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Chen J, Ma B, Yang Y, Wang B, Hao J, Zhou X. Disulfidptosis decoded: a journey through cell death mysteries, regulatory networks, disease paradigms and future directions. Biomark Res 2024; 12:45. [PMID: 38685115 PMCID: PMC11059647 DOI: 10.1186/s40364-024-00593-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 04/23/2024] [Indexed: 05/02/2024] Open
Abstract
Cell death is an important part of the life cycle, serving as a foundation for both the orderly development and the maintenance of physiological equilibrium within organisms. This process is fundamental, as it eliminates senescent, impaired, or aberrant cells while also promoting tissue regeneration and immunological responses. A novel paradigm of programmed cell death, known as disulfidptosis, has recently emerged in the scientific circle. Disulfidptosis is defined as the accumulation of cystine by cancer cells with high expression of the solute carrier family 7 member 11 (SLC7A11) during glucose starvation. This accumulation causes extensive disulfide linkages between F-actins, resulting in their contraction and subsequent detachment from the cellular membrane, triggering cellular death. The RAC1-WRC axis is involved in this phenomenon. Disulfidptosis sparked growing interest due to its potential applications in a variety of pathologies, particularly oncology, neurodegenerative disorders, and metabolic anomalies. Nonetheless, the complexities of its regulatory pathways remain elusive, and its precise molecular targets have yet to be definitively identified. This manuscript aims to meticulously dissect the historical evolution, molecular underpinnings, regulatory frameworks, and potential implications of disulfidptosis in various disease contexts, illuminating its promise as a groundbreaking therapeutic pathway and target.
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Affiliation(s)
- Jinyu Chen
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Boyuan Ma
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Yubiao Yang
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Bitao Wang
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China
| | - Jian Hao
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China.
| | - Xianhu Zhou
- The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, 510260, China.
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Avalos A, Tietsort JT, Suwankitwat N, Woods JD, Jackson SW, Christodoulou A, Morrill C, Liggitt HD, Zhu C, Li QZ, Bui KK, Park H, Iritani BM. Hem-1 regulates protective humoral immunity and limits autoantibody production in a B cell-specific manner. JCI Insight 2022; 7:e153597. [PMID: 35531955 PMCID: PMC9090261 DOI: 10.1172/jci.insight.153597] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 03/23/2022] [Indexed: 11/17/2022] Open
Abstract
Hematopoietic protein-1 (Hem-1) is a member of the actin-regulatory WASp family verprolin homolog (WAVE) complex. Loss-of-function variants in the NCKAP1L gene encoding Hem-1 were recently discovered to result in primary immunodeficiency disease (PID) in children, characterized by poor specific Ab responses, increased autoantibodies, and high mortality. However, the mechanisms of how Hem-1 deficiency results in PID are unclear. In this study, we utilized constitutive and B cell-specific Nckap1l-KO mice to dissect the importance of Hem-1 in B cell development and functions. B cell-specific disruption of Hem-1 resulted in reduced numbers of recirculating follicular (FO), marginal zone (MZ), and B1 B cells. B cell migration in response to CXCL12 and -13 were reduced. T-independent Ab responses were nearly abolished, resulting in failed protective immunity to Streptococcus pneumoniae challenge. In contrast, T-dependent IgM and IgG2c, memory B cell, and plasma cell responses were more robust relative to WT control mice. B cell-specific Hem-1-deficient mice had increased autoantibodies against multiple autoantigens, and this correlated with hyperresponsive BCR signaling and increased representation of CD11c+T-bet+ age-associated B cell (ABC cells) - alterations associated with autoimmune diseases. These results suggest that dysfunctional B cells may be part of a mechanism explaining why loss-of-function Hem-1 variants result in recurring infections and autoimmunity.
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Affiliation(s)
- Alan Avalos
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Jacob T. Tietsort
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Nutthakarn Suwankitwat
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | | | | | | | - Christopher Morrill
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - H. Denny Liggitt
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Chengsong Zhu
- Department of Immunology, Microarray and Immune Phenotyping Core Facility, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Quan-Zhen Li
- Department of Immunology, Microarray and Immune Phenotyping Core Facility, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin K. Bui
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Heon Park
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
| | - Brian M. Iritani
- The Department of Comparative Medicine, University of Washington, Seattle, Washington, USA
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3
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Ghassibe-Sabbagh M, El Hajj J, Al Saneh M, El Baba N, Abou Issa J, Al Haddad M, El Atat O, Sabbagh J, Abou Chebel N, El-Sibai M. Altered regulation of cell migration in IRF6-mutated orofacial cleft patients-derived primary cells reveals a novel role of Rho GTPases in cleft/lip palate development. Cells Dev 2021; 166:203674. [PMID: 33994351 DOI: 10.1016/j.cdev.2021.203674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/22/2021] [Accepted: 03/10/2021] [Indexed: 11/30/2022]
Abstract
Orofacial clefts are the most common congenital craniofacial birth defects. They occur from a failure in cell proliferation and fusion of neural crest cells of the lip buds and/or palatal shelves. In this study, we investigate the genetic basis and molecular mechanisms in primary cells derived from a cleft and lip palate patient presenting van der Woude syndrome (VWS). Since mutations in the integrin genes are widely correlated with VWS, Interferon Regulatory Factor 6 (IRF6) screening was conducted in a cohort of 200 participants presenting with orofacial anomalies. Primary fibroblastic cells derived from the upper right gingiva and palatal regions were isolated and two cellular populations from two participants were obtained: a control with no cleft phenotype and a patient with a cleft phenotype typical of van der Woude syndrome (VWS). IRF6 targeted sequencing revealed mutations in two distinct families. Our results showed no alteration in the viability of the CLP/VWS patient cells, suggesting the phenotype associate with the disease is not secondary to a defect in cell proliferation. We did however detect a significant decrease in the migratory ability of the CLP with Van der Woude syndrome (CLP/VWS) patient cells, which could account for the phenotype. When compared to normal cells, patient cells showed a lack of polarization, which would account for their lack of mobility. Patient cells showed protrusions all around the cells and a lack of defined leading edge. This was reflected with actin staining, WAVE2 and Arp2 around the cell, and correlated with an increase in Rac1 activation. Consistently with the increase in Rac1 activation, patient cells showed a loss in the maturation of focal adhesions needed for contractility, which also accounts for the lack in cell migration. Our findings give increased understanding of the molecular mechanisms of VWS and expands the knowledge of van der Woude syndrome (VWS) occurrence by providing a strong molecular evidence that CLP with Van der Woude syndrome (CLP/VWS) phenotype is caused by a defect in normal physiological processes of cells.
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Affiliation(s)
- Michella Ghassibe-Sabbagh
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Joelle El Hajj
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Mounir Al Saneh
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Nada El Baba
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Jamil Abou Issa
- School of Medicine, Lebanese American University, Beirut, Lebanon.
| | - Maria Al Haddad
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Oula El Atat
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
| | - Joseph Sabbagh
- Department of Restorative Dentistry and Endodontics, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon
| | - Naji Abou Chebel
- Department of Otolaryngology - Head and Neck Surgery, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
| | - Mirvat El-Sibai
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, Beirut, Lebanon.
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4
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Edwards JJ, Rouillard AD, Fernandez NF, Wang Z, Lachmann A, Shankaran SS, Bisgrove BW, Demarest B, Turan N, Srivastava D, Bernstein D, Deanfield J, Giardini A, Porter G, Kim R, Roberts AE, Newburger JW, Goldmuntz E, Brueckner M, Lifton RP, Seidman CE, Chung WK, Tristani-Firouzi M, Yost HJ, Ma'ayan A, Gelb BD. Systems Analysis Implicates WAVE2 Complex in the Pathogenesis of Developmental Left-Sided Obstructive Heart Defects. JACC Basic Transl Sci 2020; 5:376-386. [PMID: 32368696 PMCID: PMC7188873 DOI: 10.1016/j.jacbts.2020.01.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/23/2020] [Accepted: 01/24/2020] [Indexed: 12/30/2022]
Abstract
Combining CHD phenotype–driven gene set enrichment and CRISPR knockdown screening in zebrafish is an effective approach to identifying novel CHD genes. Mutations affecting genes coding for the WAVE2 protein complex and small GTPase-mediated signaling are associated with LVOTO lesions. WAVE2 complex genes brk1, nckap1, and wasf2 and regulators of small GTPase signaling cul3a and racgap1 are critical to zebrafish heart development.
Genetic variants are the primary driver of congenital heart disease (CHD) pathogenesis. However, our ability to identify causative variants is limited. To identify causal CHD genes that are associated with specific molecular functions, the study used prior knowledge to filter de novo variants from 2,881 probands with sporadic severe CHD. This approach enabled the authors to identify an association between left ventricular outflow tract obstruction lesions and genes associated with the WAVE2 complex and regulation of small GTPase-mediated signal transduction. Using CRISPR zebrafish knockdowns, the study confirmed that WAVE2 complex proteins brk1, nckap1, and wasf2 and the regulators of small GTPase signaling cul3a and racgap1 are critical to cardiac development.
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Key Words
- CHD, congenital heart disease
- CORUM, Comprehensive Resource of Mammalian Protein Complexes
- CRISPR, clustered regularly interspaced short palindromic repeats
- CTD, conotruncal defect
- GOBP, Gene Ontology biological processes
- HHE, high heart expression
- HLHS, hypoplastic left heart syndrome
- HTX, heterotaxy
- LVOTO, left ventricular outflow tract obstruction
- MGI, Mouse Genome Informatics
- PCGC, Pediatric Cardiac Genomics Consortium
- PPI, protein-protein interaction
- congenital heart disease
- systems biology
- translational genomics
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Affiliation(s)
- Jonathan J Edwards
- Department of Pediatrics, Division of Pediatric Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Andrew D Rouillard
- Department of Pharmacological Sciences, Mount Sinai Center for Bioinformatics, LINCS-BD2K DCIC, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Nicolas F Fernandez
- Department of Pharmacological Sciences, Mount Sinai Center for Bioinformatics, LINCS-BD2K DCIC, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Zichen Wang
- Department of Pharmacological Sciences, Mount Sinai Center for Bioinformatics, LINCS-BD2K DCIC, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alexander Lachmann
- Department of Pharmacological Sciences, Mount Sinai Center for Bioinformatics, LINCS-BD2K DCIC, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Sunita S Shankaran
- Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee
| | - Brent W Bisgrove
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, Utah
| | - Bradley Demarest
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Deepak Srivastava
- Gladstone Institute of Cardiovascular Disease, San Francisco, California
| | - Daniel Bernstein
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California
| | - John Deanfield
- Department of Cardiology, Great Ormond Street Hospital, University College London, London, United Kingdom
| | - Alessandro Giardini
- Department of Cardiology, Great Ormond Street Hospital, University College London, London, United Kingdom
| | - George Porter
- Department of Pediatrics, University of Rochester Medical Center, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Richard Kim
- Section of Cardiothoracic Surgery, Keck School of Medicine of USC, University of Southern California, Los Angeles, California
| | - Amy E Roberts
- Department of Cardiology, Children's Hospital Boston, Boston, Massachusetts
| | - Jane W Newburger
- Department of Cardiology, Children's Hospital Boston, Boston, Massachusetts
| | - Elizabeth Goldmuntz
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Martina Brueckner
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut
| | - Richard P Lifton
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut.,Howard Hughes Medical Institute, Yale University, New Haven, Connecticut
| | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Harvard University, Boston, Massachusetts.,Cardiovascular Division, Brigham and Women's Hospital, Harvard University, Boston, Massachusetts
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Medical Center, New York, New York.,Department of Medicine, Columbia University Medical Center, New York, New York
| | - Martin Tristani-Firouzi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah School of Medicine, Salt Lake City, Utah
| | - H Joseph Yost
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, Utah
| | - Avi Ma'ayan
- Department of Pharmacological Sciences, Mount Sinai Center for Bioinformatics, LINCS-BD2K DCIC, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Bruce D Gelb
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York
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5
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Nakashima M, Kato M, Aoto K, Shiina M, Belal H, Mukaida S, Kumada S, Sato A, Zerem A, Lerman-Sagie T, Lev D, Leong HY, Tsurusaki Y, Mizuguchi T, Miyatake S, Miyake N, Ogata K, Saitsu H, Matsumoto N. De novo hotspot variants in CYFIP2 cause early-onset epileptic encephalopathy. Ann Neurol 2019. [PMID: 29534297 DOI: 10.1002/ana.25208] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The cytoplasmic fragile X mental retardation 1 interacting proteins 2 (CYFIP2) is a component of the WASP-family verprolin-homologous protein (WAVE) regulatory complex, which is involved in actin dynamics. An obvious association of CYFIP2 variants with human neurological disorders has never been reported. Here, we identified de novo hotspot CYFIP2 variants in neurodevelopmental disorders and explore the possible involvement of the CYFIP2 mutants in the WAVE signaling pathway. METHODS We performed trio-based whole-exome sequencing (WES) in 210 families and case-only WES in 489 individuals with epileptic encephalopathies. The functional effect of CYFIP2 variants on WAVE signaling was evaluated by computational structural analysis and in vitro transfection experiments. RESULTS We identified three de novo CYFIP2 variants at the Arg87 residue in 4 unrelated individuals with early-onset epileptic encephalopathy. Structural analysis indicated that the Arg87 residue is buried at an interface between CYFIP2 and WAVE1, and the Arg87 variant may disrupt hydrogen bonding, leading to structural instability and aberrant activation of the WAVE regulatory complex. All mutant CYFIP2 showed comparatively weaker interactions to the VCA domain than wild-type CYFIP2. Immunofluorescence revealed that ectopic speckled accumulation of actin and CYFIP2 was significantly increased in cells transfected with mutant CYFIP2. INTERPRETATION Our findings suggest that de novo Arg87 variants in CYFIP2 have gain-of-function effects on the WAVE signaling pathway and are associated with severe neurological disorders. Ann Neurol 2018;83:794-806.
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Affiliation(s)
- Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.,Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan.,Department of Pediatrics, Yamagata University Faculty of Medicine, Yamagata, Japan
| | - Kazushi Aoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Masaaki Shiina
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hazrat Belal
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Souichi Mukaida
- Department of Pediatric Neurology, National Hospital Organization Utano Hospital, Kyoto, Japan
| | - Satoko Kumada
- Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan
| | - Atsushi Sato
- Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Tokyo, Japan.,Department of Pediatrics, The University of Tokyo Hospital, Tokyo, Japan
| | - Ayelet Zerem
- Pediatric Neurology Unit, Metabolic-Neurogenetic Clinic, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Tel- Aviv, Israel
| | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Metabolic-Neurogenetic Clinic, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Tel- Aviv, Israel
| | - Dorit Lev
- Institute of Medical Genetics, Metabolic-Neurogenetic Clinic, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Tel- Aviv
| | - Huey Yin Leong
- Genetic Department, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia
| | - Yoshinori Tsurusaki
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takeshi Mizuguchi
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Satoko Miyatake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuhiro Ogata
- Department of Biochemistry, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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6
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Nakahata Y, Yasuda R. Plasticity of Spine Structure: Local Signaling, Translation and Cytoskeletal Reorganization. Front Synaptic Neurosci 2018; 10:29. [PMID: 30210329 PMCID: PMC6123351 DOI: 10.3389/fnsyn.2018.00029] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/07/2018] [Indexed: 12/31/2022] Open
Abstract
Dendritic spines are small protrusive structures on dendritic surfaces, and function as postsynaptic compartments for excitatory synapses. Plasticity of spine structure is associated with many forms of long-term neuronal plasticity, learning and memory. Inside these small dendritic compartments, biochemical states and protein-protein interactions are dynamically modulated by synaptic activity, leading to the regulation of protein synthesis and reorganization of cytoskeletal architecture. This in turn causes plasticity of structure and function of the spine. Technical advances in monitoring molecular behaviors in single dendritic spines have revealed that each signaling pathway is differently regulated across multiple spatiotemporal domains. The spatial pattern of signaling activity expands from a single spine to the nearby dendritic area, dendritic branch and the nucleus, regulating different cellular events at each spatial scale. Temporally, biochemical events are typically triggered by short Ca2+ pulses (~10–100 ms). However, these signals can then trigger activation of downstream protein cascades that can last from milliseconds to hours. Recent imaging studies provide many insights into the biochemical processes governing signaling events of molecular assemblies at different spatial localizations. Here, we highlight recent findings of signaling dynamics during synaptic plasticity and discuss their roles in long-term structural plasticity of dendritic spines.
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Affiliation(s)
- Yoshihisa Nakahata
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience (MPFI), Jupiter, FL, United States
| | - Ryohei Yasuda
- Neuronal Signal Transduction, Max Planck Florida Institute for Neuroscience (MPFI), Jupiter, FL, United States
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7
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Wang Z, Shang H, Jiang Y. Chemokines and Chemokine Receptors: Accomplices for Human Immunodeficiency Virus Infection and Latency. Front Immunol 2017; 8:1274. [PMID: 29085362 PMCID: PMC5650658 DOI: 10.3389/fimmu.2017.01274] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/25/2017] [Indexed: 12/22/2022] Open
Abstract
Chemokines are small chemotactic cytokines that are involved in the regulation of immune cell migration. Multiple functional properties of chemokines, such as pro-inflammation, immune regulation, and promotion of cell growth, angiogenesis, and apoptosis, have been identified in many pathological and physiological contexts. Human immunodeficiency virus (HIV) infection is characterized by persistent inflammation and immune activation during both acute and chronic phases, and the "cytokine storm" is one of the hallmarks of HIV infection. Along with immune activation after HIV infection, an extensive range of chemokines and other cytokines are elevated, thereby generating the so-called "cytokine storm." In this review, the effects of the upregulated chemokines and chemokine receptors on the processes of HIV infection are discussed. The objective of this review was to focus on the main chemokines and chemokine receptors that have been found to be associated with HIV infection and latency. Elevated chemokines and chemokine receptors have been shown to play important roles in the HIV life cycle, disease progression, and HIV reservoir establishment. Thus, targeting these chemokines and receptors and the other proteins of related signaling pathways might provide novel therapeutic strategies, and the evidence indicates a promising future regarding the development of a functional cure for HIV.
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Affiliation(s)
- Zhuo Wang
- Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - Hong Shang
- Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - Yongjun Jiang
- Key Laboratory of AIDS Immunology of National Health and Family Planning Commission, Department of Laboratory Medicine, The First Affiliated Hospital, China Medical University, Shenyang, China
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8
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The Arp2/3 Complex Is Essential for Distinct Stages of Spine Synapse Maturation, Including Synapse Unsilencing. J Neurosci 2017; 36:9696-709. [PMID: 27629719 DOI: 10.1523/jneurosci.0876-16.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/02/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Dendritic filopodia are actin-rich structures that are thought to contribute to early spine synapse formation; however, the actin regulatory proteins important for early synaptogenesis are poorly defined. Using organotypic hippocampal slice cultures and primary neuron hippocampal cultures from Arp2/3 conditional knock-out mice, we analyze the roles of the Arp2/3 complex, an actin regulator that creates branched actin networks, and demonstrate it is essential for distinct stages of both structural and functional maturation of excitatory spine synapses. Our data show that initially the Arp2/3 complex inhibits the formation of dendritic filopodia but that later during development, the Arp2/3 complex drives the morphological maturation from filopodia to typical spine morphology. Furthermore, we demonstrate that although the Arp2/3 complex is not required for key spine maturation steps, such as presynaptic contact and recruitment of MAGUK (membrane-associated guanylate kinase) scaffolding proteins or NMDA receptors, it is necessary for the recruitment of AMPA receptors. This latter process, also known as synapse unsilencing, is a final and essential step in the neurodevelopment of excitatory postsynaptic synaptogenesis, setting the stage for neuronal interconnectivity. These findings provide the first evidence that the Arp2/3 complex is directly involved in functional maturation of dendritic spines during the developmental period of spinogenesis. SIGNIFICANCE STATEMENT Excitatory spine synapse formation (spinogenesis) is a poorly understood yet pivotal period of neurodevelopment that occurs within 2-3 weeks after birth. Neurodevelopmental disorders such as intellectual disability and autism are characterized by abnormal spine structure, which may arise from abnormal excitatory synaptogenesis. The initial stage of spinogenesis is thought to begin with the emergence of actin-rich dendritic filopodia that initiate contact with presynaptic axonal boutons. However, it remains enigmatic how actin cytoskeletal regulation directs dendritic filopodial emergence or their subsequent maturation into dendritic spines during development and on into adulthood. In this study, we provide the first evidence that the Arp2/3 complex, a key actin nucleator, is involved in distinct stages of spine formation and is required for synapse unsilencing.
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9
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Roybal KT, Buck TE, Ruan X, Cho BH, Clark DJ, Ambler R, Tunbridge HM, Zhang J, Verkade P, Wülfing C, Murphy RF. Computational spatiotemporal analysis identifies WAVE2 and cofilin as joint regulators of costimulation-mediated T cell actin dynamics. Sci Signal 2016; 9:rs3. [PMID: 27095595 DOI: 10.1126/scisignal.aad4149] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fluorescence microscopy is one of the most important tools in cell biology research because it provides spatial and temporal information to investigate regulatory systems inside cells. This technique can generate data in the form of signal intensities at thousands of positions resolved inside individual live cells. However, given extensive cell-to-cell variation, these data cannot be readily assembled into three- or four-dimensional maps of protein concentration that can be compared across different cells and conditions. We have developed a method to enable comparison of imaging data from many cells and applied it to investigate actin dynamics in T cell activation. Antigen recognition in T cells by the T cell receptor (TCR) is amplified by engagement of the costimulatory receptor CD28. We imaged actin and eight core actin regulators to generate over a thousand movies of T cells under conditions in which CD28 was either engaged or blocked in the context of a strong TCR signal. Our computational analysis showed that the primary effect of costimulation blockade was to decrease recruitment of the activator of actin nucleation WAVE2 (Wiskott-Aldrich syndrome protein family verprolin-homologous protein 2) and the actin-severing protein cofilin to F-actin. Reconstitution of WAVE2 and cofilin activity restored the defect in actin signaling dynamics caused by costimulation blockade. Thus, we have developed and validated an approach to quantify protein distributions in time and space for the analysis of complex regulatory systems.
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Affiliation(s)
- Kole T Roybal
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK. Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Taráz E Buck
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Xiongtao Ruan
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Baek Hwan Cho
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Danielle J Clark
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK
| | - Rachel Ambler
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK
| | - Helen M Tunbridge
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK
| | - Jianwei Zhang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Christoph Wülfing
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK. Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Robert F Murphy
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA. Departments of Biological Sciences, Biomedical Engineering, and Machine Learning, Carnegie Mellon University, Pittsburgh, PA 15213, USA. Freiburg Institute for Advanced Studies and Faculty of Biology, Albert Ludwig University of Freiburg, Freiburg im Breisgau 79104, Baden-Württemberg, Germany.
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10
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Booij L, Casey KF, Antunes JM, Szyf M, Joober R, Israël M, Steiger H. DNA methylation in individuals with anorexia nervosa and in matched normal-eater controls: A genome-wide study. Int J Eat Disord 2015; 48:874-82. [PMID: 25808061 DOI: 10.1002/eat.22374] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/08/2014] [Accepted: 11/19/2014] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Evidence associates anorexia nervosa (AN) with epigenetic alterations that could contribute to illness risk or entrenchment. We investigated the extent to which AN is associated with a distinct methylation profile compared to that seen in normal-eater women. METHOD Genome-wide methylation profiles, obtained using DNA from whole blood, were determined in 29 women currently ill with AN (10 with AN-restrictive type, 19 with AN-binge/purge type) and 15 normal-weight, normal-eater control women, using 450 K Illumina bead arrays. RESULTS Regardless of type, AN patients showed higher and less-variable global methylation patterns than controls. False Discovery Rate corrected comparisons identified 14 probes that were hypermethylated in women with AN relative to levels obtained in normal-eater controls, representing genes thought to be associated with histone acetylation, RNA modification, cholesterol storage and lipid transport, and dopamine and glutamate signaling. Age of onset was significantly associated with differential methylation in gene pathways involved in development of the brain and spinal cord, while chronicity of illness was significantly linked to differential methylation in pathways involved with synaptogenesis, neurocognitive deficits, anxiety, altered social functioning, and bowel, kidney, liver and immune function. DISCUSSION Although pre-existing differences cannot be ruled out, our findings are consistent with the idea of secondary alterations in methylation at genomic regions pertaining to social-emotional impairments and physical sequelae that are commonly seen in AN patients. Further investigation is needed to establish the clinical relevance of the affected genes in AN, and, importantly, reversibility of effects observed with nutritional rehabilitation and treatment.
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Affiliation(s)
- Linda Booij
- Department of Psychology, Queen's University, Kingston, ON, Canada, K7L 3N6.,Sainte-Justine Hospital Research Centre, University of Montreal, 3175, Chemin Côte Ste-Catherine, Montreal, QC, Canada, H3T 1C5.,Department of Psychiatry, McGill University, Montreal, QC, Canada, H3A1 A1
| | - Kevin F Casey
- Sainte-Justine Hospital Research Centre, University of Montreal, 3175, Chemin Côte Ste-Catherine, Montreal, QC, Canada, H3T 1C5
| | - Juliana M Antunes
- Eating Disorders Program, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3
| | - Moshe Szyf
- Department of Pharmacology, McGill University, 1309-3655 Sir William Osler Promenade, Montreal, QC, Canada, H3G 1Y6
| | - Ridha Joober
- Department of Psychiatry, McGill University, Montreal, QC, Canada, H3A1 A1.,Research Centre, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3
| | - Mimi Israël
- Department of Psychiatry, McGill University, Montreal, QC, Canada, H3A1 A1.,Eating Disorders Program, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3.,Research Centre, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3
| | - Howard Steiger
- Department of Psychiatry, McGill University, Montreal, QC, Canada, H3A1 A1.,Eating Disorders Program, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3.,Research Centre, Douglas University Institute, 6875 LaSalle Boulevard, Montreal, Quebec, Canada, H4H 1R3
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11
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Kang J, Park H, Kim E. IRSp53/BAIAP2 in dendritic spine development, NMDA receptor regulation, and psychiatric disorders. Neuropharmacology 2015; 100:27-39. [PMID: 26275848 DOI: 10.1016/j.neuropharm.2015.06.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 01/08/2023]
Abstract
IRSp53 (also known as BAIAP2) is a multi-domain scaffolding and adaptor protein that has been implicated in the regulation of membrane and actin dynamics at subcellular structures, including filopodia and lamellipodia. Accumulating evidence indicates that IRSp53 is an abundant component of the postsynaptic density at excitatory synapses and an important regulator of actin-rich dendritic spines. In addition, IRSp53 has been implicated in diverse psychiatric disorders, including autism spectrum disorders, schizophrenia, and attention deficit/hyperactivity disorder. Mice lacking IRSp53 display enhanced NMDA (N-methyl-d-aspartate) receptor function accompanied by social and cognitive deficits, which are reversed by pharmacological suppression of NMDA receptor function. These results suggest the hypothesis that defective actin/membrane modulation in IRSp53-deficient dendritic spines may lead to social and cognitive deficits through NMDA receptor dysfunction. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'.
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Affiliation(s)
- Jaeseung Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Haram Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea; Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon 305-701, South Korea.
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12
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ARF6 promotes the formation of Rac1 and WAVE-dependent ventral F-actin rosettes in breast cancer cells in response to epidermal growth factor. PLoS One 2015; 10:e0121747. [PMID: 25799492 PMCID: PMC4370635 DOI: 10.1371/journal.pone.0121747] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/03/2015] [Indexed: 12/19/2022] Open
Abstract
Coordination between actin cytoskeleton assembly and localized polarization of intracellular trafficking routes is crucial for cancer cell migration. ARF6 has been implicated in the endocytic recycling of surface receptors and membrane components and in actin cytoskeleton remodeling. Here we show that overexpression of an ARF6 fast-cycling mutant in MDA-MB-231 breast cancer-derived cells to mimick ARF6 hyperactivation observed in invasive breast tumors induced a striking rearrangement of the actin cytoskeleton at the ventral cell surface. This phenotype consisted in the formation of dynamic actin-based podosome rosette-like structures expanding outward as wave positive for F-actin and actin cytoskeleton regulatory components including cortactin, Arp2/3 and SCAR/WAVE complexes and upstream Rac1 regulator. Ventral rosette-like structures were similarly induced in MDA-MB-231 cells in response to epidermal growth factor (EGF) stimulation and to Rac1 hyperactivation. In addition, interference with ARF6 expression attenuated activation and plasma membrane targeting of Rac1 in response to EGF treatment. Our data suggest a role for ARF6 in linking EGF-receptor signaling to Rac1 recruitment and activation at the plasma membrane to promote breast cancer cell directed migration.
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13
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Hazai D, Szudoczki R, Ding J, Soderling SH, Weinberg RJ, Sótonyi P, Rácz B. Ultrastructural abnormalities in CA1 hippocampus caused by deletion of the actin regulator WAVE-1. PLoS One 2013; 8:e75248. [PMID: 24086480 PMCID: PMC3783472 DOI: 10.1371/journal.pone.0075248] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 08/12/2013] [Indexed: 11/18/2022] Open
Abstract
By conveying signals from the small GTPase family of proteins to the Arp2/3 complex, proteins of the WAVE family facilitate actin remodeling. The WAVE-1 isoform is expressed at high levels in brain, where it plays a role in normal synaptic processing, and is implicated in hippocampus-dependent memory retention. We used electron microscopy to determine whether synaptic structure is modified in the hippocampus of WAVE-1 knockout mice, focusing on the neuropil of CA1 stratum radiatum. Mice lacking WAVE-1 exhibited alterations in the morphology of both axon terminals and dendritic spines; the relationship between the synaptic partners was also modified. The abnormal synaptic morphology we observed suggests that signaling through WAVE-1 plays a critical role in establishing normal synaptic architecture in the rodent hippocampus.
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Affiliation(s)
- Diána Hazai
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Budapest, Hungary
| | - Róbert Szudoczki
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Budapest, Hungary
| | - Jindong Ding
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States of America
| | - Scott H. Soderling
- Departments of Cell Biology and Neurobiology, Duke University, Durham, North Carolina, United States of America
| | - Richard J. Weinberg
- Department of Cell Biology & Physiology and Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Péter Sótonyi
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Budapest, Hungary
| | - Bence Rácz
- Department of Anatomy and Histology, Faculty of Veterinary Science, Szent István University, Budapest, Hungary
- * E-mail:
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14
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Saengsawang W, Taylor KL, Lumbard DC, Mitok K, Price A, Pietila L, Gomez TM, Dent EW. CIP4 coordinates with phospholipids and actin-associated proteins to localize to the protruding edge and produce actin ribs and veils. J Cell Sci 2013; 126:2411-23. [PMID: 23572514 DOI: 10.1242/jcs.117473] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cdc42-interacting protein 4 (CIP4), a member of the F-BAR family of proteins, plays important roles in a variety of cellular events by regulating both membrane and actin dynamics. In many cell types, CIP4 functions in vesicle formation, endocytosis and membrane tubulation. However, recent data indicate that CIP4 is also involved in protrusion in some cell types, including cancer cells (lamellipodia and invadopodia) and neurons (ribbed lamellipodia and veils). In neurons, CIP4 localizes specifically to extending protrusions and functions to limit neurite outgrowth early in development. The mechanism by which CIP4 localizes to the protruding edge membrane and induces lamellipodial/veil protrusion and actin rib formation is not known. Here, we show that CIP4 localization to the protruding edge of neurons is dependent on both the phospholipid content of the plasma membrane and the underlying organization of actin filaments. Inhibiting phosphatidylinositol (3,4,5)-trisphosphate (PIP3) production decreases CIP4 at the membrane. CIP4 localization to the protruding edge is also dependent on Rac1/WAVE1, rather than Cdc42/N-WASP. Capping actin filaments with low concentrations of cytochalasin D or by overexpressing capping protein dramatically decreases CIP4 at the protruding edge, whereas inactivating Arp2/3 drives CIP4 to the protruding edge. We also demonstrate that CIP4 dynamically colocalizes with Ena/VASP and DAAM1, two proteins known to induce unbranched actin filament arrays and play important roles in neuronal development. Together, this is the first study to show that the localization of an F-BAR protein depends on both actin filament architecture and phospholipids at the protruding edge of developing neurons.
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Affiliation(s)
- Witchuda Saengsawang
- University of Wisconsin-Madison, Department of Neuroscience, Madison, WI 53706, USA
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15
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Brzostowski JA, Fey P, Yan J, Isik N, Jin T. The Elmo family forms an ancient group of actin-regulating proteins. Commun Integr Biol 2013; 2:337-40. [PMID: 19721884 DOI: 10.4161/cib.2.4.8549] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 01/11/2023] Open
Abstract
The Elmo protein family members are important mediators of small G protein activity, regulating actin-mediated processes such as chemotaxis and engulfment. Until recently,1 Elmo function has not been explored in professional phagocytes such as Dictyostelium discoideum. We discuss the significance of this family with respect to pathways that regulate Rac signaling, we present a comparison of Elmo proteins between representative taxa, and discuss our findings on ElmoA, one of six Elmo proteins found in D. discoideum.
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Affiliation(s)
- Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility; National Institutes of Health; Rockville, MD USA
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16
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Abstract
The Rho family of GTP binding proteins, also commonly referred to as the Rho GTPases, are master regulators of the platelet cytoskeleton and platelet function. These low-molecular-weight or 'small' GTPases act as signaling switches in the spatial and temporal transduction, and amplification of signals from platelet cell surface receptors to the intracellular signaling pathways that drive platelet function. The Rho GTPase family members RhoA, Cdc42 and Rac1 have emerged as key regulators in the dynamics of the actin cytoskeleton in platelets and play key roles in platelet aggregation, secretion, spreading and thrombus formation. Rho GTPase regulators, including GEFs and GAPs and downstream effectors, such as the WASPs, formins and PAKs, may also regulate platelet activation and function. In this review, we provide an overview of Rho GTPase signaling in platelet physiology. Previous studies of Rho GTPases and platelets have had a shared history, as platelets have served as an ideal, non-transformed cellular model to characterize Rho function. Likewise, recent studies of the cell biology of Rho GTPase family members have helped to build an understanding of the molecular regulation of platelet function and will continue to do so through the further characterization of Rho GTPases as well as Rho GAPs, GEFs, RhoGDIs and Rho effectors in actin reorganization and other Rho-driven cellular processes.
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Affiliation(s)
- J E Aslan
- Department of Biomedical Engineering and Cell & Developmental Biology, School of Medicine, Oregon Health & Science University, Portland, OR 97239, USA.
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17
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Ziel JW, Sherwood DR. Roles for netrin signaling outside of axon guidance: a view from the worm. Dev Dyn 2010; 239:1296-305. [PMID: 20108323 DOI: 10.1002/dvdy.22225] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Netrin family of extracellular ligands and their receptors were the first identified signaling pathway regulating axon guidance. Subsequent work across model systems has begun to reveal the interactions that take place downstream of Netrin reception to facilitate growth cone migration. Though intensely studied, many aspects of this signaling system remain unclear. Even less understood are the growing number of contexts in which Netrin signaling influences cells beyond axon guidance and even outside the nervous system. Genetic and cell-biological studies in C. elegans have played an instrumental role in identifying critical functions for Netrin ligands in setting up specialized and potentially adhesive membrane-associated domains within a broad range of cell types. Here we review recent literature implicating Netrin or its receptors in morphogenetic processes outside of growth cone regulation with a special focus on studies in C. elegans that suggest cell biological mechanisms for Netrin signaling.
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Affiliation(s)
- Joshua W Ziel
- Department of Biology, Duke University, Durham, North Carolina 27708, USA
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18
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Harmon B, Campbell N, Ratner L. Role of Abl kinase and the Wave2 signaling complex in HIV-1 entry at a post-hemifusion step. PLoS Pathog 2010; 6:e1000956. [PMID: 20585556 PMCID: PMC2887473 DOI: 10.1371/journal.ppat.1000956] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 05/19/2010] [Indexed: 11/18/2022] Open
Abstract
Entry of human immunodeficiency virus type 1 (HIV-1) commences with binding of the envelope glycoprotein (Env) to the receptor CD4, and one of two coreceptors, CXCR4 or CCR5. Env-mediated signaling through coreceptor results in Galphaq-mediated Rac activation and actin cytoskeleton rearrangements necessary for fusion. Guanine nucleotide exchange factors (GEFs) activate Rac and regulate its downstream protein effectors. In this study we show that Env-induced Rac activation is mediated by the Rac GEF Tiam-1, which associates with the adaptor protein IRSp53 to link Rac to the Wave2 complex. Rac and the tyrosine kinase Abl then activate the Wave2 complex and promote Arp2/3-dependent actin polymerization. Env-mediated cell-cell fusion, virus-cell fusion and HIV-1 infection are dependent on Tiam-1, Abl, IRSp53, Wave2, and Arp3 as shown by attenuation of fusion and infection in cells expressing siRNA targeted to these signaling components. HIV-1 Env-dependent cell-cell fusion, virus-cell fusion and infection were also inhibited by Abl kinase inhibitors, imatinib, nilotinib, and dasatinib. Treatment of cells with Abl kinase inhibitors did not affect cell viability or surface expression of CD4 and CCR5. Similar results with inhibitors and siRNAs were obtained when Env-dependent cell-cell fusion, virus-cell fusion or infection was measured, and when cell lines or primary cells were the target. Using membrane curving agents and fluorescence microscopy, we showed that inhibition of Abl kinase activity arrests fusion at the hemifusion (lipid mixing) step, suggesting a role for Abl-mediated actin remodeling in pore formation and expansion. These results suggest a potential utility of Abl kinase inhibitors to treat HIV-1 infected patients.
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Affiliation(s)
- Brooke Harmon
- Division of Molecular Oncology, Washington University School of Medicine, St Louis, Missouri, United States of America
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19
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The WAVE regulatory complex is inhibited. Nat Struct Mol Biol 2009; 16:561-3. [PMID: 19363480 PMCID: PMC2716658 DOI: 10.1038/nsmb.1587] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 03/12/2009] [Indexed: 11/16/2022]
Abstract
The WAVE Regulatory Complex (WRC) transmits information from the Rac GTPase to the actin nucleator, Arp2/3 complex. We have reconstituted recombinant human and Drosophila WRC in several forms and shown that they are inactive toward Arp2/3 complex, but can be activated by Rac in nucleotide dependent fashion. Our observations identify core components needed for WAVE inhibition, reconcile contradictory existing mechanisms and reveal common regulatory principles for the WAVE/WASP family.
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20
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Soderling SH. Grab your partner with both hands: cytoskeletal remodeling by Arp2/3 signaling. Sci Signal 2009; 2:pe5. [PMID: 19176514 DOI: 10.1126/scisignal.255pe5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The seemingly simple structure of the actin filament belies the elaborate signaling pathways that regulate its assembly and disassembly in eukaryotic cells. In retrospect, this signaling complexity should not be surprising. Actin regulates many dynamic cellular processes, including protein and organelle trafficking, establishment of cell polarity, directional migration, cellular traction, and the efficiency of endocytosis. Signaling events that coordinately control actin turnover during these processes must display a high degree of sophistication. Emerging data on an important regulator of actin dynamics, the actin-related protein 2 and 3 (Arp2/3) complex, suggest a model of how this may occur.
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Affiliation(s)
- Scott H Soderling
- Department of Cell Biology, Duke University Medical School, Durham, NC 27710, USA.
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21
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Park H, Staehling-Hampton K, Appleby MW, Brunkow ME, Habib T, Zhang Y, Ramsdell F, Liggitt HD, Freie B, Tsang M, Carlson G, Friend S, Frevert C, Iritani BM. A point mutation in the murine Hem1 gene reveals an essential role for Hematopoietic protein 1 in lymphopoiesis and innate immunity. ACTA ACUST UNITED AC 2008; 205:2899-913. [PMID: 19015308 PMCID: PMC2585840 DOI: 10.1084/jem.20080340] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hem1 (Hematopoietic protein 1) is a hematopoietic cell-specific member of the Hem family of cytoplasmic adaptor proteins. Orthologues of Hem1 in Dictyostelium discoideum, Drosophila melanogaster, and Caenorhabditis elegans are essential for cytoskeletal reorganization, embryonic cell migration, and morphogenesis. However, the in vivo functions of mammalian Hem1 are not known. Using a chemical mutagenesis strategy in mice to identify novel genes involved in immune cell functions, we positionally cloned a nonsense mutation in the Hem1 gene. Hem1 deficiency results in defective F-actin polymerization and actin capping in lymphocytes and neutrophils caused by loss of the Rac-controlled actin-regulatory WAVE protein complex. T cell development is disrupted in Hem1-deficient mice at the CD4−CD8− (double negative) to CD4+CD8+ (double positive) cell stages, whereas T cell activation and adhesion are impaired. Hem1-deficient neutrophils fail to migrate in response to chemotactic agents and are deficient in their ability to phagocytose bacteria. Remarkably, some Rac-dependent functions, such as Th1 differentiation and nuclear factor κB (NF-κB)–dependent transcription of proinflammatory cytokines proceed normally in Hem1-deficient mice, whereas the production of Th17 cells are enhanced. These results demonstrate that Hem1 is essential for hematopoietic cell development, function, and homeostasis by controlling a distinct pathway leading to cytoskeletal reorganization, whereas NF-κB–dependent transcription proceeds independently of Hem1 and F-actin polymerization.
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Affiliation(s)
- Heon Park
- Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA
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22
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Hanley JG. AMPA receptor trafficking pathways and links to dendritic spine morphogenesis. Cell Adh Migr 2008; 2:276-82. [PMID: 19262155 DOI: 10.4161/cam.2.4.6510] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Jonathan G Hanley
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, Bristol, UK.
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23
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Dinh H, Scholz GM, Hamilton JA. Regulation of WAVE1 expression in macrophages at multiple levels. J Leukoc Biol 2008; 84:1483-91. [DOI: 10.1189/jlb.0308216] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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24
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The actin cytoskeleton in cancer cell motility. Clin Exp Metastasis 2008; 26:273-87. [PMID: 18498004 DOI: 10.1007/s10585-008-9174-2] [Citation(s) in RCA: 411] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2008] [Accepted: 04/25/2008] [Indexed: 01/01/2023]
Abstract
Cancer cell metastasis is a multi-stage process involving invasion into surrounding tissue, intravasation, transit in the blood or lymph, extravasation, and growth at a new site. Many of these steps require cell motility, which is driven by cycles of actin polymerization, cell adhesion and acto-myosin contraction. These processes have been studied in cancer cells in vitro for many years, often with seemingly contradictory results. The challenge now is to understand how the multitude of in vitro observations relates to the movement of cancer cells in living tumour tissue. In this review we will concentrate on actin protrusion and acto-myosin contraction. We will begin by presenting some general principles summarizing the widely-accepted mechanisms for the co-ordinated regulation of actin polymerization and contraction. We will then discuss more recent studies that investigate how experimental manipulation of actin dynamics affects cancer cell invasion in complex environments and in vivo.
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25
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Maddala R, Reneker LW, Pendurthi B, Rao PV. Rho GDP dissociation inhibitor-mediated disruption of Rho GTPase activity impairs lens fiber cell migration, elongation and survival. Dev Biol 2008; 315:217-31. [PMID: 18234179 DOI: 10.1016/j.ydbio.2007.12.039] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 12/19/2007] [Accepted: 12/20/2007] [Indexed: 01/06/2023]
Abstract
To explore the role of the Rho GTPases in lens morphogenesis, we overexpressed bovine Rho GDP dissociation inhibitor (Rho GDI alpha), which serves as a negative regulator of Rho, Rac and Cdc42 GTPase activity, in a lens-specific manner in transgenic mice. This was achieved using a chimeric promoter of delta-crystallin enhancer and alpha A-crystallin, which is active at embryonic day 12. Several individual transgenic (Tg) lines were obtained, and exhibited ocular specific phenotype comprised of microphthalmic eyes with lens opacity. The overexpression of bovine Rho GDI alpha disrupted membrane translocation of Rho, Rac and Cdc42 GTPases in Tg lenses. Transgenic lenses also revealed abnormalities in the migration pattern, elongation and organization of lens fibers. These changes appeared to be associated with impaired organization of the actin cytoskeleton and cell-cell adhesions. At E14.5, the size of the Rho GDI alpha Tg lenses was larger compared to wild type (WT) and the central lens epithelium and differentiating fibers exhibited an abnormal increase of bromo-deoxy-uridine incorporation. Postnatal Tg eyes, however, were much smaller in size compared to WT eyes, revealing increased apoptosis in the disrupted lens fibers. Taken together, these data demonstrate a critical role for Rho GTPase-dependent signaling pathways in processes underlying morphogenesis, fiber cell migration, elongation and survival in the developing lens.
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Affiliation(s)
- Rupalatha Maddala
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710, USA
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26
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Eto K, Nishikii H, Ogaeri T, Suetsugu S, Kamiya A, Kobayashi T, Yamazaki D, Oda A, Takenawa T, Nakauchi H. The WAVE2/Abi1 complex differentially regulates megakaryocyte development and spreading: implications for platelet biogenesis and spreading machinery. Blood 2007; 110:3637-47. [PMID: 17664349 DOI: 10.1182/blood-2007-04-085860] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Actin polymerization is crucial in throm-bopoiesis, platelet adhesion, and mega-karyocyte (MK) and platelet spreading. The Wiskott-Aldrich syndrome protein (WASp) homolog WAVE functions downstream of Rac and plays a pivotal role in lamellipodia formation. While MKs and platelets principally express WAVE1 and WAVE2, which are associated with Abi1, the physiologic significance of WAVE isoforms remains undefined. We generated WAVE2−/− embryonic stem (ES) cells because WAVE2-null mice die by embryonic day (E) 12.5. We found that while WAVE2−/− ES cells differentiated into immature MKs on OP9 stroma, they were severely impaired in terminal differentiation and in platelet production. WAVE2−/− MKs exhibited a defect in peripheral lamellipodia on fibrinogen even with phorbol 12-myristate 13-acetate (PMA) costimulation, indicating a requirement of WAVE2 for integrin αIIbβ3-mediated full spreading. MKs in which expression of Abi1 was reduced by small interfering RNA (siRNA) exhibited striking similarity to WAVE2−/− MKs in maturation and spreading. Interestingly, the knockdown of IRSp53, a Rac effector that preferentially binds to WAVE2, impaired the development of lamellipodia without affecting proplatelet production. In contrast, thrombopoiesis in vivo and platelet spreading on fibrinogen in vitro were intact in WAVE1-null mice. These observations clarify indispensable roles for the WAVE2/Abi1 complex in αIIbβ3-mediated lamellipodia by MKs and platelets through Rac and IRSp53, and additionally in thrombopoiesis independent of Rac and IRSp53.
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Affiliation(s)
- Koji Eto
- Laboratory of Stem Cell Therapy, Center for Experimental Medicine, The Institute of Medical Science, University of Tokyo, Japan.
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El-Sibai M, Nalbant P, Pang H, Flinn RJ, Sarmiento C, Macaluso F, Cammer M, Condeelis JS, Hahn KM, Backer JM. Cdc42 is required for EGF-stimulated protrusion and motility in MTLn3 carcinoma cells. J Cell Sci 2007; 120:3465-74. [PMID: 17855387 PMCID: PMC4066376 DOI: 10.1242/jcs.005942] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cdc42 plays a central role in regulating the actin cytoskeleton and maintaining cell polarity. Here, we show that Cdc42 is crucial for epidermal growth factor (EGF)-stimulated protrusion in MTLn3 carcinoma cells. When stimulated with EGF, carcinoma cells showed a rapid increase in activated Cdc42 that is primarily localized to the protruding edge of the cells. siRNA-mediated knockdown of Cdc42 expression caused a decrease in EGF-stimulated protrusion and reduced cell motility in time-lapse studies. These changes were correlated with a decrease in barbed-end formation and Arp2/3 localization at the cell edge, and a marked defect in actin filament branching, as revealed by rotary-shadowing scanning electron microscopy. Upstream of Arp2/3, Cdc42 knockdown inhibited EGF-stimulated activation of PI 3-kinase at early (within 1 minute) but not late (within 3 minutes) time points. Membrane targeting of N-WASP, WAVE2 and IRSp53 were also inhibited. Effects on WAVE2 were not owing to Rac1 inhibition, because WAVE2 recruitment is unaffected by Rac1 knockdown. Our data suggest that Cdc42 activation is crucial for the regulation of actin polymerization in carcinoma cells, and required for both EGF-stimulated protrusion and cell motility independently of effects on Rac.
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Affiliation(s)
- Mirvat El-Sibai
- Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Peri Nalbant
- Pharmacology, University of North Carolina School of Medicine CB7365, Chapel Hill, NC 27599, USA
| | - Huan Pang
- Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Rory J. Flinn
- Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Corina Sarmiento
- Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Frank Macaluso
- Analytical Imaging Facility, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Michael Cammer
- Analytical Imaging Facility, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - John S. Condeelis
- Anatomy and Structural Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- Analytical Imaging Facility, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Klaus M. Hahn
- Pharmacology, University of North Carolina School of Medicine CB7365, Chapel Hill, NC 27599, USA
| | - Jonathan M. Backer
- Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- Author for correspondence ()
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28
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Jin H, Wang JY. Abl tyrosine kinase promotes dorsal ruffles but restrains lamellipodia extension during cell spreading on fibronectin. Mol Biol Cell 2007; 18:4143-54. [PMID: 17686996 PMCID: PMC1995715 DOI: 10.1091/mbc.e07-01-0085] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The nonreceptor Abl tyrosine kinase stimulates F-actin microspikes and membrane ruffles in response to adhesion and growth factor signals. We show here that induced dimerization of Abl-FKBP, but not the kinase-defective AblKD-FKBP, inhibits cell spreading on fibronectin. Conversely, knockdown of cellular Abl by shRNA stimulates cell spreading. The Abl kinase inhibitor, imatinib, also stimulates cell spreading and its effect is overridden by the imatinib-resistant AblT315I. Expression of Abl but not AbkKD in Abl/Arg-deficient cells again inhibits spreading. Furthermore, Abl inhibits spreading of cells that express the activated Rac, RacV12, correlating with RacV12 localization to dorsal membrane protrusions. Ectopic expression of CrkII, a Rac activator that is inactivated by Abl-mediated tyrosine phosphorylation, antagonizes Abl-mediated dorsal membrane localization of RacV12. Ectopic expression of a dynamin-2 mutant, previously shown to induce Rac-GTP localization to the dorsal membrane, abolishes the stimulatory effect of imatinib on cell spreading. These results suggest that Abl tyrosine kinase, through CrkII phosphorylation and in collaboration with dynamin-2 can regulate the partitioning of Rac-GTP to favor dorsal ruffles during cell spreading. The Abl-dependent dorsal membrane localization of activated Rac explains its positive role in ruffling and negative role in cell spreading and migration.
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Affiliation(s)
- Hua Jin
- *Division of Biological Sciences
| | - Jean Y.J. Wang
- *Division of Biological Sciences
- Division of Hematology-Oncology, Department of Medicine, School of Medicine, and
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820
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29
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Pommereit D, Wouters FS. An NGF-induced Exo70-TC10 complex locally antagonises Cdc42-mediated activation of N-WASP to modulate neurite outgrowth. J Cell Sci 2007; 120:2694-705. [PMID: 17635999 DOI: 10.1242/jcs.03475] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
NGF-induced differentiation of PC12 cells is mediated by actin-polymerisation-driven membrane protrusion, involving GTPase signalling pathways that activate actin nucleation promoting factors such as the neural Wiskott-Aldrich syndrome protein (N-WASP). Expression of the exocyst subunit Exo70 in PC12 cells and neurons leads to the generation of numerous membrane protrusions, an effect that is strongly potentiated upon NGF-induced differentiation. Förster resonance energy transfer (FRET) imaging by fluorescence lifetime microscopy (FLIM) reveals an NGF-induced interaction of activated TC10 with Exo70. Expression of dominant-negative mutants and siRNA-mediated knockdown implicates N-WASP in NGF-induced Exo70-TC10-mediated membrane protrusion. However, FRET imaging of N-WASP activation levels of cells expressing Exo70 and/or constitutively active TC10 reveals that this complex locally antagonises the NGF-induced activation of N-WASP in membrane protrusions. Experiments involving siRNA-mediated knockdown of Cdc42 and overexpression of constitutively active Cdc42 confirm that the Exo70-TC10 complex mainly targets the NGF-induced Cdc42-dependent activation of N-WASP. Our results show that Exo70 is responsible for the correct targeting of the Exo70-TC10 complex to sites of membrane protrusion. The functional uncoupling between both pathways represents a novel regulatory mechanism that enables switching between morphologically distinct – Cdc42- or TC10-dominated – forms of cellular membrane outgrowth.
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Affiliation(s)
- Dagmar Pommereit
- European Neuroscience Institute-Göttingen, Cell Biophysics Group and DFG Research Center for Molecular Physiology of the Brain (CMPB), D-37073 Göttingen, Germany
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30
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Morphogenic Signaling in Neurons Via Neurotransmitter Receptors and Small GTPases. Mol Neurobiol 2007; 35:278-87. [DOI: 10.1007/s12035-007-0023-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/30/1999] [Accepted: 12/08/2006] [Indexed: 01/21/2023]
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31
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Chen EH, Grote E, Mohler W, Vignery A. Cell-cell fusion. FEBS Lett 2007; 581:2181-93. [PMID: 17395182 DOI: 10.1016/j.febslet.2007.03.033] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 03/09/2007] [Accepted: 03/12/2007] [Indexed: 12/16/2022]
Abstract
Cell-cell fusion is a highly regulated and dramatic cellular event that is required for development and homeostasis. Fusion may also play a role in the development of cancer and in tissue repair by stem cells. While virus-cell fusion and the fusion of intracellular membranes have been the subject of intense investigation during the past decade, cell-cell fusion remains poorly understood. Given the importance of this cell-biological phenomenon, a number of investigators have begun analyses of the molecular mechanisms that mediate the specialized fusion events of a variety of cell types and species. We discuss recent genetic and biochemical studies that are beginning to yield exciting insights into the fusion mechanisms of Saccharomyces cerevisiae mating pairs, Caenorhabditis elegans epithelial cells and gametes, Drosophila melanogaster and mammalian myoblasts, and mammalian macrophages.
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Affiliation(s)
- Elizabeth H Chen
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
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32
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Bobrovskaya L, Gelain DP, Gilligan C, Dickson PW, Dunkley PR. PACAP stimulates the sustained phosphorylation of tyrosine hydroxylase at serine 40. Cell Signal 2007; 19:1141-9. [PMID: 17261361 DOI: 10.1016/j.cellsig.2006.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 12/11/2006] [Accepted: 12/14/2006] [Indexed: 11/17/2022]
Abstract
Tyrosine hydroxylase (TH) is the rate-limiting enzyme in catecholamine synthesis. Its activity is controlled by PACAP, acutely by phosphorylation at Ser40 and chronically by protein synthesis. Using bovine adrenal chromaffin cells we found that PACAP, acting via the continuous activation of PACAP 1 receptors, sustained the phosphorylation of TH at Ser40 and led to TH activation for up to 24 h in the absence of TH protein synthesis. The sustained phosphorylation of TH at Ser40 was not mediated by hierarchical phosphorylation of TH at either Ser19 or Ser31. PACAP caused sustained activation of PKA, but did not sustain activation of other protein kinases including ERK, p38 kinase, PKC, MAPKAPK2 and MSK1. The PKA inhibitor H89 substantially inhibited the acute and the sustained phosphorylation of TH mediated by PACAP. PACAP also inhibited the activity of PP2A and PP2C at 24 h. PACAP therefore sustained TH phosphorylation at Ser40 for 24 h by sustaining the activation of PKA and causing inactivation of Ser40 phosphatases. The PKA activator 8-CPT-6Phe-cAMP also caused sustained phosphorylation of TH at Ser40 that was inhibited by the PKA inhibitor H89. Using cyclic AMP agonist pairs we found that sustained phosphorylation of TH was due to both the RI and the RII isotypes of PKA. The sustained activation of TH that occurred as a result of TH phosphorylation at Ser40 could maintain the synthesis of catecholamines without the need for further stimulus of the adrenal cells or increased TH protein synthesis.
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Affiliation(s)
- Larisa Bobrovskaya
- The School of Biomedical Sciences and Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, NSW 2308, Australia
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33
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Abstract
The Rho GTPases-Rho, Rac and Cdc42-act as molecular switches, cycling between an active GTP-bound state and an inactive GDP-bound state, to regulate the actin cytoskeleton. It has recently become apparent that the Rho GTPases can be activated in subcellular zones that appear semi-stable, yet are dynamically maintained. These Rho GTPase activity zones are associated with a variety of fundamental biological processes including symmetric and asymmetric cytokinesis and cellular wound repair. Here we review the basic features of Rho GTPase activity zones, suggest that these zones represent a fundamental signaling mechanism, and discuss the implications of zone properties from the perspective of both their function and how they are likely to be controlled.
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34
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Olsen JV, Blagoev B, Gnad F, Macek B, Kumar C, Mortensen P, Mann M. Global, In Vivo, and Site-Specific Phosphorylation Dynamics in Signaling Networks. Cell 2006; 127:635-48. [PMID: 17081983 DOI: 10.1016/j.cell.2006.09.026] [Citation(s) in RCA: 2734] [Impact Index Per Article: 151.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 08/01/2006] [Accepted: 09/19/2006] [Indexed: 11/26/2022]
Abstract
Cell signaling mechanisms often transmit information via posttranslational protein modifications, most importantly reversible protein phosphorylation. Here we develop and apply a general mass spectrometric technology for identification and quantitation of phosphorylation sites as a function of stimulus, time, and subcellular location. We have detected 6,600 phosphorylation sites on 2,244 proteins and have determined their temporal dynamics after stimulating HeLa cells with epidermal growth factor (EGF) and recorded them in the Phosida database. Fourteen percent of phosphorylation sites are modulated at least 2-fold by EGF, and these were classified by their temporal profiles. Surprisingly, a majority of proteins contain multiple phosphorylation sites showing different kinetics, suggesting that they serve as platforms for integrating signals. In addition to protein kinase cascades, the targets of reversible phosphorylation include ubiquitin ligases, guanine nucleotide exchange factors, and at least 46 different transcriptional regulators. The dynamic phosphoproteome provides a missing link in a global, integrative view of cellular regulation.
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Affiliation(s)
- Jesper V Olsen
- Center for Experimental BioInformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense, Denmark
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35
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Marston DJ, Goldstein B. Actin-based forces driving embryonic morphogenesis in Caenorhabditis elegans. Curr Opin Genet Dev 2006; 16:392-8. [PMID: 16782324 DOI: 10.1016/j.gde.2006.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2006] [Accepted: 06/08/2006] [Indexed: 01/27/2023]
Abstract
Morphogenesis is the process by which multicellular organisms transform themselves from a ball of cells into an organized animal. Certain virtues of Caenorhabditis elegans make it an excellent model system for the study of this process: it is genetically tractable, develops as a transparent embryo with small cell-numbers, and yet still contains all the major tissues typical of animals. Furthermore, certain morphogenetic events are also amenable to study by direct manipulation of the cells involved. Given these advantages, it has been possible to use C. elegans to investigate the different ways in which the actin cytoskeleton drives the cellular rearrangements underlying morphogenesis, through regulated polymerization or actomyosin contraction. Recent insights from this system have determined the involvement in morphogenesis of key proteins, including the actin-regulating WASP and Ena proteins, potential guidance molecules such as the Eph and Robo receptors, and the cell-cell signaling proteins of the Wnt pathway.
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Affiliation(s)
- Daniel J Marston
- Department of Biology, CB3280, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA.
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