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Verdys P, Rey Barroso J, Girel A, Vermeil J, Bergert M, Sanchez T, Métais A, Mangeat T, Bellard E, Bigot C, Astarie-Dequeker C, Labrousse A, Girard JP, Maridonneau-Parini I, Vérollet C, Lagarrigue F, Diz-Muñoz A, Heuvingh J, Piel M, du Roure O, Le Cabec V, Carréno S, Poincloux R. Ezrin, radixin, and moesin are dispensable for macrophage migration and cellular cortex mechanics. EMBO J 2024:10.1038/s44318-024-00173-7. [PMID: 39026000 DOI: 10.1038/s44318-024-00173-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 06/17/2024] [Accepted: 07/01/2024] [Indexed: 07/20/2024] Open
Abstract
The cellular cortex provides crucial mechanical support and plays critical roles during cell division and migration. The proteins of the ERM family, comprised of ezrin, radixin, and moesin, are central to these processes by linking the plasma membrane to the actin cytoskeleton. To investigate the contributions of the ERM proteins to leukocyte migration, we generated single and triple ERM knockout macrophages. Surprisingly, we found that even in the absence of ERM proteins, macrophages still form the different actin structures promoting cell migration, such as filopodia, lamellipodia, podosomes, and ruffles. Furthermore, we discovered that, unlike every other cell type previously investigated, the single or triple knockout of ERM proteins does not affect macrophage migration in diverse contexts. Finally, we demonstrated that the loss of ERMs in macrophages does not affect the mechanical properties of their cortex. These findings challenge the notion that ERMs are universally essential for cortex mechanics and cell migration and support the notion that the macrophage cortex may have diverged from that of other cells to allow for their uniquely adaptive cortical plasticity.
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Affiliation(s)
- Perrine Verdys
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Canada
| | - Javier Rey Barroso
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Adeline Girel
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Joseph Vermeil
- PMMH, ESPCI Paris, PSL University, CNRS, Université Paris Cité, Sorbonne Université, Paris, France
| | - Martin Bergert
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Thibaut Sanchez
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Arnaud Métais
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Thomas Mangeat
- LITC Core Facility, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | - Elisabeth Bellard
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Claire Bigot
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Catherine Astarie-Dequeker
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Arnaud Labrousse
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Jean-Philippe Girard
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
- Equipe Labellisée Ligue Contre le Cancer, Paris, France
| | - Isabelle Maridonneau-Parini
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Christel Vérollet
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Frédéric Lagarrigue
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
| | - Alba Diz-Muñoz
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Julien Heuvingh
- PMMH, ESPCI Paris, PSL University, CNRS, Université Paris Cité, Sorbonne Université, Paris, France
| | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL University, CNRS, Paris, France
| | - Olivia du Roure
- PMMH, ESPCI Paris, PSL University, CNRS, Université Paris Cité, Sorbonne Université, Paris, France
| | - Véronique Le Cabec
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France.
| | - Sébastien Carréno
- Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Canada.
| | - Renaud Poincloux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France.
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2
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Dufrancais O, Verdys P, Métais A, Juzans M, Sanchez T, Bergert M, Plozza M, Halper J, Panebianco CJ, Mascarau R, Gence R, Arnaud G, Neji MB, Maridonneau-Parini I, Cabec VL, Boerckel JD, Pavlos NJ, Diz-Muñoz A, Lagarrigue F, Blin-Wakkach C, Carréno S, Poincloux R, Burkhardt JK, Raynaud-Messina B, Vérollet C. Moesin activation controls bone resorption and tunneling nanotube-dependent osteoclast fusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593799. [PMID: 38798563 PMCID: PMC11118517 DOI: 10.1101/2024.05.13.593799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Osteoclasts are multinucleated cells unique in their ability to resorb bone. Osteoclastogenesis involves several steps of actin-driven rearrangements that participate not only in the cell-cell fusion process, but also in the formation of the sealing zone, the adhesive structure determining the resorption area. Despite the importance of these actin cytoskeleton-based processes, their precise mechanisms of regulation are still poorly characterized. Here, we found that moesin, a member of the Ezrin/Radixin/Moesin (ERM) protein family, is activated during osteoclast maturation and plays an instrumental role for both osteoclast fusion and function. In mouse and human osteoclast precursors, moesin is negatively regulated to potentiate their ability to fuse and degrade bone. Accordingly, we demonstrated that moesin depletion decreases membrane-to-cortex attachment and enhances formation of tunneling nanotubes (TNTs), F-actin-containing intercellular bridges that we revealed to trigger osteoclast fusion. In addition, via a β3-integrin/RhoA/SLK pathway and independently of its role in fusion, moesin regulates the number and organization of sealing zones in mature osteoclast, and thus participates in the control of bone resorption. Supporting these findings, we found that moesin-deficient mice are osteopenic with a reduced density of trabecular bones and increased osteoclast abundance and activity. These findings provide a better understanding of the regulation of osteoclast biology, and open new opportunities to specifically target osteoclast activity in bone disease therapy.
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3
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Abstract
T cell activation is initiated by the recognition of specific antigenic peptides and subsequently accomplished by complex signaling cascades. These aspects have been extensively studied for decades as pivotal factors in the establishment of adaptive immunity. However, how receptors or signaling molecules are organized in the resting state prior to encountering antigens has received less attention. Recent advancements in super-resolution microscopy techniques have revealed topographically controlled pre-formed organization of key molecules involved in antigen recognition and signal transduction on microvillar projections of T cells before activation and substantial effort has been dedicated to characterizing the topological structure of resting T cells over the past decade. This review will summarize our current understanding of how key surface receptors are pre-organized on the T-cell plasma membrane and discuss the potential role of these receptors, which are preassembled prior to ligand binding in the early activation events of T cells.
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Affiliation(s)
- Yunmin Jung
- Department of Nano-Biomedical Engineering, Advanced Science Institute, Yonsei University, Seoul, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science, Seoul, Republic of Korea
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4
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Winkenbach LP, Parker DM, Williams RTP, Nishimura EO. The ERM-1 membrane-binding domain directs erm-1 mRNA localization to the plasma membrane in the C. elegans embryo. Development 2022; 149:279335. [PMID: 36314842 PMCID: PMC9793419 DOI: 10.1242/dev.200930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
mRNA localization and transport are integral in regulating gene expression. In Caenorhabditis elegans embryos, the maternally inherited mRNA erm-1 (Ezrin/Radixin/Moesin) becomes concentrated in anterior blastomeres. erm-1 mRNA localizes within those blastomeres to the plasma membrane where the essential ERM-1 protein, a membrane-actin linker, is also found. We demonstrate that the localization of erm-1 mRNA to the plasma membrane is translation dependent and requires its encoded N-terminal, membrane-binding (FERM) domain. By perturbing translation through multiple methods, we found that erm-1 mRNA localization at the plasma membrane persisted only if the nascent peptide remained in complex with the translating mRNA. Indeed, re-coding the erm-1 mRNA coding sequence while preserving the encoded amino acid sequence did not disrupt erm-1 mRNA localization, corroborating that the information directing mRNA localization resides within its membrane-binding protein domain. A single-molecule inexpensive fluorescence in situ hybridization screen of 17 genes encoding similar membrane-binding domains identified three plasma membrane-localized mRNAs in the early embryo. Ten additional transcripts showed potential membrane localization later in development. These findings point to a translation-dependent pathway for localization of mRNAs encoding membrane-associated proteins.
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Affiliation(s)
- Lindsay P. Winkenbach
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Dylan M. Parker
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA,Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80303, USA
| | - Robert T. P. Williams
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Erin Osborne Nishimura
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA,Author for correspondence ()
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5
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Moesin Serves as Scaffold Protein for PD-L1 in Human Uterine Cervical Squamous Carcinoma Cells. J Clin Med 2022; 11:jcm11133830. [PMID: 35807113 PMCID: PMC9267616 DOI: 10.3390/jcm11133830] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/17/2022] [Accepted: 06/30/2022] [Indexed: 02/04/2023] Open
Abstract
Immune checkpoint blockade (ICB) therapy targeting the programmed death ligand-1 (PD-L1)/PD-1 axis has emerged as a promising treatment for uterine cervical cancer; however, only a small subset of patients with uterine cervical squamous cell carcinoma (SCC) derives clinical benefit from ICB therapies. Thus, there is an urgent unmet medical need for novel therapeutic strategies to block the PD-L1/PD-1 axis in patients with uterine cervical SCC. Here, we investigated the involvement of ezrin/radixin/moesin (ERM) family scaffold proteins, which crosslink several plasma membrane proteins with the actin cytoskeleton, on the plasma membrane localization of PD-L1 in BOKU and HCS-2 cells derived from human uterine cervical SCC. Immunofluorescence analysis showed that PD-L1 colocalized with all three ERM proteins in the plasma membrane. Gene knockdown of moesin, but not ezrin and radixin, substantially reduced the plasma membrane expression of PD-L1, with limited effect on mRNA expression. An immunoprecipitation assay demonstrated the molecular interaction between PD-L1 and moesin. Moreover, phosphorylated, i.e., activated, moesin was highly colocalized with PD-L1 in the plasma membrane. In conclusion, moesin may be a scaffold protein responsible for the plasma membrane expression of PD-L1 in human uterine cervical SCC.
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6
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Membrane Homeostasis: The Role of Actin Cytoskeleton. J Indian Inst Sci 2021. [DOI: 10.1007/s41745-020-00217-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Lee H, Yu D, Park JS, Lee H, Kim J, Kim HL, Koo S, Lee J, Lee S, Ko Y. Prominin-1-Radixin axis controls hepatic gluconeogenesis by regulating PKA activity. EMBO Rep 2020; 21:e49416. [PMID: 33030802 PMCID: PMC7645247 DOI: 10.15252/embr.201949416] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 08/31/2020] [Accepted: 09/10/2020] [Indexed: 12/18/2022] Open
Abstract
Prominin-1 (Prom1) is a major cell surface marker of cancer stem cells, but its physiological functions in the liver have not been elucidated. We analyzed the levels of mRNA transcripts in serum-starved primary WT (Prom1+/+ ) and KO (Prom1-/- ) mouse hepatocytes using RNA sequencing (RNA-seq) data, and found that CREB target genes were downregulated. This initial observation led us to determine that Prom1 deficiency inhibited cAMP response element-binding protein (CREB) activation and gluconeogenesis, but not cyclic AMP (cAMP) accumulation, in glucagon-, epinephrine-, or forskolin-treated liver tissues and primary hepatocytes, and mitigated glucagon-induced hyperglycemia. Because Prom1 interacted with radixin, Prom1 deficiency prevented radixin from localizing to the plasma membrane. Moreover, systemic adenoviral knockdown of radixin inhibited CREB activation and gluconeogenesis in glucagon-treated liver tissues and primary hepatocytes, and mitigated glucagon-elicited hyperglycemia. Based on these results, we conclude that Prom1 regulates hepatic PKA signaling via radixin functioning as an A kinase-anchored protein (AKAP).
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Affiliation(s)
- Hyun Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Dong‐Min Yu
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jun Sub Park
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Hwayeon Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jun‐Seok Kim
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Hong Lim Kim
- Laboratory of Electron MicroscopeIntegrative Research Support CenterCollege of MedicineThe Catholic University of KoreaSeoulKorea
| | - Seung‐Hoi Koo
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jae‐Seon Lee
- Department of Molecular MedicineInha University College of MedicineIncheonKorea
- Hypoxia‐related Disease Research CenterInha University College of MedicineIncheonKorea
| | - Sungsoo Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Young‐Gyu Ko
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
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8
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ERM Proteins at the Crossroad of Leukocyte Polarization, Migration and Intercellular Adhesion. Int J Mol Sci 2020; 21:ijms21041502. [PMID: 32098334 PMCID: PMC7073024 DOI: 10.3390/ijms21041502] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Ezrin, radixin and moesin proteins (ERMs) are plasma membrane (PM) organizers that link the actin cytoskeleton to the cytoplasmic tail of transmembrane proteins, many of which are adhesion receptors, in order to regulate the formation of F-actin-based structures (e.g., microspikes and microvilli). ERMs also effect transmission of signals from the PM into the cell, an action mainly exerted through the compartmentalized activation of the small Rho GTPases Rho, Rac and Cdc42. Ezrin and moesin are the ERMs more highly expressed in leukocytes, and although they do not always share functions, both are mainly regulated through phosphatidylinositol 4,5-bisphosphate (PIP2) binding to the N-terminal band 4.1 protein-ERM (FERM) domain and phosphorylation of a conserved Thr in the C-terminal ERM association domain (C-ERMAD), exerting their functions through a wide assortment of mechanisms. In this review we will discuss some of these mechanisms, focusing on how they regulate polarization and migration in leukocytes, and formation of actin-based cellular structures like the phagocytic cup-endosome and the immune synapse in macrophages/neutrophils and lymphocytes, respectively, which represent essential aspects of the effector immune response.
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9
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Zhou Y, Lutz PE, Wang YC, Ragoussis J, Turecki G. Global long non-coding RNA expression in the rostral anterior cingulate cortex of depressed suicides. Transl Psychiatry 2018; 8:224. [PMID: 30337518 PMCID: PMC6193959 DOI: 10.1038/s41398-018-0267-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/10/2018] [Accepted: 09/10/2018] [Indexed: 01/17/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) are an emerging class of regulatory RNA that may be implicated in psychiatric disorders. Here we performed RNA-sequencing in the rostral anterior cingulate cortex of 26 depressed suicides and 24 matched controls. We first performed differential lncRNA expression analysis, and then conducted Weighted Gene Co-expression Network Analysis (WGCNA) to identify co-expression modules associating with depression and suicide. We identified 23 differentially expressed lncRNAs (FDR < 0.1) as well as their differentially expressed overlapping and antisense protein-coding genes. Several of these overlapping or antisense genes were associated with interferon signaling, which is a component of the innate immune response. Using WGCNA, we identified modules of highly co-expressed genes associated with depression and suicide and found protein-coding genes highly connected to differentially expressed lncRNAs within these modules. These protein-coding genes were located distal to their associated lncRNAs and were found to be part of several GO terms enriched in the significant modules, which include: cytoskeleton organization, plasma membrane, cell adhesion, nucleus, DNA-binding, and regulation of dendrite development and morphology. Altogether, we report that lncRNAs are differentially expressed in the brains of depressed individuals who died by suicide and may represent regulators of important molecular functions and biological processes.
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Grants
- R01 DA033684 NIDA NIH HHS
- Dr. G. Turecki holds a Canada Research Chair (Tier 1), FRQS Chercheur National salary award and a NARSAD Distinguished Investigator Award; he is supported by grants FDN148374, MOP93775, MOP11260, MOP119429, and MOP119430 from CIHR, by NIH grant 1R01DA033684, by the FRQS through the Quebec Network on Suicide, Mood Disorders, and Related Disorders, and through an investigator-initiated research grant from Pfizer
- Scholarships from the Fondation Fyssen, the Fondation Bettencourt-Schueller, the Canadian Institutes of Health Research, the American Foundation of Suicide Prevention, the Fondation Deniker and the Fondation pour la Recherche Médicale.
- CFI grant number 32557 and Genome Canada Genome Innovation Node awards.
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Affiliation(s)
- Yi Zhou
- McGill Group for Suicide Studies, McGill University, 6875 LaSalle Boulevard, Montreal, QC, H4H 1R3, Canada
| | - Pierre-Eric Lutz
- McGill Group for Suicide Studies, McGill University, 6875 LaSalle Boulevard, Montreal, QC, H4H 1R3, Canada
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Yu Chang Wang
- McGill University and Génome Québec Innovation Centre, 740 Dr. Penfield Avenue, Room 7104, Montréal, QC, H3A 0G1, Canada
| | - Jiannis Ragoussis
- McGill University and Génome Québec Innovation Centre, 740 Dr. Penfield Avenue, Room 7104, Montréal, QC, H3A 0G1, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, McGill University, 6875 LaSalle Boulevard, Montreal, QC, H4H 1R3, Canada.
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10
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Hiruma S, Kamasaki T, Otomo K, Nemoto T, Uehara R. Dynamics and function of ERM proteins during cytokinesis in human cells. FEBS Lett 2017; 591:3296-3309. [DOI: 10.1002/1873-3468.12844] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/31/2017] [Accepted: 09/01/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Shota Hiruma
- Graduate School of Life Science; Hokkaido University; Japan
| | | | - Kohei Otomo
- Research Institute for Electronic Science; Hokkaido University; Japan
| | - Tomomi Nemoto
- Research Institute for Electronic Science; Hokkaido University; Japan
| | - Ryota Uehara
- Graduate School of Life Science; Hokkaido University; Japan
- Creative Research Institution; Hokkaido University; Japan
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11
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Bledzka K, Bialkowska K, Sossey-Alaoui K, Vaynberg J, Pluskota E, Qin J, Plow EF. Kindlin-2 directly binds actin and regulates integrin outside-in signaling. J Cell Biol 2016; 213:97-108. [PMID: 27044892 PMCID: PMC4828686 DOI: 10.1083/jcb.201501006] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 02/22/2016] [Indexed: 02/07/2023] Open
Abstract
Bledzka et al. show that kindlin-2 binds actin via its F0 domain, and mutation of this site diminishes cell spreading, revealing a new mechanism by which kindlin-2 regulates cellular responses. Reduced levels of kindlin-2 (K2) in endothelial cells derived from K2+/− mice or C2C12 myoblastoid cells treated with K2 siRNA showed disorganization of their actin cytoskeleton and decreased spreading. These marked changes led us to examine direct binding between K2 and actin. Purified K2 interacts with F-actin in cosedimentation and surface plasmon resonance analyses and induces actin aggregation. We further find that the F0 domain of K2 binds actin. A mutation, LK47/AA, within a predicted actin binding site (ABS) of F0 diminishes its interaction with actin by approximately fivefold. Wild-type K2 and K2 bearing the LK47/AA mutation were equivalent in their ability to coactivate integrin αIIbβ3 in a CHO cell system when coexpressed with talin. However, K2-LK47/AA exhibited a diminished ability to support cell spreading and actin organization compared with wild-type K2. The presence of an ABS in F0 of K2 that influences outside-in signaling across integrins establishes a new foundation for considering how kindlins might regulate cellular responses.
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Affiliation(s)
- Kamila Bledzka
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Katarzyna Bialkowska
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Khalid Sossey-Alaoui
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Julia Vaynberg
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Elzbieta Pluskota
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Jun Qin
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Edward F Plow
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
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12
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Gungor-Ordueri NE, Celik-Ozenci C, Cheng CY. Ezrin: a regulator of actin microfilaments in cell junctions of the rat testis. Asian J Androl 2016; 17:653-8. [PMID: 25652626 PMCID: PMC4492059 DOI: 10.4103/1008-682x.146103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ezrin, radixin, moesin and merlin (ERM) proteins are highly homologous actin-binding proteins that share extensive sequence similarity with each other. These proteins tether integral membrane proteins and their cytoplasmic peripheral proteins (e.g., adaptors, nonreceptor protein kinases and phosphatases) to the microfilaments of actin-based cytoskeleton. Thus, these proteins are crucial to confer integrity of the apical membrane domain and its associated junctional complex, namely the tight junction and the adherens junction. Since ectoplasmic specialization (ES) is an F-actin-rich testis-specific anchoring junction-a highly dynamic ultrastructure in the seminiferous epithelium due to continuous transport of germ cells, in particular spermatids, across the epithelium during the epithelial cycle-it is conceivable that ERM proteins are playing an active role in these events. Although these proteins were first reported almost 25 years and have since been extensively studied in multiple epithelia/endothelia, few reports are found in the literature to examine their role in the actin filament bundles at the ES. Studies have shown that ezrin is also a constituent protein of the actin-based tunneling nanotubes (TNT) also known as intercellular bridges, which are transient cytoplasmic tubular ultrastructures that transport signals, molecules and even organelles between adjacent and distant cells in an epithelium to coordinate cell events that occur across an epithelium. Herein, we critically evaluate recent data on ERM in light of recent findings in the field in particular ezrin regarding its role in actin dynamics at the ES in the testis, illustrating additional studies are warranted to examine its physiological significance in spermatogenesis.
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Affiliation(s)
| | | | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, USA
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13
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Kannan N, Tang VW. Synaptopodin couples epithelial contractility to α-actinin-4-dependent junction maturation. J Cell Biol 2016; 211:407-34. [PMID: 26504173 PMCID: PMC4621826 DOI: 10.1083/jcb.201412003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A novel tension-sensitive junctional protein, synaptopodin, can relay biophysical input from cellular actomyosin contractility to induce biochemical changes at cell–cell contacts, resulting in structural reorganization of the junctional complex and epithelial barrier maturation. The epithelial junction experiences mechanical force exerted by endogenous actomyosin activities and from interactions with neighboring cells. We hypothesize that tension generated at cell–cell adhesive contacts contributes to the maturation and assembly of the junctional complex. To test our hypothesis, we used a hydraulic apparatus that can apply mechanical force to intercellular junction in a confluent monolayer of cells. We found that mechanical force induces α-actinin-4 and actin accumulation at the cell junction in a time- and tension-dependent manner during junction development. Intercellular tension also induces α-actinin-4–dependent recruitment of vinculin to the cell junction. In addition, we have identified a tension-sensitive upstream regulator of α-actinin-4 as synaptopodin. Synaptopodin forms a complex containing α-actinin-4 and β-catenin and interacts with myosin II, indicating that it can physically link adhesion molecules to the cellular contractile apparatus. Synaptopodin depletion prevents junctional accumulation of α-actinin-4, vinculin, and actin. Knockdown of synaptopodin and α-actinin-4 decreases the strength of cell–cell adhesion, reduces the monolayer permeability barrier, and compromises cellular contractility. Our findings underscore the complexity of junction development and implicate a control process via tension-induced sequential incorporation of junctional components.
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Affiliation(s)
- Nivetha Kannan
- Program in Global Public Health, University of Illinois, Urbana-Champaign, Champaign, IL 61801
| | - Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Champaign, IL 61801
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14
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Pore D, Gupta N. The ezrin-radixin-moesin family of proteins in the regulation of B-cell immune response. Crit Rev Immunol 2016; 35:15-31. [PMID: 25746045 DOI: 10.1615/critrevimmunol.2015012327] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Dynamic reorganization of the cortical cytoskeleton is essential for numerous cellular processes, including B- and T-cell activation and migration. The ezrin-radixin-moesin (ERM) family of proteins plays structural and regulatory roles in the rearrangement of plasma membrane flexibility and protrusions through its members' reversible interaction with cortical actin filaments and the plasma membrane. Recent studies demonstrated that ERM proteins not only are involved in cytoskeletal organization but also offer a platform for the transmission of signals in response to a variety of extracellular stimuli through their ability to cross-link transmembrane receptors with downstream signaling components. In this review, we summarize present knowledge relating to ERMs and recent progress made toward elucidating a novel role for them in the regulation of B-cell function in health and disease.
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Affiliation(s)
- Debasis Pore
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Neetu Gupta
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
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15
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Krzyzanowska A, García-Consuegra I, Pascual C, Antequera D, Ferrer I, Carro E. Expression of regulatory proteins in choroid plexus changes in early stages of Alzheimer disease. J Neuropathol Exp Neurol 2015; 74:359-69. [PMID: 25756589 DOI: 10.1097/nen.0000000000000181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Recent studies indicate that the choroid plexus has important physiologic and pathologic roles in Alzheimer disease (AD). To obtain additional insight on choroid plexus function, we performed a proteomic analysis of choroid plexus samples from patients with AD stages I to II (n = 16), III to IV (n = 16), and V to VI (n = 11) and 7 age-matched control subjects. We used 2-dimensional differential gel electrophoresis coupled with mass spectrometry to generate a complete picture of changes in choroid plexus protein expression occurring in AD patients. We identified 6 proteins: 14-3-3 β/α, 14-3-3 ε, moesin, proteasome activator complex subunit 1, annexin V, and aldehyde dehydrogenase, which were significantly regulated in AD patient samples (p < 0.05, >1.5-fold variation in expression vs control samples). These proteins are implicated in major physiologic functions including mitochondrial dysfunction and apoptosis regulation. These findings contribute additional significance to the emerging importance of molecular and functional changes of choroid plexus function in the pathophysiology of AD.
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Affiliation(s)
- Agnieszka Krzyzanowska
- From the Neuroscience Group, Research Institute Hospital; Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED); and Proteomic Unit, Research Institute Hospital, Madrid; and Institut de Neuropatologia, IDIBELL-Hospital Universitari de Bellvitge; and Universitat de Barcelona, Hospitalet de Llobregat, Barcelona, Spain
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16
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Bosanquet DC, Ye L, Harding KG, Jiang WG. FERM family proteins and their importance in cellular movements and wound healing (review). Int J Mol Med 2014; 34:3-12. [PMID: 24820650 DOI: 10.3892/ijmm.2014.1775] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 03/10/2014] [Indexed: 11/06/2022] Open
Abstract
Motility is a requirement for a number of biological processes, including embryonic development, neuronal development, immune responses, cancer progression and wound healing. Specific to wound healing is the migration of endothelial cells, fibroblasts and other key cellular players into the wound space. Aberrations in wound healing can result in either chronic wounds or abnormally healed wounds. The protein 4.1R, ezrin, radixin, moesin (FERM) superfamily consists of over 40 proteins all containing a three lobed N-terminal FERM domain which binds a variety of cell-membrane associated proteins and lipids. The C-terminal ends of these proteins typically contain an actin-binding domain (ABD). These proteins therefore mediate the linkage between the cell membrane and the actin cytoskeleton, and are involved in cellular movements and migration. Certain FERM proteins have been shown to promote cancer metastasis via this very mechanism. Herein we review the effects of a number of FERM proteins on wound healing and cancer. We show how these proteins typically aid wound healing through their effects on increasing cellular migration and movements, but also typically promote metastasis in cancer. We conclude that FERM proteins play important roles in cellular migration, with markedly different outcomes in the context of cancer and wound healing.
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Affiliation(s)
- David C Bosanquet
- Departments of Surgery and Wound Healing, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XW, UK
| | - Lin Ye
- Departments of Surgery and Wound Healing, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XW, UK
| | - Keith G Harding
- Departments of Surgery and Wound Healing, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XW, UK
| | - Wen G Jiang
- Departments of Surgery and Wound Healing, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XW, UK
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17
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Affiliation(s)
- Andrea I McClatchey
- MGH Center for Cancer Research and Harvard Medical School, Department of Pathology, Charlestown, MA 02129, USA.
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18
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Clapéron A, Debray D, Redon MJ, Mergey M, Ho-Bouldoires THN, Housset C, Fabre M, Fouassier L. Immunohistochemical profile of ezrin and radixin in human liver epithelia during fetal development and pediatric cholestatic diseases. Clin Res Hepatol Gastroenterol 2013; 37:142-51. [PMID: 23507543 DOI: 10.1016/j.clinre.2013.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 02/07/2013] [Indexed: 02/04/2023]
Abstract
AIM Ezrin and radixin are actin-binding proteins that contribute to the integrity of epithelia. Abnormalities of bile secretion occur primarily in cholestatic liver diseases and are associated with changes in cell cytoskeleton. Expression of these proteins during liver development and in cholestatic liver diseases remains poorly investigated. METHODS Ezrin and radixin expression was analyzed in fetal, adult and pediatric cholestatic human liver (i.e. biliary atresia, sclerosing cholangitis) by immunohistochemistry. RESULTS In adult and fetal livers, ezrin was expressed exclusively in the cells of the biliary lineage (i.e. biliary epithelial cells and ductal cells) whereas radixin was located not only in hepatocytes but also in cells of the biliary lineage. In the lobule of mature livers, radixin displayed a zonal distribution with predominant expression in the periportal region. In cholestatic diseases, both proteins were expressed in cells of the ductular reaction. An aberrant expression of ezrin was detected in hepatocytes of cirrhotic nodules with a CK7-positive pattern and in malignant hepatocytes in a course of cholestatic disease toward cancer. CONCLUSIONS Among the components of the liver epithelial cells, ezrin was exclusively expressed in biliary phenotype cells, while radixin was found in biliary and hepatocytic lineages, with a periportal zonal expression. In cholestatic diseases, ezrin was expressed in hepatocytes supporting the appearance of a biliary phenotype.
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Affiliation(s)
- Audrey Clapéron
- INSERM, UMR_S 938, CdR Saint-Antoine, faculté de médecine Pierre-et-Marie-Curie, site Saint-Antoine, 75012 Paris, France
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19
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Hsu YY, Shi GY, Kuo CH, Liu SL, Wu CM, Ma CY, Lin FY, Yang HY, Wu HL. Thrombomodulin is an ezrin-interacting protein that controls epithelial morphology and promotes collective cell migration. FASEB J 2012; 26:3440-52. [PMID: 22593542 DOI: 10.1096/fj.12-204917] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adhesive interactions between cells are needed to maintain tissue architecture during development, tissue renewal and wound healing. Thrombomodulin (TM) is an integral membrane protein that participates in cell-cell adhesion through its extracellular lectin-like domain. However, the molecular basis of TM-mediated cell-cell adhesion is poorly understood. Here, we demonstrate that TM is linked to the actin cytoskeleton via ezrin. In vitro binding assays showed that the TM cytoplasmic domain bound directly to the N-terminal domain of ezrin. Mutational analysis of the TM cytoplasmic domain identified (522)RKK(524) as important ezrin-binding residues. In epidermal epithelial A431 cells, TM colocalized with ezrin and actin filaments at cell-cell contacts. Knockdown of endogenous TM expression by RNA interference induced morphological changes and accelerated cell migration in A431 cells. Moreover, epidermal growth factor, upstream of ezrin activation, stimulated the interaction between ezrin and TM. In skin wound healing of mice, TM and ezrin were highly expressed in neoepidermis, implying that both proteins are key molecules in reepithelialization that requires collective cell migration of epithelial cells. Finally, exogenous expression of TM in TM-deficient melanoma A2058 cells promoted collective cell migration. In summary, TM, which associates with ezrin and actin filaments, maintains epithelial morphology and promotes collective cell migration.
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Affiliation(s)
- Yun-Yan Hsu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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20
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Activation of ezrin/radixin/moesin mediates attractive growth cone guidance through regulation of growth cone actin and adhesion receptors. J Neurosci 2012; 32:282-96. [PMID: 22219290 DOI: 10.1523/jneurosci.4794-11.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The development of a functioning neural network relies on responses of axonal growth cones to molecular guidance cues that are encountered en route to their target tissue. Nerve growth factor (NGF) and neurotrophin-3 serve as attractive cues for chick embryo sensory growth cones in vitro and in vivo, but little is known about the actin-binding proteins necessary to mediate this response. The evolutionarily conserved ezrin/radixin/moesin (ERM) family of proteins can tether actin filaments to the cell membrane when phosphorylated at a conserved threonine residue. Here we show that acute neurotrophin stimulation rapidly increases active phospho-ERM levels in chick sensory neuron growth cone filopodia, coincident with an increase in filopodial L1 and β-integrin. Disrupting ERM function with a dominant-negative construct (DN-ERM) results in smaller and less motile growth cones with disorganized actin filaments. Previously, we found that NGF treatment increases actin-depolymerizing factor (ADF)/cofilin activity and growth cone F-actin (Marsick et al., 2010). Here, we show this F-actin increase, as well as attractive turning to NGF, is blocked when ERM function is disrupted despite normal activation of ADF/cofilin. We further show that DN-ERM expression disrupts leading edge localization of active ADF/cofilin and free F-actin barbed ends. Moreover, filopodial phospho-ERM levels are increased by incorporation of active ADF/cofilin and reduced by knockdown of L1CAM.Together, these data suggest that ERM proteins organize actin filaments in sensory neuron growth cones and are crucial for neurotrophin-induced remodeling of F-actin and redistribution of adhesion receptors.
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21
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Enculescu M, Falcke M. Modeling morphodynamic phenotypes and dynamic regimes of cell motion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 736:337-58. [PMID: 22161339 DOI: 10.1007/978-1-4419-7210-1_20] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many cellular processes and signaling pathways converge onto cell morphology and cell motion, which share important components. The mechanisms used for propulsion could also be responsible for shape changes, if they are capable of generating the rich observed variety of dynamic regimes. Additionally, the analysis of cell shape changes in space and time promises insight into the state of the cytoskeleton and signaling pathways controlling it. While this has been obvious for some time by now, little effort has been made to systematically and quantitatively explore this source of information. First pioneering experimental work revealed morphodynamic phenotypes which can be associated with dynamic regimes like oscillations and excitability. Here, we review the current state of modeling of morphodynamic phenotypes, the experimental results and discuss the ideas on the mechanisms driving shape changes which are suggested by modeling.
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Affiliation(s)
- Mihaela Enculescu
- Institute for Theoretical Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany.
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22
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Tashiro E, Imoto M. Target identification of bioactive compounds. Bioorg Med Chem 2011; 20:1910-21. [PMID: 22104438 DOI: 10.1016/j.bmc.2011.10.081] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 10/17/2011] [Accepted: 10/30/2011] [Indexed: 12/31/2022]
Abstract
To fully understand the regulation of cellular events, functional analysis of each protein involved in the regulatory systems is required. Among a variety of methods to uncover protein function, chemical genetics is a remarkable approach in which small molecular compounds are used as probes to elucidate protein functions within signaling pathways. However, identifying the target of small molecular bioactive compounds isolated by cell-based assays represents a crucial hurdle that must be overcome before chemical genetic studies can commence. A variety of methods and technologies for identifying target proteins have been reported. This review therefore aims to describe approaches for identifying these molecular targets.
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Affiliation(s)
- Etsu Tashiro
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, Kanagawa 223-8522, Japan
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23
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FERNANDO HERMAN, MARTIN TRACEYA, DOUGLAS-JONES ANTHONY, KYNASTON HOWARDG, MANSEL ROBERTE, JIANG WENG. Expression of the ERM family members (ezrin, radixin and moesin) in breast cancer. Exp Ther Med 2010; 1:153-160. [PMID: 23136608 PMCID: PMC3490339 DOI: 10.3892/etm_00000025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 03/19/2009] [Indexed: 11/06/2022] Open
Abstract
The ERM family is composed of the proteins ezrin, moesin and radixin, which are cell structure-related proteins. Despite the detection of viable roles of ERM family proteins, the impact of these molecules in cancer pathogenesis has yet to be investigated. Evidence emerging from clinical and translational studies showed that the ERM family is linked to disease progression in clinical cancers. We aimed to establish the pattern of expression of the ERM proteins and deduce a possible relationship between these molecules and clinical outcome in a cohort of human breast cancers. The expression of the three ERM molecules at the mRNA and protein levels in a cohort of 122 human breast cancers and 32 normal breast tissues were analysed and correlated with pathological and clinical information as well as patient outcome. The three molecules were positively stained in mammary tissues while the staining pattern was lost in the malignant cells. Low levels of moesin and radixin transcripts were seen in tumours from patients with metastasis, local recurrence and in patients who succumbed to the disease (moesin: p=0.039, p=0.037 and p=0.066, respectively, and radixin: p=0.039, p=0.039 and p=0.04, respectively). Ezrin levels were significantly lower in tumour recurrence and in patients who succumbed to the disease (p=0.0001 and p=0.59, respectively). Using the Kaplan-Meier survival analysis, a general trend of higher levels of ERM was observed, with marginal long overall and disease-free survival. In conclusion, an inverse relationship between ERM expression and tumour behaviour of breast cancer patients was noted. However, further work needs to be conducted in other types of cancer in clinical situations to obtain consistent results.
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Affiliation(s)
- HERMAN FERNANDO
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
| | - TRACEY A. MARTIN
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
| | - ANTHONY DOUGLAS-JONES
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
| | - HOWARD G. KYNASTON
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
| | - ROBERT E. MANSEL
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
| | - WEN G. JIANG
- Metastasis and Angiogenesis Research Group, Wales College of Medicine, Cardiff University, Cardiff,
UK
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24
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Franke WW. Discovering the molecular components of intercellular junctions--a historical view. Cold Spring Harb Perspect Biol 2009; 1:a003061. [PMID: 20066111 PMCID: PMC2773636 DOI: 10.1101/cshperspect.a003061] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The organization of metazoa is based on the formation of tissues and on tissue-typical functions and these in turn are based on cell-cell connecting structures. In vertebrates, four major forms of cell junctions have been classified and the molecular composition of which has been elucidated in the past three decades: Desmosomes, which connect epithelial and some other cell types, and the almost ubiquitous adherens junctions are based on closely cis-packed glycoproteins, cadherins, which are associated head-to-head with those of the hemi-junction domain of an adjacent cell, whereas their cytoplasmic regions assemble sizable plaques of special proteins anchoring cytoskeletal filaments. In contrast, the tight junctions (TJs) and gap junctions (GJs) are formed by tetraspan proteins (claudins and occludins, or connexins) arranged head-to-head as TJ seal bands or as paracrystalline connexin channels, allowing intercellular exchange of small molecules. The by and large parallel discoveries of the junction protein families are reported.
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Affiliation(s)
- Werner W Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
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25
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Wakayama T, Nakata H, Kurobo M, Sai Y, Iseki S. Expression, localization, and binding activity of the ezrin/radixin/moesin proteins in the mouse testis. J Histochem Cytochem 2008; 57:351-62. [PMID: 19064715 DOI: 10.1369/jhc.2008.952440] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ezrin, radixin, and moesin (ERM) proteins represent a family of adaptor proteins linking transmembrane proteins to the cytoskeleton. The seminiferous epithelium undergoes extensive changes in cellular composition, location, and shape, implicating roles of the membrane-cytoskeleton interaction. It remains unknown, however, whether the ERM proteins are expressed and play significant roles in the testis. In the present study, we examined the spatiotemporal expression of ERM proteins in the mouse testis by Western blotting and immunohistochemistry. Ezrin immunoreactivity was demonstrated in the cytoplasm of steps 15 and 16 spermatids from 5 weeks postpartum through adulthood, whereas radixin immunoreactivity was in the apical cytoplasm of Sertoli cells from 1 week through 2 weeks postpartum. No immunoreactivity for moesin was detected at any age. Immunoprecipitation demonstrated that ezrin was bound to the cytoskeletal component actin, whereas radixin was bound to both actin and tubulin. Of the transmembrane proteins known to interact with ERM proteins, only cystic fibrosis transmembrane conductance regulator, a chloride transporter, was bound to ezrin in elongated spermatids. These results suggest that ezrin is involved in spermiogenesis whereas radixin is involved in the maturation of Sertoli cells, through interaction with different sets of membrane proteins and cytoskeletal components.
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Affiliation(s)
- Tomohiko Wakayama
- Department of Histology and Embryology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8640, Japan.
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26
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Mintz CD, Carcea I, McNickle DG, Dickson TC, Ge Y, Salton SRJ, Benson DL. ERM proteins regulate growth cone responses to Sema3A. J Comp Neurol 2008; 510:351-66. [PMID: 18651636 DOI: 10.1002/cne.21799] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Axonal growth cones initiate and sustain directed growth in response to cues in their environment. A variety of events such as receptor internalization, kinase activation, and actin rearrangement can be stimulated by guidance cues and are essential for mediating targeted growth cone behavior. Surprisingly little is known about how such disparate actions are coordinated. Our data suggest that ezrin, radixin, and moesin (ERMs), a family of highly homologous, multifunctional proteins may be able to coordinate growth cone responses to the guidance cue Semaphorin 3A (Sema3A). We show that active ERMs concentrate asymmetrically in neocortical growth cones, are rapidly and transiently inactivated by Sema3A, and are required for Sema3A-mediated growth cone collapse and guidance. The FERM domain of active ERMs regulates internalization of the Sema3A receptor, Npn1, and its coreceptor, L1CAM, while the ERM C-terminal domain binds and caps F-actin. Our data support a model in which ERMs can coordinate membrane and actin dynamics in response to Sema3A.
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Affiliation(s)
- C David Mintz
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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27
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Ilani T, Khanna C, Zhou M, Veenstra TD, Bretscher A. Immune synapse formation requires ZAP-70 recruitment by ezrin and CD43 removal by moesin. ACTA ACUST UNITED AC 2007; 179:733-46. [PMID: 18025306 PMCID: PMC2080902 DOI: 10.1083/jcb.200707199] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Immunological synapse (IS) formation involves receptor-ligand pair clustering and intracellular signaling molecule recruitment with a coincident removal of other membrane proteins away from the IS. As microfilament-membrane linkage is critical to this process, we investigated the involvement of ezrin and moesin, the two ezrin/radixin/moesin proteins expressed in T cells. We demonstrate that ezrin and moesin, which are generally believed to be functionally redundant, are differentially localized and have important and complementary functions in IS formation. Specifically, we find that ezrin directly interacts with and recruits the signaling kinase ZAP-70 to the IS. Furthermore, the activation of ezrin by phosphorylation is essential for this process. In contrast, moesin dephosphorylation and removal, along with CD43, are necessary to prepare a region of the cell cortex for IS. Thus, ezrin and moesin have distinct and critical functions in the T cell cortex during IS formation.
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Affiliation(s)
- Tal Ilani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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28
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Peng S, Fan S, Li X, Wang L, Liu H, Zhou M, Wang L, Shen S, Li G. The expression of ezrin in NPC and its interaction with NGX6, a novel candidate suppressor. Cancer Sci 2007; 98:341-9. [PMID: 17270023 PMCID: PMC11158500 DOI: 10.1111/j.1349-7006.2007.00410.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Ezrin, the linker between membrane protein and cytoskeleton, plays an important role in the cellular morphology, cytoskeleton reorganization, adhesion, invasion and metastasis. In this study, ezrin was found to express in high levels either in nasopharyngeal carcinoma tissues or in nasopharyngeal carcinoma 5-8F cells and the knockdown of ezrin expression in the 5-8F cells by RNA interferance could reduce invasive ability, suggesting that ezrin is involved in the progression and invasion of nasopharyngeal carcinoma. Nasopharyngeal carcinoma-associated gene 6 is a novel candidate suppressor gene of tumor metastasis, which was originally cloned in nasopharyngeal carcinoma high-frequency heterozygosity loss region 9p21-22 and is down-regulated in nasopharyngeal carcinoma. In the present study, we hypothesize that nasopharyngeal carcinoma-associated gene 6 plays an inhibitory role in the migration and invasion of nasopharyngeal carcinoma cells via modulating the function of ezrin. Firstly, different mutants of NGX6 were constructed and transfected into nasopharyngeal carcinoma 5-8F cells. The invasion and migration of 5-8F cells overexpressing nasopharyngeal carcinoma-associated gene 6 or mutants were measured. The results showed that enhanced expression of nasopharyngeal carcinoma-associated gene 6 could reduce invasive and migratory abilities of 5-8F cells, and the cytoplasmic domain was essential for nasopharyngeal carcinoma-associated gene 6 to modulate cell migration and invasion. Further experiment results showed that nasopharyngeal carcinoma-associated gene 6 protein was associated with ezrin by its cytoplasm region, and it could down-regulate the expression level of ezrin. These results demonstrated that nasopharyngeal carcinoma-associated gene 6 was probably involved in the modulation of invasive and adhesive ability of nasopharyngeal carcinoma cells by down-regulating the expression level of ezrin.
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Affiliation(s)
- Shuping Peng
- Cancer Research Institute, Xiang-Ya Shool of Medicine, Central South University, Hunan, 410078, China
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29
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Chiba H, Sakai N, Murata M, Osanai M, Ninomiya T, Kojima T, Sawada N. The nuclear receptor hepatocyte nuclear factor 4alpha acts as a morphogen to induce the formation of microvilli. ACTA ACUST UNITED AC 2007; 175:971-80. [PMID: 17178913 PMCID: PMC2064706 DOI: 10.1083/jcb.200608012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Microvilli are actin-based organelles found on apical plasma membranes that are involved in nutrient uptake and signal transduction. Numerous components, including ezrin/radixin/moesin (ERM) proteins, have been identified that link filamentous actins to transmembrane proteins, but the signals driving microvillus biogenesis are not known. In this study, we show that the conditional and/or ectopic expression of a nuclear receptor, hepatocyte nuclear factor 4α (HNF4α), triggers microvillus morphogenesis. We also demonstrate that HNF4α expression induces ERM-binding phosphoprotein 50 (EBP50) expression and that attenuation of EBP50 using RNA interference inhibits microvillus development. We conclude that HNF4α acts as a morphogen to trigger microvillus formation.
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Affiliation(s)
- Hideki Chiba
- Department of Pathology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan.
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Kahsai AW, Zhu S, Wardrop DJ, Lane WS, Fenteany G. Quinocarmycin Analog DX-52-1 Inhibits Cell Migration and Targets Radixin, Disrupting Interactions of Radixin with Actin and CD44. ACTA ACUST UNITED AC 2006; 13:973-83. [PMID: 16984887 DOI: 10.1016/j.chembiol.2006.07.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 07/13/2006] [Accepted: 07/20/2006] [Indexed: 12/25/2022]
Abstract
In the course of screening for new small-molecule modulators of cell motility, we discovered that quinocarmycin (also known as quinocarcin) analog DX-52-1 is an inhibitor of epithelial cell migration. While it has been assumed that the main target of DX-52-1 is DNA, we identified and confirmed radixin as the relevant molecular target of DX-52-1 in the cell. Radixin is a member of the ezrin/radixin/moesin family of membrane-actin cytoskeleton linker proteins that also participate in signal transduction pathways. DX-52-1 binds specifically and covalently to the C-terminal region of radixin, which contains the domain that interacts with actin filaments. Overexpression of radixin in cells abrogates their sensitivity to DX-52-1's antimigratory activity. Small interfering RNA-mediated silencing of radixin expression reduces the rate of cell migration. Finally, we found that DX-52-1 disrupts radixin's ability to interact with both actin and the cell adhesion molecule CD44.
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Affiliation(s)
- Alem W Kahsai
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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31
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Fiévet B, Louvard D, Arpin M. ERM proteins in epithelial cell organization and functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:653-60. [PMID: 16904765 DOI: 10.1016/j.bbamcr.2006.06.013] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 05/18/2006] [Accepted: 06/30/2006] [Indexed: 11/17/2022]
Abstract
ERM (Ezrin, Radixin, Moesin) proteins are membrane-cytoskeleton linkers that regulate the structure and the function of specific domains of the plasma membrane. ERM proteins are expressed in all metazoan analyzed so far. Genetic analysis of ERM protein functions has recently been performed simultaneously in three different organisms, mouse, Drosophila melanogaster and C. elegans. These studies have revealed a remarkable conservation of the protein functions through evolution. Moreover they have shed light on the crucial role these proteins play in various physiological processes that occur in epithelial cells.
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Affiliation(s)
- Bruno Fiévet
- UMR 144 CNRS-Institut Curie 26 rue d'Ulm, 75248 PARIS cedex 05, France
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Loebrich S, Bähring R, Katsuno T, Tsukita S, Kneussel M. Activated radixin is essential for GABAA receptor alpha5 subunit anchoring at the actin cytoskeleton. EMBO J 2006; 25:987-99. [PMID: 16467845 PMCID: PMC1409722 DOI: 10.1038/sj.emboj.7600995] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Accepted: 01/16/2006] [Indexed: 11/09/2022] Open
Abstract
Neurotransmitter receptor clustering is thought to represent a critical parameter for neuronal transmission. Little is known about the mechanisms that anchor and concentrate inhibitory neurotransmitter receptors in neurons. GABAA receptor (GABAAR) alpha5 subunits mainly locate at extrasynaptic sites and are thought to mediate tonic inhibition. Notably, similar as synaptic GABAARs, these receptor subtypes also appear in cluster formations at neuronal surface membranes and are of particular interest in cognitive processing. GABAAR alpha5 mutation or depletion facilitates trace fear conditioning or improves spatial learning in mice, respectively. Here, we identified the actin-binding protein radixin, a member of the ERM family, as the first directly interacting molecule that anchors GABAARs at cytoskeletal elements. Intramolecular activation of radixin is a functional prerequisite for GABAAR alpha5 subunit binding and both depletion of radixin expression as well as replacement of the radixin F-actin binding motif interferes with GABAAR alpha5 cluster formation. Our data suggest radixin to represent a critical factor in receptor localization and/or downstream signaling.
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Affiliation(s)
- Sven Loebrich
- Zentrum für Molekulare Neurobiologie Hamburg (ZMNH), Universität Hamburg, Hamburg, Germany
| | - Robert Bähring
- Zentrum für Molekulare Neurobiologie Hamburg (ZMNH), Universität Hamburg, Hamburg, Germany
| | - Tatsuya Katsuno
- Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Sachiko Tsukita
- Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
- School of Health Sciences, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Matthias Kneussel
- Zentrum für Molekulare Neurobiologie Hamburg (ZMNH), Universität Hamburg, Hamburg, Germany
- Zentrum für Molekulare Neurobiologie Hamburg (ZMNH), Universität Hamburg, Falkenried 94, 20251 Hamburg, Germany. Tel.: +49 40 42803 6275; Fax: +49 40 42803 7700; E-mail:
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Geiger KD, Stoldt P, Schlote W, Derouiche A. Ezrin Immunoreactivity Reveals Specific Astrocyte Activation in Cerebral HIV. J Neuropathol Exp Neurol 2006; 65:87-96. [PMID: 16410752 DOI: 10.1097/01.jnen.0000195943.32786.39] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The actin-binding protein ezrin is associated with cellular shape changes, motility, tumor invasion, and lymphocyte activation. We have earlier shown that ezrin immunoreactivity (IR) is faintly present in normal astrocytes but increased in malignant human astrogliomas. We studied the role of ezrin in astrocyte activation, applying immunostaining on serial paraffin sections from human autopsied brain tissues (51 cases). Cerebral HIV infection was chosen as a model displaying consistent exemplary astrocyte activation. Semiquantitative ezrin-IR was compared with the common glial markers GFAP, ferritin, and HLA-DR in relation to clinical and morphologic criteria of HIV encephalopathy. In all cases with HIV infection, GFAP-, HLA-DR-, and ferritin-IR were elevated in comparison to normal brain tissues. In contrast, high ezrin-IR in HIV infection strictly correlated with additional HIV encephalopathy. HIV encephalopathy with particularly high ezrin-IR was correlated with neuronal apoptosis (TUNEL). Combined ezrin-IR and GFAP-IR thus reveals 2 distinct states of astrocytic activation. Normal ezrin-IR, when paralleled by upregulated GFAP, reflects astroglial activation not associated with neuronal apoptosis. High ezrin-IR indicates specific astrocyte stressors related to cellular damage within the central nervous system. Ezrin-IR might also provide a diagnostic tool for the classification of HIV encephalopathy.
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Majores M, Schick V, Engels G, Fassunke J, Elger CE, Schramm J, Blümcke I, Becker AJ. Mutational and immunohistochemical analysis of ezrin-, radixin-, moesin (ERM) molecules in epilepsy-associated glioneuronal lesions. Acta Neuropathol 2005; 110:537-46. [PMID: 16231158 DOI: 10.1007/s00401-005-1088-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 08/24/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Glioneuronal lesions are frequently observed in biopsy specimens obtained from patients with pharmacoresistant epilepsies, comprising focal cortical dysplasias (FCD) and gangliogliomas. Recent findings point to the phosphoinositide 3-kinase (PI3K) pathway and tuberin/hamartin signaling cascade as being compromised in these lesions. Ezrin, radixin and moesin (ERM-/band-4.1 proteins) genes represent downstream effectors of the PI3K pathway, are involved in cytoskeleton-membrane interference, cell growth, migration and differentiation, and harbor tumor suppressor motifs. Accumulation of band-4.1 proteins has been identified in cortical tubers of tuberous sclerosis patients, which share neuropathological similarities with FCD and gangliogliomas. Here, we have studied the immunohistochemical distribution pattern of ERMs, as well as allelic variants, occurring in gangliogliomas (n=20) and FCDs (FCD(IIa), n=7; FCD(IIb), n=37). Aberrant accumulation of ERMs was observed in dysplastic neurons of FCDs and gangliogliomas as well as in balloon cells. Adjacent brain tissue without structural abnormalities was used as control and showed only faint neuropil staining. Mutational screening revealed silent polymorphisms in the ezrin gene in two individuals suffering from FCD(IIb). A transition from G to A in radixin exon 2 resulted in an exchange of valine by isoleucine at codon 50 in an additional FCD(IIb) specimen. Such sequence alterations were not found in controls. The present data suggest accumulation of ERM expression in dysplastic cellular components but do not favor mutational events of ERM in the pathogenesis of FCDs or gangliogliomas. Aberrant expression of ERMs is, however, compatible with compromised PI3K-pathway signaling in glioneuronal lesions characterized by abnormal cellular differentiation and aberrant network formation.
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Affiliation(s)
- Michael Majores
- Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud Str. 25, 53105, Bonn, Germany.
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Solomon JS, Nixon CP, McGarvey ST, Acosta LP, Manalo D, Kurtis JD. Expression, purification, and human antibody response to a 67 kDa vaccine candidate for schistosomiasis japonica. Protein Expr Purif 2005; 36:226-31. [PMID: 15249044 DOI: 10.1016/j.pep.2004.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 03/16/2004] [Indexed: 11/26/2022]
Abstract
Schistosomiasis remains a leading cause of morbidity and mortality in the developing tropical world, and vaccines to prevent these infections remain a scientific and public health priority. Sj67 is a 67 kDa Schistosoma japonicum surface membrane protein homologous to a family of actin-binding proteins. Sj67 is recognized by a mouse monoclonal antibody (mAb 6) that confers resistance to challenge infection in passive transfer experiments. These data support Sj67 as a potential vaccine candidate for schistosomiasis japonica. In the present study, we report the ligation-independent cloning of a cDNA encoding thioredoxin/elastin-like polypeptide (ELP)/rSj67 into a pET-32 Xa/LIC vector. Soluble recombinant fusion protein (Thio-ELP-rSj67) was expressed and purified using anion-exchange and size exclusion chromatography. rSj67 was cleaved from the Thio-ELP fusion partner by digestion with Factor Xa protease and purified using hydroxyapatite column chromatography. Endotoxin was reduced by absorption to a polymyxin support. Purified rSj67 had a molecular weight of 67 kDa and N-terminal sequencing confirmed that the first five amino acids of the recombinant protein matched the predicted sequence for the Sj67 gene. In Western blot analysis, rSj67 was recognized by the Sj67 specific mAb 6 antibody. IgG antibodies in sera from schistosomiasis infected volunteers living in an endemic area of the Philippines (n = 13) recognized rSj67 with 4.7-fold greater median fluorescence compared to uninfected North American controls (n = 5) (p < 0.009). Together, these data confirm the expression and purification of recombinant Sj67 and its immuno-reactivity with sera from S. japonicum infected humans.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- Antibody Formation/immunology
- Antigens, Helminth/chemistry
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Antigens, Helminth/isolation & purification
- Chromatography, Liquid
- Gene Expression
- Helminth Proteins/chemistry
- Helminth Proteins/immunology
- Helminth Proteins/isolation & purification
- Humans
- Immunoglobulin G/blood
- Microfilament Proteins/chemistry
- Microfilament Proteins/genetics
- Microfilament Proteins/immunology
- Microfilament Proteins/isolation & purification
- Molecular Weight
- Schistosoma japonicum/genetics
- Schistosoma japonicum/immunology
- Schistosomiasis japonica/blood
- Schistosomiasis japonica/immunology
- Schistosomiasis japonica/mortality
- Schistosomiasis japonica/prevention & control
- Vaccines, Subunit/chemistry
- Vaccines, Subunit/genetics
- Vaccines, Subunit/immunology
- Vaccines, Subunit/isolation & purification
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Affiliation(s)
- Julie S Solomon
- International Health Institute, Brown University, Providence, RI, USA
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Ramesh V. Merlin and the ERM proteins in Schwann cells, neurons and growth cones. Nat Rev Neurosci 2004; 5:462-70. [PMID: 15152196 DOI: 10.1038/nrn1407] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Vijaya Ramesh
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
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37
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Polesello C, Payre F. Small is beautiful: what flies tell us about ERM protein function in development. Trends Cell Biol 2004; 14:294-302. [PMID: 15183186 DOI: 10.1016/j.tcb.2004.04.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Actin dynamics is recognized as being a determinant in many developmental processes and pathologies, such as cell polarity, morphogenesis and tumour metastasis. However, how actin interacts with the plasma membrane is poorly understood. Although numerous studies in cell culture point to the crucial role of Ezrin, Radixin and Moesin (ERM) proteins in the actin-membrane link, genetic approaches in mice have not yet revealed their activity during development. Drosophila has recently become an alternative and promising system for the genetic study of ERM protein function. This article focuses on advances made in flies, providing evidence for the evolutionary conservation of functional properties of ERM proteins, in addition to shedding new light on their importance for development.
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Affiliation(s)
- Cédric Polesello
- Centre de Biologie du Développement, UMR5547 CNRS, Université Paul Sabatier, Bâtiment 4R3, 118 Route de Narbonne, 31062 Toulouse Cedex 4, France
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38
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Abstract
Dynamic actin filaments contribute to cell migration, organelle movements, memory, and gene regulation. These dynamic processes are often regulated by extracellular and?or cell cycle signals. Regulation targets, not actin itself, but the factors that determine it's dynamic properties. Thus, filament nucleation, rate and duration of elongation, and depolymerization are each controlled with regard to time and?or space. Two mechanisms exist for nucleating filaments de novo, the Arp23 complex and the formins; multiple pathways regulate each. A new filament elongates rapidly but transiently before its barbed end is capped. Rapid capping allows the cell to maintain fine temporal and spatial control over F-actin distribution. Modulation of capping protein activity and its access to barbed ends is emerging as a site of local regulation. Finally, to maintain a steady state filaments must depolymerize. Depolymerization can limit the rate of new filament nucleation and elongation. The activity of ADF?cofilin, which facilitates depolymerization, is also regulated by multiple inputs. This chapter describes (1) mechanism and regulation of new filament formation, (2) mechanism of enhancing elongation at barbed ends, (3) capping proteins and their regulators, and (4) recycling of actin monomers from filamentous actin (F-actin) back to globular actin (G-actin).
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Affiliation(s)
- Sally H Zigmond
- Biology Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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39
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Granés F, Berndt C, Roy C, Mangeat P, Reina M, Vilaró S. Identification of a novel Ezrin-binding site in syndecan-2 cytoplasmic domain. FEBS Lett 2003; 547:212-6. [PMID: 12860416 DOI: 10.1016/s0014-5793(03)00712-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
ERM (Ezrin/Radixin/Moesin) proteins are crosslinkers between plasma membrane proteins and the actin cytoskeleton, thereby involved in the formation of cell adhesion sites. Earlier work showed that Ezrin links syndecan-2 to the actin cytoskeleton. Here we provide evidence that the Ezrin N-terminal domain binds to the syndecan-2 cytoplasmic domain with an estimated K(D) of 0.71 microM and without the requirement of other proteins. We also studied the regions in the syndecan-2 cytoplasmic domain implicated in the binding to Ezrin. By truncating the syndecan-2 cytoplasmic domain and by oligopeptide competition assays we show that the Ezrin-binding sequence is not located in the positively charged juxtamembrane region (RMRKK), but in the neighboring sequence DEGSYD. We therefore conclude that the consensus sequence for Ezrin binding is unique among membrane proteins, suggesting a distinct regulation.
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Affiliation(s)
- Francesc Granés
- Department of Cellular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
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40
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Shumilina EV, Negulyaev YA, Morachevskaya EA, Hinssen H, Khaitlina SY. Regulation of sodium channel activity by capping of actin filaments. Mol Biol Cell 2003; 14:1709-16. [PMID: 12686620 PMCID: PMC153133 DOI: 10.1091/mbc.e02-09-0622] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Ion transport in various tissues can be regulated by the cortical actin cytoskeleton. Specifically, involvement of actin dynamics in the regulation of nonvoltage-gated sodium channels has been shown. Herein, inside-out patch clamp experiments were performed to study the effect of the heterodimeric actin capping protein CapZ on sodium channel regulation in leukemia K562 cells. The channels were activated by cytochalasin-induced disruption of actin filaments and inactivated by G-actin under ionic conditions promoting rapid actin polymerization. CapZ had no direct effect on channel activity. However, being added together with G-actin, CapZ prevented actin-induced channel inactivation, and this effect occurred at CapZ/actin molar ratios from 1:5 to 1:100. When actin was allowed to polymerize at the plasma membrane to induce partial channel inactivation, subsequent addition of CapZ restored the channel activity. These results can be explained by CapZ-induced inhibition of further assembly of actin filaments at the plasma membrane due to the modification of actin dynamics by CapZ. No effect on the channel activity was observed in response to F-actin, confirming that the mechanism of channel inactivation does not involve interaction of the channel with preformed filaments. Our data show that actin-capping protein can participate in the cytoskeleton-associated regulation of sodium transport in nonexcitable cells.
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41
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Smith WJ, Nassar N, Bretscher A, Cerione RA, Karplus PA. Structure of the active N-terminal domain of Ezrin. Conformational and mobility changes identify keystone interactions. J Biol Chem 2003; 278:4949-56. [PMID: 12429733 DOI: 10.1074/jbc.m210601200] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ezrin is a member of the ERM (ezrin, radixin, moesin) family of proteins that cross-link the actin cytoskeleton to the plasma membrane and also may function in signaling cascades that regulate the assembly of actin stress fibers. Here, we report a crystal structure for the free (activated) FERM domain (residues 2-297) of recombinant human ezrin at 2.3 A resolution. Structural comparison among the dormant moesin FERM domain structure and the three known active FERM domain structures (radixin, moesin, and now ezrin) allows the clear definition of regions that undergo structural changes during activation. The key regions affected are residues 135-150 and 155-180 in lobe F2 and residues 210-214 and 235-267 in lobe F3. Furthermore, we show that a large increase in the mobilities of lobes F2 and F3 accompanies activation, suggesting that their integrity is compromised. This leads us to propose a new concept that we refer to as keystone interactions. Keystone interactions occur when one protein (or protein part) contributes residues that allow another protein to complete folding, meaning that it becomes an integral part of the structure and would rarely dissociate. Such interactions are well suited for long-lived cytoskeletal protein interactions. The keystone interactions concept leads us to predict two specific docking sites within lobes F2 and F3 that are likely to bind target proteins.
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Imai K, Iida T, Takano Y, Uozumi N. Membrane-bound heparin binding proteins from HL-60 cells purified in a two-step affinity chromatography differentially eluted with divalent cations. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 780:1-12. [PMID: 12383474 DOI: 10.1016/s1570-0232(02)00404-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Solubilized membrane proteins from HL-60 cells were separated by two-step affinity chromatography. Proteins eluted with MgCl2 in the first heparin-gel were applied to the second heparin-gel and eluted with CaCl2. The eluted proteins were analysed and purified by electrophoresis. N-terminal amino acid sequences of eight proteins on the characteristic bands were determined. Homology search for the sequences indicated that three microsomal proteins, two nuclear proteins and a glycolytic enzyme were eluted with divalent cations, whereas a nuclear ribonucleoprotein and a membrane-cytoskelton linker protein were not dissociated with divalent cations, but with 2 M NaCl. Heparin affinity chromatography combined with differential elution with divalent cations can be a useful method for separation of membrane proteins.
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Affiliation(s)
- Katsuyuki Imai
- Department of Science of Human Life, City College of Mie, Issinden-Nakano, Tsu-shi, Mie 514-0112, Japan. imai_
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43
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Bretscher A, Edwards K, Fehon RG. ERM proteins and merlin: integrators at the cell cortex. Nat Rev Mol Cell Biol 2002; 3:586-99. [PMID: 12154370 DOI: 10.1038/nrm882] [Citation(s) in RCA: 1045] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A fundamental property of many plasma-membrane proteins is their association with the underlying cytoskeleton to determine cell shape, and to participate in adhesion, motility and other plasma-membrane processes, including endocytosis and exocytosis. The ezrin-radixin-moesin (ERM) proteins are crucial components that provide a regulated linkage between membrane proteins and the cortical cytoskeleton, and also participate in signal-transduction pathways. The closely related tumour suppressor merlin shares many properties with ERM proteins, yet also provides a distinct and essential function.
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Affiliation(s)
- Anthony Bretscher
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA.
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44
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Li J, Yu X, Pan W, Unger RH. Gene expression profile of rat adipose tissue at the onset of high-fat-diet obesity. Am J Physiol Endocrinol Metab 2002; 282:E1334-41. [PMID: 12006364 DOI: 10.1152/ajpendo.00516.2001] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Morbid obesity is the result of massive expansion of white adipose tissue (WAT) and requires recruitment of adipocyte precursor cells and their supporting infrastructure. To characterize the change in the expression profile of the preexisting WAT at the start of obesity, when adipocyte hypertrophy is present but hyperplasia is still minimal, we employed a cDNA subtraction screen for genes differentially expressed in epididymal fat pads harvested 1 wk after the start of a 60% fat diet. Ninety-six genes were upregulated by at least 50% above the WAT of control rats receiving a 4% fat diet. Of these genes, 30 had not previously been identified. Sixteen of the 96 genes, including leptin, adipocyte complement-related protein 30 kDa, and resistin, were predicted to encode a signal peptide. Ten of the 16 had been previously identified in other tissues and implicated in cell growth, proliferation, differentiation, cell cycle control, and angiogenesis. One was a novel gene. Twenty-nine novel fragments were identified. Thus, at the onset of high-fat-diet-induced obesity in rats, adipose tissue increases its expression of factors previously implicated in the expansion of nonadipocyte tissues and of several uncharacterized novel factors. The only one of these thus far characterized functionally was found to promote lipogenesis.
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Affiliation(s)
- Jinping Li
- Gifford Laboratories, Touchstone Center for Diabetes Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8854, USA
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45
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Sakai K, Kurimoto M, Tsugu A, Hubbard SL, Trimble WS, Rutka JT. Expression of Nedd5, a mammalian septin, in human brain tumors. J Neurooncol 2002; 57:169-77. [PMID: 12125979 DOI: 10.1023/a:1015721801075] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The septins are a family of cytoskeletal GTPases that play an essential role in cytokinesis in yeast and mammalian cells. Nedd5 is a mammalian septin known to associate with actin-based structures such as the contractile ring and stress fibers. In the present study, we examined the expression of Nedd5 in a series of human brain tumor cell lines and surgical specimens by northern and western analyses. The temporal expression of Nedd5 in U373 astrocytoma cells at various timepoints throughout the cell cycle was determined by an analysis of lovastatin- and nocodazole-treated, synchronized cell populations. The intracellular localization of Nedd5 was determined by immunocytochemistry of steady state cultures and nocodazole-treated cultures enriched in M phase cells. The effects of inhibiting Nedd5 expression in human brain tumors was determined by stably transfecting U373 astrocytoma cells with an antisense-Nedd5 cDNA expression vector and by analyzing clones for Nedd5 expression by immunocytochemistry, morphological changes, cell growth and nuclear content. All human brain tumor cell lines and surgical specimens expressed Nedd5 transcript and protein. Synchronized U373 astrocytoma cells showed a relative increase in Nedd5 transcript levels from late Gl to G2M phases; and an increase in Nedd5 protein levels from S to G2M phases. Maximum expression of both transcript and protein levels was observed at the G2M phase. By immunocytochemistry, Nedd5 was concentrated at the cleavage furrow of mitotic cells. Double staining with Nedd5 and F-actin showed co-localization of Nedd5 with actin filaments except during cytokinesis. Antisense-Nedd5 expression led to an accumulation of nuclear content. These data suggest that Nedd5 is involved in the process of cytokinesis in human brain tumours. Nedd5 expression may be cell cycle-dependent with increased levels found at G2M phase. Blocking Nedd5 expression in astrocytoma cells by antisense interferes with the process of cytokinesis during cell division.
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Affiliation(s)
- Keiichi Sakai
- The Division of Neurosurgery, The Arthur and Sonia Labatt Brain Tumour Research Centre, Toronto, Ontario, Canada
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46
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Ingraffea J, Reczek D, Bretscher A. Distinct cell type-specific expression of scaffolding proteins EBP50 and E3KARP: EBP50 is generally expressed with ezrin in specific epithelia, whereas E3KARP is not. Eur J Cell Biol 2002; 81:61-8. [PMID: 11893083 DOI: 10.1078/0171-9335-00218] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ezrin/radixin/moesin (ERM) proteins are regulated microfilament membrane linking proteins. Previous tissue localization studies have revealed that the three related proteins show distinct tissue distributions, with ezrin being found predominantly in polarized epithelial cells, whereas moesin is enriched in endothelial cells and lymphocytes. EBP50 and E3KARP are two related scaffolding proteins that bind to the activated form of ERM proteins in vitro, and through their PDZ domains to the cytoplasmic domains of specific membrane proteins, including the Na+/H+ exchanger isoform (NHE3) present in kidney proximal tubules and the beta2-adrenergic receptor. Using specific antibodies to EBP50 and E3KARP for localization in murine tissues, we find that the cellular distribution of EBP50 and E3KARP is mutually exclusive. Epithelial cells expressing ezrin generally co-express EBP50, such as intestinal epithelial cells, gastric parietal cells, the epithelial cells of the kidney proximal tubule, the terminal bronchiole of the lung, and in mesothelia. This correlation is not absolute as cells of the mucous epithelium of the stomach and in the renal corpuscle, express ezrin but no detectable EBP50, whereas the bile canaliculi of hepatocytes express EBP50 and not ezrin. E3KARP has a restricted tissue distribution with the highest expression being found in lung. It is largely colocalized with moesin and radixin, especially in the alveoli of the lung, as well as being highly enriched in the renal corpuscle. These results document a preference for co-expression of EBP50, but not E3KARP, with ezrin in polarized epithelia. These results place constraints on the physiological roles that can be proposed for these scaffolding molecules.
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Affiliation(s)
- Janet Ingraffea
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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47
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Derouiche A, Frotscher M. Peripheral astrocyte processes: monitoring by selective immunostaining for the actin-binding ERM proteins. Glia 2001; 36:330-41. [PMID: 11746770 DOI: 10.1002/glia.1120] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Astrocytes extend thin lamellate processes in the neuropil, in particular around synapses, where they can modulate synaptic function or mediate glial-neuronal communication. Previous studies have shown that these lamellate perisynaptic processes change their shape in response to neuronal activity, but the underlying mechanisms have remained unclear. Similarly, the molecular composition of these fine, sheet-like astrocytic processes (often 50-100 nm wide) is not understood but has to be related to their dynamic properties. To this end, we have studied the presence of ezrin, radixin, and moesin (ERM proteins) in the rat hippocampus and in primary cultured astrocytes, applying immunoperoxidase, immunofluorescence, and immunogold techniques. These three ERM proteins are known as actin-binding proteins that link the cell membrane to the actin cytoskeleton, particularly in microvillus-bearing epithelial cells. In cell culture, anti-ezrin and antiradixin, but not antimoesin, antibodies were specific for astrocytes, which often displayed selective staining of filopodia and microvilli. Nonoverlapping visualization of astrocytic peripheral and stem processes was obtained by immunocytochemical double labeling for ezrin and GFAP, respectively. In sections of rat hippocampus, homogeneous labeling of the neuropil, but not of cell layers, resulted from immunostaining of fine, peripheral astrocyte processes, as confirmed ultrastructurally. Our data show that the fine peripheral processes of astrocytes, which also constitute the perisynaptic glial sheath, are specialized in that they contain characteristic actin-associated molecules, likely to contribute to their dynamic properties. Applying anti-ezrin and anti-radixin as selective markers, plasticity of these perisynaptic glial processes can be analyzed.
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Affiliation(s)
- A Derouiche
- Max-Planck Institute for Brain Research, Frankfurt am Main, Germany.
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48
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James MF, Manchanda N, Gonzalez-Agosti C, Hartwig JH, Ramesh V. The neurofibromatosis 2 protein product merlin selectively binds F-actin but not G-actin, and stabilizes the filaments through a lateral association. Biochem J 2001; 356:377-86. [PMID: 11368764 PMCID: PMC1221848 DOI: 10.1042/0264-6021:3560377] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The neurofibromatosis 2 protein product merlin, named for its relatedness to the ezrin, radixin and moesin (ERM) family of proteins, is a tumour suppressor whose absence results in the occurrence of multiple tumours of the nervous system, particularly schwannomas and meningiomas. Merlin's similarity to ERMs suggests that it might share functions, acting as a link between cytoskeletal components and the cell membrane. The N-terminus of merlin has strong sequence identity to the N-terminal actin-binding region of ezrin; here we describe in detail the merlin-actin interaction. Employing standard actin co-sedimentation assays, we have determined that merlin isoform 2 binds F-actin with an apparent binding constant of 3.6 microM and a stoichiometry of 1 mol of merlin per 11.5 mol of actin in filaments at saturation. Further, solid-phase binding assays reveal that merlin isoforms 1 and 2 bind actin filaments differentially, suggesting that the intramolecular interactions in isoform 1 might hinder its ability to bind actin. However, merlin does not bind G-actin. Studies of actin filament dynamics show that merlin slows filament disassembly with no influence on the assembly rate, indicating that merlin binds along actin filament lengths. This conclusion is supported by electron microscopy, which demonstrates that merlin binds periodically along cytoskeletal actin filaments. Comparison of these findings with those reported for ERM proteins reveal a distinct role for merlin in actin filament dynamics.
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Affiliation(s)
- M F James
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Building 149, 13th Street, Charlestown, MA 02129, USA
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49
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Aono Y, Ariyoshi H, Tsuji Y, Ueda A, Tokunaga M, Sakon M, Monden M. Localized Activation of m-Calpain in Human Umbilical Vein Endothelial Cells Upon Hypoxia. Thromb Res 2001; 102:353-61. [PMID: 11369428 DOI: 10.1016/s0049-3848(01)00238-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bleb formation is an early event of cellular damage observed in a variety of cell types upon hypoxia. Although we previously found the appearance of the localized cytoplasmic ionized Ca(2+) concentration ([Ca(2+)](i)) rise before bleb formation at the same loci of human umbilical vein endothelial cell (HUVEC) upon hypoxia, the mode of [Ca(2+)](i)-rise-induced cytoskeletal alteration remains ill-defined. The aim of this study is to clarify the mechanisms causing bleb formation after localized [Ca(2+)](i) rise. We studied the activation of m-calpain associated with the alteration of cytoskeleton-related proteins, F-actin, mu-actin, or ezrin by employing specific antibodies in conjunction with a confocal laser scanning microscopy (CLSM). Specific antibodies against 80-kDa-preactivated and 78-kDa-activated m-calpain clearly demonstrated redistribution of 80-kDa m-calpain followed by autoproteolytic activation of m-calpain to the 78-kDa form at the same loci of [Ca(2+)](i) rise in hypoxia-treated HUVECs, which was associated with the decrease of ezrin and the localized appearance of beta-actin at the same loci. In conclusion, hypoxia-induced localized [Ca(2+)](i) rise causes bleb formation at the same loci through m-calpain-catalyzed destruction of cross-linking between plasma membrane and actin filaments.
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Affiliation(s)
- Y Aono
- Department of Surgery and Clinical Oncology, Graduate School of Medicine, Osaka University, Japan
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Bretscher A, Chambers D, Nguyen R, Reczek D. ERM-Merlin and EBP50 protein families in plasma membrane organization and function. Annu Rev Cell Dev Biol 2001; 16:113-43. [PMID: 11031232 DOI: 10.1146/annurev.cellbio.16.1.113] [Citation(s) in RCA: 290] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The ezrin-radixin-moesin (ERM) family of proteins have emerged as key regulatory molecules in linking F-actin to specific membrane proteins, especially in cell surface structures. Merlin, the product of the NF2 tumor suppressor gene, has sequence similarity to ERM proteins and binds to some of the same membrane proteins, but lacks a C-terminal F-actin binding site. In this review we discuss how ERM proteins and merlin are negatively regulated by an intramolecular association between their N- and C-terminal domains. Activation of at least ERM proteins can be accomplished by C-terminal phosphorylation in the presence of PIP2. We also discuss membrane proteins to which ERM and merlin bind, including those making an indirect linkage through the PDZ-containing adaptor molecules EBP50 and E3KARP. Finally, the function of these proteins in cortical structure, endocytic traffic, signal transduction, and growth control is discussed.
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Affiliation(s)
- A Bretscher
- Department of Molecular Biology and Genetics, Biotechnology Building, Cornell University, Ithaca, New York 14853, USA.
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