1
|
Benz PM, Frömel T, Laban H, Zink J, Ulrich L, Groneberg D, Boon RA, Poley P, Renne T, de Wit C, Fleming I. Cardiovascular Functions of Ena/VASP Proteins: Past, Present and Beyond. Cells 2023; 12:1740. [PMID: 37443774 PMCID: PMC10340426 DOI: 10.3390/cells12131740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Actin binding proteins are of crucial importance for the spatiotemporal regulation of actin cytoskeletal dynamics, thereby mediating a tremendous range of cellular processes. Since their initial discovery more than 30 years ago, the enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family has evolved as one of the most fascinating and versatile family of actin regulating proteins. The proteins directly enhance actin filament assembly, but they also organize higher order actin networks and link kinase signaling pathways to actin filament assembly. Thereby, Ena/VASP proteins regulate dynamic cellular processes ranging from membrane protrusions and trafficking, and cell-cell and cell-matrix adhesions, to the generation of mechanical tension and contractile force. Important insights have been gained into the physiological functions of Ena/VASP proteins in platelets, leukocytes, endothelial cells, smooth muscle cells and cardiomyocytes. In this review, we summarize the unique and redundant functions of Ena/VASP proteins in cardiovascular cells and discuss the underlying molecular mechanisms.
Collapse
Affiliation(s)
- Peter M. Benz
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
| | - Timo Frömel
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Hebatullah Laban
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Joana Zink
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Lea Ulrich
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
| | - Dieter Groneberg
- Institute of Physiology I, University of Würzburg, 97070 Würzburg, Germany
| | - Reinier A. Boon
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
- Centre of Molecular Medicine, Institute of Cardiovascular Regeneration, Goethe-University, 60596 Frankfurt am Main, Germany
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Centre, 1081 HZ Amsterdam, The Netherlands
| | - Philip Poley
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Thomas Renne
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Center for Thrombosis and Hemostasis (CTH), Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
- Irish Centre for Vascular Biology, School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, D02 VN51 Dublin, Ireland
| | - Cor de Wit
- Institut für Physiologie, Universität zu Lübeck, 23562 Lübeck, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 23562 Lübeck, Germany
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, 60596 Frankfurt am Main, Germany
- German Centre of Cardiovascular Research (DZHK), Partner Site Rhein-Main, 60596 Frankfurt am Main, Germany
- Cardiopulmonary Institute, 60596 Frankfurt am Main, Germany
| |
Collapse
|
2
|
Zink J, Frye M, Frömel T, Carlantoni C, John D, Schreier D, Weigert A, Laban H, Salinas G, Stingl H, Günther L, Popp R, Hu J, Vanhollebeke B, Schmidt H, Acker-Palmer A, Renné T, Fleming I, Benz PM. EVL regulates VEGF receptor-2 internalization and signaling in developmental angiogenesis. EMBO Rep 2021; 22:e48961. [PMID: 33512764 PMCID: PMC7857432 DOI: 10.15252/embr.201948961] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Endothelial tip cells are essential for VEGF‐induced angiogenesis, but underlying mechanisms are elusive. The Ena/VASP protein family, consisting of EVL, VASP, and Mena, plays a pivotal role in axon guidance. Given that axonal growth cones and endothelial tip cells share many common features, from the morphological to the molecular level, we investigated the role of Ena/VASP proteins in angiogenesis. EVL and VASP, but not Mena, are expressed in endothelial cells of the postnatal mouse retina. Global deletion of EVL (but not VASP) compromises the radial sprouting of the vascular plexus in mice. Similarly, endothelial‐specific EVL deletion compromises the radial sprouting of the vascular plexus and reduces the endothelial tip cell density and filopodia formation. Gene sets involved in blood vessel development and angiogenesis are down‐regulated in EVL‐deficient P5‐retinal endothelial cells. Consistently, EVL deletion impairs VEGF‐induced endothelial cell proliferation and sprouting, and reduces the internalization and phosphorylation of VEGF receptor 2 and its downstream signaling via the MAPK/ERK pathway. Together, we show that endothelial EVL regulates sprouting angiogenesis via VEGF receptor‐2 internalization and signaling.
Collapse
Affiliation(s)
- Joana Zink
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Maike Frye
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Timo Frömel
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Claudia Carlantoni
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - David John
- German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany.,Insitute for Cardiovascular Regeneration, Goethe University, Frankfurt am Main, Germany
| | - Danny Schreier
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andreas Weigert
- Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University, Frankfurt am Main, Germany
| | - Hebatullah Laban
- Department of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Gabriela Salinas
- NGS-Integrative Genomics Core Unit (NIG), Institute of Human Genetics, University Medical Center Göttingen (UMG), Göttingen, Germany
| | - Heike Stingl
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Lea Günther
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Rüdiger Popp
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Jiong Hu
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Benoit Vanhollebeke
- Laboratory of Neurovascular Signaling, ULB Neuroscience Institute Department of Molecular Biology, University of Brussels, Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences, Goethe University, Frankfurt am Main, Germany
| | - Thomas Renné
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Fleming
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| | - Peter M Benz
- Centre for Molecular Medicine, Institute for Vascular Signalling, Goethe University, Frankfurt am Main, Germany.,German Centre of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany
| |
Collapse
|
3
|
Berthiaume AA, Hartmann DA, Majesky MW, Bhat NR, Shih AY. Pericyte Structural Remodeling in Cerebrovascular Health and Homeostasis. Front Aging Neurosci 2018; 10:210. [PMID: 30065645 PMCID: PMC6057109 DOI: 10.3389/fnagi.2018.00210] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/22/2018] [Indexed: 12/21/2022] Open
Abstract
The biology of brain microvascular pericytes is an active area of research and discovery, as their interaction with the endothelium is critical for multiple aspects of cerebrovascular function. There is growing evidence that pericyte loss or dysfunction is involved in the pathogenesis of Alzheimer’s disease, vascular dementia, ischemic stroke and brain injury. However, strategies to mitigate or compensate for this loss remain limited. In this review, we highlight a novel finding that pericytes in the adult brain are structurally dynamic in vivo, and actively compensate for loss of endothelial coverage by extending their far-reaching processes to maintain contact with regions of exposed endothelium. Structural remodeling of pericytes may present an opportunity to foster pericyte-endothelial communication in the adult brain and should be explored as a potential means to counteract pericyte loss in dementia and cerebrovascular disease. We discuss the pathophysiological consequences of pericyte loss on capillary function, and the biochemical pathways that may control pericyte remodeling. We also offer guidance for observing pericytes in vivo, such that pericyte structural remodeling can be more broadly studied in mouse models of cerebrovascular disease.
Collapse
Affiliation(s)
- Andrée-Anne Berthiaume
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - David A Hartmann
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Mark W Majesky
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, United States.,Departments of Pediatrics and Pathology, University of Washington, Seattle, WA, United States
| | - Narayan R Bhat
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Andy Y Shih
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States.,Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, United States.,Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, United States
| |
Collapse
|
4
|
Prospéri MT, Lépine P, Dingli F, Paul-Gilloteaux P, Martin R, Loew D, Knölker HJ, Coudrier E. Myosin 1b functions as an effector of EphB signaling to control cell repulsion. J Cell Biol 2016. [PMID: 26195670 PMCID: PMC4508888 DOI: 10.1083/jcb.201501018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myosin 1b functions as an effector of EphB2/ephrinB signaling and controls cell morphology and cell repulsion. Eph receptors and their membrane-tethered ligands, the ephrins, have important functions in embryo morphogenesis and in adult tissue homeostasis. Eph/ephrin signaling is essential for cell segregation and cell repulsion. This process is accompanied by morphological changes and actin remodeling that drives cell segregation and tissue patterning. The actin cortex must be mechanically coupled to the plasma membrane to orchestrate the cell morphology changes. Here, we demonstrate that myosin 1b that can mechanically link the membrane to the actin cytoskeleton interacts with EphB2 receptors via its tail and is tyrosine phosphorylated on its tail in an EphB2-dependent manner. Myosin 1b regulates the redistribution of myosin II in actomyosin fibers and the formation of filopodia at the interface of ephrinB1 and EphB2 cells, which are two processes mediated by EphB2 signaling that contribute to cell repulsion. Together, our results provide the first evidence that a myosin 1 functions as an effector of EphB2/ephrinB signaling, controls cell morphology, and thereby cell repulsion.
Collapse
Affiliation(s)
| | - Priscilla Lépine
- Institut Curie, Centre de Recherche, F-75248 Paris, France Université Pierre et Marie Curie, F-75252 Paris, France
| | - Florent Dingli
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Centre de Recherche, F-75248 Paris, France
| | - Perrine Paul-Gilloteaux
- Institut Curie, Centre de Recherche, F-75248 Paris, France Cell and Tissue Imaging Facility (PICT-IBiSA), Centre National de la Recherche Scientifique, UMR 144, Paris F-75248, France
| | - René Martin
- Department of Chemistry, Technische Univesität, 01069 Dresden, Germany
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, Centre de Recherche, F-75248 Paris, France
| | | | - Evelyne Coudrier
- Institut Curie, Centre de Recherche, F-75248 Paris, France Cell and Tissue Imaging Facility (PICT-IBiSA), Centre National de la Recherche Scientifique, UMR 144, Paris F-75248, France
| |
Collapse
|
5
|
Drosophila Psidin regulates olfactory neuron number and axon targeting through two distinct molecular mechanisms. J Neurosci 2013; 32:16080-94. [PMID: 23152593 DOI: 10.1523/jneurosci.3116-12.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The formation of neuronal circuits is a key process of development, laying foundations for behavior. The cellular mechanisms regulating circuit development are not fully understood. Here, we reveal Psidin as an intracellular regulator of Drosophila olfactory system formation. We show that Psidin is required in several classes of olfactory receptor neurons (ORNs) for survival and subsequently for axon guidance. During axon guidance, Psidin functions as an actin regulator and antagonist of Tropomyosin. Accordingly, Psidin-deficient primary neurons in culture display growth cones with significantly smaller lamellipodia. This lamellipodial phenotype, as well as the mistargeting defects in vivo, is suppressed by parallel removal of Tropomyosin. In contrast, Psidin functions as the noncatalytic subunit of the N-acetyltransferase complex B (NatB) to maintain the number of ORNs. Psidin physically binds the catalytic NatB subunit CG14222 (dNAA20) and functionally interacts with it in vivo. We define the dNAA20 interaction domain within Psidin and identify a conserved serine as a candidate for phosphorylation-mediated regulation of NatB complex formation. A phosphomimetic mutation of this serine showed severely reduced binding to dNAA20 in vitro. In vivo, it fully rescued the targeting defect but not the reduction in neuron numbers. In addition, we show that a different amino acid point mutation shows exactly the opposite effect by rescuing only the cell number but not the axon targeting defect. Together, our data suggest that Psidin plays two independent developmental roles via the acquisition of separate signaling pathways, both of which contribute to the formation of olfactory circuits.
Collapse
|
6
|
Walsh R, Blumenberg M. Eph-2B, acting as an extracellular ligand, induces differentiation markers in epidermal keratinocytes. J Cell Physiol 2012; 227:2330-40. [PMID: 21809346 DOI: 10.1002/jcp.22968] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In the bi-directional signaling system comprising ephrins (EFNs) and ephrin receptors (Ephs), both EFNs and Ephs simultaneously function both as ligands and as receptors. Importantly, the EFN/Eph system is deregulated in human cancers and has been implicated in the metastatic processes because of its effects on the adhesion and migration of epithelial cells. The idiosyncratic function of Ephs, membrane-bound receptor kinases, as extracellular signaling ligands, has not been extensively studied. This prompted us to explore the transcriptional targets regulated by Ephs acting solely as ligands. To define the ligand function of EphB2 in human epidermal keratinocytes, we treated these cells with EphB2 as Fc-conjugate dimmers, which thus act exclusively as extracellular ligands. We compared the EphB2 and EFNA4 effects during a 48 h time course, using transcriptional profiling. We found that EphB2, acting as a ligand, promotes epidermal differentiation. For example, EphB2 induces expression of markers of epidermal differentiation, including keratins KRT1 and KRT10, SPRRs, desmosomal proteins and cell cycle inhibitors, while suppressing basal layer markers, integrins and cell cycle proteins. The effects of EphB2 are delayed relative to those of EFNA4. Unlike EFNA4, EphB2 did not induce lipid metabolism proteins, this particular aspect of epidermal differentiation seems not to be regulated by EphB2. Our results define the transcriptional targets of the reverse signaling by EphB2 acting exclusively as a ligand and begin to characterize this intriguing function of Ephs.
Collapse
Affiliation(s)
- Rebecca Walsh
- The Department of Dermatology, NYU Cancer Institute, NYU School of Medicine, New York 10016, USA
| | | |
Collapse
|
7
|
Marsick BM, Roche FK, Letourneau PC. Repulsive axon guidance cues ephrin-A2 and slit3 stop protrusion of the growth cone leading margin concurrently with inhibition of ADF/cofilin and ERM proteins. Cytoskeleton (Hoboken) 2012; 69:496-505. [PMID: 22328420 DOI: 10.1002/cm.21016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 02/01/2012] [Indexed: 11/08/2022]
Abstract
Axonal growth cones turn away from repulsive guidance cues. This may start with reduced protrusive motility in the region the growth cone leading margin that is closer to the source of repulsive cue. Using explants of E7 chick temporal retina, we examine the effects of two repulsive guidance cues, ephrin-A2 and slit3, on retinal ganglion cell growth cone protrusive activity, total F-actin, free F-actin barbed ends, and the activities (phosphorylation states) of actin regulatory proteins, ADF/cofilin and ezrin, radixin, moesin (ERM) proteins. Ephrin-A2 rapidly stops protrusive activity simultaneously with reducing F-actin, free barbed ends and the activities of ADF/cofilin and ERM proteins. Slit3 also stops protrusion and reduces the activities of ADF/cofilin and ERM proteins. We interpret these results as indicating that repulsive guidance cues inhibit actin polymerization and actin-membrane linkage to stop protrusive activity. Retrograde F-actin flow withdraws actin to the C-domain, where F-actin bundles interact with myosin II to generate contractile forces that can collapse and retract the growth cone. Our results suggest that common mechanisms are used by repulsive guidance cue to disable growth cone motility and remodel growing axon terminals.
Collapse
Affiliation(s)
- Bonnie M Marsick
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | |
Collapse
|
8
|
Mohamed AM, Boudreau JR, Yu FPS, Liu J, Chin-Sang ID. The Caenorhabditis elegans Eph receptor activates NCK and N-WASP, and inhibits Ena/VASP to regulate growth cone dynamics during axon guidance. PLoS Genet 2012; 8:e1002513. [PMID: 22383893 PMCID: PMC3285579 DOI: 10.1371/journal.pgen.1002513] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 12/13/2011] [Indexed: 01/18/2023] Open
Abstract
The Eph receptor tyrosine kinases (RTKs) are regulators of cell migration and axon guidance. However, our understanding of the molecular mechanisms by which Eph RTKs regulate these processes is still incomplete. To understand how Eph receptors regulate axon guidance in Caenorhabditis elegans, we screened for suppressors of axon guidance defects caused by a hyperactive VAB-1/Eph RTK. We identified NCK-1 and WSP-1/N-WASP as downstream effectors of VAB-1. Furthermore, VAB-1, NCK-1, and WSP-1 can form a complex in vitro. We also report that NCK-1 can physically bind UNC-34/Enabled (Ena), and suggest that VAB-1 inhibits the NCK-1/UNC-34 complex and negatively regulates UNC-34. Our results provide a model of the molecular events that allow the VAB-1 RTK to regulate actin dynamics for axon guidance. We suggest that VAB-1/Eph RTK can stop axonal outgrowth by inhibiting filopodia formation at the growth cone by activating Arp2/3 through a VAB-1/NCK-1/WSP-1 complex and by inhibiting UNC-34/Ena activity. The correct wiring of the nervous system depends on the ability of axons to properly interpret extracellular cues that guide them to their targets. The Eph receptor tyrosine kinases (RTKs) have roles in guiding axons, but their signaling pathways are not completely understood. In this study, we used the nematode Caenorhabditis elegans to study how the VAB-1 Eph RTK regulates the growth cone structure for axon guidance. Genetic and molecular data show that VAB-1 regulates the conserved molecules NCK-1, WSP-1/N-WASP, and UNC-34/Ena. Our study provides a model of how the VAB-1 Eph RTK modulates the growth cone structure to inhibit axonal outgrowth. We show that activated VAB-1 can inhibit an NCK-1/UNC-34 interaction by binding to the NCK-1 SH2 domain. We also show that NCK-1 and WSP-1 can physically interact and that VAB-1/NCK-1 and WSP-1 form a complex in vitro. We suggest that the VAB-1 Eph RTK can contribute to the termination of axon outgrowth by two methods: 1) The VAB-1/NCK-1/WSP-1 complex activates ARP-2/3 to change the actin growth cone dynamics to that of a branched structure thus reducing the number of filopodia, and 2) VAB-1 inhibits axon extension by inhibiting UNC-34/Ena's function in actin polymerization.
Collapse
Affiliation(s)
| | | | | | - Jun Liu
- Department of Biology, Queen's University, Kingston, Canada
| | - Ian D. Chin-Sang
- Department of Biology, Queen's University, Kingston, Canada
- * E-mail:
| |
Collapse
|
9
|
Walsh R, Blumenberg M. Specific and shared targets of ephrin A signaling in epidermal keratinocytes. J Biol Chem 2010; 286:9419-28. [PMID: 21193391 DOI: 10.1074/jbc.m110.197087] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Both ephrins (EFNs) and their receptors (Ephs) are membrane-bound, restricting their interactions to the sites of direct cell-to-cell interfaces. They are widely expressed, often co-expressed, and regulate developmental processes, cell adhesion, motility, survival, proliferation, and differentiation. Both tumor suppressor and oncogene activities are ascribed to EFNs and Ephs in various contexts. A major conundrum regarding the EFN/Eph system concerns their large number and functional redundancy given the promiscuous cross-activation of ligands and receptors and the overlapping intracellular signaling pathways. To address this issue, we treated human epidermal keratinocytes with five EFNAs individually and defined the transcriptional responses in the cells. We found that a large set of genes is coregulated by all EFNAs. However, although the responses to EFNA3, EFNA4, and EFNA5 are identical, the responses to EFNA1 and EFNA2 are characteristic and distinctive. All EFNAs induce epidermal differentiation markers and suppress cell adhesion genes, especially integrins. Ontological analysis showed that all EFNAs induce cornification and keratin genes while suppressing wound healing-associated, signaling, receptor, and extracellular matrix-associated genes. Transcriptional targets of AP1 are selectively suppressed by EFNAs. EFNA1 and EFNA2, but not the EFNA3, EFNA4, EFNA5 cluster, regulate the members of the ubiquitin-associated proteolysis genes. EFNA1 specifically induces collagen production. Our results demonstrate that the EFN-Eph interactions in the epidermis, although promiscuous, are not redundant but specific. This suggests that different members of the EFN/Eph system have specific, clearly demarcated functions.
Collapse
Affiliation(s)
- Rebecca Walsh
- Department of Dermatology and the New York University Cancer Institute, NYU School of Medicine, New York, New York 10016, USA
| | | |
Collapse
|
10
|
Petros TJ, Bryson JB, Mason C. Ephrin-B2 elicits differential growth cone collapse and axon retraction in retinal ganglion cells from distinct retinal regions. Dev Neurobiol 2010; 70:781-94. [PMID: 20629048 DOI: 10.1002/dneu.20821] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The circuit for binocular vision and stereopsis is established at the optic chiasm, where retinal ganglion cell (RGC) axons diverge into the ipsilateral and contralateral optic tracts. In the mouse retina, ventrotemporal (VT) RGCs express the guidance receptor EphB1, which interacts with the repulsive guidance cue ephrin-B2 on radial glia at the optic chiasm to direct VT RGC axons ipsilaterally. RGCs in the ventral retina also express EphB2, which interacts with ephrin-B2, whereas dorsal RGCs express low levels of EphB receptors. To investigate how growth cones of RGCs from different retinal regions respond upon initial contact with ephrin-B2, we utilized time-lapse imaging to characterize the effects of ephrin-B2 on growth cone collapse and axon retraction in real time. We demonstrate that bath application of ephrin-B2 induces rapid and sustained growth cone collapse and axon retraction in VT RGC axons, whereas contralaterally-projecting dorsotemporal RGCs display moderate growth cone collapse and little axon retraction. Dose response curves reveal that contralaterally-projecting ventronasal axons are less sensitive to ephrin-B2 treatment compared to VT axons. Additionally, we uncovered a specific role for Rho kinase signaling in the retraction of VT RGC axons but not in growth cone collapse. The detailed characterization of growth cone behavior in this study comprises an assay for the study of Eph signaling in RGCs, and provides insight into the phenomena of growth cone collapse and axon retraction in general.
Collapse
Affiliation(s)
- Timothy J Petros
- Department of Pathology and Cell Biology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
| | | | | |
Collapse
|
11
|
Tucker PK, Evans IR, Wood W. Ena drives invasive macrophage migration in Drosophila embryos. Dis Model Mech 2010; 4:126-34. [PMID: 21045209 PMCID: PMC3008967 DOI: 10.1242/dmm.005694] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is seldom the primary tumour that proves fatal in cancer, with metastasis the fundamental pathological process for disease progression. Upregulation of Mena, a member of the evolutionarily conserved Ena/VASP family of actin cytoskeletal regulators, promotes metastasis and invasive motility of breast cancer cells in vivo. To complement in vitro studies of Ena/VASP function in fibroblasts, we manipulated levels of Ena, the Drosophila homologue of Mena, in migrating embryonic macrophages (haemocytes). Consistent with data from fibroblasts in vitro, Ena localises to regions of actin dynamics within migrating haemocytes, stimulates lamellipodial dynamics and positively regulates the number and length of filopodia. However, whereas Ena overexpression in fibroblasts reduces migration speeds, overexpressing Ena in haemocytes leads to a dramatic increase in migration speeds, more closely resembling the increased motility of breast cancer cells that overexpress Mena. We provide evidence that this key difference is due to spatial constraints imposed on cells within the three-dimensional environment of the embryo; this might explain how Mena can be used to promote aggressive migratory behaviour during cancer progression.
Collapse
Affiliation(s)
- Philippa K Tucker
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | | | | |
Collapse
|
12
|
Reverse signaling via a glycosyl-phosphatidylinositol-linked ephrin prevents midline crossing by migratory neurons during embryonic development in Manduca. J Neurosci 2008; 28:3846-60. [PMID: 18400884 DOI: 10.1523/jneurosci.5691-07.2008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have investigated whether reverse signaling via a glycosyl-phosphatidylinositol (GPI)-linked ephrin controls the behavior of migratory neurons in vivo. During the formation of the enteric nervous system (ENS) in the moth Manduca, approximately 300 neurons [enteric plexus (EP) cells] migrate onto the midgut via bilaterally paired muscle bands but avoid adjacent midline regions. As they migrate, the EP cells express a single ephrin ligand (MsEphrin; a GPI-linked ligand), whereas the midline cells express the corresponding Eph receptor (MsEph). Blocking endogenous MsEphrin-MsEph receptor interactions in cultured embryos resulted in aberrant midline crossing by the neurons and their processes. In contrast, activating endogenous MsEphrin on the EP cells with dimeric MsEph-Fc constructs inhibited their migration and outgrowth, supporting a role for MsEphrin-dependent reverse signaling in this system. In short-term cultures, blocking endogenous MsEph receptors allowed filopodia from the growth cones of the neurons to invade the midline, whereas activating neuronal MsEphrin led to filopodial retraction. MsEphrin-dependent signaling may therefore guide the migratory enteric neurons by restricting the orientation of their leading processes. Knocking down MsEphrin expression in the EP cells with morpholino antisense oligonucleotides also induced aberrant midline crossing, consistent with the effects of blocking endogenous MsEphrin-MsEph interactions. Unexpectedly, this treatment enhanced the overall extent of migration, indicating that MsEphrin-dependent signaling may also modulate the general motility of the EP cells. These results demonstrate that MsEphrin-MsEph receptor interactions normally prevent midline crossing by migratory neurons within the developing ENS, an effect that is most likely mediated by reverse signaling through this GPI-linked ephrin ligand.
Collapse
|
13
|
Trichet L, Sykes C, Plastino J. Relaxing the actin cytoskeleton for adhesion and movement with Ena/VASP. ACTA ACUST UNITED AC 2008; 181:19-25. [PMID: 18378777 PMCID: PMC2287277 DOI: 10.1083/jcb.200710168] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
At cell–cell contacts, as well as at the leading edge of motile cells, the plasticity of actin structures is maintained, in part, through labile connections to the plasma membrane. Here we explain how and why Drosophila enabled/vasodilator stimulated phosphoprotein (Ena/VASP) proteins are candidates for driving this cytoskeleton modulation under the membrane.
Collapse
Affiliation(s)
- Léa Trichet
- Laboratoire Matière et Systèmes Complexes, Centre National de la Recherche Scientifique, Paris 7, 75205 Paris Cedex 13, France
| | | | | |
Collapse
|