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PFN1 Inhibits Myogenesis of Bovine Myoblast Cells via Cdc42-PAK/JNK. Cells 2022; 11:cells11203188. [PMID: 36291059 PMCID: PMC9600610 DOI: 10.3390/cells11203188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Myoblast differentiation is essential for the formation of skeletal muscle myofibers. Profilin1 (Pfn1) has been identified as an actin-associated protein, and has been shown to be critically important to cellular function. Our previous study found that PFN1 may inhibit the differentiation of bovine skeletal muscle satellite cells, but the underlying mechanism is not known. Here, we confirmed that PFN1 negatively regulated the myogenic differentiation of bovine skeletal muscle satellite cells. Immunoprecipitation assay combined with mass spectrometry showed that Cdc42 was a binding protein of PFN1. Cdc42 could be activated by PFN1 and could inhibit the myogenic differentiation like PFN1. Mechanistically, activated Cdc42 increased the phosphorylation level of p2l-activated kinase (PAK), which further activated the phosphorylation activity of c-Jun N-terminal kinase (JNK), whereas PAK and JNK are inhibitors of myogenic differentiation. Taken together, our results reveal that PFN1 is a repressor of bovine myogenic differentiation, and provide the regulatory mechanism.
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2
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Stejerean-Todoran I, Gimotty PA, Watters A, Brafford P, Krepler C, Godok T, Li H, Bonilla Del Rio Z, Zieseniss A, Katschinski DM, Sertel SM, Rizzoli SO, Garman B, Nathanson KL, Xu X, Chen Q, Oswald JH, Lotem M, Mills GB, Davies MA, Schön MP, Bogeski I, Herlyn M, Vultur A. A distinct pattern of growth and RAC1 signaling in melanoma brain metastasis cells. Neuro Oncol 2022; 25:674-686. [PMID: 36054930 PMCID: PMC10076948 DOI: 10.1093/neuonc/noac212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Melanoma, the deadliest of skin cancers, has a high propensity to form brain metastases that are associated with a markedly worsened prognosis. In spite of recent therapeutic advances, melanoma brain lesions remain a clinical challenge, biomarkers predicting brain dissemination are not clear and differences with other metastatic sites are poorly understood. METHODS We examined a genetically diverse panel of human-derived melanoma brain metastasis (MBM) and extracranial cell lines using targeted sequencing, a Reverse Phase Protein Array, protein expression analyses, and functional studies in vitro and in vivo. RESULTS Brain-specific genetic alterations were not detected; however, MBM cells in vitro displayed lower proliferation rates and MBM-specific protein expression patterns associated with proliferation, DNA damage, adhesion, and migration. MBM lines displayed higher levels of RAC1 expression, involving a distinct RAC1-PAK1-JNK1 signaling network. RAC1 knockdown or treatment with small molecule inhibitors contributed to a less aggressive MBM phenotype in vitro, while RAC1 knockdown in vivo led to reduced tumor volumes and delayed tumor appearance. Proliferation, adhesion, and migration were higher in MBM vs. non-MBM lines in the presence of insulin or brain-derived factors and were affected by RAC1 levels. CONCLUSIONS Our findings indicate that despite their genetic variability, MBM engage specific molecular processes such as RAC1 signaling to adapt to the brain microenvironment and this can be used for the molecular characterization and treatment of brain metastases.
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Affiliation(s)
- Ioana Stejerean-Todoran
- Molecular Physiology, Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Phyllis A Gimotty
- Department of Biostatistics, Informatics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Andrea Watters
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Patricia Brafford
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Clemens Krepler
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Tetiana Godok
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Haiyin Li
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Zuriñe Bonilla Del Rio
- Molecular Physiology, Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Anke Zieseniss
- Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Dörthe M Katschinski
- Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Sinem M Sertel
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Bradley Garman
- Department of Medicine, Div. Translational Medicine and Human Genetics; Abramson Cancer Center; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Katherine L Nathanson
- Department of Medicine, Div. Translational Medicine and Human Genetics; Abramson Cancer Center; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Xiaowei Xu
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Qing Chen
- Immunology Microenvironment & Metastasis, The Wistar Institute, Philadelphia, PA, USA
| | - Jack H Oswald
- Immunology Microenvironment & Metastasis, The Wistar Institute, Philadelphia, PA, USA
| | - Michal Lotem
- Sharett Institute of Oncology, Hadassah Hebrew University Medical Center, Jerusalem, IL
| | - Gordon B Mills
- Department of Melanoma Medical Oncology, MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Michael A Davies
- Department of Melanoma Medical Oncology, MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Michael P Schön
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Ivan Bogeski
- Molecular Physiology, Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany
| | - Meenhard Herlyn
- Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
| | - Adina Vultur
- Molecular Physiology, Department of Cardiovascular Physiology, University Medical Center Göttingen, Göttingen, Germany.,Program of Cellular and Molecular Oncogenesis, Melanoma Research Center, The Wistar Institute, Philadelphia, PA, USA
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Lafrance AE, Chimalapati S, Garcia Rodriguez N, Kinch LN, Kaval KG, Orth K. Enzymatic Specificity of Conserved Rho GTPase Deamidases Promotes Invasion of Vibrio parahaemolyticus at the Expense of Infection. mBio 2022; 13:e0162922. [PMID: 35862776 PMCID: PMC9426531 DOI: 10.1128/mbio.01629-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 06/17/2022] [Indexed: 11/23/2022] Open
Abstract
Vibrio parahaemolyticus is among the leading causes of bacterial seafood-borne acute gastroenteritis. Like many intracellular pathogens, V. parahaemolyticus invades host cells during infection by deamidating host small Rho GTPases. The Rho GTPase deamidating activity of VopC, a type 3 secretion system (T3SS) translocated effector, drives V. parahaemolyticus invasion. The intracellular pathogen uropathogenic Escherichia coli (UPEC) invades host cells by secreting a VopC homolog, the secreted toxin cytotoxic necrotizing factor 1 (CNF1). Because of the homology between VopC and CNF1, we hypothesized that topical application of CNF1 during V. parahaemolyticus infection could supplement VopC activity. Here, we demonstrate that CNF1 improves the efficiency of V. parahaemolyticus invasion, a bottleneck in V. parahaemolyticus infection, across a range of doses. CNF1 increases V. parahaemolyticus invasion independent of both VopC and the T3SS altogether but leaves a disproportionate fraction of intracellular bacteria unable to escape the endosome and complete their infection cycle. This phenomenon holds true in the presence or absence of VopC but is particularly pronounced in the absence of a T3SS. The native VopC, by contrast, promotes a far less efficient invasion but permits the majority of internalized bacteria to escape the endosome and complete their infection cycle. These studies highlight the significance of enzymatic specificity during infection, as virulence factors (VopC and CNF1 in this instance) with similarities in function (bacterial uptake), catalytic activity (deamidation), and substrates (Rho GTPases) are not sufficiently interchangeable for mediating a successful invasion for neighboring bacterial pathogens. IMPORTANCE Many species of intracellular bacterial pathogens target host small Rho GTPases to initiate invasion, including the human pathogens Vibrio parahaemolyticus and uropathogenic Escherichia coli (UPEC). The type three secretion system (T3SS) effector VopC of V. parahaemolyticus promotes invasion through the deamidation of Rac1 and CDC42 in the host, whereas the secreted toxin cytotoxic necrotizing factor 1 (CNF1) drives UPEC's internalization through the deamidation of Rac1, CDC42, and RhoA. Despite these similarities in the catalytic activity of CNF1 and VopC, we observed that the two enzymes were not interchangeable. Although CNF1 increased V. parahaemolyticus endosomal invasion, most intracellular V. parahaemolyticus aborted their infection cycle and remained trapped in endosomes. Our findings illuminate how the precise biochemical fine-tuning of T3SS effectors is essential for efficacious pathogenesis. Moreover, they pave the way for future investigations into the biochemical mechanisms underpinning V. parahaemolyticus endosomal escape and, more broadly, the regulation of successful pathogenesis.
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Affiliation(s)
- Alexander E. Lafrance
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Suneeta Chimalapati
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Nalleli Garcia Rodriguez
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lisa N. Kinch
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Karan Gautam Kaval
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Kislev N, Mor-Yossef Moldovan L, Barak R, Egozi M, Benayahu D. MYH10 Governs Adipocyte Function and Adipogenesis through Its Interaction with GLUT4. Int J Mol Sci 2022; 23:ijms23042367. [PMID: 35216482 PMCID: PMC8875441 DOI: 10.3390/ijms23042367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 12/10/2022] Open
Abstract
Adipogenesis is dependent on cytoskeletal remodeling that determines and maintains cellular shape and function. Cytoskeletal proteins contribute to the filament-based network responsible for controlling the shape of adipocytes and promoting the intracellular trafficking of cellular components. Currently, the understanding of these mechanisms and their effect on differentiation and adipocyte function remains incomplete. In this study, we identified the non-muscle myosin 10 (MYH10) as a novel regulator of adipogenesis and adipocyte function through its interaction with the insulin-dependent glucose transporter 4 (GLUT4). MYH10 depletion in preadipocytes resulted in impaired adipogenesis, with knockdown cells exhibiting an absence of morphological alteration and molecular signals. MYH10 was shown in a complex with GLUT4 in adipocytes, an interaction regulated by insulin induction. The missing adipogenic capacity of MYH10 knockdown cells was restored when the cells took up GLUT4 vesicles from neighbor wildtype cells in a co-culture system. This signaling cascade is regulated by the protein kinase C ζ (PKCζ), which interacts with MYH10 to modify the localization and interaction of both GLUT4 and MYH10 in adipocytes. Overall, our study establishes MYH10 as an essential regulator of GLUT4 translocation, affecting both adipogenesis and adipocyte function, highlighting its importance in future cytoskeleton-based studies in adipocytes.
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Barvitenko N, Aslam M, Lawen A, Saldanha C, Skverchinskaya E, Uras G, Manca A, Pantaleo A. Two Motors and One Spring: Hypothetic Roles of Non-Muscle Myosin II and Submembrane Actin-Based Cytoskeleton in Cell Volume Sensing. Int J Mol Sci 2021; 22:7967. [PMID: 34360739 PMCID: PMC8347689 DOI: 10.3390/ijms22157967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/16/2021] [Accepted: 07/23/2021] [Indexed: 12/12/2022] Open
Abstract
Changes in plasma membrane curvature and intracellular ionic strength are two key features of cell volume perturbations. In this hypothesis we present a model of the responsible molecular apparatus which is assembled of two molecular motors [non-muscle myosin II (NMMII) and protrusive actin polymerization], a spring [a complex between the plasma membrane (PM) and the submembrane actin-based cytoskeleton (smACSK) which behaves like a viscoelastic solid] and the associated signaling proteins. We hypothesize that this apparatus senses changes in both the plasma membrane curvature and the ionic strength and in turn activates signaling pathways responsible for regulatory volume increase (RVI) and regulatory volume decrease (RVD). During cell volume changes hydrostatic pressure (HP) changes drive alterations in the cell membrane curvature. HP difference has opposite directions in swelling versus shrinkage, thus allowing distinction between them. By analogy with actomyosin contractility that appears to sense stiffness of the extracellular matrix we propose that NMMII and actin polymerization can actively probe the transmembrane gradient in HP. Furthermore, NMMII and protein-protein interactions in the actin cortex are sensitive to ionic strength. Emerging data on direct binding to and regulating activities of transmembrane mechanosensors by NMMII and actin cortex provide routes for signal transduction from transmembrane mechanosensors to cell volume regulatory mechanisms.
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Affiliation(s)
| | - Muhammad Aslam
- Department of Internal Medicine I, Experimental Cardiology, Justus Liebig University, 35392 Giessen, Germany;
| | - Alfons Lawen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, VIC 3800, Australia;
| | - Carlota Saldanha
- Institute of Biochemistry, Institute of Molecular Medicine, Faculty of Medicine University of Lisbon, 1649-028 Lisboa, Portugal;
| | | | - Giuseppe Uras
- Department of Clinical and Movement Neurosciences, Institute of Neurology, University College London, London NW3 2PF, UK;
| | - Alessia Manca
- Department of Biomedical Science, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy;
| | - Antonella Pantaleo
- Department of Biomedical Science, University of Sassari, Viale San Pietro 43/B, 07100 Sassari, Italy;
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Physiological Basis of Smut Infectivity in the Early Stages of Sugar Cane Colonization. J Fungi (Basel) 2021; 7:jof7010044. [PMID: 33445484 PMCID: PMC7827540 DOI: 10.3390/jof7010044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/04/2021] [Accepted: 01/09/2021] [Indexed: 12/11/2022] Open
Abstract
Sugar cane smut (Sporisorium scitamineum) interactions have been traditionally considered from the plant’s point of view: How can resistant sugar cane plants defend themselves against smut disease? Resistant plants induce several defensive mechanisms that oppose fungal attacks. Herein, an overall view of Sporisorium scitamineum’s mechanisms of infection and the defense mechanisms of plants are presented. Quorum sensing effects and a continuous reorganization of cytoskeletal components, where actin, myosin, and microtubules are required to work together, seem to be some of the keys to a successful attack.
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7
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Kłopocka W, Korczyński J, Pomorski P. Cytoskeleton and Nucleotide Signaling in Glioma C6 Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:109-128. [PMID: 32034711 DOI: 10.1007/978-3-030-30651-9_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This chapter describes signaling pathways, stimulated by the P2Y2 nucleotide receptor (P2Y2R), that regulate cellular processes dependent on actin cytoskeleton dynamics in glioma C6 cells. P2Y2R coupled with G-proteins, in response to ATP or UTP, regulates the level of iphosphatidylinositol-4,5-bisphosphate (PIP2) which modulates a variety of actin binding proteins and is involved in calcium response and activates Rac1 and RhoA proteins. The RhoA/ROCK signaling pathway plays an important role in contractile force generation needed for the assembly of stress fibers, focal adhesions and for tail retraction during cell migration. Blocking of this pathway by a specific Rho-kinase inhibitor induces changes in F-actin organization and cell shape and decreases the level of phosphorylated myosin II and cofilin. In glioma C6 cells these changes are reversed after UTP stimulation of P2Y2R. Signaling pathways responsible for this compensation are calcium signaling which regulates MLC kinase activation via calmodulin, and the Rac1/PAK/LIMK cascade. Stimulation of the Rac1 mediated pathway via Go proteins needs additional interaction between αvβ5 integrins and P2Y2Rs. Calcium free medium, or growing of the cells in suspension, prevents Gαo activation by P2Y2 receptors. Rac1 activation is necessary for cofilin phosphorylation as well as integrin activation needed for focal complexes formation and stabilization of lamellipodium. Inhibition of positive Rac1 regulation prevents glioma C6 cells from recovery of control cell like morphology.
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Affiliation(s)
- Wanda Kłopocka
- Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszynski University, Warsaw, Poland.
| | - Jarosław Korczyński
- M. Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Paweł Pomorski
- M. Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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8
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Yang B, Liu H, Bi Y, Cheng C, Li G, Kong P, Zhang L, Shi R, Zhang Y, Zhang R, Cheng X. MYH9 promotes cell metastasis via inducing Angiogenesis and Epithelial Mesenchymal Transition in Esophageal Squamous Cell Carcinoma. Int J Med Sci 2020; 17:2013-2023. [PMID: 32788880 PMCID: PMC7415390 DOI: 10.7150/ijms.46234] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 07/10/2020] [Indexed: 12/18/2022] Open
Abstract
Non-muscle myosin heavy chain 9 (MYH9) is one novel low frequency mutated gene identified in esophageal squamous cell carcinoma (ESCC) using next-generation sequencing. However, its clinical relevance, potential function and mechanisms remain elusive. Methods: Genomic sequencing datas from 104 esophageal squamous cell carcinoma (ESCC) cases were screened a series of low frequency mutant genes. MYH9 was selected to further analyze its clinical significance, function and PCR-array was performed to explore its potential mechanism. Results: MHY9 is a low frequency mutant gene with a mutation frequency of 2.88% in ESCC. Immunohistochemical analysis showed that MYH9 expression was significantly higher in ESCC tumor tissues, and the expression levels were associated with lymph node metastasis of ESCC patients. Moreover, we found that MYH9 knock-down led to inhibition of cell migration and invasion. PCR-array showed MYH9 knockdown led to a significant change of genes expression associated with angiogenesis and epithelial-to-mesenchymal transition (EMT). This observation is further confirmed in TCGA database of LUSC (lung squamous cell carcinoma), CESC (cervical squamous cell carcinomas) and HNSC (head and neck squamous cell carcinoma). Conclusions: Collectively, our study identifies a novel role and mechanism of MYH9, highlights a significance of MYH9 as a metastatic biomarker, and offers potential therapeutic targets for ESCC patients harboring MYH9 mutations.
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Affiliation(s)
- Bin Yang
- The Department of Thoracic Surgery (Ⅲ), Shanxi Cancer Hospital, Taiyuan, Shanxi 030013, P.R. China.,Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Huijuan Liu
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Yanghui Bi
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Caixia Cheng
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China.,Department of Pathology, The First Hospital, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Guodong Li
- Department of Otorhinolaryngology, Shanxi Provincial People's Hospital Affiliated to Shanxi Medical University, Taiyuan, Shanxi 030012, P.R. China.,Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital Affiliated to Shandong University, Jinan, Shandong 250000, P.R. China
| | - Pengzhou Kong
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Ling Zhang
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Ruyi Shi
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
| | - Yunkui Zhang
- The Department of Thoracic Surgery (Ⅲ), Shanxi Cancer Hospital, Taiyuan, Shanxi 030013, P.R. China
| | - Rongsheng Zhang
- The Department of Thoracic Surgery (Ⅲ), Shanxi Cancer Hospital, Taiyuan, Shanxi 030013, P.R. China
| | - Xiaolong Cheng
- Department of Pathology & Shanxi Key Laboratory of Carcinogenesis and Translational Research of Esophageal Cancer, Shanxi Medical University, Taiyuan, Shanxi 030001, P.R. China
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9
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Vestre K, Kjos I, Guadagno NA, Borg Distefano M, Kohler F, Fenaroli F, Bakke O, Progida C. Rab6 regulates cell migration and invasion by recruiting Cdc42 and modulating its activity. Cell Mol Life Sci 2019; 76:2593-2614. [PMID: 30830239 PMCID: PMC11105640 DOI: 10.1007/s00018-019-03057-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 12/22/2022]
Abstract
Rab proteins are master regulators of intracellular membrane trafficking, but they also contribute to cell division, signaling, polarization, and migration. The majority of the works describing the mechanisms used by Rab proteins to regulate cell motility involve intracellular transport of key molecules important for migration. Interestingly, a few studies indicate that Rabs can modulate the activity of Rho GTPases, important regulators for the cytoskeleton rearrangements, but the mechanisms behind this crosstalk are still poorly understood. In this work, we identify Rab6 as a negative regulator of cell migration in vitro and in vivo. We show that the loss of Rab6 promotes formation of actin protrusions and influences actomyosin dynamics by upregulating Cdc42 activity and downregulating myosin II phosphorylation. We further provide the molecular mechanism behind this regulation demonstrating that Rab6 interacts with both Cdc42 and Trio, a GEF for Cdc42. In sum, our results uncover a mechanism used by Rab proteins to ensure spatial regulation of Rho GTPase activity for coordination of cytoskeleton rearrangements required in migrating cells.
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Affiliation(s)
- Katharina Vestre
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Ingrid Kjos
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Noemi Antonella Guadagno
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Marita Borg Distefano
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Felix Kohler
- Department of Physics, The NJORD Centre, University of Oslo, Oslo, Norway
| | | | - Oddmund Bakke
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences, University of Oslo, Oslo, Norway.
- Centre for Immune Regulation, University of Oslo, Oslo, Norway.
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Abstract
Fertilizable eggs develop from diploid precursor cells termed oocytes. Once every menstrual cycle, an oocyte matures into a fertilizable egg in the ovary. To this end, the oocyte eliminates half of its chromosomes into a small cell termed a polar body. The egg is then released into the Fallopian tube, where it can be fertilized. Upon fertilization, the egg completes the second meiotic division, and the mitotic division of the embryo starts. This review highlights recent work that has shed light on the cytoskeletal structures that drive the meiotic divisions of the oocyte in mammals. In particular, we focus on how mammalian oocytes assemble a microtubule spindle in the absence of centrosomes, how they position the spindle in preparation for polar body extrusion, and how the spindle segregates the chromosomes. We primarily focus on mouse oocytes as a model system but also highlight recent insights from human oocytes.
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Affiliation(s)
- Binyam Mogessie
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Current affiliation: School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Kathleen Scheffler
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
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11
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Mansur N, Raziul Hasan M, Shah ZI, Villarreal FJ, Kim YT, Iqbal SM. Discrimination of metastatic breast cancer cells from indolent cells on aptamer-functionalized surface with imaging-based contour-following techniques. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aa942a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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12
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Mansur N, Raziul Hasan M, Kim YT, Iqbal SM. Functionalization of nanotextured substrates for enhanced identification of metastatic breast cancer cells. NANOTECHNOLOGY 2017; 28:385101. [PMID: 28703710 DOI: 10.1088/1361-6528/aa7f84] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metastasis is the major cause of low survival rates among cancer patients. Once cancer cells metastasize, it is extremely difficult to contain the disease. We report on a nanotextured platform for enhanced detection of metastatic cells. We captured metastatic (MDA-MDB-231) and non-metastatic (MCF-7) breast cancer cells on anti-EGFR aptamer modified plane and nanotextured substrates. Metastatic cells were seen to change their morphology at higher rates when captured on nanotextured substrates than on plane substrates. Analysis showed statistically different morphological behaviors of metastatic cells that were very pronounced on the nanotextured substrates. Several distance matrices were calculated to quantify the dissimilarity of cell shape change. Nanotexturing increased the dissimilarity of the metastatic cells and as a result the contrast between metastatic and non-metastatic cells increased. Jaccard distance measurements found that the shape change ratio of the non-metastatic and metastatic cells was enhanced from 1:1.01 to 1:1.81, going from plane to nanotextured substrates. The shape change ratio of the non-metastatic to metastatic cells improved from 1:1.48 to 1:2.19 for the Hausdorff distance and from 1:1.87 to 1:4.69 for the Mahalanobis distance after introducing nanotexture. Distance matrix analysis showed that nanotexture increased the shape change ratios of non-metastatic and metastatic cells. Hence, the detectability of metastatic cells increased. These calculated matrices provided clear and explicit measures to discriminate single cells for their metastatic state on functional nanotextured substrates.
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Affiliation(s)
- Nuzhat Mansur
- Nano-Bio Lab, University of Texas at Arlington, Arlington, Texas 76019, United States of America. Department of Electrical Engineering, University of Texas at Arlington, Arlington, Texas 76019, United States of America. Nanotechnology Research Center, University of Texas at Arlington, Arlington, Texas 76019, United States of America
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13
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Abstract
Malignant carcinomas are often characterized by metastasis, the movement of carcinoma cells from a primary site to colonize distant organs. For metastasis to occur, carcinoma cells first must adopt a pro-migratory phenotype and move through the surrounding stroma towards a blood or lymphatic vessel. Currently, there are very limited possibilities to target these processes therapeutically. The family of Rho GTPases is an ubiquitously expressed division of GTP-binding proteins involved in the regulation of cytoskeletal dynamics and intracellular signaling. The best characterized members of the Rho family GTPases are RhoA, Rac1 and Cdc42. Abnormalities in Rho GTPase function have major consequences for cancer progression. Rho GTPase activation is driven by cell surface receptors that activate GTP exchange factors (GEFs) and GTPase-activating proteins (GAPs). In this review, we summarize our current knowledge on Rho GTPase function in the regulation of metastasis. We will focus on key discoveries in the regulation of epithelial-mesenchymal-transition (EMT), cell-cell junctions, formation of membrane protrusions, plasticity of cell migration and adaptation to a hypoxic environment. In addition, we will emphasize on crosstalk between Rho GTPase family members and other important oncogenic pathways, such as cyclic AMP-mediated signaling, canonical Wnt/β-catenin, Yes-associated protein (YAP) and hypoxia inducible factor 1α (Hif1α) and provide an overview of the advancements and challenges in developing pharmacological tools to target Rho GTPase and the aforementioned crosstalk in the context of cancer therapeutics.
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Integrin-Dependent Regulation of Small GTPases: Role in Cell Migration. J Indian Inst Sci 2017. [DOI: 10.1007/s41745-016-0010-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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15
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Receptor-stimulated transamidation induces activation of Rac1 and Cdc42 and the regulation of dendritic spines. Neuropharmacology 2017; 117:93-105. [PMID: 28161375 DOI: 10.1016/j.neuropharm.2017.01.034] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/26/2017] [Accepted: 01/29/2017] [Indexed: 11/21/2022]
Abstract
Regulation of dendritic spines is an important component of synaptic function and plasticity whereas dendritic spine dysregulation is related to several psychiatric and neurological diseases. In the present study, we tested the hypothesis that serotonin (5-HT)2A/2C receptor-induced Rho family transamidation and activation regulates dendritic spine morphology and that activation of multiple types of receptors can induce transglutaminase (TGase)-catalyzed transamidation of small G proteins. We previously reported a novel 5-HT2A receptor downstream effector, TGase-catalyzed serotonylation of the small G protein Rac1 in A1A1v cells, a rat embryonic cortical cell line. We now extend these findings to rat primary cortical cultures which develop dendritic spines; stimulation of 5-HT2A/2C receptors increased transamidation of Rac1 and Cdc42, but not RhoA. Inhibition of TGases significantly decreased transamidation and activation of Rac1 and Cdc42, suggesting that transamidation led to their activation. In primary cortical cultures, stimulation of 5-HT2A/2C receptors by 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) caused a transient dendritic spine enlargement, which was blocked by TGase inhibition. Stimulation of both 5-HT2A and 5-HT2C receptors contributed to DOI-induced Rac1 transamidation in primary cortical cultures as demonstrated by selective antagonists. Furthermore, stimulation of muscarinic acetylcholine receptors and NMDA receptors also increased TGase-catalyzed Rac1 activation in SH-SY5Y cells and N2a cells, respectively. Receptor-stimulated TGase-catalyzed transamidation of Rac1 occurs at Q61, a site previously reported to be important in the inactivation of Rac1. These studies demonstrate that TGase-catalyzed transamidation and activation of small G proteins results from stimulation of multiple types of receptors and this novel signaling pathway can regulate dendritic spine morphology and plasticity.
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Yap CV, Subramaniam KS, Khor SW, Chung I. Annonacin Exerts Antitumor Activity through Induction of Apoptosis and Extracellular Signal-regulated Kinase Inhibition. Pharmacognosy Res 2017; 9:378-383. [PMID: 29263632 PMCID: PMC5717791 DOI: 10.4103/pr.pr_19_17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background: Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries. Annonacin, a natural pure compound extracted from the seeds of Annona muricata, is a potential alternative therapeutic agent to treat EC. Objective: To study the antitumor activity of annonacin and its mechanism of action in EC cells (ECCs). Materials and Methods: Viability of ECCs treated with annonacin for 72 h was determined using methyl thiazolyl tetrazolium assay. The induction of cell cycle arrest and apoptotic cell death was evaluated using propidium iodide and annexin V-PE/7-AAD assay, respectively. DNA strand breaks were visualized using transferase dUTP nick end labeling assay, and the effects of annonacin on survival signaling were determined using western blotting. Results: Annonacin exhibited antiproliferative effects on EC cell lines (ECC-1 and HEC-1A) and primary cells (EC6-ept and EC14-ept) with EC50values ranging from 4.62 to 4.92 μg/ml. EC cells were shown arrested at G2/M phase after treated with 4 μg/ml of annonacin for 72 h. This led to a significant increase in apoptotic cell death (65.7%) in these cells when compared to vehicle-treated cells (P < 0.005). We further showed that annonacin-mediated apoptotic cell death was associated with an increase in caspase-3 cleavage and DNA fragmentation. Cell apoptosis was accompanied with downregulation of extracellular signal-regulated kinase survival protein expression and induction of G2/M cell cycle arrest. Conclusion: Annonacin may be a potential novel therapeutic agent for EC patients. SUMMARY We aimed to study the antitumor activity of annonacin and its mechanism of action in endometrial cancer cells. Annonacin exerted antiproliferation effects on both endometrial cancer cell lines and primary cells via induction of apoptosis and inhibition of extracellular signal-regulated kinase. Our data represented that annonacin could be an alternative therapeutic treatment to combat endometrial cancer.
Abbreviations Used: 7-AAD: 7-Amino-Actinomycin, ATP: Adenosine diphosphate, BSA: Bovine serum albumin, DNA: Deoxyribonucleic acid, EC: Endometrial cancer, ECC-1: Endometrial cancer cell-1, EC50: Half maximal effective concentration, Ept: Epithelial, FBS: Fetal bovine serum, HEC-1A: Human endometrial carcinoma-1A, MTT: Methyl thiazolyl tetrazolium, NaCl: Sodium chloride, NADH: Nicotinamide adenine dinucleotide, RPMI 1640: Roswell Park Memorial Institute Medium, SDS: Sodium dodecyl sulfate
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Affiliation(s)
- Chee Voon Yap
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.,Department of Pharmacology, UM Cancer Research Institute, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Kavita S Subramaniam
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.,Department of Pharmacology, UM Cancer Research Institute, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Sik Wey Khor
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.,Department of Pharmacology, UM Cancer Research Institute, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
| | - Ivy Chung
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia.,Department of Pharmacology, UM Cancer Research Institute, Faculty of Medicine, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia
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Wigton EJ, Thompson SB, Long RA, Jacobelli J. Myosin-IIA regulates leukemia engraftment and brain infiltration in a mouse model of acute lymphoblastic leukemia. J Leukoc Biol 2016; 100:143-53. [PMID: 26792819 DOI: 10.1189/jlb.1a0815-342r] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 01/04/2016] [Indexed: 01/07/2023] Open
Abstract
Leukemia dissemination (the spread of leukemia cells from the bone marrow) and relapse are associated with poor prognosis. Often, relapse occurs in peripheral organs, such as the CNS, which acts as a sanctuary site for leukemia cells to escape anti-cancer treatments. Similar to normal leukocyte migration, leukemia dissemination entails migration of cells from the blood circulation into tissues by extravasation. To extravasate, leukemia cells cross through vascular endothelial walls via a process called transendothelial migration, which requires cytoskeletal remodeling. However, the specific molecular players in leukemia extravasation are not fully known. We examined the role of myosin-IIA a cytoskeletal class II myosin motor protein, in leukemia progression and dissemination into the CNS by use of a mouse model of Bcr-Abl-driven B cell acute lymphoblastic leukemia. Small hairpin RNA-mediated depletion of myosin-IIA did not affect apoptosis or the growth rate of B cell acute lymphoblastic leukemia cells. However, in an in vivo leukemia transfer model, myosin-IIA depletion slowed leukemia progression and prolonged survival, in part, by reducing the ability of B cell acute lymphoblastic leukemia cells to engraft efficiently. Finally, myosin-IIA inhibition, either by small hairpin RNA depletion or chemical inhibition by blebbistatin, drastically reduced CNS infiltration of leukemia cells. The effects on leukemia cell entry into tissues were mostly a result of the requirement for myosin-IIA to enable leukemia cells to complete the transendothelial migration process during extravasation. Overall, our data implicate myosin-IIA as a key mediator of leukemia cell migration, making it a promising target to inhibit leukemia dissemination in vivo and potentially reduce leukemia relapses.
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Affiliation(s)
- Eric J Wigton
- Department of Biomedical Research, National Jewish Health, Denver, Colorado, USA; and
| | - Scott B Thompson
- Department of Biomedical Research, National Jewish Health, Denver, Colorado, USA; and Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Colorado, USA
| | - Robert A Long
- Department of Biomedical Research, National Jewish Health, Denver, Colorado, USA; and
| | - Jordan Jacobelli
- Department of Biomedical Research, National Jewish Health, Denver, Colorado, USA; and Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Colorado, USA
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MacKay JL, Kumar S. Simultaneous and independent tuning of RhoA and Rac1 activity with orthogonally inducible promoters. Integr Biol (Camb) 2015; 6:885-94. [PMID: 25044255 DOI: 10.1039/c4ib00099d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The GTPases RhoA and Rac1 are key regulators of cell spreading, adhesion, and migration, and they exert distinct effects on the actin cytoskeleton. While RhoA classically stimulates stress fiber assembly and contraction, Rac1 promotes branched actin polymerization and membrane protrusion. These competing influences are reinforced by antagonistic crosstalk between RhoA and Rac1, which has complicated efforts to identify the specific mechanisms by which each GTPase regulates cell behavior. We therefore wondered whether RhoA and Rac1 are intrinsically coupled or whether they can be manipulated independently. To address this question, we placed constitutively active (CA) RhoA under a doxycycline-inducible promoter and CA Rac1 under an orthogonal cumate-inducible promoter, and we stably introduced both constructs into glioblastoma cells. We found that doxycycline addition increased RhoA activity without altering Rac1, and similarly cumate addition increased Rac1 activity without altering RhoA. Furthermore, co-expression of both mutants enabled high activation of RhoA and Rac1 simultaneously. When cells were cultured on collagen hydrogels, RhoA activation prevented cell spreading and motility, whereas Rac1 activation stimulated migration and dynamic cell protrusions. Interestingly, high activation of both GTPases induced a third phenotype, in which cells migrated at intermediate speeds similar to control cells but also aggregated into large, contractile clusters. In addition, we demonstrate dynamic and reversible switching between high RhoA and high Rac1 phenotypes. Overall, this approach represents a unique way to access different combinations of RhoA and Rac1 activity levels in a single cell and may serve as a valuable tool for multiplexed dissection and control of mechanobiological signals.
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Affiliation(s)
- Joanna L MacKay
- Department of Chemical and Biomolecular Engineering, University of California-Berkeley, Berkeley, California 94720, USA
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19
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Rac1 GTPase-deficient HeLa cells present reduced DNA repair, proliferation, and survival under UV or gamma irradiation. Mol Cell Biochem 2015; 404:281-97. [DOI: 10.1007/s11010-015-2388-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/05/2015] [Indexed: 12/21/2022]
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20
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Twal WO, Hammad SM, Guffy SL, Argraves WS. A novel intracellular fibulin-1D variant binds to the cytoplasmic domain of integrin beta 1 subunit. Matrix Biol 2015; 43:97-108. [PMID: 25661773 DOI: 10.1016/j.matbio.2015.01.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/26/2015] [Accepted: 01/26/2015] [Indexed: 01/03/2023]
Abstract
Fibulin-1 is a member of a growing family of proteins that includes eight members and is involved in cellular functions such as adhesion, migration and differentiation. Fibulin-1 has also been implicated in embryonic development of the heart and neural crest-derived structures. It is an integral part of the extracellular matrix (ECM) and has been shown to bind to a multitude of ECM proteins. However, fibulin-1 was first identified as a protein purified from placental extracts that binds to the cytoplasmic domain of integrin β1. Human fibulin-1 is alternatively spliced into four different isoforms namely A-D. These isoforms share a common N-terminus sequence that contains a secretion sequence but differ in their carboxy-terminal fibulin-1 module. In this report we identify a new splice variant of fibulin-1 that differs from all other fibulin-1 variants in the N-terminus sequence and has a similar carboxy-terminus sequence as fibulin-1D. This variant that we named fibulin-1D prime (fibulin-1D') lacks a secretion sequence and the anaphlatoxin region of fibulin-1 variants. The protein has an apparent molecular weight of 70.5kDa. Herein we show that fibulin-1D' binds to the intracellular domain of integrin β1 as well as to integrin α5β1. The protein was localized intracellularly in CHO cells transfected with a pEF4 plasmid containing full-length coding sequence of fibulin-1D'. We also localized the protein in human placenta. We propose that the fibulin-1D' variant might play a role in early embryo development as well as in modulating integrin β1 functions including adhesion and motility.
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Affiliation(s)
- Waleed O Twal
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, MSC 508, Charleston, SC 29412, USA.
| | - Samar M Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, MSC 508, Charleston, SC 29412, USA.
| | - Sharon L Guffy
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, MSC 508, Charleston, SC 29412, USA
| | - William S Argraves
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 173 Ashley Avenue, MSC 508, Charleston, SC 29412, USA
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Dulyaninova NG, Bresnick AR. The heavy chain has its day: regulation of myosin-II assembly. BIOARCHITECTURE 2015; 3:77-85. [PMID: 24002531 DOI: 10.4161/bioa.26133] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nonmuscle myosin-II is an actin-based motor that converts chemical energy into force and movement, and thus functions as a key regulator of the eukaryotic cytoskeleton. Although it is established that phosphorylation on the regulatory light chain increases the actin-activated MgATPase activity of the motor and promotes myosin-II filament assembly, studies have begun to characterize alternative mechanisms that regulate filament assembly and disassembly. These investigations have revealed that all three nonmuscle myosin-II isoforms are subject to additional regulatory controls, which impact diverse cellular processes. In this review, we discuss current knowledge on mechanisms that regulate the oligomerization state of nonmuscle myosin-II filaments by targeting the myosin heavy chain.
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Pasapera AM, Plotnikov SV, Fischer RS, Case LB, Egelhoff TT, Waterman CM. Rac1-dependent phosphorylation and focal adhesion recruitment of myosin IIA regulates migration and mechanosensing. Curr Biol 2014; 25:175-186. [PMID: 25544611 DOI: 10.1016/j.cub.2014.11.043] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 07/14/2014] [Accepted: 11/14/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Cell migration requires coordinated formation of focal adhesions (FAs) and assembly and contraction of the actin cytoskeleton. Nonmuscle myosin II (MII) is a critical mediator of contractility and FA dynamics in cell migration. Signaling downstream of the small GTPase Rac1 also regulates FA and actin dynamics, but its role in regulation of MII during migration is less clear. RESULTS We found that Rac1 promotes association of MIIA with FA. Live-cell imaging showed that, whereas most MIIA at the leading edge assembled into dorsal contractile arcs, a substantial subset assembled in or was captured within maturing FA, and this behavior was promoted by active Rac1. Protein kinase C (PKC) activation was necessary and sufficient for integrin- and Rac1-dependent phosphorylation of MIIA heavy chain (HC) on serine1916 (S1916) and recruitment to FA. S1916 phosphorylation of MIIA HC and localization in FA was enhanced during cell spreading and ECM stiffness mechanosensing, suggesting upregulation of this pathway during physiological Rac1 activation. Phosphomimic and nonphosphorylatable MIIA HC mutants demonstrated that S1916 phosphorylation was necessary and sufficient for the capture and assembly of MIIA minifilaments in FA. S1916 phosphorylation was also sufficient to promote the rapid assembly of FAs to enhance cell migration and for the modulation of traction force, spreading, and migration by ECM stiffness. CONCLUSIONS Our study reveals for the first time that Rac1 and integrin activation regulates MIIA HC phosphorylation through a PKC-dependent mechanism that promotes MIIA association with FAs and acts as a critical modulator of cell migration and mechanosensing.
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Affiliation(s)
- Ana M Pasapera
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sergey V Plotnikov
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Robert S Fischer
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lindsay B Case
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas T Egelhoff
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Clare M Waterman
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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You E, Park S, Kim D, Jung J, Ko P, Park CM, Rhee S. Role of the intracellular juxtamembrane domain of discoidin domain receptor 2 in focal adhesion formation. Anim Cells Syst (Seoul) 2014. [DOI: 10.1080/19768354.2014.969770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Nayak RC, Chang KH, Vaitinadin NS, Cancelas JA. Rho GTPases control specific cytoskeleton-dependent functions of hematopoietic stem cells. Immunol Rev 2014; 256:255-68. [PMID: 24117826 DOI: 10.1111/imr.12119] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Rho family of guanosine triphosphatases (GTPases) is composed of members of the Ras superfamily of proteins. They are GTP-bound molecules with a modest intrinsic GTPase activity that can be accelerated upon activation/localization of specialized guanine nucleotide exchange factors. Members of this family act as molecular switches and are required for coordinated cytoskeletal rearrangements that are crucial in a set of specialized functions of mammalian stem cells. These functions include self-renewal, adhesion, and migration. Mouse gene-targeting studies have provided convincing evidence of the indispensable and dispensable roles of individual members of the Rho GTPase family and the putative upstream and downstream mediators in stem cell-specific functions. The role of Rho GTPases and related signaling pathways previously seen in other cell types and organisms have been confirmed in mammalian hematopoietic stem cells (HSCs), and new signaling pathways and unexpected functions unique to HSCs have been identified and dissected. This review summarizes our current understanding of the role of Rho family of GTPases on HSC and progenitor activity through cytoskeleton-mediated signaling pathways, providing insight about relevant signaling pathways that regulate mammalian stem cell self-renewal, adhesion, and migration.
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Affiliation(s)
- Ramesh C Nayak
- Stem Cell Program, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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Non-muscle myosin II regulates neuronal actin dynamics by interacting with guanine nucleotide exchange factors. PLoS One 2014; 9:e95212. [PMID: 24752242 PMCID: PMC3994028 DOI: 10.1371/journal.pone.0095212] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 03/25/2014] [Indexed: 11/24/2022] Open
Abstract
Background Non-muscle myosin II (NM II) regulates a wide range of cellular functions, including neuronal differentiation, which requires precise spatio-temporal activation of Rho GTPases. The molecular mechanism underlying the NM II-mediated activation of Rho GTPases is poorly understood. The present study explored the possibility that NM II regulates neuronal differentiation, particularly morphological changes in growth cones and the distal axon, through guanine nucleotide exchange factors (GEFs) of the Dbl family. Principal Findings NM II colocalized with GEFs, such as βPIX, kalirin and intersectin, in growth cones. Inactivation of NM II by blebbistatin (BBS) led to the increased formation of short and thick filopodial actin structures at the periphery of growth cones. In line with these observations, FRET analysis revealed enhanced Cdc42 activity in BBS-treated growth cones. BBS treatment also induced aberrant targeting of various GEFs to the distal axon where GEFs were seldom observed under physiological conditions. As a result, numerous protrusions and branches were generated on the shaft of the distal axon. The disruption of the NM II–GEF interactions by overexpression of the DH domains of βPIX or Tiam1, or by βPIX depletion with specific siRNAs inhibited growth cone formation and induced slender axons concomitant with multiple branches in cultured hippocampal neurons. Finally, stimulation with nerve growth factor induced transient dissociation of the NM II–GEF complex, which was closely correlated with the kinetics of Cdc42 and Rac1 activation. Conclusion Our results suggest that NM II maintains proper morphology of neuronal growth cones and the distal axon by regulating actin dynamics through the GEF–Rho GTPase signaling pathway.
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Natarajan P, Crothers JM, Rosen JE, Nakada SL, Rakholia M, Okamoto CT, Forte JG, Machen TE. Myosin IIB and F-actin control apical vacuolar morphology and histamine-induced trafficking of H-K-ATPase-containing tubulovesicles in gastric parietal cells. Am J Physiol Gastrointest Liver Physiol 2014; 306:G699-710. [PMID: 24578340 PMCID: PMC3989701 DOI: 10.1152/ajpgi.00316.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Selective inhibitors of myosin or actin function and confocal microscopy were used to test the role of an actomyosin complex in controlling morphology, trafficking, and fusion of tubulovesicles (TV) containing H-K-ATPase with the apical secretory canaliculus (ASC) of primary-cultured rabbit gastric parietal cells. In resting cells, myosin IIB and IIC, ezrin, and F-actin were associated with ASC, whereas H-K-ATPase localized to intracellular TV. Histamine caused fusion of TV with ASC and subsequent expansion resulting from HCl and water secretion; F-actin and ezrin remained associated with ASC whereas myosin IIB and IIC appeared to dissociate from ASC and relocalize to the cytoplasm. ML-7 (inhibits myosin light chain kinase) caused ASC of resting cells to collapse and most myosin IIB, F-actin, and ezrin to dissociate from ASC. TV were unaffected by ML-7. Jasplakinolide (stabilizes F-actin) caused ASC to develop large blebs to which actin, myosin II, and ezrin, as well as tubulin, were prominently localized. When added prior to stimulation, ML-7 and jasplakinolide prevented normal histamine-stimulated transformations of ASC/TV and the cytoskeleton, but they did not affect cells that had been previously stimulated with histamine. These results indicate that dynamic pools of actomyosin are required for maintenance of ASC structure in resting cells and for trafficking of TV to ASC during histamine stimulation. However, the dynamic pools of actomyosin are not required once the histamine-stimulated transformation of TV/ASC and cytoskeleton has occurred. These results also show that vesicle trafficking in parietal cells shares mechanisms with similar processes in renal collecting duct cells, neuronal synapses, and skeletal muscle.
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Affiliation(s)
- Paramasivam Natarajan
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - James M. Crothers
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Jared E. Rosen
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Stephanie L. Nakada
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Milap Rakholia
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Curtis T. Okamoto
- 2Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | - John G. Forte
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
| | - Terry E. Machen
- 1Department of Molecular and Cell Biology, University of California, Berkeley, California; and
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FilGAP and its close relatives: a mediator of Rho-Rac antagonism that regulates cell morphology and migration. Biochem J 2013; 453:17-25. [PMID: 23763313 DOI: 10.1042/bj20130290] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cell migration, phagocytosis and cytokinesis are mechanically intensive cellular processes that are mediated by the dynamic assembly and contractility of the actin cytoskeleton. GAPs (GTPase-activating proteins) control activities of the Rho family proteins including Cdc42, Rac1 and RhoA, which are prominent upstream regulators of the actin cytoskeleton. The present review concerns a class of Rho GAPs, FilGAP (ARHGAP24 gene product) and its close relatives (ARHGAP22 and AHRGAP25 gene products). FilGAP is a GAP for Rac1 and a binding partner of FLNa (filamin A), a widely expressed F-actin (filamentous actin)-cross-linking protein that binds many different proteins that are important in cell regulation. Phosphorylation of FilGAP serine/threonine residues and binding to FLNa modulate FilGAP's GAP activity and, as a result, its ability to regulate cell protrusion and spreading. FLNa binds to FilGAP at F-actin-enriched sites, such as at the leading edge of the cell where Rac1 activity is controlled to inhibit actin assembly. FilGAP then dissociates from FLNa in actin networks by myosin-dependent mechanical deformation of FLNa's FilGAP-binding site to relocate at the plasma membrane by binding to polyphosphoinositides. Since actomyosin contraction is activated downstream of RhoA-ROCK (Rho-kinase), RhoA activity regulates Rac1 through FilGAP by signalling to the force-generating system. FilGAP and the ARHGAP22 gene product also act as mediators between RhoA and Rac1 pathways, which lead to amoeboid and mesenchymal modes of cell movements respectively. Therefore FilGAP and its close relatives are key regulators that promote the reciprocal inhibitory relationship between RhoA and Rac1 in cell shape changes and the mesenchymal-amoeboid transition in tumour cells.
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Cytoskeleton and nucleotide signaling in glioma C6 cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 986:103-19. [PMID: 22879066 DOI: 10.1007/978-94-007-4719-7_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This chapter describes signaling pathways stimulated by the P2Y(2) nucleotide receptor (P2Y(2)R), that regulate cellular processes dependent on actin cytoskeleton dynamics in glioma C6 cells. P2Y(2)R coupled with G-proteins, in response to ATP or UTP, regulates the level of phosphatidylinositol-4,5-bisphosphate (PIP(2)) which modulates a variety of actin binding proteins and is involved in calcium response and activates Rac1 and RhoA proteins. The RhoA/ROCK signaling pathway plays an important role in contractile force generation needed for the assembly of stress fibers, focal adhesions and for tail retraction during cell migration. Blocking of this pathway by a specific Rho-kinase inhibitor induces changes in F-actin organization and cell shape and decreases the level of phosphorylated myosin II and cofilin. In glioma C6 cells these changes are reversed after UTP stimulation of P2Y(2)R. Signaling pathways responsible for this compensation are connected with calcium signaling. Stimulation of the Rac1 mediated pathway via G(o) proteins needs additional interaction between α(v)β(5) integrins and P2Y(2)Rs. Rac1 activation is necessary for cofilin phosphorylation as well as integrin activation needed for focal complexes formation and stabilization of lamellipodium. Inhibition of positive Rac1 regulation prevents glioma C6 cells from recovery of control cell like morphology.
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Lontay B, Pál B, Serfőző Z, Kőszeghy Á, Szücs G, Rusznák Z, Erdődi F. Protein phosphatase-1M and Rho-kinase affect exocytosis from cortical synaptosomes and influence neurotransmission at a glutamatergic giant synapse of the rat auditory system. J Neurochem 2012; 123:84-99. [PMID: 22817114 DOI: 10.1111/j.1471-4159.2012.07882.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein phosphatase-1M (PP1M, myosin phosphatase) consists of a PP1 catalytic subunit (PP1c) and the myosin phosphatase target subunit-1 (MYPT1). RhoA-activated kinase (ROK) regulates PP1M via inhibitory phosphorylation of MYPT1. Using multidisciplinary approaches, we have studied the roles of PP1M and ROK in neurotransmission. Electron microscopy demonstrated the presence of MYPT1 and ROK in both pre- and post-synaptic terminals. Tautomycetin (TMC), a PP1-specific inhibitor, decreased the depolarization-induced exocytosis from cortical synaptosomes. trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide dihydrochloride, a ROK-specific inhibitor, had the opposite effect. Mass spectrometry analysis identified several MYPT1-bound synaptosomal proteins, of which interactions of synapsin-I, syntaxin-1, calcineurin-A subunit, and Ca(2+) /calmodulin-dependent kinase II with MYPT1 were confirmed. In intact synaptosomes, TMC increased, whereas Y27632 decreased the phosphorylation levels of MYPT1(Thr696) , myosin-II light chain(Ser19) , synapsin-I(Ser9) , and syntaxin-1(Ser14) , indicating that PP1M and ROK influence their phosphorylation status. Confocal microscopy indicated that MYPT1 and ROK are present in the rat ventral cochlear nucleus both pre- and post-synaptically. Analysis of the neurotransmission in an auditory glutamatergic giant synapse demonstrated that PP1M and ROK affect neurotransmission via both pre- and post-synaptic mechanisms. Our data suggest that both PP1M and ROK influence synaptic transmission, but further studies are needed to give a full account of their mechanism of action.
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Affiliation(s)
- Beáta Lontay
- Department of Medical Chemistry and Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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Park YM, Drazba JA, Vasanji A, Egelhoff T, Febbraio M, Silverstein RL. Oxidized LDL/CD36 interaction induces loss of cell polarity and inhibits macrophage locomotion. Mol Biol Cell 2012; 23:3057-68. [PMID: 22718904 PMCID: PMC3418302 DOI: 10.1091/mbc.e11-12-1051] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 04/30/2012] [Accepted: 06/13/2012] [Indexed: 02/06/2023] Open
Abstract
Cell polarization is essential for migration and the exploratory function of leukocytes. However, the mechanism by which cells maintain polarity or how cells revert to the immobilized state by gaining cellular symmetry is not clear. Previously we showed that interaction between oxidized low-density lipoprotein (oxLDL) and CD36 inhibits macrophage migration; in the current study we tested the hypothesis that oxLDL/CD36-induced inhibition of migration is the result of intracellular signals that regulate cell polarity. Live cell imaging of macrophages showed that oxLDL actuated retraction of macrophage front end lamellipodia and induced loss of cell polarity. Cd36 null and macrophages null for Vav, a guanine nucleotide exchange factor (GEF), did not show this effect. These findings were caused by Rac-mediated inhibition of nonmuscle myosin II, a cell polarity determinant. OxLDL induced dephosphorylation of myosin regulatory light chain (MRLC) by increasing the activity of Rac. Six-thioguanine triphosphate (6-thio-GTP), which inhibits Vav-mediated activation of Rac, abrogated the effect of oxLDL. Activation of the Vav-Rac-myosin II pathway by oxidant stress may induce trapping of macrophages at sites of chronic inflammation such as atherosclerotic plaque.
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Affiliation(s)
- Young Mi Park
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
| | - Judith A. Drazba
- Imaging Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Amit Vasanji
- Biomedical Imaging and Analysis Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Thomas Egelhoff
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
| | - Maria Febbraio
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
| | - Roy L. Silverstein
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195
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TGFβ1 regulates endothelial cell spreading and hypertrophy through a Rac-p38-mediated pathway. Biol Cell 2012; 100:537-50. [DOI: 10.1042/bc20080021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Ruiz-Loredo AY, López-Colomé AM. New insights into the regulation of myosin light chain phosphorylation in retinal pigment epithelial cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:85-121. [PMID: 22251559 DOI: 10.1016/b978-0-12-394304-0.00008-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The retinal pigment epithelium (RPE) plays an essential role in the function of the neural retina and the maintenance of vision. Most of the functions displayed by RPE require a dynamic organization of the acto-myosin cytoskeleton. Myosin II, a main cytoskeletal component in muscle and non-muscle cells, is directly involved in force generation required for organelle movement, selective molecule transport within cell compartments, exocytosis, endocytosis, phagocytosis, and cell division, among others. Contractile processes are triggered by the phosphorylation of myosin II light chains (MLCs), which promotes actin-myosin interaction and the assembly of contractile fibers. Considerable evidence indicates that non-muscle myosin II activation is critically involved in various pathological states, increasing the interest in studying the signaling pathways controlling MLC phosphorylation. Particularly, recent findings suggest a role for non-muscle myosin II-induced contraction in RPE cell transformation involved in the establishment of numerous retinal diseases. This review summarizes the current knowledge regarding myosin function in RPE cells, as well as the signaling networks leading to MLC phosphorylation under pathological conditions. Understanding the molecular mechanisms underlying RPE dysfunction would improve the development of new therapies for the treatment or prevention of different ocular disorders leading to blindness.
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Affiliation(s)
- Ariadna Yolanda Ruiz-Loredo
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico DF, Mexico
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Zhou L, Zhang Z, Zheng Y, Zhu Y, Wei Z, Xu H, Tang Q, Kong X, Hu L. SKAP2, a novel target of HSF4b, associates with NCK2/F-actin at membrane ruffles and regulates actin reorganization in lens cell. J Cell Mol Med 2011; 15:783-95. [PMID: 20219016 PMCID: PMC3922667 DOI: 10.1111/j.1582-4934.2010.01048.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In addition to roles in stress response, heat shock factors (HSFs) play crucial roles in differentiation and development. Heat shock transcription factor 4 (HSF4) deficiency leads to defect in lens epithelial cell (LEC) differentiation and cataract formation. However, the mechanism remains obscure. Here, we identified Src kinase-associated phosphoprotein 2 (SKAP2) as a downstream target of HSF4b and it was highly expressed at the anterior tip of lens elongating fibre cells in vivo. The HSF4-deficient lenses showed reduced SKAP2 expression and defects in actin reorganization. The disassembly of stress fibres and formation of cortical actin fibres are critical for the initiation of LEC differentiation. SKAP2 localized at actin-rich ruffles in human LECs (SRA01/04 cells) and knockdown SKAP2 using RNA interference impaired the disassembly of cellular stress fibres in response to fibroblast growth factor (FGF)-b. Overexpression of SKAP2, but not the N-terminal deletion mutant of SKAP2, induced the actin remodelling. We further found that SKAP2 interacted with the SH2 domain of non-catalytic region of tyrosine kinase adaptor protein 2 (NCK2) via its N-terminus. The complex of SKAP2-NCK2-F-actin accumulated at the leading edge of the lamellipodium, where FGF receptors and focal adhesion were also recruited. These results revealed an essential role for HSF4-mediated SKAP2 expression in the regulation of actin reorganization during lens differentiation, likely through a mechanism that SKAP2 anchors the complex of NCK2/focal adhesion to FGF receptors at the lamellipodium in lens epithelial cells.
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Affiliation(s)
- Li Zhou
- The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS) & Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, People's Republic of China
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Moore CC, Lakner AM, Yengo CM, Schrum LW. Nonmuscle myosin II regulates migration but not contraction in rat hepatic stellate cells. World J Hepatol 2011; 3:184-97. [PMID: 21866250 PMCID: PMC3158907 DOI: 10.4254/wjh.v3.i7.184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 05/06/2011] [Accepted: 05/13/2011] [Indexed: 02/06/2023] Open
Abstract
AIM To identify and characterize the function of nonmuscle myosin II (NMM II) isoforms in primary rat hepatic stellate cells (HSCs). METHODS Primary HSCs were isolated from male Sprague-Dawley rats by pronase/collagenase digestion. Total RNA and protein were harvested from quiescent and culture-activated HSCs. NMM II isoform (II-A, II-B and II-C) gene and protein expression were measured by RealTime polymerase chain reaction and Western blot analyses respectively. NMM II protein localization was visualized in vitro using immunocytochemical analysis. For in vivo assessment, liver tissue was harvested from bile duct-ligated (BDL) rats and NMM IIisoform expression determined by immunohistochemistry. Using a selective myosin II inhibitor and siRNA-mediated knockdown of each isoform, NMM II functionality in primary rat HSCs was determined by contraction and migration assays. RESULTS NMM II-A and II-B mRNA expression was increased in culture-activated HSCs (Day 14) with significant increases seen in all pair-wise comparisons (II-A: 12.67 ± 0.99 (quiescent) vs 17.36 ± 0.78 (Day 14), P < 0.05; II-B: 4.94 ± 0.62 (quiescent) vs 13.90 ±0.85 (Day 14), P < 0.001). Protein expression exhibited similar expression patterns (II-A: 1.87 ± 2.50 (quiescent) vs 58.64 ± 8.76 (Day 14), P < 0.05; II-B: 1.17 ± 1.93 (quiescent) vs 103.71 ± 21.73 (Day 14), P < 0.05). No significant differences were observed in NMM II-C mRNA and protein expression between quiescent and activated HSCs. In culture-activated HSCs, NMM II-A and II-B merged with F-actin at the cellular periphery and throughout cytoplasm respectively. In vitro studies showed increased expression of NMM II-B in HSCs activated by BDL compared to sham-operated animals. There were no apparent increases of NMM II-A and II-C protein expression in HSCs during hepatic BDL injury. To determine the contribution of NMM II-A and II-B to migration and contraction, NMM II-A and II-B expression were downregulated with siRNA. NMM II-A and/or II-B siRNA inhibited HSC migration by approximately 25% compared to scramble siRNA-treated cells. Conversely, siRNA-mediated NMM II-A and II-B inhibition had no significant effect on HSC contraction; however, contraction was inhibited with the myosin II inhibitor, blebbistatin (38.7% ± 1.9%). CONCLUSION Increased expression of NMM II-A and II-B regulates HSC migration, while other myosin IIclasses likely modulate contraction, contributing to development and severity of liver fibrosis.
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Affiliation(s)
- Cathy C Moore
- Cathy C Moore, Ashley M Lakner, Christopher M Yengo, Laura W Schrum, Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, United States
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Auer M, Hausott B, Klimaschewski L. Rho GTPases as regulators of morphological neuroplasticity. Ann Anat 2011; 193:259-66. [PMID: 21459565 PMCID: PMC3143277 DOI: 10.1016/j.aanat.2011.02.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Accepted: 02/28/2011] [Indexed: 11/17/2022]
Abstract
GTPases function as intracellular, bimolecular switches by adopting different conformational states in response to binding GDP or GTP. Their activation is mediated through cell-surface receptors. Rho GTPases act on several downstream effectors involved in cellular morphogenesis, cell polarity, migration and cell division. In neurons, Rho GTPases regulate various features of dendritic and axonal outgrowth during development and regeneration mainly through their effects on the cytoskeleton. This review summarizes the main functions of Rho, Rac and Cdc42 GTPases as key regulators of morphological neuroplasticity under normal and pathological conditions.
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Affiliation(s)
- Maria Auer
- Division of Neuroanatomy, Medical University of Innsbruck, Muellerstrasse 59, Innsbruck, Austria
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Park SS, Byeon YE, Ryu HH, Kang BJ, Kim Y, Kim WH, Kang KS, Han HJ, Kweon OK. Comparison of canine umbilical cord blood-derived mesenchymal stem cell transplantation times: involvement of astrogliosis, inflammation, intracellular actin cytoskeleton pathways, and neurotrophin-3. Cell Transplant 2011; 20:1867-80. [PMID: 21375803 DOI: 10.3727/096368911x566163] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Canine mesenchymal stem cells (cMSCs) derived from umbilical cord blood represent a potentially useful source of stem cells for therapy. The aim of this study was to compare the effects of different transplantation times of cMSCs after spinal cord injury (SCI). A total of 21 dogs were subjected to SCI by balloon-induced compression of the first lumbar vertebrae for 12 h. Of the 21 dogs, 12 were divided into four groups of three according to the time of stem cell (1 × 10(6)) transplantation at the injury site: control no treatment, 12 h, 1 week, and 2 weeks. The remaining 9 animals were negative harvest (HA) time controls for each treatment group (n = 3). Olby and Tarlov scores were used to evaluate functional recovery of the hindlimbs. Markers for neuronal regeneration (Tuj-1, nestin, MAP2, and NF-M), astrogliosis (GALC, GFAP, and pSTAT3), signal molecules for actin cytoskeleton (RhoA, Cdc42, and Rac1), inflammation (COX-2), and neurotrophins (NT-3) were evaluated by Western blot analysis. Scores of the 1-week transplantation group showed significant improvement compared to controls. Hematoxylin and eosin (H&E) staining revealed less fibrosis at the injury site in the 1-week transplantation group compared to other groups and immunohistochemistry showed increased expression of neuronal markers. Furthermore, in both 1-week and 2-week transplantation groups, Tuj-1, nestin, MAP2, NF-M, NT-3, and GFAP increased, but pSTAT3, GALC, and COX2 decreased. RhoA decreased and Rac1 and Cdc42 increased in the 1-week transplantation group. In conclusion, transplantation of cMSCs 1 week after SCI was more effective in improving clinical signs and neuronal regeneration and reducing fibrosis formation compared to the other transplantation times evaluated. Subsequently, these data may contribute to the optimization of timing for MSC transplantation used as a therapeutic modality.
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Affiliation(s)
- Sung-Su Park
- Department of Veterinary Surgery, College of Veterinary Medicine, Seoul National University, Seoul, Korea
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Vlachos S, Harden N. Genetic evidence for antagonism between Pak protein kinase and Rho1 small GTPase signaling in regulation of the actin cytoskeleton during Drosophila oogenesis. Genetics 2011; 187:501-12. [PMID: 21098722 PMCID: PMC3030492 DOI: 10.1534/genetics.110.120998] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/18/2010] [Indexed: 12/15/2022] Open
Abstract
During Drosophila oogenesis, basally localized F-actin bundles in the follicle cells covering the egg chamber drive its elongation along the anterior-posterior axis. The basal F-actin of the follicle cell is an attractive system for the genetic analysis of the regulation of the actin cytoskeleton, and results obtained in this system are likely to be broadly applicable in understanding tissue remodeling. Mutations in a number of genes, including that encoding the p21-activated kinase Pak, have been shown to disrupt organization of the basal F-actin and in turn affect egg chamber elongation. pak mutant egg chambers have disorganized F-actin distribution and remain spherical due to a failure to elongate. In a genetic screen to identify modifiers of the pak rounded egg chamber phenotype several second chromosome deficiencies were identified as suppressors. One suppressing deficiency removes the rho1 locus, and we determined using several rho1 alleles that removal of a single copy of rho1 can suppress the pak phenotype. Reduction of any component of the Rho1-activated actomyosin contractility pathway suppresses pak oogenesis defects, suggesting that Pak counteracts Rho1 signaling. There is ectopic myosin light chain phosphorylation in pak mutant follicle cell clones in elongating egg chambers, probably due at least in part to mislocalization of RhoGEF2, an activator of the Rho1 pathway. In early egg chambers, pak mutant follicle cells have reduced levels of myosin phosphorylation and we conclude that Pak both promotes and restricts myosin light chain phosphorylation in a temporally distinct manner during oogenesis.
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Affiliation(s)
| | - Nicholas Harden
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
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Phospholipase C, Ca2+, and calmodulin signaling are required for 5-HT2A receptor-mediated transamidation of Rac1 by transglutaminase. Psychopharmacology (Berl) 2011; 213:403-12. [PMID: 20717650 PMCID: PMC3033764 DOI: 10.1007/s00213-010-1984-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/28/2010] [Indexed: 01/12/2023]
Abstract
RATIONALE Serotonin and especially serotonin 2A (5-HT(2A)) receptor signaling are important in the etiology and treatment of schizophrenia and affective disorders. We previously reported a novel 5-HT(2A) receptor effector, increased transglutaminase (TGase)-catalyzed transamidation, and activation of the small G protein Rac1 in A1A1v cells, a rat embryonic cortical cell line. OBJECTIVES In this study, we explore the signaling pathway involved in 5-HT(2A) receptor-mediated Rac1 transamidation. METHODS A1A1v cells were pretreated with pharmacological inhibitors of phospholipase C (PLC) or calmodulin (CaM), and then stimulated by the 5-HT(2A) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI). Intracellular Ca(2+) concentration and TGase-modified Rac1 transamidation were monitored. The effect of manipulation of intracellular Ca(2+) by a Ca(2+) ionophore or a chelating agent on Rac1 transamidation was also evaluated. RESULTS In cells pretreated with a PLC inhibitor U73122, DOI-stimulated increases in the intracellular Ca(2+) concentration and TGase-modified Rac1 were significantly attenuated as compared to those pretreated with U73343, an inactive analog. The membrane-permeant Ca(2+) chelator, BAPTA-AM strongly reduced TGase-catalyzed Rac1 transamidation upon DOI stimulation. Conversely, the Ca(2+) ionophore ionomycin, at a concentration that induced an elevation of cytosolic Ca(2+) to a level comparable to cells treated with DOI, produced an increase in TGase-modified Rac1 without 5-HT(2A) receptor activation. Moreover, the CaM inhibitor W-7, significantly decreased Rac1 transamidation in a dose-dependent manner in DOI-treated cells. CONCLUSIONS These results indicate that 5-HT(2A) receptor-coupled PLC activation and subsequent Ca(2+) and CaM signaling are necessary for TGase-catalyzed Rac1 transamidation, and an increase in intracellular Ca(2+) is sufficient to induce Rac1 transamidation.
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Liu Z, Van Rossen E, Timmermans JP, Geerts A, van Grunsven LA, Reynaert H. Distinct roles for non-muscle myosin II isoforms in mouse hepatic stellate cells. J Hepatol 2011; 54:132-41. [PMID: 20932596 DOI: 10.1016/j.jhep.2010.06.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 06/02/2010] [Accepted: 06/10/2010] [Indexed: 12/25/2022]
Abstract
BACKGROUND & AIMS Upon liver injury, hepatic stellate cells (HSCs) undergo dramatic morphological and functional changes including migration and contraction. In the present study, we investigated the role of myosin II isoforms in the development of the contractile phenotype of mouse HSCs, which are considered therapeutic targets to decrease portal hypertension and fibrosis. METHODS We characterized the expression of myosin IIA and IIB in primary mouse HSCs and addressed their function by gene knock-down using isoform-specific siRNAs. RESULTS We found that myosin IIA and IIB are differentially expressed and localized and have clearly different functions in HSCs. Myosin IIA is mainly located in the subcortical area of quiescent HSCs and at α-SMA-containing stress fibres after activation, while myosin IIB is located in the cytoplasm and at the edge of protrusions of quiescent HSCs, at stress fibres of activated cells, and at the leading edge of lamellipodia. Knock-down of myosin IIA in HSCs influences cell size and shape, results in the disruption of stress fibres and in a decrease of focal adhesions, and inhibits contractility and intra-cellular Ca(2+) release but increases cell migration. Myosin IIB contributes to the extension of lamellipodia and cell spreading but has no direct role in stress fibres and focal adhesion formation, contraction, or intra-cellular Ca(2+) signalling. CONCLUSIONS In mouse HSCs, myosin IIA and IIB clearly fulfil distinct roles. Our results provide an insight into the contractile machinery of HSCs, that could be important in the search for new molecules to treat portal hypertension.
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Affiliation(s)
- Zhenan Liu
- Liver Cell Biology Lab, Vrije Universiteit Brussel (V.U.B.), Belgium
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Parri M, Chiarugi P. Rac and Rho GTPases in cancer cell motility control. Cell Commun Signal 2010; 8:23. [PMID: 20822528 PMCID: PMC2941746 DOI: 10.1186/1478-811x-8-23] [Citation(s) in RCA: 444] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 09/07/2010] [Indexed: 12/29/2022] Open
Abstract
Rho GTPases represent a family of small GTP-binding proteins involved in cell cytoskeleton organization, migration, transcription, and proliferation. A common theme of these processes is a dynamic reorganization of actin cytoskeleton which has now emerged as a major switch control mainly carried out by Rho and Rac GTPase subfamilies, playing an acknowledged role in adaptation of cell motility to the microenvironment. Cells exhibit three distinct modes of migration when invading the 3 D environment. Collective motility leads to movement of cohorts of cells which maintain the adherens junctions and move by photolytic degradation of matrix barriers. Single cell mesenchymal-type movement is characterized by an elongated cellular shape and again requires extracellular proteolysis and integrin engagement. In addition it depends on Rac1-mediated cell polarization and lamellipodia formation. Conversely, in amoeboid movement cells have a rounded morphology, the movement is independent from proteases but requires high Rho GTPase to drive elevated levels of actomyosin contractility. These two modes of cell movement are interconvertible and several moving cells, including tumor cells, show an high degree of plasticity in motility styles shifting ad hoc between mesenchymal or amoeboid movements. This review will focus on the role of Rac and Rho small GTPases in cell motility and in the complex relationship driving the reciprocal control between Rac and Rho granting for the opportunistic motile behaviour of aggressive cancer cells. In addition we analyse the role of these GTPases in cancer progression and metastatic dissemination.
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Affiliation(s)
- Matteo Parri
- Department of Biochemical Sciences, University of Florence, Tuscany Tumor Institute and "Center for Research, Transfer and High Education DenoTHE", 50134 Florence, Italy.
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Theveneau E, Mayor R. Integrating chemotaxis and contact-inhibition during collective cell migration: Small GTPases at work. Small GTPases 2010; 1:113-117. [PMID: 21686264 PMCID: PMC3116595 DOI: 10.4161/sgtp.1.2.13673] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 09/15/2010] [Accepted: 09/20/2010] [Indexed: 01/22/2023] Open
Abstract
For directional cell migration to occur cells must interpret guiding cues present in their environment. Chemotaxis based on negative or positive signals has been long thought as the main driving force of guided cell migration. However during collective cell migration cells do receive information from external signals but also upon interactions with their direct neighbours. These multiple inputs must be translated into intracellular reorganisation in order to promote efficient directional migration. Small GTPases, being involved in establishing cell polarity and regulating protrusive activity, are likely to play a central role in signal integration. Indeed, recent findings from our laboratory indicate that Contact-Inhibition of Locomotion controlled by N-Cadherin and chemotaxis dependent on Sdf1/Cxcr4 signaling converge towards regulation of the localized activity of RhoA and Rac1. All together they establish cell polarity and select well-oriented cell protrusions to ensure directional cell migration.
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Affiliation(s)
- Eric Theveneau
- Department of Cell and Developmental Biology; University College London; London UK
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Protrusion and actin assembly are coupled to the organization of lamellar contractile structures. Exp Cell Res 2010; 316:2027-41. [PMID: 20406634 DOI: 10.1016/j.yexcr.2010.04.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 04/11/2010] [Accepted: 04/13/2010] [Indexed: 11/21/2022]
Abstract
Directed cell migration requires continuous cycles of protrusion of the leading edge and contraction to pull up the cell rear. How these spatially distributed processes are coordinated to maintain a state of persistent protrusion remains unknown. During wound healing responses of epithelial sheets, cells along the wound edge display two distinct morphologies: 'leader cells' exhibit persistent edge protrusions, while the greater majority of 'follower cells' randomly cycle between protrusion and retraction. Here, we exploit the heterogeneity in cell morphodynamic behaviors to deduce the requirements in terms of cytoskeleton dynamics for persistent and sporadic protrusion events. We used quantitative Fluorescent Speckle Microscopy (qFSM) to compare rates of F-actin assembly and flow relative to the local protrusion and retraction dynamics of the leading edge. Persistently protruding cells are characterized by contractile actomyosin structures that align with the direction of migration, with converging F-actin flows interpenetrating over a wide band in the lamella. Conversely, non-persistent protruders have their actomyosin structures aligned perpendicular to the axis of migration, and are characterized by prominent F-actin retrograde flows that end into transverse arcs. Analysis of F-actin kinetics in the lamellipodia showed that leader cells have three-fold higher assembly rates when compared to followers. To further investigate a putative relationship between actomyosin contraction and F-actin assembly, myosin II was inhibited by blebbistatin. Treated cells at the wound edge adopted a homogeneously persistent protrusion behavior, with rates matching those of leader cells. Surprisingly, we found that disintegration of actomyosin structures led to a significant decrease in F-actin assembly. Our data suggests that persistent protrusion in these cells is achieved by a reduction in overall F-actin retrograde flow, with lower assembly rates now sufficient to propel forward the leading edge. Based on our data we propose that differences in the protrusion persistence of leaders and followers originate in the distinct actomyosin contraction modules that differentially regulate leading edge protrusion-promoting F-actin assembly, and retraction-promoting retrograde flow.
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Chantler PD, Wylie SR, Wheeler-Jones CP, McGonnell IM. Conventional myosins - unconventional functions. Biophys Rev 2010; 2:67-82. [PMID: 28510009 DOI: 10.1007/s12551-010-0030-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 12/22/2009] [Indexed: 10/24/2022] Open
Abstract
While the discovery of unconventional myosins raised expectations that their actions were responsible for most aspects of actin-based cell motility, few anticipated the wide range of cellular functions that would remain the purview of conventional two-headed myosins. The three nonsarcomeric, cellular myosins-M2A, M2B and M2C-participate in diverse roles including, but not limited to: neuronal dynamics, axon guidance and synaptic transmission; endothelial cell migration; cell adhesion, polarity, fusion and cytokinesis; vesicle trafficking and viral egress. These three conventional myosins each take on specific, differing functional roles during development and maturity, characteristic of each cell lineage; exact roles depend on the developmental stage of the cell, cellular location, upstream regulatory controls, relative isoform expression, orientation and associated state of the actin cytoscaffolds in which these myosins operate. Here, we discuss the separate yet related roles that characterise the actions of M2A, M2B and M2C in various cell types and show that these conventional myosins are responsible for functions as unconventional as any performed by unconventional myosins.
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Affiliation(s)
- Peter D Chantler
- Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London, NW1 0TU, UK.
| | - Steven R Wylie
- Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London, NW1 0TU, UK
| | - Caroline P Wheeler-Jones
- Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London, NW1 0TU, UK
| | - Imelda M McGonnell
- Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London, NW1 0TU, UK
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Lin YF, Yeh TS, Chen SF, Tsai YH, Chou CM, Yang YY, Huang HM. Nonmuscle myosin IIA (myosin heavy polypeptide 9): a novel class of signal transducer mediating the activation of G alpha h/phospholipase C-delta 1 pathway. Endocrinology 2010; 151:876-85. [PMID: 20068007 DOI: 10.1210/en.2009-0722] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The dimeric Gh protein is comprised of alpha (tissue transglutaminase) and beta (Calreticulin) subunits and known to be associated with FSH-, oxytocin-, or epinephrine-receptors/functions in their respective target cells. After establishing the FSH-induced activation of G alpha h/phospholipase C (PLC)-delta 1 pathway in rat Sertoli cells (SCs), we have attempted to identify a possible G alpha h-coupled novel FSH receptor (FSH-R). Remarkably, a protein with approximately 240-kDa molecular mass was coimmunoprecipitated with G alpha h in the fractionated membrane proteins of rat SCs. The protein was identified as myosin heavy polypeptide 9 (MyH9) by mass spectrometric analysis and immunoblotting. In addition, immunoprecipitation analysis reveals that MyH9 is constitutively associated with classical Gs-coupled FSH-R and inactive GDP-bound G alpha h at resting state of rat SCs, but did not interact with FSH directly as judged by Far-Western analysis. Upon the stimulation of higher levels of extracellular FSH (>1000 IU/liter), classical FSH-R induces the phosphorylation of MyH9, the dissociation of active GTP-bound G alpha h from FSH-R:MyH9 complexes, and the elicitation of G alpha h/PLC-delta 1 pathway-dependent Ca(2+)-influx in rat SCs. Furthermore, the specific inhibition of MyH9 ATPase activity with Blebbistatin dose-dependently suppressed FSH-induced G alpha h/PLC-delta 1 signaling and Ca(2+)-influx, but not intracellular cAMP accumulation in rat SCs, implying that MyH9 mediates FSH-induced activation of G alpha h/PLC-delta 1/IP(3)/Ca(2+)-influx pathway in rat SCs. This is the first to demonstrate that the filament protein MyH9 constitutively forms a ternary complex with FSH-R and inactive GDP-bound G alpha h. At higher FSH levels, this ternary complex executes an alternative signaling of classical Gs-coupled FSH-R through activating a Gs/cAMP-independent, G alpha h/PLC-delta 1 pathway in rat SCs.
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Affiliation(s)
- Yuan-Feng Lin
- School of Pharmacy, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Picard M, Petrie RJ, Antoine-Bertrand J, Saint-Cyr-Proulx E, Villemure JF, Lamarche-Vane N. Spatial and temporal activation of the small GTPases RhoA and Rac1 by the netrin-1 receptor UNC5a during neurite outgrowth. Cell Signal 2009; 21:1961-73. [DOI: 10.1016/j.cellsig.2009.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 08/11/2009] [Accepted: 09/06/2009] [Indexed: 11/29/2022]
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Chen Z, Shivdasani RA. Regulation of platelet biogenesis: insights from the May-Hegglin anomaly and other MYH9-related disorders. J Thromb Haemost 2009; 7 Suppl 1:272-6. [PMID: 19630815 DOI: 10.1111/j.1538-7836.2009.03425.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Megakaryocyte (MK) maturation culminates in release of blood platelets through proplatelet extensions. MKs presumably delay elaborating proplatelets until synthesis of platelet constituents is complete. Recent insights from investigation of a classic human congenital macrothrombocytopenia, the May-Hegglin anomaly, and related MYH9-associated disorders shed new light on underlying mechanisms. The findings reviewed in this article implicate myosin IIA, the non-muscle myosin heavy chain product of the MYH9 gene, in restraining proplatelet formation until MKs achieve terminal maturity. Loss of myosin IIA function, through dominant inhibitory mutations in humans, targeted gene disruption in mice, or manipulation of cultured MKs, seems to accelerate proplatelet formation. The resulting process is inefficient and produces platelets that vary widely in size, shape and content. Several lines of evidence suggest that the Rho-ROCK-myosin light chain pathway restrains proplatelet formation through myosin IIA. These findings illustrate that mammalian thrombopoiesis is complex and subject to both positive and negative regulation.
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Affiliation(s)
- Z Chen
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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Marcos S, Moreau J, Backer S, Job D, Andrieux A, Bloch-Gallego E. Tubulin tyrosination is required for the proper organization and pathfinding of the growth cone. PLoS One 2009; 4:e5405. [PMID: 19404406 PMCID: PMC2672595 DOI: 10.1371/journal.pone.0005405] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 03/18/2009] [Indexed: 12/03/2022] Open
Abstract
Background During development, neuronal growth cones integrate diffusible and contact guidance cues that are conveyed to both actin and microtubule (MT) cytoskeletons and ensure axon outgrowth and pathfinding. Although several post-translational modifications of tubulin have been identified and despite their strong conservation among species, their physiological roles during development, especially in the nervous sytem, are still poorly understood. Methodology/Findings Here, we have dissected the role of a post-translational modification of the last amino acid of the α-tubulin on axonal growth by analyzing the phenotype of precerebellar neurons in Tubulin tyrosin ligase knock-out mice (TTL−/−) through in vivo, ex vivo and in vitro analyses. TTL−/− neurons are devoid of tyrosinated tubulin. Their pathway shows defects in vivo, ex vivo, in hindbrains open-book preparations or in vitro, in a collagen matrix. Their axons still orient toward tropic cues, but they emit supernumerary branches and their growth cones are enlarged and exhibit an emission of mis-oriented filopodia. Further analysis of the TTL−/− growth cone intracellular organization also reveals that the respective localization of actin and MT filaments is disturbed, with a decrease in the distal accumulation of Myosin IIB, as well as a concomitant Rac1 over-activation in the hindbrain. Pharmacological inhibition of Rac1 over-activation in TTL−/− neurons can rescue Myosin IIB localization. Conclusions/Significance In the growth cone, we propose that tubulin tyrosination takes part in the relative arrangement of actin and MT cytoskeletons, in the regulation of small GTPases activity, and consequently, in the proper morphogenesis, organization and pathfinding of the growth cone during development.
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Affiliation(s)
- Séverine Marcos
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Département Génétique et Développement, Paris, France
| | - Julie Moreau
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Département Génétique et Développement, Paris, France
| | - Stéphanie Backer
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Département Génétique et Développement, Paris, France
| | - Didier Job
- Grenoble Institut des Neurosciences, Centre de Recherche Inserm U.836 – UJF-CEA-CHU, Bâtiment Edmond J. Safra, Université Joseph Fourier, Site Santé à La Tronche, Grenoble, France
| | - Annie Andrieux
- Grenoble Institut des Neurosciences, Centre de Recherche Inserm U.836 – UJF-CEA-CHU, Bâtiment Edmond J. Safra, Université Joseph Fourier, Site Santé à La Tronche, Grenoble, France
| | - Evelyne Bloch-Gallego
- Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France
- Inserm, U567, Département Génétique et Développement, Paris, France
- * E-mail:
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Hauser PV, Perco P, Mühlberger I, Pippin J, Blonski M, Mayer B, Alpers CE, Oberbauer R, Shankland SJ. Microarray and bioinformatics analysis of gene expression in experimental membranous nephropathy. Nephron Clin Pract 2009; 112:e43-58. [PMID: 19390219 DOI: 10.1159/000213505] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 01/12/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Passive Heymann nephritis (PHN), the best characterized animal model of experimental membranous nephropathy, is characterized by subepithelial immune deposits, podocyte foot processes effacement and massive proteinuria beginning 4 days following disease induction. Although single genes involved in PHN have been studied, no whole genome-wide expression analysis of kidney tissue has been performed. METHODS Microarray analysis was performed to identify gene expression changes in PHN rat kidneys during the onset of proteinuria. RESULTS Our results showed that 234 transcripts were differentially expressed in diseased animals compared to controls. Genes exclusively upregulated in diseased animals were mainly required for cell structure and motility, immunity and defense, cell cycle, and developmental processes. The single most increased gene was transgelin (Tagln) showing a 70-fold upregulation in animals with PHN. Protein-protein interaction analysis revealed the following four processes of major relevance in disease manifestation: (i) DNA damage and repair; (ii) changes in the extracellular matrix; (iii) deregulation of cytokines and growth factors, as well as (iv) rearrangements of the cytoskeleton. CONCLUSION We show for the first time the complex interplay between multiple different genes in experimental membranous nephropathy, supporting a role for genomic approaches to better understanding and defining specific disease processes.
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Affiliation(s)
- Peter V Hauser
- Division of Nephrology & Hypertension, University of Washington School of Medicine, Seattle, Wash. 98195, USA.
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Bustos RI, Forget MA, Settleman JE, Hansen SH. Coordination of Rho and Rac GTPase function via p190B RhoGAP. Curr Biol 2008; 18:1606-11. [PMID: 18948007 DOI: 10.1016/j.cub.2008.09.019] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 09/08/2008] [Accepted: 09/09/2008] [Indexed: 12/30/2022]
Abstract
The Rac GTPase regulates Rho signaling in a broad range of physiological settings and in oncogenic transformation [1-3]. Here, we report a novel mechanism by which crosstalk between Rac and Rho GTPases is achieved. Activated Rac1 binds directly to p190B Rho GTPase-activating protein (RhoGAP), a major modulator of Rho signaling. p190B colocalizes with constitutively active Rac1 in membrane ruffles. Moreover, activated Rac1 is sufficient to recruit p190B into a detergent-insoluble membrane fraction, a process that is accompanied by a decrease in GTP-bound RhoA from membranes. p190B is recruited to the plasma membrane in response to integrin engagement [4]. We demonstrate that collagen type I, a potent inducer of Rac1-dependent cell motility in HeLa cells, counteracts cytoskeletal collapse resulting from overexpression of wild-type p190B, but not that resulting from overexpression of a p190B mutant specifically lacking the Rac1-binding sequence. Furthermore, this p190B mutant exhibits dramatically enhanced RhoGAP activity, consistent with a model whereby binding of Rac1 relieves autoinhibition of p190B RhoGAP function. Collectively, these observations establish that activated Rac1, through direct interaction with p190B, modulates subcellular RhoGAP localization and activity, thereby providing a novel mechanism for Rac control of Rho signaling in a broad range of physiological processes.
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Affiliation(s)
- Rodrigo I Bustos
- GI Cell Biology Laboratory, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA
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Crosstalk between small GTPases and polarity proteins in cell polarization. Nat Rev Mol Cell Biol 2008; 9:846-59. [PMID: 18946474 DOI: 10.1038/nrm2521] [Citation(s) in RCA: 331] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell polarization is crucial for the development of multicellular organisms, and aberrant cell polarization contributes to various diseases, including cancer. How cell polarity is established and how it is maintained remain fascinating questions. Conserved proteins of the partitioning defective (PAR), Scribble and Crumbs complexes guide the establishment of cell polarity in various organisms. Moreover, GTPases that regulate actin cytoskeletal dynamics have been implicated in cell polarization. Recent findings provide insights into polarization mechanisms and show intriguing crosstalk between small GTPases and members of polarity complexes in regulating cell polarization in different cellular contexts and cell types.
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