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Turn RE, Hu Y, Dewees SI, Devi N, East MP, Hardin KR, Khatib T, Linnert J, Wolfrum U, Lim MJ, Casanova JE, Caspary T, Kahn RA. The ARF GAPs ELMOD1 and ELMOD3 act at the Golgi and cilia to regulate ciliogenesis and ciliary protein traffic. Mol Biol Cell 2022; 33:ar13. [PMID: 34818063 PMCID: PMC9236152 DOI: 10.1091/mbc.e21-09-0443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/11/2022] Open
Abstract
ELMODs are a family of three mammalian paralogues that display GTPase-activating protein (GAP) activity toward a uniquely broad array of ADP-ribosylation factor (ARF) family GTPases that includes ARF-like (ARL) proteins. ELMODs are ubiquitously expressed in mammalian tissues, highly conserved across eukaryotes, and ancient in origin, being present in the last eukaryotic common ancestor. We described functions of ELMOD2 in immortalized mouse embryonic fibroblasts (MEFs) in the regulation of cell division, microtubules, ciliogenesis, and mitochondrial fusion. Here, using similar strategies with the paralogues ELMOD1 and ELMOD3, we identify novel functions and locations of these cell regulators and compare them to those of ELMOD2, allowing the determination of functional redundancy among the family members. We found strong similarities in phenotypes resulting from deletion of either Elmod1 or Elmod3 and marked differences from those arising in Elmod2 deletion lines. Deletion of either Elmod1 or Elmod3 results in the decreased ability of cells to form primary cilia, loss of a subset of proteins from cilia, and accumulation of some ciliary proteins at the Golgi, predicted to result from compromised traffic from the Golgi to cilia. These phenotypes are reversed upon activating mutant expression of either ARL3 or ARL16, linking their roles to ELMOD1/3 actions.
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Affiliation(s)
- Rachel E. Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
- Department of Microbiology and Immunology, Stanford University, Palo Alto, CA 94305
| | - Yihan Hu
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, 410008 Hunan, China
| | - Skylar I. Dewees
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Narra Devi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
| | - Michael P. East
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Katherine R. Hardin
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Tala Khatib
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322
- Biochemistry, Cell & Developmental Biology Graduate Program, Emory University, Atlanta, GA 30322
| | - Joshua Linnert
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, Mainz 55128, Germany
| | - Michael J. Lim
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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Jin L, Lorkiewicz P, Xie Z, Bhatnagar A, Srivastava S, Conklin DJ. Acrolein but not its metabolite, 3-Hydroxypropylmercapturic acid (3HPMA), activates vascular transient receptor potential Ankyrin-1 (TRPA1): Physiological to toxicological implications. Toxicol Appl Pharmacol 2021; 426:115647. [PMID: 34271065 PMCID: PMC8343963 DOI: 10.1016/j.taap.2021.115647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/17/2022]
Abstract
Acrolein, an electrophilic α,β-unsaturated aldehyde, is present in foods and beverages, and is a product of incomplete combustion, and thus, reaches high ppm levels in tobacco smoke and structural fires. Exposure to acrolein is linked with cardiopulmonary toxicity and cardiovascular disease risk. The hypothesis of this study is the direct effects of acrolein in isolated murine blood vessels (aorta and superior mesenteric artery, SMA) are transient receptor potential ankyrin-1 (TRPA1) dependent. Using isometric myography, isolated aorta and SMA were exposed to increasing levels of acrolein. Acrolein inhibited phenylephrine (PE)-induced contractions (approximately 90%) in aorta and SMA of male and female mice in a concentration-dependent (0.01-100 μM) manner. The major metabolite of acrolein, 3-hydroxypropylmercapturic acid (3HPMA), also relaxed PE-precontracted SMA. As the SMA was 20× more sensitive to acrolein than aorta (SMA EC50 0.8 ± 0.2 μM; aorta EC50 > 29.4 ± 4.4 μM), the mechanisms of acrolein-induced relaxation were studied in SMA. The potency of acrolein-induced relaxation was inhibited significantly by: 1) mechanically-impaired endothelium; 2) Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME); 3) guanylyl cyclase (GC) inhibitor (ODQ); and, 4) a TRPA1 antagonist (A967079). TRPA1 positive immunofluorescence was present in the endothelium. Compared with other known TRPA1 agonists, including allyl isothiocyanate (AITC), cinnamaldehyde, crotonaldehyde, and formaldehyde, acrolein stimulated a more potent TRPA1-dependent relaxation. Acrolein, at high concentration [100 μM], induced tension oscillations (spasms) independent of TRPA1 in precontracted SMA but not in aorta. In conclusion, acrolein is vasorelaxant at low levels (physiological) yet vasotoxic at high levels (toxicological).
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Affiliation(s)
- L Jin
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA; American Heart Association-Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA
| | - P Lorkiewicz
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA; American Heart Association-Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA
| | - Z Xie
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA
| | - A Bhatnagar
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA; American Heart Association-Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA; Superfund Research Center, University of Louisville, Louisville, KY, USA
| | - S Srivastava
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA; American Heart Association-Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA; Superfund Research Center, University of Louisville, Louisville, KY, USA
| | - D J Conklin
- Christina Lee Brown Envirome Institute, University of Louisville, Louisville, KY, USA; Diabetes and Obesity Center, University of Louisville, Louisville, KY, USA; American Heart Association-Tobacco Regulation and Addiction Center, University of Louisville, Louisville, KY, USA; Superfund Research Center, University of Louisville, Louisville, KY, USA.
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3
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Wan B, Li C, Wang M, Kong F, Ding Q, Zhang C, Liu H, Qian D, Deng W, Chen J, Tang P, Wang Q, Zhao S, Zhou Z, Xu T, Huang Y, Gu J, Fan J, Yin G. GIT1 protects traumatically injured spinal cord by prompting microvascular endothelial cells to clear myelin debris. Aging (Albany NY) 2021; 13:7067-7083. [PMID: 33621952 PMCID: PMC7993661 DOI: 10.18632/aging.202560] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/27/2020] [Indexed: 12/12/2022]
Abstract
The clearance of myelin debris is a critical step in the functional recovery following spinal cord injury (SCI). As phagocytes do, microvascular endothelial cells (MECs) participate in myelin debris clearance at the injury site within one week. Our group has verified that G protein-coupled receptor kinase 2 interacting protein-1 (GIT1) is essential in autophagy and angiogenesis, both of which are tightly related to the uptake and degradation of myelin debris by MECs. Here, we analyzed the performance and mechanism of GIT1 in myelin debris clearance after SCI. The SCI contusion model was established and in vitro MECs were treated with myelin debris. Better recovery from traumatic SCI was observed in the GIT1 WT mice than in the GIT1 KO mice. More importantly, we found that GIT1 prompted MECs to clear myelin debris and further enhanced MECs angiogenesis in vivo and in vitro. Mechanistically, GIT1-mediated autophagy contributed to the clearance of myelin debris by MECs. In this study, we demonstrated that GIT1 may prompt MECs to clear myelin debris via autophagy and further stimulate MECs angiogenesis via upregulating VEGF. Our results indicate that GITI may serve as a promising target for accelerating myelin debris clearance and improving SCI recovery.
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Affiliation(s)
- Bowen Wan
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Cong Li
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Ming Wang
- Department of Plastic and Burn Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Fanqi Kong
- Department of Orthopedics, Changzheng Hospital, The Second Military Medical University, Shanghai 200003, China
| | - Qirui Ding
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Chenliang Zhang
- Department of Orthopedics, The Affiliated Shuyang Hospital of Xuzhou Medical University, Suqian 223600, China
| | - Hao Liu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Dingfei Qian
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Wenlin Deng
- Department of Orthopedics, The Affiliated Suqian First People's Hospital of Nanjing Medical University, Suqian 223800, China
| | - Jian Chen
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Pengyu Tang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Qian Wang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Shujie Zhao
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Zheng Zhou
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Tao Xu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Yifan Huang
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Jun Gu
- Department of Orthopedics, Xishan People's Hospital, Wuxi 214000, China
| | - Jin Fan
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Guoyong Yin
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
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Jaafar L, Fakhoury I, Saab S, El-Hajjar L, Abou-Kheir W, El-Sibai M. StarD13 differentially regulates migration and invasion in prostate cancer cells. Hum Cell 2021; 34:607-623. [PMID: 33420961 DOI: 10.1007/s13577-020-00479-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/24/2020] [Indexed: 11/26/2022]
Abstract
Prostate cancer is the second most commonly diagnosed cancer in men and one of the main leading causes of cancer deaths among men worldwide. Rapid uncontrolled growth and the ability to metastasize to other sites are key hallmarks in cancer development and progression. The Rho family of GTPases and its activators the GTPase-activating proteins (GAPs) are required for regulating cancer cell proliferation and migration. StarD13 is a GAP for Rho GTPases, specifically for RhoA and Cdc42. We have previously shown that StarD13 acts as a tumor suppressor in astrocytoma as well as breast and colorectal cancer. In this study, we performed a functional comparative analysis of StarD13 targets/and or interacting molecules to understand the general role that StarD13 plays in cancers. Our data highlight the importance of StarD13 in modulating several hallmarks of cancer. Findings from database mining and immunohistochemistry revealed that StarD13 is underexpressed in prostate cancers, in addition knocking down Stard13 increased cancer cell proliferation, consistent with its role as a tumor suppressor. Stard13 depletion, however, led to an increase in cell adhesion, which inhibited 2D cell migration. Most interestingly, StarD13 depletion increases invasion and matrix degradation, at least in part, through its regulation of Cdc42. Altogether, the data presented suggest that StarD13 acts as a tumor suppressor inhibiting prostate cancer cell invasion.
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Affiliation(s)
- Leila Jaafar
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Chouran, P.O. Box 13-5053, Beirut, 1102 2801, Lebanon
| | - Isabelle Fakhoury
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Chouran, P.O. Box 13-5053, Beirut, 1102 2801, Lebanon
| | - Sahar Saab
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Chouran, P.O. Box 13-5053, Beirut, 1102 2801, Lebanon
| | - Layal El-Hajjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Abou-Kheir
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Mirvat El-Sibai
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Chouran, P.O. Box 13-5053, Beirut, 1102 2801, Lebanon.
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5
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Hook SC, Chadt A, Heesom KJ, Kishida S, Al-Hasani H, Tavaré JM, Thomas EC. TBC1D1 interacting proteins, VPS13A and VPS13C, regulate GLUT4 homeostasis in C2C12 myotubes. Sci Rep 2020; 10:17953. [PMID: 33087848 PMCID: PMC7578007 DOI: 10.1038/s41598-020-74661-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/07/2020] [Indexed: 01/01/2023] Open
Abstract
Proteins involved in the spaciotemporal regulation of GLUT4 trafficking represent potential therapeutic targets for the treatment of insulin resistance and type 2 diabetes. A key regulator of insulin- and exercise-stimulated glucose uptake and GLUT4 trafficking is TBC1D1. This study aimed to identify proteins that regulate GLUT4 trafficking and homeostasis via TBC1D1. Using an unbiased quantitative proteomics approach, we identified proteins that interact with TBC1D1 in C2C12 myotubes including VPS13A and VPS13C, the Rab binding proteins EHBP1L1 and MICAL1, and the calcium pump SERCA1. These proteins associate with TBC1D1 via its phosphotyrosine binding (PTB) domains and their interactions with TBC1D1 were unaffected by AMPK activation, distinguishing them from the AMPK regulated interaction between TBC1D1 and AMPKα1 complexes. Depletion of VPS13A or VPS13C caused a post-transcriptional increase in cellular GLUT4 protein and enhanced cell surface GLUT4 levels in response to AMPK activation. The phenomenon was specific to GLUT4 because other recycling proteins were unaffected. Our results provide further support for a role of the TBC1D1 PTB domains as a scaffold for a range of Rab regulators, and also the VPS13 family of proteins which have been previously linked to fasting glycaemic traits and insulin resistance in genome wide association studies.
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Affiliation(s)
- Sharon C Hook
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Alexandra Chadt
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Medical Faculty, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Kate J Heesom
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Shosei Kishida
- Department of Biochemistry and Genetics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hadi Al-Hasani
- Institute of Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University, Medical Faculty, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Jeremy M Tavaré
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Elaine C Thomas
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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RAHARDINI ELDAPUTRI, IKEDA KOJI, NUGROHO DHITEBAYU, HIRATA KENICHI, EMOTO NORIAKI. Loss of Family with Sequence Similarity 13, Member A Exacerbates Pulmonary Fibrosis Potentially by Promoting Epithelial to Mesenchymal Transition. Kobe J Med Sci 2020; 65:E100-E109. [PMID: 32029695 PMCID: PMC7012324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a devastating disease with poor prognosis due to limited clinical treatment options. IPF is characterized by the augmented deposition of extracellular matrix driven by myofibroblasts, and the epithelial-mesenchymal transition (EMT) has been known to play an essential role in the mechanism of pulmonary fibrosis. Previous genome-wide association study identified Fam13a as one of genes that showed genetic link with IPF and chronic obstructive pulmonary disease. Here, we analyzed the role of Fam13a in the pathogenesis of pulmonary fibrosis using Fam13a-deficient mice. We found that Fam13a was down-regulated in mouse lungs of bleomycin-induced pulmonary fibrosis model. Of note, genetic deletion of Fam13a exacerbated the lung fibrosis induced by bleomycin in association with enhanced EMT in mice. Moreover, silencing of Fam13a accelerated EMT induced by TGF-β and TNF-α in alveolar epithelial cells, accompanied by increased active β-catenin and its nuclear accumulation. Our data revealed a crucial role of Fam13a in the development of pulmonary fibrosis potentially through inhibiting EMT, and thus Fam13a has a therapeutic potential in the treatment of IPF.
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Affiliation(s)
- ELDA PUTRI RAHARDINI
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, 4-19-1 Motoyamakita, Higashinada, Kobe 658-8558, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chuo, Kobe 6500017, Japan
| | - KOJI IKEDA
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, 4-19-1 Motoyamakita, Higashinada, Kobe 658-8558, Japan
| | - DHITE BAYU NUGROHO
- Department of Internal Medicine, Faculty of Medicine, Public Health, and Nursing, Gadjah Mada University, Jl.Farmako Sekip Utara,Yogyakarta 55281, Indonesia
| | - KEN-ICHI HIRATA
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chuo, Kobe 6500017, Japan
| | - NORIAKI EMOTO
- Laboratory of Clinical Pharmaceutical Science, Kobe Pharmaceutical University, 4-19-1 Motoyamakita, Higashinada, Kobe 658-8558, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chuo, Kobe 6500017, Japan
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7
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Ferreira SM, Costa-Júnior JM, Kurauti MA, Leite NC, Ortis F, Rezende LF, Barbosa HC, Boschero AC, Santos GJ. ARHGAP21 Acts as an Inhibitor of the Glucose-Stimulated Insulin Secretion Process. Front Endocrinol (Lausanne) 2020; 11:599165. [PMID: 33324349 PMCID: PMC7726208 DOI: 10.3389/fendo.2020.599165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
ARHGAP21 is a RhoGAP protein implicated in the modulation of insulin secretion and energy metabolism. ARHGAP21 transient-inhibition increase glucose-stimulated insulin secretion (GSIS) in neonatal islets; however, ARHGAP21 heterozygote mice have a reduced insulin secretion. These discrepancies are not totally understood, and it might be related to functional maturation of beta cells and peripheral sensitivity. Here, we investigated the real ARHGAP21 role in the insulin secretion process using an adult mouse model of acute ARHGAP21 inhibition, induced by antisense. After ARHGAP21 knockdown induction by antisense injection in 60-day old male mice, we investigated glucose and insulin tolerance test, glucose-induced insulin secretion, glucose-induced intracellular calcium dynamics, and gene expression. Our results showed that ARHGAP21 acts negatively in the GSIS of adult islet. This effect seems to be due to the modulation of important points of insulin secretion process, such as the energy metabolism (PGC1α), Ca2+ signalization (SYTVII), granule-extrusion (SNAP25), and cell-cell interaction (CX36). Therefore, based on these finds, ARHGAP21 may be an important target in Diabetes Mellitus (DM) treatment.
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Affiliation(s)
- Sandra M. Ferreira
- Obestity and Comorbidities Research Center/Biology Institute, University State of Campinas (UNICAMP), Campinas, Brazil
| | - José M. Costa-Júnior
- Obestity and Comorbidities Research Center/Biology Institute, University State of Campinas (UNICAMP), Campinas, Brazil
| | - Mirian A. Kurauti
- Departament Physiological Sciences, University State of Maringá (UEM), Maringá, Brazil
| | - Nayara C. Leite
- Obestity and Comorbidities Research Center/Biology Institute, University State of Campinas (UNICAMP), Campinas, Brazil
| | - Fernanda Ortis
- Department of Cellular Biology and Development, Institute of Biomedical Sciences, University State of São Paulo (USP), São Paulo, Brazil
| | - Luiz F. Rezende
- Departament of Physiopathology, University State of Montes Claros (UNIMONTES), Montes Claros, Brazil
| | - Helena C. Barbosa
- Obestity and Comorbidities Research Center/Biology Institute, University State of Campinas (UNICAMP), Campinas, Brazil
| | - Antonio C. Boschero
- Obestity and Comorbidities Research Center/Biology Institute, University State of Campinas (UNICAMP), Campinas, Brazil
| | - Gustavo J. Santos
- Departament of Physiological Sciences, Center for Biological Sciences, University Federal of Santa Catarina (UFSC), Florianópolis, Brazil
- *Correspondence: Gustavo J. Santos,
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8
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Ren C, Yuan Q, Braun M, Zhang X, Petri B, Zhang J, Kim D, Guez-Haddad J, Xue W, Pan W, Fan R, Kubes P, Sun Z, Opatowsky Y, Polleux F, Karatekin E, Tang W, Wu D. Leukocyte Cytoskeleton Polarization Is Initiated by Plasma Membrane Curvature from Cell Attachment. Dev Cell 2019; 49:206-219.e7. [PMID: 30930167 DOI: 10.1016/j.devcel.2019.02.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 01/15/2019] [Accepted: 02/25/2019] [Indexed: 12/30/2022]
Abstract
Cell polarization is important for various biological processes. However, its regulation, particularly initiation, is incompletely understood. Here, we investigated mechanisms by which neutrophils break their symmetry and initiate their cytoskeleton polarization from an apolar state in circulation for their extravasation during inflammation. We show here that a local increase in plasma membrane (PM) curvature resulting from cell contact to a surface triggers the initial breakage of the symmetry of an apolar neutrophil and is required for subsequent polarization events induced by chemical stimulation. This local increase in PM curvature recruits SRGAP2 via its F-BAR domain, which in turn activates PI4KA and results in PM PtdIns4P polarization. Polarized PM PtdIns4P is targeted by RPH3A, which directs PIP5K1C90 and subsequent phosphorylated myosin light chain polarization, and this polarization signaling axis regulates neutrophil firm attachment to endothelium. Thus, this study reveals a mechanism for the initiation of cell cytoskeleton polarization.
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Affiliation(s)
- Chunguang Ren
- Department of Pharmacology, Vascular Biology and Therapeutic Program, Yale University, New Haven, CT 06520, USA
| | - Qianying Yuan
- Department of Pharmacology, Vascular Biology and Therapeutic Program, Yale University, New Haven, CT 06520, USA
| | - Martha Braun
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA; Nanobiology Institute, Yale University, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520, USA
| | - Xia Zhang
- Department of Geriatrics, the First affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Björn Petri
- Snyder Institute for Chronic Diseases Mouse Phenomics Resource Laboratory, University of Calgary, Calgary AB T2N 4N1, Canada; Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary AB T2N 4N1, Canada
| | - Jiasheng Zhang
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Dongjoo Kim
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Julia Guez-Haddad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Wenzhi Xue
- Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Weijun Pan
- Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Rong Fan
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Paul Kubes
- Snyder Institute for Chronic Diseases Mouse Phenomics Resource Laboratory, University of Calgary, Calgary AB T2N 4N1, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, and Calvin, Phoebe, and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary AB T2N 4N1, Canada
| | - Zhaoxia Sun
- Department of Genetics, Yale University, New Haven, CT 06520, USA
| | - Yarden Opatowsky
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Franck Polleux
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10025, USA
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT 06520, USA; Nanobiology Institute, Yale University, New Haven, CT 06520, USA; Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, Yale University, New Haven, CT 06520, USA; Centre National de la Recherche Scientifique (CNRS), Paris, France.
| | - Wenwen Tang
- Department of Pharmacology, Vascular Biology and Therapeutic Program, Yale University, New Haven, CT 06520, USA.
| | - Dianqing Wu
- Department of Pharmacology, Vascular Biology and Therapeutic Program, Yale University, New Haven, CT 06520, USA.
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9
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Bouffard J, Cecchetelli AD, Clifford C, Sethi K, Zaidel-Bar R, Cram EJ. The RhoGAP SPV-1 regulates calcium signaling to control the contractility of the Caenorhabditis elegans spermatheca during embryo transits. Mol Biol Cell 2019; 30:907-922. [PMID: 30726159 PMCID: PMC6589790 DOI: 10.1091/mbc.e18-10-0633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 01/30/2023] Open
Abstract
Contractility of the nonmuscle and smooth muscle cells that comprise biological tubing is regulated by the Rho-ROCK (Rho-associated protein kinase) and calcium signaling pathways. Although many molecular details about these signaling pathways are known, less is known about how they are coordinated spatiotemporally in biological tubes. The spermatheca of the Caenorhabditis elegans reproductive system enables study of the signaling pathways regulating actomyosin contractility in live adult animals. The RhoGAP (GTPase--activating protein toward Rho family small GTPases) SPV-1 was previously identified as a negative regulator of RHO-1/Rho and spermathecal contractility. Here, we uncover a role for SPV-1 as a key regulator of calcium signaling. spv-1 mutants expressing the calcium indicator GCaMP in the spermatheca exhibit premature calcium release, elevated calcium levels, and disrupted spatial regulation of calcium signaling during spermathecal contraction. Although RHO-1 is required for spermathecal contractility, RHO-1 does not play a significant role in regulating calcium. In contrast, activation of CDC-42 recapitulates many aspects of spv-1 mutant calcium signaling. Depletion of cdc-42 by RNA interference does not suppress the premature or elevated calcium signal seen in spv-1 mutants, suggesting other targets remain to be identified. Our results suggest that SPV-1 works through both the Rho-ROCK and calcium signaling pathways to coordinate cellular contractility.
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Affiliation(s)
- Jeff Bouffard
- Department of Bioengineering, Northeastern University, Boston, MA 02143
| | | | - Coleman Clifford
- Department of Biology, Northeastern University, Boston, MA 02143
| | - Kriti Sethi
- Mechanobiology Institute, National University of Singapore, Singapore 117411
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, National University of Singapore, Singapore 117411
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Erin J. Cram
- Department of Biology, Northeastern University, Boston, MA 02143
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10
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Ruiz JC, Hunter OV, Conrad NK. Kaposi's sarcoma-associated herpesvirus ORF57 protein protects viral transcripts from specific nuclear RNA decay pathways by preventing hMTR4 recruitment. PLoS Pathog 2019; 15:e1007596. [PMID: 30785952 PMCID: PMC6398867 DOI: 10.1371/journal.ppat.1007596] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/04/2019] [Accepted: 01/25/2019] [Indexed: 12/15/2022] Open
Abstract
Nuclear RNAs are subject to a number of RNA decay pathways that serve quality control and regulatory functions. As a result, any virus that expresses its genes in the nucleus must have evolved mechanisms that avoid these pathways, but the how viruses evade nuclear RNA decay remains largely unknown. The multifunctional Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 (Mta) protein is required for the nuclear stability of viral transcripts. In the absence of ORF57, we show that viral transcripts are subject to degradation by two specific nuclear RNA decay pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) in which decay factors are recruited through poly(A) tails, and an ARS2-mediated RNA decay pathway dependent on the 5ʹ RNA cap. In transcription pulse chase assays, ORF57 appears to act primarily by inhibiting the ARS2-mediated RNA decay pathway. In the context of viral infection in cultured cells, inactivation of both decay pathways by RNAi is necessary for the restoration of ORF57-dependent viral genes produced from an ORF57-null bacmid. Mechanistically, we demonstrate that ORF57 protects viral transcripts by preventing the recruitment of the exosome co-factor hMTR4. In addition, our data suggest that ORF57 recruitment of ALYREF inhibits hMTR4 association with some viral RNAs, whereas other KSHV transcripts are stabilized by ORF57 in an ALYREF-independent fashion. In conclusion, our studies show that KSHV RNAs are subject to nuclear degradation by two specific host pathways, PPD and ARS2-mediated decay, and ORF57 protects viral transcripts from decay by inhibiting hMTR4 recruitment. Eukaryotic cells contain numerous nuclear RNA quality control (QC) systems that ensure transcriptome fidelity by detecting and degrading aberrant RNAs. Some viral RNAs are also predicted to be degraded by these RNA QC systems, so viruses have evolved mechanisms that counter host RNA QC pathways. Previous studies showed that the Kaposi’s sarcoma-associated herpesvirus (KSHV) expresses the ORF57 protein to protect its RNAs from nuclear decay. However, neither the specific host pathways that degrade KSHV RNAs nor the mechanisms describing ORF57 protection of viral RNAs were known. Our data suggest that ORF57 protects viral RNAs from two different nuclear RNA QC pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) and an ARS2-mediated RNA decay pathway. Mechanistically, we show that ORF57 binds directly to viral RNAs and prevents the recruitment of hMTR4, a cellular factor whose function is to recruit the exosome, the complex responsible for RNA decay, to the transcript. We conclude that by preventing hMTR4 recruitment, ORF57 protects viral RNAs from degradation resulting in robust expression of viral genes.
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Affiliation(s)
- Julio C. Ruiz
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Olga V. Hunter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nicholas K. Conrad
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
- * E-mail:
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11
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Abstract
Disrupted flow into and out of the nucleus may kill neurons.
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12
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Abstract
The prevalence of high blood pressure (also known as hypertension) has steadily increased over the last few decades. Known as a silent killer, hypertension increases the risk for cardiovascular disease and can lead to stroke, heart attack, kidney failure and associated sequela. While numerous hypertensive therapies are currently available, it is estimated that only half of medicated patients exhibit blood pressure control. This signifies the need for a better understanding of the underlying cause of disease and for more effective therapies. While blood pressure homeostasis is very complex and involves the integrated control of multiple body systems, smooth muscle contractility and arterial resistance are important contributors. Strong evidence from pre-clinical animal models and genome-wide association studies indicate that smooth muscle contraction and BP homeostasis are governed by the small GTPase RhoA and its downstream target, Rho kinase. In this review, we summarize the signaling pathways and regulators that impart tight spatial-temporal control of RhoA activity in smooth muscle cells and discuss current therapeutic strategies to target these RhoA pathway components. We also discuss known allelic variations in the RhoA pathway and consider how these polymorphisms may affect genetic risk for hypertension and its clinical manifestations.
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Affiliation(s)
- Rachel A Dee
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kevin D Mangum
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Xue Bai
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Christopher P Mack
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Joan M Taylor
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; McAllister Heart Institute, University of North Carolina, Chapel Hill, NC 27599, USA.
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13
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Shu Y, Zhang W, Hou Q, Zhao L, Zhang S, Zhou J, Song X, Zhang Y, Jiang D, Chen X, Wang P, Xia X, Liao F, Yin D, Chen X, Zhou X, Zhang D, Yin S, Yang K, Liu J, Fu L, Zhang L, Wang Y, Zhang J, An Y, Cheng H, Zheng B, Sun H, Zhao Y, Wang Y, Xie D, Ouyang L, Wang P, Zhang W, Qiu M, Fu X, Dai L, He G, Yang H, Cheng W, Yang L, Liu B, Li W, Dong B, Zhou Z, Wei Y, Peng Y, Xu H, Hu J. Prognostic significance of frequent CLDN18-ARHGAP26/6 fusion in gastric signet-ring cell cancer. Nat Commun 2018; 9:2447. [PMID: 29961079 PMCID: PMC6026495 DOI: 10.1038/s41467-018-04907-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/31/2018] [Indexed: 02/05/2023] Open
Abstract
Signet-ring cell carcinoma (SRCC) has specific epidemiology and oncogenesis in gastric cancer, however, with no systematical investigation for prognostic genomic features. Here we report a systematic investigation conducted in 1868 Chinese gastric cancer patients indicating that signet-ring cells content was related to multiple clinical characteristics and treatment outcomes. We thus perform whole-genome sequencing on 32 pairs of SRC samples, and identify frequent CLDN18-ARHGAP26/6 fusion (25%). With 797 additional patients for validation, prevalence of CLDN18-ARHGAP26/6 fusion is noticed to be associated with signet-ring cell content, age at diagnosis, female/male ratio, and TNM stage. Importantly, patients with CLDN18-ARHGAP26/6 fusion have worse survival outcomes, and get no benefit from oxaliplatin/fluoropyrimidines-based chemotherapy, which is consistent with the fact of chemo-drug resistance acquired in CLDN18-ARHGAP26 introduced cell lines. Overall, this study provides insights into the clinical and genomic features of SRCC, and highlights the importance of frequent CLDN18-ARHGAP26/6 fusions in chemotherapy response for SRCC.
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Affiliation(s)
- Yang Shu
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Weihan Zhang
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Qianqian Hou
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Linyong Zhao
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Shouyue Zhang
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Jiankang Zhou
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Xiaohai Song
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Yan Zhang
- Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Dan Jiang
- Department of Pathology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Xinzu Chen
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Peiqi Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China
| | - Xuyang Xia
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Fei Liao
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Dandan Yin
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Xiaolong Chen
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Xueyan Zhou
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Duyu Zhang
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Senlin Yin
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Kun Yang
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Jianping Liu
- Department of Pathology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Leilei Fu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Lan Zhang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Yuelan Wang
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Junlong Zhang
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Yunfei An
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Hua Cheng
- WuxiNextCODE, 200131, Shanghai, China
| | - Bin Zheng
- WuxiNextCODE, 200131, Shanghai, China
| | | | - Yinglan Zhao
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Yongsheng Wang
- Department of Thoracic Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Dan Xie
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Liang Ouyang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Ping Wang
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Zhang
- Department of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Xiangya Hospital, Central South University, 410008, Changsha, China
| | - Meng Qiu
- Department of Abdominal Oncology, Cancer Center, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Xianghui Fu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Lunzhi Dai
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Gu He
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Hanshuo Yang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Wei Cheng
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Li Yang
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Bo Liu
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Weimin Li
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China
| | - Biao Dong
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Zongguang Zhou
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Yuquan Wei
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China
| | - Yong Peng
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China.
| | - Heng Xu
- Precision Medicine Center, State Key Laboratory of Biotherapy and Precision Medicine, Key Laboratory of Sichuan Province, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China.
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China.
- Department of Laboratory Medicine/Research Center of Clinical Laboratory Medicine, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan, China.
| | - Jiankun Hu
- Department of Gastrointestinal Surgery, Institute of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center, 610041, Chengdu, Sichuan, China.
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14
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Zhang C, Jiang Y, Liu J, Jin M, Qin N, Chen Y, Niu W, Duan H. AMPK/AS160 mediates tiliroside derivatives-stimulated GLUT4 translocation in muscle cells. Drug Des Devel Ther 2018; 12:1581-1587. [PMID: 29910604 PMCID: PMC5989705 DOI: 10.2147/dddt.s164441] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION The Chinese herb Potentilla chinensis can reduce blood glucose level of diabetic mice. Tiliroside is the main effective component, but the detailed mechanism is not clear. Skeletal muscles play an important role in whole body glucose homeostasis. Insulin and exercise/contraction stimulate glucose uptake by muscle cells via redistribution of glucose transporter GLUT4 to the cell surface. MATERIALS AND METHODS We explored the effects of tiliroside derivatives on cell surface GLUT4 level (GLUT4 translocation) and the underlying mechanism in L6-GLUT4myc muscle cells. RESULTS We showed that tiliroside derivatives D1-22 stimulated GLUT4myc translocation in L6-GLUT4myc skeletal muscle cells. Derivatives D1, D8 and D18 regulated GLUT4myc translocation in a time- and dose-dependent manner. Their effects on GLUT4 were additive with that of acute insulin stimulation. Moreover, they increased phosphorylated adenosine monophosphate-activated protein kinase (AMPK), but not protein kinase B (PKB, also called Akt). Their effects on GLUT4 were inhibited by Compound C. In addition, derivative D8 significantly stimulated AMPK and Akt substrate of 160 kDa (AS160) phosphorylation and GLUT4myc translocation in L6-GLUT4myc cells, but not in L6-AS160 4A-GLUT4myc cells. CONCLUSION Tiliroside derivatives D1, D8 and D18 stimulated GLUT4myc translocation by a mechanism different to that of insulin in skeletal muscle cells. The effect of derivative D8 on GLUT4myc translocation is mediated by AMPK/AS160 signaling pathway.
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Affiliation(s)
- Chang Zhang
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Yue Jiang
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Jia Liu
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Meina Jin
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Nan Qin
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Ying Chen
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Wenyan Niu
- Department of Immunology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Metabolic Diseases Hospital, Tianjin Medical University, Tianjin 300070, People’s Republic of China
| | - Hongquan Duan
- School of Pharmacy, Research Center of Basic Medical Science, Tianjin Medical University, Tianjin 300070, People’s Republic of China
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15
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Wardhana DA, Ikeda K, Barinda AJ, Nugroho DB, Qurania KR, Yagi K, Miyata K, Oike Y, Hirata KI, Emoto N. Family with sequence similarity 13, member A modulates adipocyte insulin signaling and preserves systemic metabolic homeostasis. Proc Natl Acad Sci U S A 2018; 115:1529-1534. [PMID: 29386390 PMCID: PMC5816206 DOI: 10.1073/pnas.1720475115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Adipose tissue dysfunction is causally implicated in the impaired metabolic homeostasis associated with obesity; however, detailed mechanisms underlying dysregulated adipocyte functions in obesity remain to be elucidated. Here we searched for genes that provide a previously unknown mechanism in adipocyte metabolic functions and identified family with sequence similarity 13, member A (Fam13a) as a factor that modifies insulin signal cascade in adipocytes. Fam13a was highly expressed in adipose tissue, predominantly in mature adipocytes, and its expression was substantially reduced in adipose tissues of obese compared with lean mice. We revealed that Fam13a accentuated insulin signaling by recruiting protein phosphatase 2A with insulin receptor substrate 1 (IRS1), leading to protection of IRS1 from proteasomal degradation. We further demonstrated that genetic loss of Fam13a exacerbated obesity-related metabolic disorders, while targeted activation of Fam13a in adipocytes ameliorated it in association with altered adipose tissue insulin sensitivity in mice. Our data unveiled a previously unknown mechanism in the regulation of adipocyte insulin signaling by Fam13a and identified its significant role in systemic metabolic homeostasis, shedding light on Fam13a as a pharmacotherapeutic target to treat obesity-related metabolic disorders.
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Affiliation(s)
- Donytra Arby Wardhana
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, 6500017 Kobe, Japan
| | - Koji Ikeda
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan;
| | - Agian Jeffilano Barinda
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
| | - Dhite Bayu Nugroho
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, 6500017 Kobe, Japan
| | - Kikid Rucira Qurania
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, 6500017 Kobe, Japan
| | - Keiko Yagi
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
| | - Keishi Miyata
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, 860-8556 Kumamoto, Japan
- Department of Immunology, Allergy and Vascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, 860-8556 Kumamoto, Japan
| | - Yuichi Oike
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, 860-8556 Kumamoto, Japan
| | - Ken-Ichi Hirata
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, 6500017 Kobe, Japan
| | - Noriaki Emoto
- Department of Clinical Pharmacy, Kobe Pharmaceutical University, Higashinada, 658-8558 Kobe, Japan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo, 6500017 Kobe, Japan
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Molina-Ortiz P, Orban T, Martin M, Habets A, Dequiedt F, Schurmans S. Rasa3 controls turnover of endothelial cell adhesion and vascular lumen integrity by a Rap1-dependent mechanism. PLoS Genet 2018; 14:e1007195. [PMID: 29381707 PMCID: PMC5806903 DOI: 10.1371/journal.pgen.1007195] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/09/2018] [Accepted: 01/09/2018] [Indexed: 11/18/2022] Open
Abstract
Rasa3 is a GTPase activating protein of the GAP1 family which targets R-Ras and Rap1. Although catalytic inactivation or deletion of Rasa3 in mice leads to severe hemorrhages and embryonic lethality, the biological function and cellular location of Rasa3 underlying these defects remains unknown. Here, using a combination of loss of function studies in mouse and zebrafish as well as in vitro cell biology approaches, we identify a key role for Rasa3 in endothelial cells and vascular lumen integrity. Specific ablation of Rasa3 in the mouse endothelium, but not in megakaryocytes and platelets, lead to embryonic bleeding and death at mid-gestation, recapitulating the phenotype observed in full Rasa3 knock-out mice. Reduced plexus/sprouts formation and vascular lumenization defects were observed when Rasa3 was specifically inactivated in mouse endothelial cells at the postnatal or adult stages. Similar results were obtained in zebrafish after decreasing Rasa3 expression. In vitro, depletion of Rasa3 in cultured endothelial cells increased β1 integrin activation and cell adhesion to extracellular matrix components, decreased cell migration and blocked tubulogenesis. During migration, these Rasa3-depleted cells exhibited larger and more mature adhesions resulting from a perturbed dynamics of adhesion assembly and disassembly which significantly increased their life time. These defects were due to a hyperactivation of the Rap1 GTPase and blockade of FAK/Src signaling. Finally, Rasa3-depleted cells showed reduced turnover of VE-cadherin-based adhesions resulting in more stable endothelial cell-cell adhesion and decreased endothelial permeability. Altogether, our results indicate that Rasa3 is a critical regulator of Rap1 in endothelial cells which controls adhesions properties and vascular lumen integrity; its specific endothelial cell inactivation results in occluded blood vessels, hemorrhages and early embryonic death in mouse, mimicking thus the Rasa3-/- mouse phenotype. Because it delivers oxygen and nutriments to every tissue in the body, the vascular system is essential to vertebrate life. Blood vessels consist of a layer of interconnected endothelial cells delineating a luminal space through which blood flows. Formation of vascular lumens is a critical step in vascular development, as vessels should allow unrestricted blood flow while absorbing the pressure from cardiac activity yet retaining flexibility to adapt to homeostatic needs. Our current knowledge of how lumens are established and maintained is still modest and has come essentially from in vitro systems. Here, using a combination of loss of function studies in mouse and zebrafish and in vitro cell biology approaches, we show that Rasa3, a GTPase activating protein of the GAP1 family, controls Rap1 activation, endothelial cell adhesion and migration as well as formation of vascular lumens. We also found that inactivation of Rasa3 specifically in mouse endothelial cells lead to embryonic bleeding and death at mid-gestation, recapitulating the phenotype observed in full Rasa3 knock-out mice.
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Affiliation(s)
- Patricia Molina-Ortiz
- Laboratory of Functional Genetics, GIGA-Molecular Biology of Disease, University of Liège, Liège, Belgium
| | - Tanguy Orban
- Laboratory of Protein signaling and Interactions Signalisation, GIGA-Molecular Biology of Diseases, University of Liège, Liège, Belgium
| | - Maud Martin
- Laboratory of Functional Genetics, GIGA-Molecular Biology of Disease, University of Liège, Liège, Belgium
- Laboratory of Protein signaling and Interactions Signalisation, GIGA-Molecular Biology of Diseases, University of Liège, Liège, Belgium
| | - Audrey Habets
- Laboratory of Protein signaling and Interactions Signalisation, GIGA-Molecular Biology of Diseases, University of Liège, Liège, Belgium
| | - Franck Dequiedt
- Laboratory of Protein signaling and Interactions Signalisation, GIGA-Molecular Biology of Diseases, University of Liège, Liège, Belgium
| | - Stéphane Schurmans
- Laboratory of Functional Genetics, GIGA-Molecular Biology of Disease, University of Liège, Liège, Belgium
- * E-mail:
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Xavier-Ferrucio J, Ricon L, Vieira K, Longhini AL, Lazarini M, Bigarella CL, Franchi G, Krause DS, Saad STO. Hematopoietic defects in response to reduced Arhgap21. Stem Cell Res 2017; 26:17-27. [PMID: 29212046 PMCID: PMC6084430 DOI: 10.1016/j.scr.2017.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 11/13/2017] [Accepted: 11/20/2017] [Indexed: 12/28/2022] Open
Abstract
Arhgap21 is a member of the Rho GTPase activating protein (RhoGAP) family, which function as negative regulators of Rho GTPases. Arhgap21 has been implicated in adhesion and migration of cancer cells. However, the role of Arhgap21 has never been investigated in hematopoietic cells. Herein, we evaluated functional aspects of hematopoietic stem and progenitor cells (HSPC) using a haploinsufficient (Arhgap21+/-) mouse. Our results show that Arhgap21+/- mice have an increased frequency of phenotypic HSC, impaired ability to form progenitor colonies in vitro and decreased hematopoietic engraftment in vivo, along with a decrease in LSK cell frequency during serial bone marrow transplantation. Arhgap21+/- hematopoietic progenitor cells have impaired adhesion and enhanced mobilization of immature LSK and myeloid progenitors. Arhgap21+/- mice also exhibit reduced erythroid commitment and differentiation, which was recapitulated in human primary cells, in which knockdown of ARHGAP21 in CMP and MEP resulted in decreased erythroid commitment. Finally, we observed enhanced RhoC activity in the bone marrow cells of Arhgap21+/- mice, indicating that Arhgap21 functions in hematopoiesis may be at least partially mediated by RhoC inactivation.
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Affiliation(s)
- Juliana Xavier-Ferrucio
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil; Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA.; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, USA
| | - Lauremília Ricon
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Karla Vieira
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Ana Leda Longhini
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Mariana Lazarini
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil; Department of Biological Sciences, Federal University of São Paulo, Diadema, Brazil
| | - Carolina Louzão Bigarella
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Gilberto Franchi
- Onco-Hematological Child Research Center (CIPOI), Faculty of Medical Sciences, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Diane S Krause
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA.; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, USA
| | - Sara T O Saad
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil.
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18
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Rapti G, Li C, Shan A, Lu Y, Shaham S. Glia initiate brain assembly through noncanonical Chimaerin-Furin axon guidance in C. elegans. Nat Neurosci 2017; 20:1350-1360. [PMID: 28846083 PMCID: PMC5614858 DOI: 10.1038/nn.4630] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/19/2017] [Indexed: 01/08/2023]
Abstract
Brain assembly is hypothesized to begin when pioneer axons extend over non-neuronal cells, forming tracts guiding follower axons. Yet pioneer-neuron identities, their guidance substrates, and their interactions are not well understood. Here, using time-lapse embryonic imaging, genetics, protein-interaction, and functional studies, we uncover the early events of C. elegans brain assembly. We demonstrate that C. elegans glia are key for assembly initiation, guiding pioneer and follower axons using distinct signals. Pioneer sublateral neurons, with unique growth properties, anatomy, and innervation, cooperate with glia to mediate follower-axon guidance. We further identify a Chimaerin (CHIN-1)- Furin (KPC-1) double-mutant that severely disrupts assembly. CHIN-1 and KPC-1 function noncanonically, in glia and pioneer neurons, for guidance-cue trafficking. We exploit this bottleneck to define roles for glial Netrin and Semaphorin in pioneer- and follower-axon guidance, respectively, and for glial and pioneer-neuron Flamingo (CELSR) in follower-axon navigation. Taken together, our studies reveal previously undescribed glial roles in pioneer-axon guidance, suggesting conserved principles of brain assembly.
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Affiliation(s)
- Georgia Rapti
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065 USA
| | - Chang Li
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065 USA
- These authors contributed equally to this work
| | - Alan Shan
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065 USA
- These authors contributed equally to this work
| | - Yun Lu
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065 USA
| | - Shai Shaham
- Laboratory of Developmental Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065 USA
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Abstract
Recycling endosomes are generally thought to play a central role in endocytic recycling, but recent evidence has indicated that they also participate in other cellular events, including cytokinesis, autophagy, and neurite outgrowth. Rab small GTPases are key regulators in membrane trafficking, and although several Rab isoforms, e.g., Rab11, have been shown to regulate recycling endosomal trafficking, the precise mechanism by which these Rabs regulate recycling endosomes is not fully understood. In this study, we focused on a Rab-GTPase-activating protein (Rab-GAP), one of the key regulators of Rabs, and comprehensively screened 43 mammalian Tre-2/Bub2/Cdc16 (TBC)/Rab-GAP-domain-containing proteins (TBC proteins) for proteins that specifically localize on recycling endosomes in mouse embryonic fibroblasts (MEFs). Four of the 43 mammalian TBC proteins screened, i.e., TBC1D11, TBC1D12, TBC1D14, and EVI5, were found to colocalize well with transferrin receptor, a well-known recycling endosome marker. We further investigated the biochemical properties of TBC1D12, a previously uncharacterized TBC protein. The results showed that TBC1D12 interacted with active Rab11 through its middle region and that it did not display Rab11-GAP activity in vitro. The recycling endosomal localization of TBC1D12 was found to depend on the expression of Rab11. We also found that TBC1D12 expression had no effect on common Rab11-dependent cellular events, e.g., transferrin recycling, in MEFs and that it promoted neurite outgrowth, a specialized Rab11-dependent cellular event, of PC12 cells independently of its GAP activity. These findings indicated that TBC1D12 is a novel Rab11-binding protein that modulates neurite outgrowth of PC12 cells.
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Affiliation(s)
- Mai E. Oguchi
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Kenta Noguchi
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
- * E-mail:
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Compagnucci C, Barresi S, Petrini S, Billuart P, Piccini G, Chiurazzi P, Alfieri P, Bertini E, Zanni G. Rho Kinase Inhibition Is Essential During In Vitro Neurogenesis and Promotes Phenotypic Rescue of Human Induced Pluripotent Stem Cell-Derived Neurons With Oligophrenin-1 Loss of Function. Stem Cells Transl Med 2016; 5:860-9. [PMID: 27160703 DOI: 10.5966/sctm.2015-0303] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/23/2016] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED : Rho-GTPases have relevant functions in various aspects of neuronal development, such as differentiation, migration, and synaptogenesis. Loss of function of the oligophrenin-1 gene (OPHN1) causes X-linked intellectual disability with cerebellar hypoplasia and leads to hyperactivation of the rho kinase (ROCK) pathway. ROCK mainly acts through phosphorylation of the myosin phosphatase targeting subunit 1, triggering actin-myosin contractility. We show that during in vitro neurogenesis, ROCK activity decreases from day 10 until terminal differentiation, whereas in OPHN1-deficient human induced pluripotent stem cells (h-iPSCs), the levels of ROCK are elevated throughout differentiation. ROCK inhibition favors neuronal-like appearance of h-iPSCs, in parallel with transcriptional upregulation of nuclear receptor NR4A1, which is known to induce neurite outgrowth. This study analyzed the morphological, biochemical, and functional features of OPHN1-deficient h-iPSCs and their rescue by treatment with the ROCK inhibitor fasudil, shedding light on the relevance of the ROCK pathway during neuronal differentiation and providing a neuronal model for human OPHN1 syndrome and its treatment. SIGNIFICANCE The analysis of the levels of rho kinase (ROCK) activity at different stages of in vitro neurogenesis of human induced pluripotent stem cells reveals that ROCK activity decreases progressively in parallel with the appearance of neuronal-like morphology and upregulation of nuclear receptor NR4A1. These results shed light on the role of the ROCK pathway during early stages of human neurogenesis and provide a neuronal stem cell-based model for the treatment of OPHN1 syndrome and other neurological disorders due to ROCK dysfunction.
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Affiliation(s)
- Claudia Compagnucci
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Sabina Barresi
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Stefania Petrini
- Research Laboratories, Confocal Microscopy Core Facility, and Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Pierre Billuart
- Department of Genetic and Development, Institut Cochin, Université Paris Descartes, Paris, France
| | - Giorgia Piccini
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Pietro Chiurazzi
- Institute of Human and Medical Genetics, Catholic University, Rome, Italy
| | - Paolo Alfieri
- Unit of Child Neuropsychiatry, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
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21
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Rodriguez-Fernandez IA, Dell’Angelica EC. Identification of Atg2 and ArfGAP1 as Candidate Genetic Modifiers of the Eye Pigmentation Phenotype of Adaptor Protein-3 (AP-3) Mutants in Drosophila melanogaster. PLoS One 2015; 10:e0143026. [PMID: 26565960 PMCID: PMC4643998 DOI: 10.1371/journal.pone.0143026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/29/2015] [Indexed: 11/19/2022] Open
Abstract
The Adaptor Protein (AP)-3 complex is an evolutionary conserved, molecular sorting device that mediates the intracellular trafficking of proteins to lysosomes and related organelles. Genetic defects in AP-3 subunits lead to impaired biogenesis of lysosome-related organelles (LROs) such as mammalian melanosomes and insect eye pigment granules. In this work, we have performed a forward screening for genetic modifiers of AP-3 function in the fruit fly, Drosophila melanogaster. Specifically, we have tested collections of large multi-gene deletions–which together covered most of the autosomal chromosomes–to identify chromosomal regions that, when deleted in single copy, enhanced or ameliorated the eye pigmentation phenotype of two independent AP-3 subunit mutants. Fine-mapping led us to define two non-overlapping, relatively small critical regions within fly chromosome 3. The first critical region included the Atg2 gene, which encodes a conserved protein involved in autophagy. Loss of one functional copy of Atg2 ameliorated the pigmentation defects of mutants in AP-3 subunits as well as in two other genes previously implicated in LRO biogenesis, namely Blos1 and lightoid, and even increased the eye pigment content of wild-type flies. The second critical region included the ArfGAP1 gene, which encodes a conserved GTPase-activating protein with specificity towards GTPases of the Arf family. Loss of a single functional copy of the ArfGAP1 gene ameliorated the pigmentation phenotype of AP-3 mutants but did not to modify the eye pigmentation of wild-type flies or mutants in Blos1 or lightoid. Strikingly, loss of the second functional copy of the gene did not modify the phenotype of AP-3 mutants any further but elicited early lethality in males and abnormal eye morphology when combined with mutations in Blos1 and lightoid, respectively. These results provide genetic evidence for new functional links connecting the machinery for biogenesis of LROs with molecules implicated in autophagy and small GTPase regulation.
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Affiliation(s)
- Imilce A. Rodriguez-Fernandez
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Esteban C. Dell’Angelica
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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22
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Basak P, Dillon R, Leslie H, Raouf A, Mowat MRA. The Deleted in Liver Cancer 1 (Dlc1) tumor suppressor is haploinsufficient for mammary gland development and epithelial cell polarity. BMC Cancer 2015; 15:630. [PMID: 26353792 PMCID: PMC4565020 DOI: 10.1186/s12885-015-1642-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 09/01/2015] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Deleted in Liver Cancer 1 (Dlc1) is a tumor suppressor gene, which maps to human chromosome 8p21-22 and is found frequently deleted in many cancers including breast cancer. The promoter of the remaining allele is often found methylated. The Dlc1 gene encodes a RhoGAP protein that regulates cell proliferation, migration and inhibits cell growth and invasion when restored in Dlc1 deficient tumor cell lines. This study focuses on determining the role of Dlc1 in normal mammary gland development and epithelial cell polarity in a Dlc1 gene trapped (gt) mouse. METHODS Mammary gland whole mount preparations from 10-week virgin heterozygous Dlc1(gt/+) gene-trapped mice were compared with age-matched wild type (WT) controls. Hematoxylin-Eosin (H&E) and Masson's Trichrome staining of histological sections were carried out. Mammary glands from Dlc1(gt/+) mice and WT controls were enzymatically digested with collagenase and dispase and then cultured overnight to deplete hematopoietic and endothelial cells. The single cell suspensions were then cultured in Matrigel for 12 days. To knockdown Dlc1 expression, primary WT mammary epithelial cells were infected with short hairpin (sh) RNA expressing lentivirus or with a scrambled shRNA control. RESULTS Dlc1(gt/+) mice showed anomalies in the mammary gland that included increased ductal branching and deformities in terminal end buds and branch points. Compared to the WT controls, Masson's Trichrome staining showed a thickened stromal layer with increased collagen deposition in mammary glands from Dlc1(gt/+) mice. Dlc1(gt/+) primary mammary epithelial cells formed increased solid acinar spheres in contrast with WT and scrambled shRNA control cells, which mostly formed hollow acinar structures when plated in 3D Matrigel cultures. These solid acinar structures were similar to the acinar structures formed when Dlc1 gene expression was knocked down in WT mammary cells by shRNA lentiviral transduction. The solid acinar structures were not due to a defect in apoptosis as determined by a lack of detectible cleaved caspase 3 antibody staining. Primary mammary cells from Dlc1(gt/+) mice showed increased RhoA activity compared with WT cells. CONCLUSIONS The results illustrate that decreased Dlc1 expression can disrupt the normal cell polarization and mammary ductal branching. Altogether this study suggests that Dlc1 plays a role in maintaining normal mammary epithelial cell polarity and that Dlc1 is haploinsufficient.
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Affiliation(s)
- Pratima Basak
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB, Canada.
- Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.
- Regenerative Medicine Program, University of Manitoba, Winnipeg, MB, Canada.
| | - Rachelle Dillon
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.
| | - Heather Leslie
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.
| | - Afshin Raouf
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.
- Department of Immunology, University of Manitoba, Winnipeg, MB, Canada.
- Regenerative Medicine Program, University of Manitoba, Winnipeg, MB, Canada.
| | - Michael R A Mowat
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, MB, R3E 0V9, Canada.
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB, Canada.
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23
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Abraham S, Scarcia M, Bagshaw RD, McMahon K, Grant G, Harvey T, Yeo M, Esteves FO, Thygesen HH, Jones PF, Speirs V, Hanby AM, Selby PJ, Lorger M, Dear TN, Pawson T, Marshall CJ, Mavria G. A Rac/Cdc42 exchange factor complex promotes formation of lateral filopodia and blood vessel lumen morphogenesis. Nat Commun 2015; 6:7286. [PMID: 26129894 PMCID: PMC4507007 DOI: 10.1038/ncomms8286] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 04/26/2015] [Indexed: 12/18/2022] Open
Abstract
During angiogenesis, Rho-GTPases influence endothelial cell migration and cell-cell adhesion; however it is not known whether they control formation of vessel lumens, which are essential for blood flow. Here, using an organotypic system that recapitulates distinct stages of VEGF-dependent angiogenesis, we show that lumen formation requires early cytoskeletal remodelling and lateral cell-cell contacts, mediated through the RAC1 guanine nucleotide exchange factor (GEF) DOCK4 (dedicator of cytokinesis 4). DOCK4 signalling is necessary for lateral filopodial protrusions and tubule remodelling prior to lumen formation, whereas proximal, tip filopodia persist in the absence of DOCK4. VEGF-dependent Rac activation via DOCK4 is necessary for CDC42 activation to signal filopodia formation and depends on the activation of RHOG through the RHOG GEF, SGEF. VEGF promotes interaction of DOCK4 with the CDC42 GEF DOCK9. These studies identify a novel Rho-family GTPase activation cascade for the formation of endothelial cell filopodial protrusions necessary for tubule remodelling, thereby influencing subsequent stages of lumen morphogenesis.
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Affiliation(s)
- Sabu Abraham
- Institute of Cancer Research, Division of Cancer Biology, 237 Fulham Road, London SW3 6JB, UK
| | - Margherita Scarcia
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Richard D. Bagshaw
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, M5G 1X5 Ontario, Canada
| | - Kathryn McMahon
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Gary Grant
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Tracey Harvey
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Maggie Yeo
- Institute of Cancer Research, Division of Cancer Biology, 237 Fulham Road, London SW3 6JB, UK
| | - Filomena O.G. Esteves
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Helene H. Thygesen
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Pamela F. Jones
- Leeds Institutes of Molecular Medicine, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Valerie Speirs
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Andrew M. Hanby
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Peter J. Selby
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Mihaela Lorger
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - T. Neil Dear
- Leeds Institutes of Molecular Medicine, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
| | - Tony Pawson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, M5G 1X5 Ontario, Canada
| | - Christopher J. Marshall
- Institute of Cancer Research, Division of Cancer Biology, 237 Fulham Road, London SW3 6JB, UK
| | - Georgia Mavria
- Leeds Institute of Cancer and Pathology, University of Leeds, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK
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Yang J, Song Q, Cai Y, Wang P, Wang M, Zhang D. RLIP76-dependent suppression of PI3K/AKT/Bcl-2 pathway by miR-101 induces apoptosis in prostate cancer. Biochem Biophys Res Commun 2015; 463:900-6. [PMID: 26067553 DOI: 10.1016/j.bbrc.2015.06.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/05/2015] [Indexed: 12/20/2022]
Abstract
MicroRNA-101 (miR-101) participates in carcinogenesis and tumor progression in various cancers. However, its biological functions in prostate cancer are still unclear. Here, we demonstrate that miR-101 represents a critical role in regulating cell apoptosis in prostate cancer cells. We first demonstrated that miR-101 treatment promoted apoptosis in DU145 and PC3 cells by using flow cytometric analysis and transmission electron microscopy (TEM). To verify the mechanisms, we identified a novel miR-101 target, Ral binding protein 1 (RLIP76). We found miR-101 transfection significantly suppresses RLIP76 expression, which can transactivate phosphorylation of PI3K-Akt signaling, and resulted in an amplification of Bcl2-induced apoptosis. Furthermore, we demonstrated that RLIP76 overexpression could reverse the anti-tumor effects of miR-101 in DU145 and PC3 cells by using flow cytometry assay and MTT assay. Taken together, our results revealed that the effect of miR-101 on prostate cancer cell apoptosis was due to RLIP76 regulation of the PI3K/Akt/Bcl-2 signaling pathway.
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Affiliation(s)
- Jing Yang
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China
| | - Qi Song
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China
| | - Yi Cai
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China
| | - Peng Wang
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China
| | - Min Wang
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China
| | - Dong Zhang
- Chinese PLA General Hospital, Department of Oncology, 28 Fuxing Road, Beijing, 100853, China.
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Haixia P, Yifeng B, Honglin H. [Role and clinical significance of RLIP76 in regulation of multi-drug resistance of small cell lung cancer]. Zhonghua Zhong Liu Za Zhi 2015; 37:266-271. [PMID: 26462890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To investigate the role of RLIP76 in regulating multi-drug resistance in small cell lung cancer (SCLC), and to analyze the relationship between its expression and prognosis. METHODS The expressions of RLIP76 protein and gene were detected by Western blotting and real-time PCR (RT-PCR) in both the chemosensitive SCLC H69 cell line and chemoresistant H69AR cell line, respectively. siRNA was transfected into the H69AR cells to inhibit RLIP76 expression, and eGFP-RLIP76 was transfected into the H69 cells to enhance RLIP76 expression. The drug-sensitivity of cells to chemotherapeutic drugs (ADM, DDP, VP-16) were detected by CCK8 assay. The expression of RLIP76 in the SCLC tissues was detected by immunohistochemistry. The relationship of RLIP76 expression with clinicopathological features and prognosis of the patients was analyzed. RESULTS The expression of RLIP76 in H69AR cells was 13.675 ± 0.983, significantly higher than 1.074 ± 0.107 in the H69 cells (P < 0.01). The drug-sensitivities of H69AR cells to chemotherapeutic drugs were significantly increased when the expression of RLIP76 was down-regulated (P< 0.001). The sensitivities of H69 cells to chemotherapeutic drugs ADM, DDP and VP-16 were significantly decreased after transfection with eGFP-RLIP76 up-regulating the RLIP76 expression (P = 0.003). The positive expression rates were 61.3% and 9.4% in the SCLC tumor tissues and para-cancerous tissues, respectively (P < 0.01). The expression of RLIP76 was significantly correlated with clinical stage, chemosensitivity and overall survival of the SCLC patients (P < 0.05). CONCLUSIONS Our results suggest that RLIP76 is involved in the regulation of small cell lung cancer multidrug resistance. RLIP76 may serve as a potential target gene to evaluate the chemosensitivity and clinical prognostic for small cell lung cancer.
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Stefanini L, Paul DS, Robledo RF, Chan ER, Getz TM, Campbell RA, Kechele DO, Casari C, Piatt R, Caron KM, Mackman N, Weyrich AS, Parrott MC, Boulaftali Y, Adams MD, Peters LL, Bergmeier W. RASA3 is a critical inhibitor of RAP1-dependent platelet activation. J Clin Invest 2015; 125:1419-32. [PMID: 25705885 DOI: 10.1172/jci77993] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/13/2015] [Indexed: 01/15/2023] Open
Abstract
The small GTPase RAP1 is critical for platelet activation and thrombus formation. RAP1 activity in platelets is controlled by the GEF CalDAG-GEFI and an unknown regulator that operates downstream of the adenosine diphosphate (ADP) receptor, P2Y12, a target of antithrombotic therapy. Here, we provide evidence that the GAP, RASA3, inhibits platelet activation and provides a link between P2Y12 and activation of the RAP1 signaling pathway. In mice, reduced expression of RASA3 led to premature platelet activation and markedly reduced the life span of circulating platelets. The increased platelet turnover and the resulting thrombocytopenia were reversed by concomitant deletion of the gene encoding CalDAG-GEFI. Rasa3 mutant platelets were hyperresponsive to agonist stimulation, both in vitro and in vivo. Moreover, activation of Rasa3 mutant platelets occurred independently of ADP feedback signaling and was insensitive to inhibitors of P2Y12 or PI3 kinase. Together, our results indicate that RASA3 ensures that circulating platelets remain quiescent by restraining CalDAG-GEFI/RAP1 signaling and suggest that P2Y12 signaling is required to inhibit RASA3 and enable sustained RAP1-dependent platelet activation and thrombus formation at sites of vascular injury. These findings provide insight into the antithrombotic effect of P2Y12 inhibitors and may lead to improved diagnosis and treatment of platelet-related disorders.
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Abstract
This review focuses on two paralogue Rab GTPase activating proteins known as TBC1D1 Tre-2/BUB2/cdc 1 domain family (TBC1D) 1 and TBC1D4 (also called Akt Substrate of 160 kDa, AS160) and their roles in controlling skeletal muscle glucose transport in response to the independent and combined effects of insulin and exercise. Convincing evidence implicates Akt2-dependent TBC1D4 phosphorylation on T642 as a key part of the mechanism for insulin-stimulated glucose uptake by skeletal muscle. TBC1D1 phosphorylation on several insulin-responsive sites (including T596, a site corresponding to T642 in TBC1D4) does not appear to be essential for in vivo insulin-stimulated glucose uptake by skeletal muscle. In vivo exercise or ex vivo contraction of muscle result in greater TBC1D1 phosphorylation on S237 that is likely to be secondary to increased AMP-activated protein kinase activity and potentially important for contraction-stimulated glucose uptake. Several studies that evaluated both normal and insulin-resistant skeletal muscle stimulated with a physiological insulin concentration after a single exercise session found that greater post-exercise insulin-stimulated glucose uptake was accompanied by greater TBC1D4 phosphorylation on several sites. In contrast, enhanced post-exercise insulin sensitivity was not accompanied by greater insulin-stimulated TBC1D1 phosphorylation. The mechanism for greater TBC1D4 phosphorylation in insulin-stimulated muscles after acute exercise is uncertain, and a causal link between enhanced TBC1D4 phosphorylation and increased post-exercise insulin sensitivity has yet to be established. In summary, TBC1D1 and TBC1D4 have important, but distinct roles in regulating muscle glucose transport in response to insulin and exercise.
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Affiliation(s)
- Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI, 48109-2214, USA,
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Machida K, Feldman DE, Tsukamoto H. TLR4-dependent tumor-initiating stem cell-like cells (TICs) in alcohol-associated hepatocellular carcinogenesis. Adv Exp Med Biol 2015; 815:131-44. [PMID: 25427905 PMCID: PMC10578031 DOI: 10.1007/978-3-319-09614-8_8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alcohol abuse predisposes individuals to the development of hepatocellular carcinoma (HCC) and synergistically heightens the HCC risk in patients infected with hepatitis C virus (HCV). The mechanisms of this synergism have been elusive until our recent demonstration of the obligatory role of ectopically expressed TLR4 in liver tumorigenesis in alcohol-fed HCV Ns5a or Core transgenic mice. CD133+/CD49f+ tumor-initiating stem cell-like cells (TICs) isolated from these models are tumorigenic in a manner dependent on TLR4 and NANOG. TICs' tumor-initiating activity and chemoresistance are causally associated with inhibition of TGF-β tumor suppressor pathway due to NANOG-mediated expression of IGF2BP3 and YAP1. TLR4/NANOG activation causes p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncoprotein TBC1D15. Nutrient deprivation reduces overexpressed TBC1D15 in TICs via autophagy-mediated degradation, suggesting a possible role of this oncoprotein in linking metabolic reprogramming and self-renewal.
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Affiliation(s)
- Keigo Machida
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, 1333 San Pablo Street, MMR-402, Los Angeles, CA, 90089-9141, USA,
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Um K, Niu S, Duman JG, Cheng JX, Tu YK, Schwechter B, Liu F, Hiles L, Narayanan AS, Ash RT, Mulherkar S, Alpadi K, Smirnakis SM, Tolias KF. Dynamic control of excitatory synapse development by a Rac1 GEF/GAP regulatory complex. Dev Cell 2014; 29:701-15. [PMID: 24960694 DOI: 10.1016/j.devcel.2014.05.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/23/2014] [Accepted: 05/14/2014] [Indexed: 11/18/2022]
Abstract
The small GTPase Rac1 orchestrates actin-dependent remodeling essential for numerous cellular processes including synapse development. While precise spatiotemporal regulation of Rac1 is necessary for its function, little is known about the mechanisms that enable Rac1 activators (GEFs) and inhibitors (GAPs) to act in concert to regulate Rac1 signaling. Here, we identify a regulatory complex composed of a Rac-GEF (Tiam1) and a Rac-GAP (Bcr) that cooperate to control excitatory synapse development. Disruption of Bcr function within this complex increases Rac1 activity and dendritic spine remodeling, resulting in excessive synaptic growth that is rescued by Tiam1 inhibition. Notably, EphB receptors utilize the Tiam1-Bcr complex to control synaptogenesis. Following EphB activation, Tiam1 induces Rac1-dependent spine formation, whereas Bcr prevents Rac1-mediated receptor internalization, promoting spine growth over retraction. The finding that a Rac-specific GEF/GAP complex is required to maintain optimal levels of Rac1 signaling provides an important insight into the regulation of small GTPases.
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Affiliation(s)
- Kyongmi Um
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Sanyong Niu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Brandon Schwechter
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Feng Liu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Laura Hiles
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Anjana S Narayanan
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ryan T Ash
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kannan Alpadi
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Stelios M Smirnakis
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Huo XL, Min JJ, Pan CY, Zhao CC, Pan LL, Gui FF, Jin L, Wang XT. Efficacy of lovastatin on learning and memory deficits caused by chronic intermittent hypoxia-hypercapnia: through regulation of NR2B-containing NMDA receptor-ERK pathway. PLoS One 2014; 9:e94278. [PMID: 24718106 PMCID: PMC3981803 DOI: 10.1371/journal.pone.0094278] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 03/14/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Chronic intermittent hypoxia-hypercapnia (CIHH) exposure leads to learnning and memory deficits in rats. Overactivation of N-methyl-D-aspartate receptors(NMDARs) can lead to the death of neurons through a process termed excitotoxicity, which is involved in CIHH-induced cognitive deficits. Excessively activated NR2B (GluN2B)-containing NMDARs was reported as the main cause of excitotoxicity. The ERK1/2 (extracellular signal-regulated kinase 1/2) signaling cascade acts as a key component in NMDARs-dependent neuronal plasticity and survival. Ca2+/calmodulin-dependent protein kinase II (CaMKII), synapse-associated protein 102 (SAP102) and Ras GTPase-activating protein (SynGAP) have been shown to be involved in the regulation of NMDAR-ERK signalling cascade. Recent studies revealed statins (the HMG-CoA reductase inhibitor) have effect on the expression of NMDARs. The present study intends to explore the potential effect of lovastatin on CIHH-induced cognitive deficits and the NR2B-ERK signaling pathway. METHODS AND FINDINGS Eighty male Sprague Dawley rats were randomly divided into five groups. Except for those in the control group, the rats were exposed to chronic intermittent hypoxia-hypercapnia (CIHH) (9 ∼ 11%O2, 5.5 ∼ 6.5%CO2) for 4 weeks. After lovastatin administration, the rats performed better in the Morris water maze test. Electron microscopy showed alleviated hippocampal neuronal synaptic damage. Further observation suggested that either lovastatin or ifenprodil (a selective NR2B antagonist) administration similarly downregulated NR2B subunit expression leading to a suppression of CaMKII/SAP102/SynGAP signaling cascade, which in turn enhanced the phosphorylation of ERK1/2. The phosphorylated ERK1/2 induced signaling cascade involving cAMP-response element-binding protein (CREB) phosphorylation and brain-derived neurotrophic factor (BDNF) activation, which is responsible for neuroprotection. CONCLUSIONS These findings suggest that the ameliorative cognitive deficits caused by lovastatin are due to the downregulation of excessive NR2B expression accompanied by increased expression of ERK signaling cascade. The effect of NR2B in upregulating pERK1/2 maybe due, at least in part, to inactivation of CaMKII/SAP102/SynGAP signaling cascade.
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Affiliation(s)
- Xin-long Huo
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jing-jing Min
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Cai-yu Pan
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Cui-cui Zhao
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Lu-lu Pan
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Fei-fei Gui
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Lu Jin
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiao-tong Wang
- The Center of Neurology and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Affiliation(s)
- Susanne Muehlich
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University Munich, Germany
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Feldman DE, Chen C, Punj V, Machida K. The TBC1D15 oncoprotein controls stem cell self-renewal through destabilization of the Numb-p53 complex. PLoS One 2013; 8:e57312. [PMID: 23468968 PMCID: PMC3584131 DOI: 10.1371/journal.pone.0057312] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 01/21/2013] [Indexed: 01/22/2023] Open
Abstract
Stem cell populations are maintained through self-renewing divisions in which one daughter cell commits to a specific fate while the other retains the multipotent characteristics of its parent. The p53 tumor suppressor, in conjunction with its interacting partner protein Numb, preserves this asymmetry and functions as a vital barrier against the unchecked expansion of tumor stem cell pools; however, little is known about the biological control of the Numb-p53 interaction. We show here that Numb and p53 are the constituents of a high molecular mass complex, which is disintegrated upon activation of aPKCζ, a Numb kinase. Using large-scale affinity purification and tandem mass spectrometry, we identify TBC1D15 as a Numb-associated protein and demonstrate that its amino-terminal domain disengages p53 from Numb, triggering p53 proteolysis and promoting self-renewal and pluripotency. Cellular levels of TBC1D15 are diminished upon acute nutrient deprivation through autophagy-mediated degradation, indicating that TBC1D15 serves as a conduit through which cellular metabolic status is linked to self-renewal. The profound deregulation of TBC1D15 expression exhibited in a diverse array of patient tumors underscores its proposed function as an oncoprotein.
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Affiliation(s)
- Douglas E. Feldman
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, California, United States of America
| | - Chialin Chen
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, California, United States of America
| | - Vasu Punj
- Bioinformatics Core, Norris Comprehensive Cancer Center at University of Southern California and Division of Hematology, University of Southern California, Keck School of Medicine, Los Angeles, California, United States of America
| | - Keigo Machida
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, California, United States of America
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California, Keck School of Medicine, Los Angeles, California, United States of America
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Lazarini M, Traina F, Machado-Neto JA, Barcellos KSA, Moreira YB, Brandão MM, Verjovski-Almeida S, Ridley AJ, Saad STO. ARHGAP21 is a RhoGAP for RhoA and RhoC with a role in proliferation and migration of prostate adenocarcinoma cells. Biochim Biophys Acta 2013; 1832:365-74. [PMID: 23200924 DOI: 10.1016/j.bbadis.2012.11.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/15/2012] [Accepted: 11/16/2012] [Indexed: 01/30/2023]
Abstract
BACKGROUND Several Rho GTPase-activating proteins (RhoGAPs) are implicated in tumor progression through their effects on Rho GTPase activity. ARHGAP21 is a RhoGAP with increased expression in head and neck squamous cell carcinoma and with a possible role in glioblastoma tumor progression, yet little is known about the function of ARHGAP21 in cancer cells. Here we studied the role of ARHGAP21 in two prostate adenocarcinoma cell lines, LNCaP and PC3, which respectively represent initial and advanced stages of prostate carcinogenesis. RESULTS ARHGAP21 is located in the nucleus and cytoplasm of both cell lines and its depletion resulted in decreased proliferation and increased migration of PC3 cells but not LNCaP cells. In PC3 cells, ARHGAP21 presented GAP activity for RhoA and RhoC and induced changes in cell morphology. Moreover, its silencing altered the expression of genes involved in cell proliferation and cytoskeleton organization, as well as the endothelin-1 canonical pathway. CONCLUSIONS Our results reveal new functions and signaling pathways regulated by ARHGAP21, and indicate that it could contribute to prostate cancer progression.
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Affiliation(s)
- Mariana Lazarini
- Hematology and Hemotherapy Center, University of Campinas/Hemocentro-Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, INCTS, Campinas, São Paulo, Brazil.
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Gong T, Liao Y, He F, Yang Y, Yang DD, Chen XD, Gao XD. Control of polarized growth by the Rho family GTPase Rho4 in budding yeast: requirement of the N-terminal extension of Rho4 and regulation by the Rho GTPase-activating protein Bem2. Eukaryot Cell 2013; 12:368-77. [PMID: 23264647 PMCID: PMC3571307 DOI: 10.1128/ec.00277-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/19/2012] [Indexed: 11/20/2022]
Abstract
In the budding yeast Saccharomyces cerevisiae, Rho4 GTPase partially plays a redundant role with Rho3 in the control of polarized growth, as deletion of RHO4 and RHO3 together, but not RHO4 alone, caused lethality and a loss of cell polarity at 30°C. Here, we show that overexpression of the constitutively active rho4(Q131L) mutant in an rdi1Δ strain caused a severe growth defect and generated large, round, unbudded cells, suggesting that an excess of Rho4 activity could block bud emergence. We also generated four temperature-sensitive rho4-Ts alleles in a rho3Δ rho4Δ strain. These mutants showed growth and morphological defects at 37°C. Interestingly, two rho4-Ts alleles contain mutations that cause amino acid substitutions in the N-terminal region of Rho4. Rho4 possesses a long N-terminal extension that is unique among the six Rho GTPases in the budding yeast but is common in Rho4 homologs in other yeasts and filamentous fungi. We show that the N-terminal extension plays an important role in Rho4 function since rho3Δ rho4(Δ)(61) cells expressing truncated Rho4 lacking amino acids (aa) 1 to 61 exhibited morphological defects at 24°C and a growth defect at 37°C. Furthermore, we show that Rho4 interacts with Bem2, a Rho GTPase-activating protein (RhoGAP) for Cdc42 and Rho1, by yeast two-hybrid, bimolecular fluorescence complementation (BiFC), and glutathione S-transferase (GST) pulldown assays. Bem2 specifically interacts with the GTP-bound form of Rho4, and the interaction is mediated by its RhoGAP domain. Overexpression of BEM2 aggravates the defects of rho3Δ rho4 mutants. These results suggest that Bem2 might be a novel GAP for Rho4.
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Affiliation(s)
- Ting Gong
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China
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Zuccotti P, Cartelli D, Stroppi M, Pandini V, Venturin M, Aliverti A, Battaglioli E, Cappelletti G, Riva P. Centaurin-α₂ interacts with β-tubulin and stabilizes microtubules. PLoS One 2012; 7:e52867. [PMID: 23285209 PMCID: PMC3527619 DOI: 10.1371/journal.pone.0052867] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 11/23/2012] [Indexed: 01/01/2023] Open
Abstract
Centaurin-α₂ is a GTPase-activating protein for ARF (ARFGAP) showing a diffuse cytoplasmic localization capable to translocate to membrane, where it binds phosphatidylinositols. Taking into account that Centaurin-α₂ can localize in cytoplasm and that its cytoplasmatic function is not well defined, we searched for further interactors by yeast two-hybrid assay to investigate its biological function. We identified a further Centaurin-α₂ interacting protein, β-Tubulin, by yeast two-hybrid assay. The interaction, involving the C-terminal region of β-Tubulin, has been confirmed by coimmunoprecipitation experiments. After Centaurin-α₂ overexpression in HeLa cells and extraction of soluble (αβ dimers) and insoluble (microtubules) fractions of Tubulin, we observed that Centaurin-α₂ mainly interacts with the polymerized Tubulin fraction, besides colocalizing with microtubules (MTs) in cytoplasm accordingly. Even following the depolimerizing Tubulin treatments Centaurin-α₂ remains mainly associated to nocodazole- and cold-resistant MTs. We found an increase of MT stability in transfected HeLa cells, evaluating as marker of stability the level of MT acetylation. In vitro assays using purified Centaurin-α₂ and tubulin confirmed that Centaurin-α₂ promotes tubulin assembly and increases microtubule stability. The biological effect of Centaurin-α₂ overexpression, assessed through the detection of an increased number of mitotic HeLa cells with bipolar spindles and with the correct number of centrosomes in both dividing and not dividing cells, is consistent with the Centaurin-α₂ role on MT stabilization. Centaurin-α₂ interacts with β-Tubulin and it mainly associates to MTs, resistant to destabilizing agents, in vitro and in cell. We propose Centaurin-α₂ as a new microtubule-associated protein (MAP) increasing MT stability.
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Affiliation(s)
- Paola Zuccotti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | - Daniele Cartelli
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Michela Stroppi
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | - Vittorio Pandini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Marco Venturin
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | | | - Elena Battaglioli
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
| | | | - Paola Riva
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Milano, Italy
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Elbediwy A, Zihni C, Terry SJ, Clark P, Matter K, Balda MS. Epithelial junction formation requires confinement of Cdc42 activity by a novel SH3BP1 complex. J Cell Biol 2012; 198:677-93. [PMID: 22891260 PMCID: PMC3514035 DOI: 10.1083/jcb.201202094] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 07/11/2012] [Indexed: 12/28/2022] Open
Abstract
Epithelial cell-cell adhesion and morphogenesis require dynamic control of actin-driven membrane remodeling. The Rho guanosine triphosphatase (GTPase) Cdc42 regulates sequential molecular processes during cell-cell junction formation; hence, mechanisms must exist that inactivate Cdc42 in a temporally and spatially controlled manner. In this paper, we identify SH3BP1, a GTPase-activating protein for Cdc42 and Rac, as a regulator of junction assembly and epithelial morphogenesis using a functional small interfering ribonucleic acid screen. Depletion of SH3BP1 resulted in loss of spatial control of Cdc42 activity, stalled membrane remodeling, and enhanced growth of filopodia. SH3BP1 formed a complex with JACOP/paracingulin, a junctional adaptor, and CD2AP, a scaffolding protein; both were required for normal Cdc42 signaling and junction formation. The filamentous actin-capping protein CapZ also associated with the SH3BP1 complex and was required for control of actin remodeling. Epithelial junction formation and morphogenesis thus require a dual activity complex, containing SH3BP1 and CapZ, that is recruited to sites of active membrane remodeling to guide Cdc42 signaling and cytoskeletal dynamics.
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Affiliation(s)
- Ahmed Elbediwy
- Department of Cell Biology, Institute of
Ophthalmology, University College London, EC1V 9EL London, England,
UK
| | - Ceniz Zihni
- Department of Cell Biology, Institute of
Ophthalmology, University College London, EC1V 9EL London, England,
UK
| | - Stephen J. Terry
- Department of Cell Biology, Institute of
Ophthalmology, University College London, EC1V 9EL London, England,
UK
| | - Peter Clark
- National Heart and Lung Institute, Imperial
College London, South Kensington Campus, SW7 2AZ London, England,
UK
| | - Karl Matter
- Department of Cell Biology, Institute of
Ophthalmology, University College London, EC1V 9EL London, England,
UK
| | - Maria S. Balda
- Department of Cell Biology, Institute of
Ophthalmology, University College London, EC1V 9EL London, England,
UK
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38
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Abstract
The functional significance of decreased RAP1GAP protein expression in human tumors is unclear. To identify targets of RAP1GAP downregulation in the thyroid gland, RAP1 and RAP2 protein expression in human thyroid cells and in primary thyroid tumors were analyzed. RAP1GAP and RAP2 were co-expressed in normal thyroid follicular cells. Intriguingly, RAP1 was not detected in normal thyroid cells, although it was detected in papillary thyroid carcinomas, which also expressed RAP2. Both RAP proteins were detected at the membrane in papillary thyroid tumors, suggesting that they are activated when RAP1GAP is downregulated. To explore the functional significance of RAP1GAP depletion, RAP1GAP was transiently expressed at the lowest level that is sufficient to block endogenous RAP2 activity in papillary and anaplastic thyroid carcinoma cell lines. RAP1GAP impaired the ability of cells to spread and migrate on collagen. Although RAP1GAP had no effect on protein tyrosine phosphorylation in growing cells, RAP1GAP impaired phosphorylation of focal adhesion kinase and paxillin at sites phosphorylated by SRC in cells acutely plated on collagen. SRC activity was increased in suspended cells, where it was inhibited by RAP1GAP. Inhibition of SRC kinase activity impaired cell spreading and motility. These findings identify SRC as a target of RAP1GAP depletion and suggest that the downregulation of RAP1GAP in thyroid tumors enhances SRC-dependent signals that regulate cellular architecture and motility.
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Affiliation(s)
- Xiaoyun Dong
- Department of Pharmacology - Head and Neck Surgery, School of Medicine, University of Pennsylvania, 421 Curie Boulevard, BRB II/III, Philadelphia, PA 19104, USA
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39
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Abstract
The Deleted in liver cancer one (Dlc1) tumor suppressor gene encodes a RhoGTPase activating protein (RhoGAP). The Dlc1 gene has multiple transcriptional isoforms and we have previously established a mouse strain containing a gene trap (gt) insertion, which specifically reduces the expression of the 6.1 kb isoform (isoform 2). This gene trapped allele when homozygous results in embryonic lethality and the heterozygous gene trapped mice do not show an increased incidence of cancers, suggesting that cooperating oncogenic changes may be required for transformation. In the present work, we have studied the in vivo cooperation between oncogenic K-Ras2 and Dlc1 genes in tumourigenesis. We have observed an increase in invasive thymic cancers, including both thymomas and lymphomas, resulting in significantly shortened life spans in mice heterozygous for the gt Dlc1 allele and an inducible LSL-K-Ras2G12D allele compared with the LSL-K-Ras2G12D only mice. The heterozygous mice showed a high degree of metastasis in the lung. We have found tumour specific selective hypermethylation of the Dlc1 isoform 2 promoter and reduction of the corresponding protein expression in thymic lymphoma (TL) and thymic epithelial carcinoma (TEC) derived from the thymic tumours. The Dlc1 deficient thymic lymphoma cell lines exhibited increased trans-endothelial cell migration. TEC cell lines also exhibited increased stress fiber formation and Rho activity. Introduction of the three Dlc1 isoforms tagged with GFP into these cells resulted in different morphological changes. These results suggest that loss of expression of only isoform 2 may be sufficient for the development of thymic tumors and metastasis.
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MESH Headings
- Animals
- Base Sequence
- Cell Shape
- Cell Surface Extensions
- Chromosome Mapping
- CpG Islands
- Cyclin-Dependent Kinase Inhibitor p21/metabolism
- DNA Methylation
- GTPase-Activating Proteins/genetics
- GTPase-Activating Proteins/metabolism
- GTPase-Activating Proteins/physiology
- Gene Expression Regulation, Neoplastic
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Lung Neoplasms/secondary
- Lymphoma, T-Cell/genetics
- Lymphoma, T-Cell/metabolism
- Lymphoma, T-Cell/pathology
- Mice
- Mice, Transgenic
- Molecular Sequence Data
- Mutation, Missense
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/pathology
- Promoter Regions, Genetic
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Isoforms/physiology
- Proto-Oncogene Proteins p21(ras)/genetics
- Stress Fibers/metabolism
- Thymoma/genetics
- Thymoma/metabolism
- Thymoma/secondary
- Thymus Neoplasms/genetics
- Thymus Neoplasms/metabolism
- Thymus Neoplasms/pathology
- Transendothelial and Transepithelial Migration
- Tumor Cells, Cultured
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
- Tumor Suppressor Proteins/physiology
- rho GTP-Binding Proteins/metabolism
- rhoA GTP-Binding Protein
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Affiliation(s)
- Mohammad Golam Sabbir
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, Manitoba, Canada
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Heather Prieditis
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, Manitoba, Canada
| | - Esther Ravinsky
- Department of Pathology, Health Sciences Centre, Winnipeg, Manitoba, Canada
| | - Michael R. A. Mowat
- Manitoba Institute of Cell Biology, CancerCare Manitoba, Winnipeg, Manitoba, Canada
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
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40
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Abstract
Deleted in liver cancer 1 (DLC1) is a GTPase-activating protein (GAP) domain containing tumor suppressor that localizes to focal adhesions. In cancer cells, loss of DLC1 is known to enhance cancer cell migration. However, the role of DLC1 in normal cell migration has not been well studied. Here, we show that silencing of DLC1 (shDLC1) in normal prostate epithelial cells reduces cell migration in both Transwell and wound-healing assays. This migration defect is mainly due to upregulation of plasminogen activator inhibitor 1 (PAI-1). Silencing of PAI-1 rescues the shDLC1-reduced migration phenotype. Reexpression of DLC1 suppresses PAI-1 and restores the migration defect as well. In contrast, DLC1-K714E (GAP inactive) mutant neither decreases the PAI-1 level nor rescues the shDLC1 migration defect. Interestingly, DLC1-Y442F (tensin-binding and focal adhesion-localizing defective) mutant is able to suppress PAI-1 expression but does not restore the migration defect. Furthermore, PAI-1 upregulation in shDLC1 cells is EGFR-MEK pathway dependent and is able to promote in vitro angiogenesis. Together, our results show that at least the following two new mechanisms are involved in DLC1-mediated normal cell migration: (i) DLC1 modulates the expression of PAI-1, which is a negative regulator for cell migration, in a GAP domain and EGFR-MEK-dependent manner and (ii) Independent of PAI-1, the interaction of DLC1 with tensin members positively regulates cell migration.
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Affiliation(s)
- Yi-Ping Shih
- Center for Tissue Regeneration and Repair, University of California-Davis, Sacramento, CA 95817
- Department of Biochemistry and Molecular Medicine, University of California-Davis, Sacramento, CA 95817
| | - Yoshikazu Takada
- Department of Biochemistry and Molecular Medicine, University of California-Davis, Sacramento, CA 95817
- Department of Dermatology, University of California-Davis, Sacramento, CA 95817
| | - Su Hao Lo
- Center for Tissue Regeneration and Repair, University of California-Davis, Sacramento, CA 95817
- Department of Biochemistry and Molecular Medicine, University of California-Davis, Sacramento, CA 95817
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41
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Heckman-Stoddard BM, Vargo-Gogola T, Herrick MP, Visbal AP, Lewis MT, Settleman J, Rosen JM. P190A RhoGAP is required for mammary gland development. Dev Biol 2011; 360:1-10. [PMID: 21945077 DOI: 10.1016/j.ydbio.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/17/2011] [Accepted: 09/05/2011] [Indexed: 11/19/2022]
Abstract
P190A and p190B Rho GTPase activating proteins (GAPs) are essential genes that have distinct, but overlapping roles in the developing nervous system. Previous studies from our laboratory demonstrated that p190B is required for mammary gland morphogenesis, and we hypothesized that p190A might have a distinct role in the developing mammary gland. To test this hypothesis, we examined mammary gland development in p190A-deficient mice. P190A expression was detected by in situ hybridization in the developing E14.5day embryonic mammary bud and within the ducts, terminal end buds (TEBs), and surrounding stroma of the developing virgin mammary gland. In contrast to previous results with p190B, examination of p190A heterozygous mammary glands demonstrated that p190A deficiency disrupted TEB morphology, but did not significantly delay ductal outgrowth indicating haploinsufficiency for TEB development. To examine the effects of homozygous deletion of p190A, embryonic mammary buds were rescued by transplantation into the cleared fat pads of SCID/Beige mice. Complete loss of p190A function inhibited ductal outgrowth in comparison to wildtype transplants (51% vs. 94% fat pad filled). In addition, the transplantation take rate of p190A deficient whole gland transplants from E18.5 embryos was significantly reduced compared to wildtype transplants (31% vs. 90%, respectively). These results suggest that p190A function in both the epithelium and stroma is required for mammary gland development. Immunostaining for p63 demonstrated that the myoepithelial cell layer is disrupted in the p190A deficient glands, which may result from the defective cell adhesion between the cap and body cell layers detected in the TEBs. The number of estrogen- and progesterone receptor-positive cells, as well as the expression levels of these receptors was increased in p190A deficient outgrowths. These data suggest that p190A is required in both the epithelial and stromal compartments for ductal outgrowth and that it may play a role in mammary epithelial cell differentiation.
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Affiliation(s)
- B M Heckman-Stoddard
- Cancer Prevention Fellowship Program, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD 20892, USA.
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42
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Parrini MC, Sadou-Dubourgnoux A, Aoki K, Kunida K, Biondini M, Hatzoglou A, Poullet P, Formstecher E, Yeaman C, Matsuda M, Rossé C, Camonis J. SH3BP1, an exocyst-associated RhoGAP, inactivates Rac1 at the front to drive cell motility. Mol Cell 2011; 42:650-61. [PMID: 21658605 DOI: 10.1016/j.molcel.2011.03.032] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 02/10/2011] [Accepted: 03/30/2011] [Indexed: 11/18/2022]
Abstract
The coordination of the several pathways involved in cell motility is poorly understood. Here, we identify SH3BP1, belonging to the RhoGAP family, as a partner of the exocyst complex and establish a physical and functional link between two motility-driving pathways, the Ral/exocyst and Rac signaling pathways. We show that SH3BP1 localizes together with the exocyst to the leading edge of motile cells and that SH3BP1 regulates cell migration via its GAP activity upon Rac1. SH3BP1 loss of function induces abnormally high Rac1 activity at the front, as visualized by in vivo biosensors, and disorganized and instable protrusions, as revealed by cell morphodynamics analysis. Consistently, constitutively active Rac1 mimics the phenotype of SH3BP1 depletion: slow migration and aberrant cell morphodynamics. Our finding that SH3BP1 downregulates Rac1 at the motile-cell front indicates that Rac1 inactivation in this location, as well as its activation by GEF proteins, is a fundamental requirement for cell motility.
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43
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Yi C, Troutman S, Fera D, Stemmer-Rachamimov A, Avila JL, Christian N, Persson NL, Shimono A, Speicher DW, Marmorstein R, Holmgren L, Kissil JL. A tight junction-associated Merlin-angiomotin complex mediates Merlin's regulation of mitogenic signaling and tumor suppressive functions. Cancer Cell 2011; 19:527-40. [PMID: 21481793 PMCID: PMC3075552 DOI: 10.1016/j.ccr.2011.02.017] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 10/20/2010] [Accepted: 02/22/2011] [Indexed: 01/12/2023]
Abstract
The Merlin/NF2 tumor suppressor restrains cell growth and tumorigenesis by controlling contact-dependent inhibition of proliferation. We have identified a tight-junction-associated protein complex comprising Merlin, Angiomotin, Patj, and Pals1. We demonstrate that Angiomotin functions downstream of Merlin and upstream of Rich1, a small GTPase Activating Protein, as a positive regulator of Rac1. Merlin, through competitive binding to Angiomotin, releases Rich1 from the Angiomotin-inhibitory complex, allowing Rich1 to inactivate Rac1, ultimately leading to attenuation of Rac1 and Ras-MAPK pathways. Patient-derived Merlin mutants show diminished binding capacities to Angiomotin and are unable to dissociate Rich1 from Angiomotin or inhibit MAPK signaling. Depletion of Angiomotin in Nf2(-/-) Schwann cells attenuates the Ras-MAPK signaling pathway, impedes cellular proliferation in vitro and tumorigenesis in vivo.
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Affiliation(s)
- Chunling Yi
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
| | - Scott Troutman
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
| | - Daniela Fera
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - Jacqueline L. Avila
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
| | - Neepa Christian
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
| | - Nathalie Luna Persson
- Department of Oncology-Pathology, Cancer Center Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Akihiko Shimono
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117456
| | - David W. Speicher
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
| | - Ronen Marmorstein
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Lars Holmgren
- Department of Oncology-Pathology, Cancer Center Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Joseph L. Kissil
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA
- Corresponding author. ; Phone: 1-215-898-3874
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44
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Chotard L, Skorobogata O, Sylvain MA, Shrivastava S, Rocheleau CE. TBC-2 is required for embryonic yolk protein storage and larval survival during L1 diapause in Caenorhabditis elegans. PLoS One 2010; 5:e15662. [PMID: 21203392 PMCID: PMC3011002 DOI: 10.1371/journal.pone.0015662] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 11/18/2010] [Indexed: 12/03/2022] Open
Abstract
C. elegans first stage (L1) larvae hatched in the absence of food, arrest development and enter an L1 diapause, whereby they can survive starvation for several weeks. The physiological and metabolic requirements for survival during L1 diapause are poorly understood. However, yolk, a cholesterol binding/transport protein, has been suggested to serve as an energy source. Here, we demonstrate that C. elegans TBC-2, a RAB-5 GTPase Activating Protein (GAP) involved in early-to-late endosome transition, is important for yolk protein storage during embryogenesis and for L1 survival during starvation. We found during embryogenesis, that a yolk::green fluorescent protein fusion (YP170::GFP), disappeared much more quickly in tbc-2 mutant embryos as compared with wild-type control embryos. The premature disappearance of YP170::GFP in tbc-2 mutants is likely due to premature degradation in the lysosomes as we found that YP170::GFP showed increased colocalization with Lysotracker Red, a marker for acidic compartments. Furthermore, YP170::GFP disappearance in tbc-2 mutants required RAB-7, a regulator of endosome to lysosome trafficking. Although tbc-2 is not essential in fed animals, we discovered that tbc-2 mutant L1 larvae have strongly reduced survival when hatched in the absence of food. We show that tbc-2 mutant larvae are not defective in maintaining L1 diapause and that mutants defective in yolk uptake, rme-1 and rme-6, also had strongly reduced L1 survival when hatched in the absence of food. Our findings demonstrate that TBC-2 is required for yolk protein storage during embryonic development and provide strong correlative data indicating that yolk constitutes an important energy source for larval survival during L1 diapause.
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Affiliation(s)
- Laëtitia Chotard
- Division of Endocrinology and Metabolism, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Olga Skorobogata
- Division of Endocrinology and Metabolism, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Marc-André Sylvain
- Division of Endocrinology and Metabolism, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Sanhita Shrivastava
- Division of Endocrinology and Metabolism, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Christian E. Rocheleau
- Division of Endocrinology and Metabolism, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
- * E-mail:
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45
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Abstract
There is now considerable and increasing evidence for a causal role for aberrant activity of the Ras superfamily of small GTPases in human cancers. These GTPases function as GDP-GTP-regulated binary switches that control many fundamental cellular processes. A common mechanism of GTPase deregulation in cancer is the deregulated expression and/or activity of their regulatory proteins, guanine nucleotide exchange factors (GEFs) that promote formation of the active GTP-bound state and GTPase-activating proteins (GAPs) that return the GTPase to its GDP-bound inactive state. In this Review, we assess the association of GEFs and GAPs with cancer and their druggability for cancer therapeutics.
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Affiliation(s)
- Dominico Vigil
- University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Department of Pharmacology, Chapel Hill, North Carolina 27599, USA
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46
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Scholz RP, Gustafsson JOR, Hoffmann P, Jaiswal M, Ahmadian MR, Eisler SA, Erlmann P, Schmid S, Hausser A, Olayioye MA. The tumor suppressor protein DLC1 is regulated by PKD-mediated GAP domain phosphorylation. Exp Cell Res 2010; 317:496-503. [PMID: 21087603 DOI: 10.1016/j.yexcr.2010.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 10/21/2010] [Accepted: 11/04/2010] [Indexed: 11/18/2022]
Abstract
Deleted in liver cancer 1 (DLC1) is a tumor suppressor protein that is frequently downregulated in various tumor types. DLC1 contains a Rho GTPase activating protein (GAP) domain that appears to be required for its tumor suppressive functions. Little is known about the molecular mechanisms that regulate DLC1. By mass spectrometry we have mapped a novel phosphorylation site within the DLC1 GAP domain on serine 807. Using a phospho-S807-specific antibody, our results identify protein kinase D (PKD) to phosphorylate this site in DLC1 in intact cells. Although phosphorylation on serine 807 did not directly impact on in vitro GAP activity, a DLC1 serine-to-alanine exchange mutant inhibited colony formation more potently than the wild type protein. Our results thus show that PKD-mediated phosphorylation of DLC1 on serine 807 negatively regulates DLC1 cellular function.
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Affiliation(s)
- Rolf-Peter Scholz
- University of Stuttgart, Institute of Cell Biology and Immunology, Allmandring 31, 70569 Stuttgart, Germany
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47
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Sato K. [Selective protein export from the ER mediated by COPII-coated vesicles]. Seikagaku 2010; 82:1011-1020. [PMID: 21226330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Ken Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
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48
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Freisinger CM, Fisher RA, Slusarski DC. Regulator of g protein signaling 3 modulates wnt5b calcium dynamics and somite patterning. PLoS Genet 2010; 6:e1001020. [PMID: 20628572 PMCID: PMC2900303 DOI: 10.1371/journal.pgen.1001020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 06/07/2010] [Indexed: 01/01/2023] Open
Abstract
Vertebrate development requires communication among cells of the embryo in order to define the body axis, and the Wnt-signaling network plays a key role in axis formation as well as in a vast array of other cellular processes. One arm of the Wnt-signaling network, the non-canonical Wnt pathway, mediates intracellular calcium release via activation of heterotrimeric G proteins. Regulator of G protein Signaling (RGS) proteins can accelerate inactivation of G proteins by acting as G protein GTPase-activating proteins (GAPs), however, the possible role of RGS proteins in non-canonical Wnt signaling and development is not known. Here, we identify rgs3 as having an overlapping expression pattern with wnt5b in zebrafish and reveal that individual knockdown of either rgs3 or wnt5b gene function produces similar somite patterning defects. Additionally, we describe endogenous calcium release dynamics in developing zebrafish somites and determine that both rgs3 and wnt5b function are required for appropriate frequency and amplitude of calcium release activity. Using rescue of gene knockdown and in vivo calcium imaging assays, we demonstrate that the activity of Rgs3 requires its ability to interact with Gα subunits and function as a G protein GAP. Thus, Rgs3 function is necessary for appropriate frequency and amplitude of calcium release during somitogenesis and is downstream of Wnt5 activity. These results provide the first evidence for an essential developmental role of RGS proteins in modulating the duration of non-canonical Wnt signaling. Vertebrate development requires communication among cells in order to define the body axis (front/back, head/tail, or left/right). Secreted factors such as Wnts play key roles in a vast array of cellular processes, including patterning of the body axis. One arm of the Wnt-signaling network, the non-canonical pathway, mediates intracellular calcium release via activation of heterotrimeric G proteins. Regulator of G protein Signaling (RGS) proteins can accelerate inactivation of G proteins by acting as G protein GAPs and are uniquely situated to control the amplitude of a Wnt signal. Here, we combine cellular, molecular, and genetic analyses with high resolution calcium imaging to identify a role for RGS modulation of Wnt-mediated calcium release dynamics and developmental patterning events. We find that loss of rgs3 gene function produced body patterning defects like those observed with loss of wnt5b gene function. Analysis of endogenous calcium release dynamics in developing zebrafish revealed that both rgs3 and wnt5b are required for appropriate frequency and amplitude of calcium release. Our results provide new evidence that a member of the RGS protein family is essential for modulating the non-canonical Wnt network to assure normal tissue patterning during development.
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Affiliation(s)
| | - Rory A. Fisher
- Department of Pharmacology, University of Iowa College of Medicine, Iowa City, Iowa, United States of America
| | - Diane C. Slusarski
- Department of Biology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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49
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Zuo H, Gandhi M, Edreira MM, Hochbaum D, Nimgaonkar VL, Zhang P, Dipaola J, Evdokimova V, Altschuler DL, Nikiforov YE. Downregulation of Rap1GAP through epigenetic silencing and loss of heterozygosity promotes invasion and progression of thyroid tumors. Cancer Res 2010; 70:1389-97. [PMID: 20124489 DOI: 10.1158/0008-5472.can-09-2812] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Thyroid cancer is the most common type of endocrine malignancy, encompassing tumors with various levels of invasive growth and aggressiveness. Rap1GAP, a Rap1 GTPase-activating protein, inhibits the RAS superfamily protein Rap1 by facilitating hydrolysis of GTP to GDP. In this study, we analyzed 197 thyroid tumor samples and showed that Rap1GAP was frequently lost or downregulated in various types of tumors, particularly in the most invasive and aggressive forms of thyroid cancer. The downregulation was due to promoter hypermethylation and/or loss of heterozygosity, found in the majority of thyroid tumors. Treatment with demethylating agent 5-aza-deoxycytidine and/or histone deacetylation inhibitor trichostatin A induced gene reexpression in thyroid cells. A genetic polymorphism, Y609C, was seen in 7% of thyroid tumors but was not related to gene downregulation. Loss of Rap1GAP expression correlated with tumor invasiveness but not with specific mutations activating the mitogen-activated protein kinase pathway. Rap1GAP downregulation was required in vitro for cell migration and Matrigel invasion. Recovery of Rap1GAP expression inhibited thyroid cell proliferation and colony formation. Overall, our findings indicate that epigenetic or genetic loss of Rap1GAP is very common in thyroid cancer, where these events are sufficient to promote cell proliferation and invasion.
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Affiliation(s)
- Hui Zuo
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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50
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Han K, Kim MH, Seeburg D, Seo J, Verpelli C, Han S, Chung HS, Ko J, Lee HW, Kim K, Heo WD, Meyer T, Kim H, Sala C, Choi SY, Sheng M, Kim E. Regulated RalBP1 binding to RalA and PSD-95 controls AMPA receptor endocytosis and LTD. PLoS Biol 2009; 7:e1000187. [PMID: 19823667 PMCID: PMC2730530 DOI: 10.1371/journal.pbio.1000187] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 07/30/2009] [Indexed: 11/18/2022] Open
Abstract
Long-term depression (LTD) is a long-lasting activity-dependent decrease in synaptic strength. NMDA receptor (NMDAR)-dependent LTD, an extensively studied form of LTD, involves the endocytosis of AMPA receptors (AMPARs) via protein dephosphorylation, but the underlying mechanism has remained unclear. We show here that a regulated interaction of the endocytic adaptor RalBP1 with two synaptic proteins, the small GTPase RalA and the postsynaptic scaffolding protein PSD-95, controls NMDAR-dependent AMPAR endocytosis during LTD. NMDAR activation stimulates RalA, which binds and translocates widespread RalBP1 to synapses. In addition, NMDAR activation dephosphorylates RalBP1, promoting the interaction of RalBP1 with PSD-95. These two regulated interactions are required for NMDAR-dependent AMPAR endocytosis and LTD and are sufficient to induce AMPAR endocytosis in the absence of NMDAR activation. RalA in the basal state, however, maintains surface AMPARs. We propose that NMDAR activation brings RalBP1 close to PSD-95 to promote the interaction of RalBP1-associated endocytic proteins with PSD-95-associated AMPARs. This suggests that scaffolding proteins at specialized cellular junctions can switch their function from maintenance to endocytosis of interacting membrane proteins in a regulated manner.
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Affiliation(s)
- Kihoon Han
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Myoung-Hwan Kim
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Daniel Seeburg
- The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Jinsoo Seo
- Department of Physiology and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Chiara Verpelli
- CNR Institute of Neuroscience and Department of Neurological Sciences, University of Milan, Milan, Italy
| | - Seungnam Han
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Hye Sun Chung
- Department of Anatomy and Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - Jaewon Ko
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Hyun Woo Lee
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Karam Kim
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Won Do Heo
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Tobias Meyer
- Department of Chemical and Systems Biology, Stanford University, Stanford, California, United States of America
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - Carlo Sala
- CNR Institute of Neuroscience and Department of Neurological Sciences, University of Milan, Milan, Italy
| | - Se-Young Choi
- Department of Physiology and Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea
| | - Morgan Sheng
- The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Eunjoon Kim
- National Creative Research Initiative Center for Synaptogenesis and Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- * E-mail:
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