/2008] [Indexed: 01/13/2023] Open
Abstract
We reported previously that a guanine nucleotide exchange factor, MyoGEF, localizes to the central spindle, activates RhoA, and is required for cytokinesis. In this study, we have found that Plk1 (polo-like kinase 1) can phosphorylate MyoGEF, thereby recruiting MyoGEF to the central spindle as well as enhancing MyoGEF activity toward RhoA. The in vitro kinase assay shows that Plk1 can phosphorylate MyoGEF on threonine 574. Immunoprecipitation/immunoblot analysis demonstrates that mutation of threonine 574 to alanine dramatically decreases threonine phosphorylation of MyoGEF in transfected HeLa cells, suggesting that threonine 574 is phosphorylated in vivo. Consistent with these observations, immunofluorescence shows that Plk1 and MyoGEF colocalize at the spindle pole and central spindle during mitosis and cytokinesis. Importantly, RNA interference-mediated depletion of Plk1 interferes with the localization of MyoGEF at the spindle pole and central spindle. Moreover, mutation of threonine 574 to alanine in MyoGEF or depletion of Plk1 by RNA interference leads to a decrease in MyoGEF activity toward RhoA in HeLa cells. Therefore, our results suggest that Plk1 can regulate MyoGEF activity and localization, contributing to the regulation of cytokinesis.
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Affiliation(s)
- Michael Asiedu
- Department of Biochemistry, Kansas State University, Manhattan, Kansas 66506, USA
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Loss of p120 catenin and links to mitotic alterations, inflammation, and skin cancer. Proc Natl Acad Sci U S A 2008; 105:15399-404. [PMID: 18809907 DOI: 10.1073/pnas.0807301105] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tumor formation involves epigenetic modifications and microenvironmental changes as well as cumulative genetic alterations encompassing somatic mutations, loss of heterozygosity, and aneuploidy. Here, we show that conditional targeting of p120 catenin in mice leads to progressive development of skin neoplasias associated with intrinsic NF-kappaB activation. We find that, similarly, squamous cell carcinomas in humans display altered p120 and activated NF-kappaB. We show that epidermal hyperproliferation arising from p120 loss can be abrogated by IkappaB kinase 2 inhibitors. Although this underscores the importance of this pathway, the role of NF-kappaB in hyperproliferation appears rooted in its impact on epidermal microenvironment because as p120-null keratinocytes display a growth-arrested phenotype in culture. We trace this to a mitotic defect, resulting in unstable, binucleated cells in vitro and in vivo. We show that the abnormal mitoses can be ameliorated by inhibiting RhoA, the activity of which is abnormally high. Conversely, we can elicit such mitotic defects in control keratinocytes by elevating RhoA activity. The ability of p120 deficiency to elicit mitotic alterations and chronic inflammatory responses, that together may facilitate the development of genetic instability in vivo, provides insights into why it figures so prominently in skin cancer progression.
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Papazyan R, Doche M, Waldron RT, Rozengurt E, Moyer MP, Rey O. Protein kinase D isozymes activation and localization during mitosis. Exp Cell Res 2008; 314:3057-68. [PMID: 18692497 DOI: 10.1016/j.yexcr.2008.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 07/01/2008] [Accepted: 07/15/2008] [Indexed: 01/02/2023]
Abstract
The protein kinase D (PKD) family consists of three serine/threonine protein kinases involved in the regulation of fundamental biological processes in response to their activation and intracellular redistribution. Although a substantial amount of information is available describing the mechanisms regulating the activation and intracellular distribution of the PKD isozymes during interphase, nothing is known of their activation status, localization and role during mitosis. The results presented in this study indicate that during mitosis, PKD3 and PKD are phosphorylated at Ser(731) and Ser(744) within their activation loop by a mechanism that requires protein kinase C. Mitosis-associated PKD3 Ser(731) and PKD Ser(744) phosphorylation is related to the catalytic activation of these kinases as evidenced by in vivo phosphorylation of histone deacetylase 5, a substrate of PKD and PKD3. Activation loop-phosphorylated PKD3 and PKD, as well as PKD2, associate with centrosomes, spindles and midbody suggesting that these activated kinases establish dynamic interactions with the mitotic apparatus. Thus, this study reveals a connection between the PKD isozymes and cell division, suggesting a novel role for this family of serine/threonine kinases.
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Affiliation(s)
- Romeo Papazyan
- Unit of Signal Transduction and Gastrointestinal Cancer, Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, 90095-1786, USA
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Mueller AM, Pedré X, Stempfl T, Kleiter I, Couillard-Despres S, Aigner L, Giegerich G, Steinbrecher A. Novel role for SLPI in MOG-induced EAE revealed by spinal cord expression analysis. J Neuroinflammation 2008; 5:20. [PMID: 18501024 PMCID: PMC2438345 DOI: 10.1186/1742-2094-5-20] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Accepted: 05/26/2008] [Indexed: 11/10/2022] Open
Abstract
Background Experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte protein (MOG) in female Dark Agouti (DA) rats is a chronic demyelinating animal model of multiple sclerosis (MS). To identify new candidate molecules involved in the evolution or repair of EAE-lesions we used Affymetrix oligonucleotide microarrays to compare the spinal cord transcriptome at the peak of EAE, during remission and at the first relapse with healthy DA rats. Methods Untreated DA rats and DA rats immunised with MOG protein were sacrificed at defined time points. Total RNA was isolated from spinal cord tissue and used for hybridization of Affymetrix rat genome arrays RG U34 A-C. Selected expression values were confirmed by RealTime PCR. Adult neural stem cells were incubated with recombinant secretory leukocyte protease inhibitor (SLPI). Proliferation was assessed by BrdU incorporation, cyclin D1 and HES1 expression by RealTime PCR, cell differentiation by immunofluorescence analysis and IkappaBalpha degradation by Western blot. Results Among approximately 26,000 transcripts studied more than 1,100 were differentially regulated. Focussing on functional themes, we noticed a sustained downregulation of most of the transcripts of the cholesterol biosynthesis pathway. Furthermore, we found new candidate genes possibly contributing to regenerative processes in the spinal cord. Twelve transcripts were solely upregulated in the recovery phase, including genes not previously associated with repair processes. Expression of SLPI was upregulated more than hundredfold during EAE attack. Using immunohistochemistry, SLPI was identified in macrophages, activated microglia, neuronal cells and astrocytes. Incubation of adult neural stem cells (NSC) with recombinant SLPI resulted in an increase of cell proliferation and of differentiation towards oligodendrocytes. These processes were paralleled by an upregulation of the cell-cycle promotor cyclin D1 and a suppression of the cell differentiation regulator HES1. Finally, SLPI prevented the degradation of IkappaBalpha, which may explain the suppression of the cell differentiation inhibitor HES1 suggesting a possible mechanism of oligodendroglial differentiation. Conclusion We identified novel features of gene expression in the CNS during EAE, in particular the suppression of genes of cholesterol biosynthesis and a strong upregulation of SLPI, a gene which is for the first time associated with autoimmune inflammation. The capacity of SLPI to increase proliferation of adult NSC and of oligodendroglial differentiation suggests a novel role for SLPI in the promotion of tissue repair, beyond its known functions in the prevention of tissue damages by protease inhibition damage and modulation of inflammatory reactions.
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Affiliation(s)
- Andre M Mueller
- Department of Neurology, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
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Mruk DD, Silvestrini B, Cheng CY. Anchoring junctions as drug targets: role in contraceptive development. Pharmacol Rev 2008; 60:146-80. [PMID: 18483144 DOI: 10.1124/pr.107.07105] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In multicellular organisms, cell-cell interactions are mediated in part by cell junctions, which underlie tissue architecture. Throughout spermatogenesis, for instance, preleptotene leptotene spermatocytes residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier to enter the adluminal compartment for continued development. At the same time, germ cells must also remain attached to Sertoli cells, and numerous studies have reported extensive restructuring at the Sertoli-Sertoli and Sertoli-germ cell interface during germ cell movement across the seminiferous epithelium. Furthermore, the proteins and signaling cascades that regulate adhesion between testicular cells have been largely delineated. These findings have unveiled a number of potential "druggable" targets that can be used to induce premature release of germ cells from the seminiferous epithelium, resulting in transient infertility. Herein, we discuss a novel approach with the aim of developing a nonhormonal male contraceptive for future human use, one that involves perturbing adhesion between Sertoli and germ cells in the testis.
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Affiliation(s)
- Dolores D Mruk
- Population Council, Center for Biomedical Research, The Mary M Wohlford Laboratory for Male Contraceptive Research, 1230 York Avenue, New York, NY 10065, USA.
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50
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Bass-Zubek AE, Hobbs RP, Amargo EV, Garcia NJ, Hsieh SN, Chen X, Wahl JK, Denning MF, Green KJ. Plakophilin 2: a critical scaffold for PKC alpha that regulates intercellular junction assembly. ACTA ACUST UNITED AC 2008; 181:605-13. [PMID: 18474624 PMCID: PMC2386101 DOI: 10.1083/jcb.200712133] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plakophilins (PKPs) are armadillo family members related to the classical cadherin-associated protein p120ctn. PKPs localize to the cytoplasmic plaque of intercellular junctions and participate in linking the intermediate filament (IF)-binding protein desmoplakin (DP) to desmosomal cadherins. In response to cell–cell contact, PKP2 associates with DP in plaque precursors that form in the cytoplasm and translocate to nascent desmosomes. Here, we provide evidence that PKP2 governs DP assembly dynamics by scaffolding a DP–PKP2–protein kinase Cα (PKCα) complex, which is disrupted by PKP2 knockdown. The behavior of a phosphorylation-deficient DP mutant that associates more tightly with IF is mimicked by PKP2 and PKCα knockdown and PKC pharmacological inhibition, all of which impair junction assembly. PKP2 knockdown is accompanied by increased phosphorylation of PKC substrates, raising the possibility that global alterations in PKC signaling may contribute to pathogenesis of congenital defects caused by PKP2 deficiency.
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Affiliation(s)
- Amanda E Bass-Zubek
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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