1
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Bement WM, Goryachev AB, Miller AL, von Dassow G. Patterning of the cell cortex by Rho GTPases. Nat Rev Mol Cell Biol 2024; 25:290-308. [PMID: 38172611 DOI: 10.1038/s41580-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2023] [Indexed: 01/05/2024]
Abstract
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
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Affiliation(s)
- William M Bement
- Center for Quantitative Cell Imaging, Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Andrew B Goryachev
- Center for Engineering Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Ann L Miller
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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2
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López-Hidalgo R, Ballestín R, Lorenzo L, Sánchez-Martí S, Blasco-Ibáñez JM, Crespo C, Nacher J, Varea E. Early chronic fasudil treatment rescues hippocampal alterations in the Ts65Dn model for down syndrome. Neurochem Int 2024; 174:105679. [PMID: 38309665 DOI: 10.1016/j.neuint.2024.105679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/05/2024]
Abstract
Down syndrome (DS) is the most common genetic disorder associated with intellectual disability. To study this syndrome, several mouse models have been developed. Among the most common is the Ts65Dn model, which mimics most of the alterations observed in DS. Ts65Dn mice, as humans with DS, show defects in the structure, density, and distribution of dendritic spines in the cerebral cortex and hippocampus. Fasudil is a potent inhibitor of the RhoA kinase pathway, which is involved in the formation and stabilization of dendritic spines. Our study analysed the effect of early chronic fasudil treatment on the alterations observed in the hippocampus of the Ts65Dn model. We observed that treating Ts65Dn mice with fasudil induced an increase in neural plasticity in the hippocampus: there was an increment in the expression of PSA-NCAM and BDNF, in the dendritic branching and spine density of granule neurons, as well as in cell proliferation and neurogenesis in the subgranular zone. Finally, the treatment reduced the unbalance between excitation and inhibition present in this model. Overall, early chronic treatment with fasudil increases cell plasticity and eliminates differences with euploid animals.
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Affiliation(s)
- Rosa López-Hidalgo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Raúl Ballestín
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Lorena Lorenzo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Sandra Sánchez-Martí
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - José Miguel Blasco-Ibáñez
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Carlos Crespo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Juan Nacher
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain; CIBERSAM, Spanish National Network for Research in Mental Health, Madrid, Spain; Institute of research of the Clinic Hospital from Valencia (INCLIVA), Valencia, Spain
| | - Emilio Varea
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain.
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3
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Ledoux B, Zanin N, Yang J, Mercier V, Coster C, Dupont-Gillain C, Alsteens D, Morsomme P, Renard HF. Plasma membrane nanodeformations promote actin polymerization through CIP4/CDC42 recruitment and regulate type II IFN signaling. SCIENCE ADVANCES 2023; 9:eade1660. [PMID: 38091386 PMCID: PMC10848735 DOI: 10.1126/sciadv.ade1660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/10/2023] [Indexed: 12/18/2023]
Abstract
In their environment, cells must cope with mechanical stresses constantly. Among these, nanoscale deformations of plasma membrane induced by substrate nanotopography are now largely accepted as a biophysical stimulus influencing cell behavior and function. However, the mechanotransduction cascades involved and their precise molecular effects on cellular physiology are still poorly understood. Here, using homemade fluorescent nanostructured cell culture surfaces, we explored the role of Bin/Amphiphysin/Rvs (BAR) domain proteins as mechanosensors of plasma membrane geometry. Our data reveal that distinct subsets of BAR proteins bind to plasma membrane deformations in a membrane curvature radius-dependent manner. Furthermore, we show that membrane curvature promotes the formation of dynamic actin structures mediated by the Rho GTPase CDC42, the F-BAR protein CIP4, and the presence of PI(4,5)P2. In addition, these actin-enriched nanodomains can serve as platforms to regulate receptor signaling as they appear to contain interferon-γ receptor (IFNγ-R) and to lead to the partial inhibition of IFNγ-induced JAK/STAT signaling.
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Affiliation(s)
- Benjamin Ledoux
- UCLouvain, Louvain Institute of Biomolecular Science and Technology, Group of Molecular Physiology, Croix du Sud 4-5 bte L7.07.14, Louvain-la-Neuve 1348, Belgium
- UCLouvain, Louvain Institute of Biomolecular Science and Technology, NanoBiophysics lab, Croix du Sud 4-5 bte L7.07.07, Louvain-la-Neuve 1348, Belgium
- UNamur, Morph-Im platform, Rue de Bruxelles 61, Namur 5000, Belgium
| | - Natacha Zanin
- UNamur, NAmur Research Institute for LIfe Sciences, Unité de Recherche en Biologie Cellulaire animale, Rue de Bruxelles 61, Namur 5000, Belgium
| | - Jinsung Yang
- Gyeongsang National University, Department of Biochemistry, College of Medicine, Department of Convergence Medical Sciences, Institute of Medical Science, Jinju 52727, South Korea
| | - Vincent Mercier
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Charlotte Coster
- UCLouvain, Louvain Institute of Biomolecular Science and Technology, Group of Molecular Physiology, Croix du Sud 4-5 bte L7.07.14, Louvain-la-Neuve 1348, Belgium
| | - Christine Dupont-Gillain
- UCLouvain, Institute of Condensed Matter and Nanosciences, Bio- and Soft Matter, Place Louis Pasteur 1 bte L4.01.10, Louvain-la-Neuve 1348, Belgium
| | - David Alsteens
- UCLouvain, Louvain Institute of Biomolecular Science and Technology, NanoBiophysics lab, Croix du Sud 4-5 bte L7.07.07, Louvain-la-Neuve 1348, Belgium
| | - Pierre Morsomme
- UCLouvain, Louvain Institute of Biomolecular Science and Technology, Group of Molecular Physiology, Croix du Sud 4-5 bte L7.07.14, Louvain-la-Neuve 1348, Belgium
| | - Henri-François Renard
- UNamur, Morph-Im platform, Rue de Bruxelles 61, Namur 5000, Belgium
- UNamur, NAmur Research Institute for LIfe Sciences, Unité de Recherche en Biologie Cellulaire animale, Rue de Bruxelles 61, Namur 5000, Belgium
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4
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A current overview of RhoA, RhoB, and RhoC functions in vascular biology and pathology. Biochem Pharmacol 2022; 206:115321. [DOI: 10.1016/j.bcp.2022.115321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
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5
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Chau JE, Vish KJ, Boggon TJ, Stiegler AL. SH3 domain regulation of RhoGAP activity: Crosstalk between p120RasGAP and DLC1 RhoGAP. Nat Commun 2022; 13:4788. [PMID: 35970859 PMCID: PMC9378701 DOI: 10.1038/s41467-022-32541-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/04/2022] [Indexed: 11/10/2022] Open
Abstract
RhoGAP proteins are key regulators of Rho family GTPases and influence a variety of cellular processes, including cell migration, adhesion, and cytokinesis. These GTPase activating proteins (GAPs) downregulate Rho signaling by binding and enhancing the intrinsic GTPase activity of Rho proteins. Deleted in liver cancer 1 (DLC1) is a tumor suppressor and ubiquitously expressed RhoGAP protein; its activity is regulated in part by binding p120RasGAP, a GAP protein for the Ras GTPases. In this study, we report the co-crystal structure of the p120RasGAP SH3 domain bound directly to DLC1 RhoGAP, at a site partially overlapping the RhoA binding site and impinging on the catalytic arginine finger. We demonstrate biochemically that mutation of this interface relieves inhibition of RhoGAP activity by the SH3 domain. These results reveal the mechanism for inhibition of DLC1 RhoGAP activity by p120RasGAP and demonstrate the molecular basis for direct SH3 domain modulation of GAP activity.
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Affiliation(s)
- Jocelyn E Chau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kimberly J Vish
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA.
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6
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A novel partial duplication in OPHN1, associated with vermis cerebellar hypoplasia, seizures and developmental delay. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Fixing the GAP: the role of RhoGAPs in cancer. Eur J Cell Biol 2022; 101:151209. [DOI: 10.1016/j.ejcb.2022.151209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/29/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022] Open
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8
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Liaci C, Camera M, Caslini G, Rando S, Contino S, Romano V, Merlo GR. Neuronal Cytoskeleton in Intellectual Disability: From Systems Biology and Modeling to Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22116167. [PMID: 34200511 PMCID: PMC8201358 DOI: 10.3390/ijms22116167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/25/2021] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
Intellectual disability (ID) is a pathological condition characterized by limited intellectual functioning and adaptive behaviors. It affects 1–3% of the worldwide population, and no pharmacological therapies are currently available. More than 1000 genes have been found mutated in ID patients pointing out that, despite the common phenotype, the genetic bases are highly heterogeneous and apparently unrelated. Bibliomic analysis reveals that ID genes converge onto a few biological modules, including cytoskeleton dynamics, whose regulation depends on Rho GTPases transduction. Genetic variants exert their effects at different levels in a hierarchical arrangement, starting from the molecular level and moving toward higher levels of organization, i.e., cell compartment and functions, circuits, cognition, and behavior. Thus, cytoskeleton alterations that have an impact on cell processes such as neuronal migration, neuritogenesis, and synaptic plasticity rebound on the overall establishment of an effective network and consequently on the cognitive phenotype. Systems biology (SB) approaches are more focused on the overall interconnected network rather than on individual genes, thus encouraging the design of therapies that aim to correct common dysregulated biological processes. This review summarizes current knowledge about cytoskeleton control in neurons and its relevance for the ID pathogenesis, exploiting in silico modeling and translating the implications of those findings into biomedical research.
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Affiliation(s)
- Carla Liaci
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Mattia Camera
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Giovanni Caslini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Simona Rando
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
| | - Salvatore Contino
- Department of Engineering, University of Palermo, Viale delle Scienze Ed. 8, 90128 Palermo, Italy;
| | - Valentino Romano
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Ed. 16, 90128 Palermo, Italy;
| | - Giorgio R. Merlo
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Via Nizza 52, 10126 Torino, Italy; (C.L.); (M.C.); (G.C.); (S.R.)
- Correspondence: ; Tel.: +39-0116706449; Fax: +39-0116706432
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9
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Altered Cl - homeostasis hinders forebrain GABAergic interneuron migration in a mouse model of intellectual disability. Proc Natl Acad Sci U S A 2021; 118:2016034118. [PMID: 33376209 DOI: 10.1073/pnas.2016034118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Impairments of inhibitory circuits are at the basis of most, if not all, cognitive deficits. The impact of OPHN1, a gene associate with intellectual disability (ID), on inhibitory neurons remains elusive. We addressed this issue by analyzing the postnatal migration of inhibitory interneurons derived from the subventricular zone in a validated mouse model of ID (OPHN1-/y mice). We found that the speed and directionality of migrating neuroblasts were deeply perturbed in OPHN1-/y mice. The significant reduction in speed was due to altered chloride (Cl-) homeostasis, while the overactivation of the OPHN1 downstream signaling pathway, RhoA kinase (ROCK), caused abnormalities in the directionality of the neuroblast progression in mutants. Blocking the cation-Cl- cotransporter KCC2 almost completely rescued the migration speed while proper directionality was restored upon ROCK inhibition. Our data unveil a strong impact of OPHN1 on GABAergic inhibitory interneurons and identify putative targets for successful therapeutic approaches.
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10
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Kim S, Kim J, Park S, Park JJ, Lee S. Drosophila Graf regulates mushroom body β-axon extension and olfactory long-term memory. Mol Brain 2021; 14:73. [PMID: 33892766 PMCID: PMC8067379 DOI: 10.1186/s13041-021-00782-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/15/2021] [Indexed: 11/10/2022] Open
Abstract
Loss-of-function mutations in the human oligophrenin-1 (OPHN1) gene cause intellectual disability, a prevailing neurodevelopmental condition. However, the role OPHN1 plays during neuronal development is not well understood. We investigated the role of the Drosophila OPHN1 ortholog Graf in the development of the mushroom body (MB), a key brain structure for learning and memory in insects. We show that loss of Graf causes abnormal crossing of the MB β lobe over the brain midline during metamorphosis. This defect in Graf mutants is rescued by MB-specific expression of Graf and OPHN1. Furthermore, MB α/β neuron-specific RNA interference experiments and mosaic analyses indicate that Graf acts via a cell-autonomous mechanism. Consistent with the negative regulation of epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) signaling by Graf, activation of this pathway is required for the β-lobe midline-crossing phenotype of Graf mutants. Finally, Graf mutants have impaired olfactory long-term memory. Our findings reveal a role for Graf in MB axon development and suggest potential neurodevelopmental functions of human OPHN1.
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Affiliation(s)
- Sungdae Kim
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, 08826, Republic of Korea
| | - Joohyung Kim
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sunyoung Park
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, 08826, Republic of Korea
| | - Joong-Jean Park
- Department of Physiology, College of Medicine, Korea University, Seoul, 02841, Republic of Korea
| | - Seungbok Lee
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, 08826, Republic of Korea.
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11
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Oligophrenin-1 moderates behavioral responses to stress by regulating parvalbumin interneuron activity in the medial prefrontal cortex. Neuron 2021; 109:1636-1656.e8. [PMID: 33831348 DOI: 10.1016/j.neuron.2021.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 02/09/2021] [Accepted: 03/10/2021] [Indexed: 12/28/2022]
Abstract
Ample evidence indicates that individuals with intellectual disability (ID) are at increased risk of developing stress-related behavioral problems and mood disorders, yet a mechanistic explanation for such a link remains largely elusive. Here, we focused on characterizing the syndromic ID gene oligophrenin-1 (OPHN1). We find that Ophn1 deficiency in mice markedly enhances helpless/depressive-like behavior in the face of repeated/uncontrollable stress. Strikingly, Ophn1 deletion exclusively in parvalbumin (PV) interneurons in the prelimbic medial prefrontal cortex (PL-mPFC) is sufficient to induce helplessness. This behavioral phenotype is mediated by a diminished excitatory drive onto Ophn1-deficient PL-mPFC PV interneurons, leading to hyperactivity in this region. Importantly, suppressing neuronal activity or RhoA/Rho-kinase signaling in the PL-mPFC reverses helpless behavior. Our results identify OPHN1 as a critical regulator of adaptive behavioral responses to stress and shed light onto the mechanistic links among OPHN1 genetic deficits, mPFC circuit dysfunction, and abnormalities in stress-related behaviors.
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12
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Nuovo S, Brankovic V, Caputi C, Casella A, Nigro V, Leuzzi V, Valente EM. Novel unconventional variants expand the allelic spectrum of OPHN1 gene. Am J Med Genet A 2021; 185:1575-1581. [PMID: 33638601 DOI: 10.1002/ajmg.a.62144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/01/2021] [Accepted: 02/13/2021] [Indexed: 11/08/2022]
Abstract
Mutations in the OPHN1 gene cause a rare X-linked recessive neurodevelopmental disorder characterized by intellectual disability, variably associated with cerebellar hypoplasia and distinctive facial appearance. In most of cases so far reported, the identified genomic variants involve the region encoding the central RhoGAP domain of the oligophrenin-1 protein, and are predicted to result in a complete loss of function. By using a NGS-based diagnostic approach, we identified three male and a female patients from two unrelated families carrying novel non-disruptive OPHN1 variants (the in-frame c.116_127 deletion and the missense c.2129C>T change, respectively), affecting either the BAR domain or the C-terminus proline-rich domain of the protein. Clinical and neuroimaging findings in the patients recapitulated the main features of OPHN1-related syndrome, including developmental delay, intellectual disability, behavioral disorder, dysmorphic features, seizures, cerebellar hypoplasia, and ventriculomegaly. Yet, we observed a wide variability even among affected siblings, confirming the lack of clear genotype-phenotype correlation. Our results expand the allelic spectrum of OPHN1 and illustrate the challenges for clinical interpretation of non-disruptive variants affecting X-linked genes.
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Affiliation(s)
- Sara Nuovo
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Vesna Brankovic
- Clinic for Child Neurology and Psychiatry, University of Belgrade, Belgrade, Serbia
| | - Caterina Caputi
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Antonella Casella
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,IRCCS Mondino Foundation, Pavia, Italy
| | - Vincenzo Nigro
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy.,Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Enza Maria Valente
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,IRCCS Mondino Foundation, Pavia, Italy
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13
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Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics. Cells 2020; 9:cells9040835. [PMID: 32244264 PMCID: PMC7226772 DOI: 10.3390/cells9040835] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/22/2020] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed.
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14
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ROCK/PKA Inhibition Rescues Hippocampal Hyperexcitability and GABAergic Neuron Alterations in a Oligophrenin-1 Knock-Out Mouse Model of X-Linked Intellectual Disability. J Neurosci 2020; 40:2776-2788. [PMID: 32098904 DOI: 10.1523/jneurosci.0462-19.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 01/28/2020] [Accepted: 02/03/2020] [Indexed: 01/19/2023] Open
Abstract
Oligophrenin-1 (Ophn1) encodes a Rho GTPase activating protein whose mutations cause X-linked intellectual disability (XLID) in humans. Loss of function of Ophn1 leads to impairments in the maturation and function of excitatory and inhibitory synapses, causing deficits in synaptic structure, function and plasticity. Epilepsy is a frequent comorbidity in patients with Ophn1-dependent XLID, but the cellular bases of hyperexcitability are poorly understood. Here we report that male mice knock-out (KO) for Ophn1 display hippocampal epileptiform alterations, which are associated with changes in parvalbumin-, somatostatin- and neuropeptide Y-positive interneurons. Because loss of function of Ophn1 is related to enhanced activity of Rho-associated protein kinase (ROCK) and protein kinase A (PKA), we attempted to rescue Ophn1-dependent pathological phenotypes by treatment with the ROCK/PKA inhibitor fasudil. While acute administration of fasudil had no impact on seizure activity, seven weeks of treatment in adulthood were able to correct electrographic, neuroanatomical and synaptic alterations of Ophn1 deficient mice. These data demonstrate that hyperexcitability and the associated changes in GABAergic markers can be rescued at the adult stage in Ophn1-dependent XLID through ROCK/PKA inhibition.SIGNIFICANCE STATEMENT In this study we demonstrate enhanced seizure propensity and impairments in hippocampal GABAergic circuitry in Ophn1 mouse model of X-linked intellectual disability (XLID). Importantly, the enhanced susceptibility to seizures, accompanied by an alteration of GABAergic markers were rescued by Rho-associated protein kinase (ROCK)/protein kinase A (PKA) inhibitor fasudil, a drug already tested on humans. Because seizures can significantly impact the quality of life of XLID patients, the present data suggest a potential therapeutic pathway to correct alterations in GABAergic networks and dampen pathological hyperexcitability in adults with XLID.
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15
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Pillet LE, Cresto N, Saillour Y, Ghézali G, Bemelmans AP, Livet J, Bienvenu T, Rouach N, Billuart P. The intellectual disability protein Oligophrenin-1 controls astrocyte morphology and migration. Glia 2020; 68:1729-1742. [PMID: 32073702 DOI: 10.1002/glia.23801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 02/06/2023]
Abstract
Astrocytes are involved in several aspects of neuronal development and properties which are altered in intellectual disability (ID). Oligophrenin-1 is a RhoGAP protein implicated in actin cytoskeleton regulation, and whose mutations are associated with X-linked ID. Oligophrenin-1 is expressed in neurons, where its functions have been widely reported at the synapse, as well as in glial cells. However, its roles in astrocytes are still largely unexplored. Using in vitro and in vivo models of oligophrenin1 disruption in astrocytes, we found that oligophrenin1 regulates at the molecular level the RhoA/ROCK/MLC2 pathway in astroglial cells. We also showed at the cellular level that oligophrenin1 modulates astrocyte morphology and migration both in vitro and in vivo, and is involved in glial scar formation. Altogether, these data suggest that oligophrenin1 deficiency alters not only neuronal but also astrocytic functions, which might contribute to the development of ID.
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Affiliation(s)
- Laure-Elise Pillet
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°562, Paris Descartes University, Paris, France.,Institut Cochin, INSERM UMR 1016, CNRS UMR 8104, Université de Paris, Paris, France
| | - Noémie Cresto
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Yoann Saillour
- Institut Cochin, INSERM UMR 1016, CNRS UMR 8104, Université de Paris, Paris, France
| | - Grégory Ghézali
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Alexis-Pierre Bemelmans
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale, Institut de biologie François Jacob, MIRCen, and CNRS UMR 9199, Université Paris-Sud, Neurodegenerative Diseases Laboratory, Fontenay-aux-Roses, France
| | - Jean Livet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Thierry Bienvenu
- Institut Cochin, INSERM UMR 1016, CNRS UMR 8104, Université de Paris, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Pierre Billuart
- Institut Cochin, INSERM UMR 1016, CNRS UMR 8104, Université de Paris, Paris, France
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Gasilina A, Vitali T, Luo R, Jian X, Randazzo PA. The ArfGAP ASAP1 Controls Actin Stress Fiber Organization via Its N-BAR Domain. iScience 2019; 22:166-180. [PMID: 31785555 PMCID: PMC6889188 DOI: 10.1016/j.isci.2019.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/30/2019] [Accepted: 11/06/2019] [Indexed: 12/11/2022] Open
Abstract
ASAP1 is a multi-domain ArfGAP that controls cell migration, spreading, and focal adhesion dynamics. Although its GAP activity contributes to remodeling of the actin cytoskeleton, it does not fully explain all cellular functions of ASAP1. Here we find that ASAP1 regulates actin filament assembly directly through its N-BAR domain and controls stress fiber maintenance. ASAP1 depletion caused defects in stress fiber organization. Conversely, overexpression of ASAP1 enhanced actin remodeling. The BAR-PH fragment was sufficient to affect actin. ASAP1 with the BAR domain replaced with the BAR domain of the related ACAP1 did not affect actin. The BAR-PH tandem of ASAP1 bound and bundled actin filaments directly, whereas the presence of the ArfGAP and the C-terminal linker/SH3 domain reduced binding and bundling of filaments by BAR-PH. Together these data provide evidence that ASAP1 may regulate the actin cytoskeleton through direct interaction of the BAR-PH domain with actin filaments.
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Affiliation(s)
- Anjelika Gasilina
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA; Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC 20007, USA
| | - Teresa Vitali
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Ruibai Luo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Xiaoying Jian
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Section on Regulation of Ras Superfamily, Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bldg. 37, Rm. 2042, Bethesda, MD 20892, USA.
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BAR domain proteins-a linkage between cellular membranes, signaling pathways, and the actin cytoskeleton. Biophys Rev 2018; 10:1587-1604. [PMID: 30456600 DOI: 10.1007/s12551-018-0467-7] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 10/17/2018] [Indexed: 12/23/2022] Open
Abstract
Actin filament assembly typically occurs in association with cellular membranes. A large number of proteins sit at the interface between actin networks and membranes, playing diverse roles such as initiation of actin polymerization, modulation of membrane curvature, and signaling. Bin/Amphiphysin/Rvs (BAR) domain proteins have been implicated in all of these functions. The BAR domain family of proteins comprises a diverse group of multi-functional effectors, characterized by their modular architecture. In addition to the membrane-curvature sensing/inducing BAR domain module, which also mediates antiparallel dimerization, most contain auxiliary domains implicated in protein-protein and/or protein-membrane interactions, including SH3, PX, PH, RhoGEF, and RhoGAP domains. The shape of the BAR domain itself varies, resulting in three major subfamilies: the classical crescent-shaped BAR, the more extended and less curved F-BAR, and the inverse curvature I-BAR subfamilies. Most members of this family have been implicated in cellular functions that require dynamic remodeling of the actin cytoskeleton, such as endocytosis, organelle trafficking, cell motility, and T-tubule biogenesis in muscle cells. Here, we review the structure and function of mammalian BAR domain proteins and the many ways in which they are interconnected with the actin cytoskeleton.
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Rho GTPases in Intellectual Disability: From Genetics to Therapeutic Opportunities. Int J Mol Sci 2018; 19:ijms19061821. [PMID: 29925821 PMCID: PMC6032284 DOI: 10.3390/ijms19061821] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/14/2018] [Accepted: 06/16/2018] [Indexed: 12/22/2022] Open
Abstract
Rho-class small GTPases are implicated in basic cellular processes at nearly all brain developmental steps, from neurogenesis and migration to axon guidance and synaptic plasticity. GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Rho GTPases are highly regulated by a complex set of activating (GEFs) and inactivating (GAPs) partners, via protein:protein interactions (PPI). Misregulated RhoA, Rac1/Rac3 and cdc42 activity has been linked with intellectual disability (ID) and other neurodevelopmental conditions that comprise ID. All genetic evidences indicate that in these disorders the RhoA pathway is hyperactive while the Rac1 and cdc42 pathways are consistently hypoactive. Adopting cultured neurons for in vitro testing and specific animal models of ID for in vivo examination, the endophenotypes associated with these conditions are emerging and include altered neuronal networking, unbalanced excitation/inhibition and altered synaptic activity and plasticity. As we approach a clearer definition of these phenotype(s) and the role of hyper- and hypo-active GTPases in the construction of neuronal networks, there is an increasing possibility that selective inhibitors and activators might be designed via PPI, or identified by screening, that counteract the misregulation of small GTPases and result in alleviation of the cognitive condition. Here we review all knowledge in support of this possibility.
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Joensuu M, Lanoue V, Hotulainen P. Dendritic spine actin cytoskeleton in autism spectrum disorder. Prog Neuropsychopharmacol Biol Psychiatry 2018; 84:362-381. [PMID: 28870634 DOI: 10.1016/j.pnpbp.2017.08.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/21/2017] [Accepted: 08/30/2017] [Indexed: 01/01/2023]
Abstract
Dendritic spines are small actin-rich protrusions from neuronal dendrites that form the postsynaptic part of most excitatory synapses. Changes in the shape and size of dendritic spines correlate with the functional changes in excitatory synapses and are heavily dependent on the remodeling of the underlying actin cytoskeleton. Recent evidence implicates synapses at dendritic spines as important substrates of pathogenesis in neuropsychiatric disorders, including autism spectrum disorder (ASD). Although synaptic perturbations are not the only alterations relevant for these diseases, understanding the molecular underpinnings of the spine and synapse pathology may provide insight into their etiologies and could reveal new drug targets. In this review, we will discuss recent findings of defective actin regulation in dendritic spines associated with ASD.
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Affiliation(s)
- Merja Joensuu
- Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland; Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Vanessa Lanoue
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Pirta Hotulainen
- Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland.
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Moortgat S, Lederer D, Deprez M, Buzatu M, Clapuyt P, Boulanger S, Benoit V, Mary S, Guichet A, Ziegler A, Colin E, Bonneau D, Maystadt I. Expanding the phenotypic spectrum associated with OPHN1 mutations: Report of 17 individuals with intellectual disability but no cerebellar hypoplasia. Eur J Med Genet 2018; 61:442-450. [PMID: 29510240 DOI: 10.1016/j.ejmg.2018.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 03/02/2018] [Accepted: 03/02/2018] [Indexed: 01/20/2023]
Abstract
Mutations in the oligophrenin 1 gene (OPHN1) have been identified in patients with X-linked intellectual disability (XLID) associated with cerebellar hypoplasia and ventriculomegaly, suggesting it could be a recognizable syndromic intellectual disability (ID). Affected individuals share additional clinical features including speech delay, seizures, strabismus, behavioral difficulties, and slight facial dysmorphism. OPHN1 is located in Xq12 and encodes a Rho-GTPase-activating protein involved in the regulation of the G-protein cycle. Rho protein members play an important role in dendritic growth and in plasticity of excitatory synapses. Here we report on 17 individuals from four unrelated families affected by mild to severe intellectual disability due to OPHN1 mutations without cerebellar anomaly on brain MRI. We describe clinical, genetic and neuroimaging data of affected patients. Among the identified OPHN1 mutations, we report for the first time a missense mutation occurring in a mosaic state. We discuss the intrafamilial clinical variability of the disease and compare our patients with those previously reported. We emphasize the power of next generation techniques (X-exome sequencing, whole-exome sequencing and targeted multi-gene panel) to expand the phenotypic and mutational spectrum of OPHN1-related ID.
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Affiliation(s)
- Stéphanie Moortgat
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium.
| | - Damien Lederer
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium
| | - Marie Deprez
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium; Département de Neuro-pédiatrie, Clinique Sainte-Elisabeth, Namur, Belgium
| | - Marga Buzatu
- Département de Neuro-pédiatrie, Hôpital Civil Marie Curie, Charleroi, Belgium
| | - Philippe Clapuyt
- Department of Radiology, Pediatric Imaging Unit, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Sébastien Boulanger
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium
| | - Valérie Benoit
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium
| | - Sandrine Mary
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium
| | - Agnès Guichet
- Department of Biochemistry and Genetics, Angers University Hospital, and UMR INSERM 1083, CNRS 6015, Angers, France
| | - Alban Ziegler
- Department of Biochemistry and Genetics, Angers University Hospital, and UMR INSERM 1083, CNRS 6015, Angers, France
| | - Estelle Colin
- Department of Biochemistry and Genetics, Angers University Hospital, and UMR INSERM 1083, CNRS 6015, Angers, France
| | - Dominique Bonneau
- Department of Biochemistry and Genetics, Angers University Hospital, and UMR INSERM 1083, CNRS 6015, Angers, France
| | - Isabelle Maystadt
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Charleroi, Gosselies, Belgium
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Ringer P, Colo G, Fässler R, Grashoff C. Sensing the mechano-chemical properties of the extracellular matrix. Matrix Biol 2017; 64:6-16. [DOI: 10.1016/j.matbio.2017.03.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 03/29/2017] [Accepted: 03/30/2017] [Indexed: 12/13/2022]
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22
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The minor histocompatibility antigen 1 (HMHA1)/ArhGAP45 is a RacGAP and a novel regulator of endothelial integrity. Vascul Pharmacol 2017; 101:38-47. [PMID: 29174013 DOI: 10.1016/j.vph.2017.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/14/2017] [Accepted: 11/18/2017] [Indexed: 12/25/2022]
Abstract
Endothelial cells line the vasculature and act as gatekeepers that control the passage of plasma, macromolecules and cells from the circulation to the interstitial space. Dysfunction of the endothelial barrier can lead to uncontrolled leak or edema. Vascular leakage is a hallmark of a range of diseases and despite its large impact no specialized therapies are available to prevent or reduce it. RhoGTPases are known key regulators of cellular behavior that are directly involved in the regulation of the endothelial barrier. We recently performed a comprehensive analysis of the effect of all RhoGTPases and their regulators on basal endothelial integrity. In addition to novel positive regulators of endothelial barrier function, we also identified novel negative regulators, of which the ArhGAP45 (also known as HMHA1) was the most significant. We now demonstrate that ArhGAP45 acts as a Rac-GAP (GTPase-Activating Protein) in endothelial cells, which explains its negative effect on endothelial barrier function. Silencing ArhGAP45 not only promotes basal endothelial barrier function, but also increases cellular surface area and induces sprout formation in a 3D-fibrin matrix. Our data further shows that loss of ArhGAP45 promotes migration and shear stress adaptation. In conclusion, we identify ArhGAP45 (HMHA1) as a novel regulator, which contributes to the fine-tuning of the regulation of basal endothelial integrity.
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Majoul IV, Ernesti JS, Butkevich EV, Duden R. Drebrins and Connexins: A Biomedical Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:225-247. [DOI: 10.1007/978-4-431-56550-5_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Redolfi N, Galla L, Maset A, Murru L, Savoia E, Zamparo I, Gritti A, Billuart P, Passafaro M, Lodovichi C. Oligophrenin-1 regulates number, morphology and synaptic properties of adult-born inhibitory interneurons in the olfactory bulb. Hum Mol Genet 2017; 25:5198-5211. [PMID: 27742778 DOI: 10.1093/hmg/ddw340] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 09/28/2016] [Indexed: 12/27/2022] Open
Abstract
Among the X-linked genes associated with intellectual disability, Oligophrenin-1 (OPHN1) encodes for a Rho GTPase-activating protein, a key regulator of several developmental processes, such as dendrite and spine formation and synaptic activity. Inhibitory interneurons play a key role in the development and function of neuronal circuits. Whether a mutation of OPHN1 can affect morphology and synaptic properties of inhibitory interneurons remains poorly understood. To address these open questions, we studied in a well-established mouse model of X-linked intellectual disability, i.e. a line of mice carrying a null mutation of OPHN1, the development and function of adult generated inhibitory interneurons in the olfactory bulb. Combining quantitative morphological analysis and electrophysiological recordings we found that the adult generated inhibitory interneurons were dramatically reduced in number and exhibited a higher proportion of filopodia-like spines, with the consequences on their synaptic function, in OPHN1 ko mice. Furthermore, we found that olfactory behaviour was perturbed in OPHN1 ko mice. Chronic treatment with a Rho kinase inhibitor rescued most of the defects of the newly generated neurons. Altogether, our data indicated that OPHN1 plays a key role in regulating the number, morphology and function of adult-born inhibitory interneurons and contributed to identify potential therapeutic targets.
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Affiliation(s)
- Nelly Redolfi
- Neuroscience Institute - CNR, Padova, Italy.,VIMM Padova, Italy
| | - Luisa Galla
- Neuroscience Institute - CNR, Padova, Italy.,VIMM Padova, Italy
| | | | - Luca Murru
- Neuroscience Institute, CNR, Milano, Italy
| | | | | | - Angela Gritti
- San Raffaele Telethon Institute for Gene Therapy (TIGET) Milano, Italy
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26
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Huang GH, Sun ZL, Li HJ, Feng DF. Rho GTPase-activating proteins: Regulators of Rho GTPase activity in neuronal development and CNS diseases. Mol Cell Neurosci 2017; 80:18-31. [PMID: 28163190 DOI: 10.1016/j.mcn.2017.01.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 01/06/2017] [Accepted: 01/29/2017] [Indexed: 12/22/2022] Open
Abstract
The Rho family of small GTPases was considered as molecular switches in regulating multiple cellular events, including cytoskeleton reorganization. The Rho GTPase-activating proteins (RhoGAPs) are one of the major families of Rho GTPase regulators. RhoGAPs were initially considered negative mediators of Rho signaling pathways via their GAP domain. Recent studies have demonstrated that RhoGAPs also regulate numerous aspects of neuronal development and are related to various neurodegenerative diseases in GAP-dependent and GAP-independent manners. Moreover, RhoGAPs are regulated through various mechanisms, such as phosphorylation. To date, approximately 70 RhoGAPs have been identified; however, only a small portion has been thoroughly investigated. Thus, the characterization of important RhoGAPs in the central nervous system is crucial to understand their spatiotemporal role during different stages of neuronal development. In this review, we summarize the current knowledge of RhoGAPs in the brain with an emphasis on their molecular function, regulation mechanism and disease implications in the central nervous system.
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Affiliation(s)
- Guo-Hui Huang
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Zhao-Liang Sun
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Hong-Jiang Li
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Dong-Fu Feng
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China; Institute of Traumatic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China.
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27
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Pharmacological rescue of adult hippocampal neurogenesis in a mouse model of X-linked intellectual disability. Neurobiol Dis 2017; 100:75-86. [PMID: 28088401 PMCID: PMC5346071 DOI: 10.1016/j.nbd.2017.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 12/23/2016] [Accepted: 01/10/2017] [Indexed: 01/17/2023] Open
Abstract
Oligophrenin-1 (OPHN1) is a Rho GTPase activating protein whose mutations cause X-linked intellectual disability (XLID). How loss of function of Ophn1 affects neuronal development is only partly understood. Here we have exploited adult hippocampal neurogenesis to dissect the steps of neuronal differentiation that are affected by Ophn1 deletion. We found that mice lacking Ophn1 display a reduction in the number of newborn neurons in the dentate gyrus. A significant fraction of the Ophn1-deficient newly generated neurons failed to extend an axon towards CA3, and showed an altered density of dendritic protrusions. Since Ophn1-deficient mice display overactivation of Rho-associated protein kinase (ROCK) and protein kinase A (PKA) signaling, we administered a clinically approved ROCK/PKA inhibitor (fasudil) to correct the neurogenesis defects. While administration of fasudil was not effective in rescuing axon formation, the same treatment completely restored spine density to control levels, and enhanced the long-term survival of adult-born neurons in mice lacking Ophn1. These results identify specific neurodevelopmental steps that are impacted by Ophn1 deletion, and indicate that they may be at least partially corrected by pharmacological treatment.
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28
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Amin E, Jaiswal M, Derewenda U, Reis K, Nouri K, Koessmeier KT, Aspenström P, Somlyo AV, Dvorsky R, Ahmadian MR. Deciphering the Molecular and Functional Basis of RHOGAP Family Proteins: A SYSTEMATIC APPROACH TOWARD SELECTIVE INACTIVATION OF RHO FAMILY PROTEINS. J Biol Chem 2016; 291:20353-71. [PMID: 27481945 PMCID: PMC5034035 DOI: 10.1074/jbc.m116.736967] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/15/2016] [Indexed: 12/30/2022] Open
Abstract
RHO GTPase-activating proteins (RHOGAPs) are one of the major classes of regulators of the RHO-related protein family that are crucial in many cellular processes, motility, contractility, growth, differentiation, and development. Using database searches, we extracted 66 distinct human RHOGAPs, from which 57 have a common catalytic domain capable of terminating RHO protein signaling by stimulating the slow intrinsic GTP hydrolysis (GTPase) reaction. The specificity of the majority of the members of RHOGAP family is largely uncharacterized. Here, we comprehensively investigated the sequence-structure-function relationship between RHOGAPs and RHO proteins by combining our in vitro data with in silico data. The activity of 14 representatives of the RHOGAP family toward 12 RHO family proteins was determined in real time. We identified and structurally verified hot spots in the interface between RHOGAPs and RHO proteins as critical determinants for binding and catalysis. We have found that the RHOGAP domain itself is nonselective and in some cases rather inefficient under cell-free conditions. Thus, we propose that other domains of RHOGAPs confer substrate specificity and fine-tune their catalytic efficiency in cells.
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Affiliation(s)
- Ehsan Amin
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Mamta Jaiswal
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Urszula Derewenda
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Katarina Reis
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Kazem Nouri
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Katja T Koessmeier
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Pontus Aspenström
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Avril V Somlyo
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Radovan Dvorsky
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
| | - Mohammad R Ahmadian
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
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29
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Oligophrenin1 protects mice against myocardial ischemia and reperfusion injury by modulating inflammation and myocardial apoptosis. Cell Signal 2016; 28:967-78. [DOI: 10.1016/j.cellsig.2016.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 04/11/2016] [Accepted: 04/21/2016] [Indexed: 12/12/2022]
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Oligophrenin-1 Connects Exocytotic Fusion to Compensatory Endocytosis in Neuroendocrine Cells. J Neurosci 2015; 35:11045-55. [PMID: 26245966 DOI: 10.1523/jneurosci.4048-14.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Oligophrenin-1 (OPHN1) is a protein with multiple domains including a Rho family GTPase-activating (Rho-GAP) domain, and a Bin-Amphiphysin-Rvs (BAR) domain. Involved in X-linked intellectual disability, OPHN1 has been reported to control several synaptic functions, including synaptic plasticity, synaptic vesicle trafficking, and endocytosis. In neuroendocrine cells, hormones and neuropeptides stored in large dense core vesicles (secretory granules) are released through calcium-regulated exocytosis, a process that is tightly coupled to compensatory endocytosis, allowing secretory granule recycling. We show here that OPHN1 is expressed and mainly localized at the plasma membrane and in the cytosol in chromaffin cells from adrenal medulla. Using carbon fiber amperometry, we found that exocytosis is impaired at the late stage of membrane fusion in Ophn1 knock-out mice and OPHN1-silenced bovine chromaffin cells. Experiments performed with ectopically expressed OPHN1 mutants indicate that OPHN1 requires its Rho-GAP domain to control fusion pore dynamics. On the other hand, compensatory endocytosis assessed by measuring dopamine-β-hydroxylase (secretory granule membrane) internalization is severely inhibited in Ophn1 knock-out chromaffin cells. This inhibitory effect is mimicked by the expression of a truncated OPHN1 mutant lacking the BAR domain, demonstrating that the BAR domain implicates OPHN1 in granule membrane recapture after exocytosis. These findings reveal for the first time that OPHN1 is a bifunctional protein that is able, through distinct mechanisms, to regulate and most likely link exocytosis to compensatory endocytosis in chromaffin cells.
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Kessels MM, Qualmann B. Different functional modes of BAR domain proteins in formation and plasticity of mammalian postsynapses. J Cell Sci 2015; 128:3177-85. [PMID: 26285709 DOI: 10.1242/jcs.174193] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A plethora of cell biological processes involve modulations of cellular membranes. By using extended lipid-binding interfaces, some proteins have the power to shape membranes by attaching to them. Among such membrane shapers, the superfamily of Bin-Amphiphysin-Rvs (BAR) domain proteins has recently taken center stage. Extensive structural work on BAR domains has revealed a common curved fold that can serve as an extended membrane-binding interface to modulate membrane topologies and has allowed the grouping of the BAR domain superfamily into subfamilies with structurally slightly distinct BAR domain subtypes (N-BAR, BAR, F-BAR and I-BAR). Most BAR superfamily members are expressed in the mammalian nervous system. Neurons are elaborately shaped and highly compartmentalized cells. Therefore, analyses of synapse formation and of postsynaptic reorganization processes (synaptic plasticity) - a basis for learning and memory formation - has unveiled important physiological functions of BAR domain superfamily members. These recent advances, furthermore, have revealed that the functions of BAR domain proteins include different aspects. These functions are influenced by the often complex domain organization of BAR domain proteins. In this Commentary, we review these recent insights and propose to classify BAR domain protein functions into (1) membrane shaping, (2) physical integration, (3) action through signaling components, and (4) suppression of other BAR domain functions.
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Affiliation(s)
- Michael M Kessels
- Institute of Biochemistry I, Jena University Hospital/Friedrich-Schiller-University, Nonnenplan 2-4, 07743 Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital/Friedrich-Schiller-University, Nonnenplan 2-4, 07743 Jena, Germany
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Elvers M. RhoGAPs and Rho GTPases in platelets. Hamostaseologie 2015; 36:168-77. [PMID: 25639730 DOI: 10.5482/hamo-14-09-0046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 01/13/2015] [Indexed: 01/03/2023] Open
Abstract
Platelet cytoskeletal reorganization is essential for platelet adhesion and thrombus formation in hemostasis and thrombosis. The Rho GTPases RhoA, Rac1 and Cdc42 are the main players in cytoskeletal dynamics of platelets responsible for the formation of filopodia and lamellipodia to strongly increase the platelet surface upon activation. They are involved in platelet activation and aggregate formation including platelet secretion, integrin activation and arterial thrombus formation. The activity of Rho GTPases is tightly controlled by different proteins such as GTPase-activating proteins (GAPs). GAPs stimulate GTP hydrolysis to terminate Rho signaling. The role and impact of GAPs in platelets is not well-defined and many of the RhoGAPs identified are not known to be present in platelets or to have any function in platelets. The recently identified RhoGAPs Oligophrenin1 (OPHN1) and Nadrin regulate the activity of RhoA, Rac1 and Cdc42 and subsequent platelet cytoskeletal reorganization, platelet activation and thrombus formation. In the last years, the analysis of genetically modified mice helped to gain the understanding of Rho GTPases and their regulators in cytoskeletal rearrangements and other Rho mediated cellular processes in platelets.
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Affiliation(s)
- Margitta Elvers
- Margitta Elvers, Ph.D., Department of Clinical and Experimental Hemostasis, Hemotherapy and Transfusion Medicine, Heinrich-Heine-University Duesseldorf, Moorenstr. 5, 40225 Duesseldorf, Germany, Tel. +49/(0)211/81-08851, Fax -17498., E-mail:
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Lefort R. Reversing synapse loss in Alzheimer's disease: Rho-guanosine triphosphatases and insights from other brain disorders. Neurotherapeutics 2015; 12:19-28. [PMID: 25588580 PMCID: PMC4322073 DOI: 10.1007/s13311-014-0328-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Alzheimer's disease (AD) is a monumental public health crisis with no effective cure or treatment. To date, therapeutic strategies have focused almost exclusively on upstream signaling events in the disease, namely on β-amyloid and amyloid precursor protein processing, and have, unfortunately, yielded few, if any, promising results. An alternative approach may be to target signaling events downstream of β-amyloid and even tau. However, with so many pathways already linked to the disease, understanding which ones are "drivers" versus "passengers" in the pathogenesis of the disease remains a tremendous challenge. Given the critical roles of Rho-guanosine triphosphatases (GTPases) in regulating the actin cytoskeleton and spine dynamics, and the strong association between spine abnormalities and cognition, it is not surprising that mutations in a number of genes involved in Rho-GTPase signaling have been implicated in several brain disorders, including schizophrenia and autism. And now, there is mounting literature implicating Rho-GTPase signaling in AD pathogenesis as well. Here, I review this evidence, with a particular emphasis on the regulators of Rho-GTPase signaling, namely guanine nucleotide exchange factors and GTPase-activating proteins. Several of these have been linked to various aspects of AD, and each offers a novel potential therapeutic target for AD.
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Affiliation(s)
- Roger Lefort
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, and Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, 10032, USA,
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34
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Goto K, Oue N, Hayashi T, Shinmei S, Sakamoto N, Sentani K, Teishima J, Matsubara A, Yasui W. Oligophrenin-1 is associated with cell adhesion and migration in prostate cancer. Pathobiology 2014; 81:190-8. [PMID: 25170626 DOI: 10.1159/000363345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 05/01/2014] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We performed Escherichia coli ampicillin secretion trap (CAST) analysis in prostate cancer (PCa) to identify novel biomarkers. We show here that OPHN1, which encodes oligophrenin-1 protein, is upregulated in PCa. OPHN1 was first determined to be one of the genes associated with X-linked mental retardation; however, neither the gene's function nor the link between its expression and survival of patients has been investigated. METHODS We investigate the expression of oligophrenin-1 in 141 PCa tissue samples by immunohistochemistry and perform functional analysis using RNA interference. RESULTS Immunohistochemical analysis of oligophrenin-1 demonstrated that 60 (43%) PCa cases were positive for oligophrenin-1. Positive oligophrenin-1 expression was significantly correlated with a high Gleason score (p = 0.0198). Furthermore, patients with oligophrenin-1-positive PCa had a worse biochemical recurrence-free survival rate than patients with oligophrenin-1-negative PCa (p = 0.0079). Cell adhesion to fibronectin was significantly reduced in OPHN1 small interfering (si)RNA-transfected LNCaP and PC3 cells in comparison to negative-control siRNA-transfected cells. Knockdown of OPHN1 reduced the expression of ITGA5 and stress fiber formation in LNCaP and PC3 cells. CONCLUSION These results suggest that oligophrenin-1 is involved in tumor progression in PCa.
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Affiliation(s)
- Keisuke Goto
- Department of Molecular Pathology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan
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35
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De Filippis B, Romano E, Laviola G. Aberrant Rho GTPases signaling and cognitive dysfunction: in vivo evidence for a compelling molecular relationship. Neurosci Biobehav Rev 2014; 46 Pt 2:285-301. [PMID: 24971827 DOI: 10.1016/j.neubiorev.2014.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 05/30/2014] [Accepted: 06/17/2014] [Indexed: 01/11/2023]
Abstract
Rho GTPases are key intracellular signaling molecules that coordinate dynamic changes in the actin cytoskeleton, thereby stimulating a variety of processes, including morphogenesis, migration, neuronal development, cell division and adhesion. Deviations from normal Rho GTPases activation state have been proposed to disrupt cognition and synaptic plasticity. This review focuses on the functional consequences of genetic ablation of upstream and downstream Rho GTPases molecules on cognitive function and neuronal morphology and connectivity. Available information on this issue is described and compared to that gained from mice carrying mutations in the most studied Rho GTPases and from pharmacological in vivo studies in which brain Rho GTPases signaling was modulated. Results from reviewed literature provide definitive evidence of a compelling link between Rho GTPases signaling and cognitive function, thus supporting the notion that Rho GTPases and their downstream effectors may represent important therapeutic targets for disorders associated with cognitive dysfunction.
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Affiliation(s)
- Bianca De Filippis
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy.
| | - Emilia Romano
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy; Bambino Gesù, Children Hospital, IRCCS, Roma, Italy
| | - Giovanni Laviola
- Sect. Behavioural Neuroscience, Department of Cell Biology & Neuroscience, Istituto Superiore di Sanità, Roma, Italy
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36
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Lamprecht R. The actin cytoskeleton in memory formation. Prog Neurobiol 2014; 117:1-19. [DOI: 10.1016/j.pneurobio.2014.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/02/2014] [Accepted: 02/03/2014] [Indexed: 01/21/2023]
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Powell AD, Saintot PP, Gill KK, Bharathan A, Buck SC, Morris G, Jiruska P, Jefferys JGR. Reduced gamma oscillations in a mouse model of intellectual disability: a role for impaired repetitive neurotransmission? PLoS One 2014; 9:e95871. [PMID: 24800744 PMCID: PMC4011727 DOI: 10.1371/journal.pone.0095871] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 04/01/2014] [Indexed: 11/19/2022] Open
Abstract
Intellectual disability affects 2-3% of the population; mutations of the X-chromosome are a major cause of moderate to severe cases. The link between the molecular consequences of the mutation and impaired cognitive function remains unclear. Loss of function mutations of oligophrenin-1 (OPHN1) disrupt Rho-GTPase signalling. Here we demonstrate abnormal neurotransmission at CA3 synapses in hippocampal slices from Ophn1-/y mice, resulting from a substantial decrease in the readily releasable pool of vesicles. As a result, synaptic transmission fails at high frequencies required for oscillations associated with cognitive functions. Both spontaneous and KA-induced gamma oscillations were reduced in Ophn1-/y hippocampal slices. Spontaneous oscillations were rapidly rescued by inhibition of the downstream signalling pathway of oligophrenin-1. These findings suggest that the intellectual disability due to mutations of oligophrenin-1 results from a synaptopathy and consequent network malfunction, providing a plausible mechanism for the learning disabilities. Furthermore, they raise the prospect of drug treatments for affected individuals.
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Affiliation(s)
- Andrew D. Powell
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail:
| | - Pierre-Philippe Saintot
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Kalbinder K. Gill
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ashtami Bharathan
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - S. Caroline Buck
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Gareth Morris
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Premysl Jiruska
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of Czech Republic, Prague, Czech Republic
- Department of Neurology, Charles University, 2 School of Medicine, Prague, Czech Republic
| | - John G. R. Jefferys
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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38
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Barresi S, Tomaselli S, Athanasiadis A, Galeano F, Locatelli F, Bertini E, Zanni G, Gallo A. Oligophrenin-1 (OPHN1), a gene involved in X-linked intellectual disability, undergoes RNA editing and alternative splicing during human brain development. PLoS One 2014; 9:e91351. [PMID: 24637888 PMCID: PMC3956665 DOI: 10.1371/journal.pone.0091351] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/11/2014] [Indexed: 12/25/2022] Open
Abstract
Oligophrenin-1 (OPHN1) encodes for a Rho-GTPase-activating protein, important for dendritic morphogenesis and synaptic function. Mutations in this gene have been identified in patients with X-linked intellectual disability associated with cerebellar hypoplasia. ADAR enzymes are responsible for A-to-I RNA editing, an essential post-transcriptional RNA modification contributing to transcriptome and proteome diversification. Specifically, ADAR2 activity is essential for brain development and function. Herein, we show that the OPHN1 transcript undergoes post-transcriptional modifications such as A-to-I RNA editing and alternative splicing in human brain and other tissues. We found that OPHN1 editing is detectable already at the 18th week of gestation in human brain with a boost of editing at weeks 20 to 33, concomitantly with OPHN1 expression increase and the appearance of a novel OPHN1 splicing isoform. Our results demonstrate that multiple post-transcriptional events occur on OPHN1, a gene playing an important role in brain function and development.
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Affiliation(s)
- Sabina Barresi
- Molecular Medicine Laboratory, Neurosciences Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Sara Tomaselli
- RNA Editing Laboratory, Oncohaematology Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | | | - Federica Galeano
- RNA Editing Laboratory, Oncohaematology Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Franco Locatelli
- RNA Editing Laboratory, Oncohaematology Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
- Università di Pavia, Pavia, Italy
| | - Enrico Bertini
- Molecular Medicine Laboratory, Neurosciences Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
| | - Ginevra Zanni
- Molecular Medicine Laboratory, Neurosciences Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
- * E-mail: (GZ); (AG)
| | - Angela Gallo
- RNA Editing Laboratory, Oncohaematology Department, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
- * E-mail: (GZ); (AG)
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39
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Jaiswal M, Dvorsky R, Amin E, Risse SL, Fansa EK, Zhang SC, Taha MS, Gauhar AR, Nakhaei-Rad S, Kordes C, Koessmeier KT, Cirstea IC, Olayioye MA, Häussinger D, Ahmadian MR. Functional cross-talk between ras and rho pathways: a Ras-specific GTPase-activating protein (p120RasGAP) competitively inhibits the RhoGAP activity of deleted in liver cancer (DLC) tumor suppressor by masking the catalytic arginine finger. J Biol Chem 2014; 289:6839-6849. [PMID: 24443565 DOI: 10.1074/jbc.m113.527655] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The three deleted in liver cancer genes (DLC1-3) encode Rho-specific GTPase-activating proteins (RhoGAPs). Their expression is frequently silenced in a variety of cancers. The RhoGAP activity, which is required for full DLC-dependent tumor suppressor activity, can be inhibited by the Src homology 3 (SH3) domain of a Ras-specific GAP (p120RasGAP). Here, we comprehensively investigated the molecular mechanism underlying cross-talk between two distinct regulators of small GTP-binding proteins using structural and biochemical methods. We demonstrate that only the SH3 domain of p120 selectively inhibits the RhoGAP activity of all three DLC isoforms as compared with a large set of other representative SH3 or RhoGAP proteins. Structural and mutational analyses provide new insights into a putative interaction mode of the p120 SH3 domain with the DLC1 RhoGAP domain that is atypical and does not follow the classical PXXP-directed interaction. Hence, p120 associates with the DLC1 RhoGAP domain by targeting the catalytic arginine finger and thus by competitively and very potently inhibiting RhoGAP activity. The novel findings of this study shed light on the molecular mechanisms underlying the DLC inhibitory effects of p120 and suggest a functional cross-talk between Ras and Rho proteins at the level of regulatory proteins.
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Affiliation(s)
- Mamta Jaiswal
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Ehsan Amin
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Sarah L Risse
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Eyad K Fansa
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Si-Cai Zhang
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Mohamed S Taha
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Aziz R Gauhar
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Saeideh Nakhaei-Rad
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Claus Kordes
- Clinic for Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University, 40225 Düsseldorf
| | - Katja T Koessmeier
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf
| | - Ion C Cirstea
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf; Leibniz Institute for Age Research, 07745 Jena
| | - Monilola A Olayioye
- Institute of Cell Biology and Immunology, University of Stuttgart, 70569 Stuttgart, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University, 40225 Düsseldorf
| | - Mohammad R Ahmadian
- Institute of Biochemistry and Molecular Biology II, Heinrich Heine University, 40225 Düsseldorf.
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40
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Khelfaoui M, Gambino F, Houbaert X, Ragazzon B, Müller C, Carta M, Lanore F, Srikumar BN, Gastrein P, Lepleux M, Zhang CL, Kneib M, Poulain B, Reibel-Foisset S, Vitale N, Chelly J, Billuart P, Lüthi A, Humeau Y. Lack of the presynaptic RhoGAP protein oligophrenin1 leads to cognitive disabilities through dysregulation of the cAMP/PKA signalling pathway. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130160. [PMID: 24298161 DOI: 10.1098/rstb.2013.0160] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Loss-of-function mutations in the gene encoding for the RhoGAP protein of oligophrenin-1 (OPHN1) lead to cognitive disabilities (CDs) in humans, yet the underlying mechanisms are not known. Here, we show that in mice constitutive lack of Ophn1 is associated with dysregulation of the cyclic adenosine monophosphate/phosphate kinase A (cAMP/PKA) signalling pathway in a brain-area-specific manner. Consistent with a key role of cAMP/PKA signalling in regulating presynaptic function and plasticity, we found that PKA-dependent presynaptic plasticity was completely abolished in affected brain regions, including hippocampus and amygdala. At the behavioural level, lack of OPHN1 resulted in hippocampus- and amygdala-related learning disabilities which could be fully rescued by the ROCK/PKA kinase inhibitor fasudil. Together, our data identify OPHN1 as a key regulator of presynaptic function and suggest that, in addition to reported postsynaptic deficits, loss of presynaptic plasticity contributes to the pathophysiology of CDs.
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Affiliation(s)
- Malik Khelfaoui
- Centre National de la Recherche Scientifique UPR3212, CNRS, Université de Strasbourg, , Strasbourg 67084, France
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41
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A novel in-frame deletion affecting the BAR domain of OPHN1 in a family with intellectual disability and hippocampal alterations. Eur J Hum Genet 2013; 22:644-51. [PMID: 24105372 DOI: 10.1038/ejhg.2013.216] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/12/2013] [Accepted: 08/16/2013] [Indexed: 12/13/2022] Open
Abstract
Oligophrenin-1 (OPHN1) is one of at least seven genes located on chromosome X that take part in Rho GTPase-dependent signaling pathways involved in X-linked intellectual disability (XLID). Mutations in OPHN1 were primarily described as an exclusive cause of non-syndromic XLID, but the re-evaluation of the affected individuals using brain imaging displayed fronto-temporal atrophy and cerebellar hypoplasia as neuroanatomical marks. In this study, we describe clinical, genetic and neuroimaging data of a three generation Brazilian XLID family co-segregating a novel intragenic deletion in OPHN1. This deletion results in an in-frame loss of exon 7 at transcription level (c.781_891del; r.487_597del), which is predicted to abolish 37 amino acids from the highly conserved N-terminal BAR domain of OPHN1. cDNA expression analysis demonstrated that the mutant OPHN1 transcript is stable and no abnormal splicing was observed. Features shared by the affected males of this family include neonatal hypotonia, strabismus, prominent root of the nose, deep set eyes, hyperactivity and instability/intolerance to frustration. Cranial MRI scans showed large lateral ventricles, vermis hypoplasia and cystic dilatation of the cisterna magna in all affected males. Interestingly, hippocampal alterations that have not been reported in patients with loss-of-function OPHN1 mutations were found in three affected individuals, suggesting an important function for the BAR domain in the hippocampus. This is the first description of an in-frame deletion within the BAR domain of OPHN1 and could provide new insights into the role of this domain in relation to brain and cognitive development or function.
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de Kreuk BJ, Schaefer A, Anthony EC, Tol S, Fernandez-Borja M, Geerts D, Pool J, Hambach L, Goulmy E, Hordijk PL. The human minor histocompatibility antigen 1 is a RhoGAP. PLoS One 2013; 8:e73962. [PMID: 24086303 PMCID: PMC3781157 DOI: 10.1371/journal.pone.0073962] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 07/24/2013] [Indexed: 01/17/2023] Open
Abstract
The human minor Histocompatibility Antigen HMHA-1 is a major target of immune responses after allogeneic stem cell transplantation applied for the treatment of leukemia and solid tumors. The restriction of its expression to hematopoietic cells and many solid tumors raised questions regarding its cellular functions. Sequence analysis of the HMHA-1 encoding HMHA1 protein revealed the presence of a possible C-terminal RhoGTPase Activating Protein (GAP) domain and an N-terminal BAR domain. Rho-family GTPases, including Rac1, Cdc42, and RhoA are key regulators of the actin cytoskeleton and control cell spreading and migration. RhoGTPase activity is under tight control as aberrant signaling can lead to pathology, including inflammation and cancer. Whereas Guanine nucleotide Exchange Factors (GEFs) mediate the exchange of GDP for GTP resulting in RhoGTPase activation, GAPs catalyze the low intrinsic GTPase activity of active RhoGTPases, resulting in inactivation. Here we identify the HMHA1 protein as a novel RhoGAP. We show that HMHA1 constructs, lacking the N-terminal region, negatively regulate the actin cytoskeleton as well as cell spreading. Furthermore, we show that HMHA1 regulates RhoGTPase activity in vitro and in vivo. Finally, we demonstrate that the HMHA1 N-terminal BAR domain is auto-inhibitory as HMHA1 mutants lacking this region, but not full-length HMHA1, showed GAP activity towards RhoGTPases. In conclusion, this study shows that HMHA1 acts as a RhoGAP to regulate GTPase activity, cytoskeletal remodeling and cell spreading, which are crucial functions in normal hematopoietic and cancer cells.
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Affiliation(s)
- Bart-Jan de Kreuk
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Antje Schaefer
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eloise C. Anthony
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Simon Tol
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Mar Fernandez-Borja
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Dirk Geerts
- Department of Pediatric Oncology/Hematology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jos Pool
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Lothar Hambach
- Department of Hematology, Hemostaseology, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Els Goulmy
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter L. Hordijk
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- * E-mail:
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Bleijerveld OB, van Holten TC, Preisinger C, van der Smagt JJ, Farndale RW, Kleefstra T, Willemsen MH, Urbanus RT, de Groot PG, Heck AJ, Roest M, Scholten A. Targeted Phosphotyrosine Profiling of Glycoprotein VI Signaling Implicates Oligophrenin-1 in Platelet Filopodia Formation. Arterioscler Thromb Vasc Biol 2013; 33:1538-43. [DOI: 10.1161/atvbaha.112.300916] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Objective—
Platelet adhesion to subendothelial collagen is dependent on the integrin α
2
β
1
and glycoprotein VI (GPVI) receptors. The major signaling routes in collagen-dependent platelet activation are outlined; however, crucial detailed knowledge of the actual phosphorylation events mediating them is still limited. Here, we explore phosphotyrosine signaling events downstream of GPVI with site-specific detail.
Approach and Results—
Immunoprecipitations of phosphotyrosine-modified peptides from protein digests of GPVI-activated and resting human platelets were compared by stable isotope-based quantitative mass spectrometry. We surveyed 214 unique phosphotyrosine sites over 2 time points, of which 28 showed a significant increase in phosphorylation on GPVI activation. Among these was Tyr370 of oligophrenin-1 (OPHN1), a Rho GTPase–activating protein. To elucidate the function of OPHN1 in platelets, we performed an array of functional platelet analyses within a small cohort of patients with rare oligophrenia. Because of germline mutations in the
OPHN1
gene locus, these patients lack OPHN1 expression entirely and are in essence a human knockout model. Our studies revealed that among other unaltered properties, patients with oligophrenia show normal P-selectin exposure and α
IIb
β
3
activation in response to GPVI, as well as normal aggregate formation on collagen under shear conditions. Finally, the major difference in OPHN1-deficient platelets turned out to be a significantly reduced collagen-induced filopodia formation.
Conclusions—
In-depth phosphotyrosine screening revealed many novel signaling recipients downstream of GPVI activation uncovering a new level of detail within this important pathway. To illustrate the strength of such data, functional follow-up of OPHN1 in human platelets deficient in this protein showed reduced filopodia formation on collagen, an important parameter of platelet hemostatic function.
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Affiliation(s)
- Onno B. Bleijerveld
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Thijs C. van Holten
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Christian Preisinger
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jasper J. van der Smagt
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Richard W. Farndale
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tjitske Kleefstra
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marjolein H. Willemsen
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rolf T. Urbanus
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Philip G. de Groot
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Albert J.R. Heck
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark Roest
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
| | - Arjen Scholten
- From the Biomolecular Mass Spectrometry and Proteomics and Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Netherlands Proteomics Centre, Utrecht, The Netherlands (O.B.B., C.P., A.J.R.H., A.S.); Departments of Clinical Chemistry and Haematology (T.C.v.H., R.T.U., P.G.d.G., M.R.) and Medical Genetics (J.J.v.d.S.), University Medical Center Utrecht, Utrecht, The Netherlands
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Neuropathological features in a female fetus with OPHN1 deletion and cerebellar hypoplasia. Eur J Med Genet 2013; 56:270-3. [DOI: 10.1016/j.ejmg.2013.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/27/2013] [Indexed: 11/19/2022]
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Abstract
Small GTPases use GDP/GTP alternation to actuate a variety of functional switches that are pivotal for cell dynamics. The GTPase switch is turned on by GEFs, which stimulate dissociation of the tightly bound GDP, and turned off by GAPs, which accelerate the intrinsically sluggish hydrolysis of GTP. For Ras, Rho, and Rab GTPases, this switch incorporates a membrane/cytosol alternation regulated by GDIs and GDI-like proteins. The structures and core mechanisms of representative members of small GTPase regulators from most families have now been elucidated, illuminating their general traits combined with scores of unique features. Recent studies reveal that small GTPase regulators have themselves unexpectedly sophisticated regulatory mechanisms, by which they process cellular signals and build up specific cell responses. These mechanisms include multilayered autoinhibition with stepwise release, feedback loops mediated by the activated GTPase, feed-forward signaling flow between regulators and effectors, and a phosphorylation code for RhoGDIs. The flipside of these highly integrated functions is that they make small GTPase regulators susceptible to biochemical abnormalities that are directly correlated with diseases, notably a striking number of missense mutations in congenital diseases, and susceptible to bacterial mimics of GEFs, GAPs, and GDIs that take command of small GTPases in infections. This review presents an overview of the current knowledge of these many facets of small GTPase regulation.
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Affiliation(s)
- Jacqueline Cherfils
- Laboratoire d’Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, Centre deRecherche de Gif, Gif-sur-Yvette, France
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Csépányi-Kömi R, Lévay M, Ligeti E. Small G proteins and their regulators in cellular signalling. Mol Cell Endocrinol 2012; 353:10-20. [PMID: 22108439 DOI: 10.1016/j.mce.2011.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/27/2011] [Accepted: 11/07/2011] [Indexed: 01/04/2023]
Abstract
Small molecular weight GTPases (small G proteins) are essential in the transduction of signals from different plasma membrane receptors. Due to their endogenous GTP-hydrolyzing activity, these proteins function as time-dependent biological switches controlling diverse cellular functions including cell shape and migration, cell proliferation, gene transcription, vesicular transport and membrane-trafficking. This review focuses on endocrine diseases linked to small G proteins. We provide examples for the regulation of the activity of small G proteins by various mechanisms such as posttranslational modifications, guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs) or guanine nucleotide dissociation inhibitors (GDIs). Finally we summarize endocrine diseases where small G proteins or their regulatory proteins have been revealed as the cause.
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Affiliation(s)
- Roland Csépányi-Kömi
- Department of Physiology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary
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Elvers M, Beck S, Fotinos A, Ziegler M, Gawaz M. The GRAF family member oligophrenin1 is a RhoGAP with BAR domain and regulates Rho GTPases in platelets. Cardiovasc Res 2012; 94:526-36. [DOI: 10.1093/cvr/cvs079] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Sel S, Kaiser M, Nass N, Trau S, Roepke A, Storsberg J, Hampel U, Paulsen F, Kalinski T. Oligophrenin-1 (Ophn1) is expressed in mouse retinal vessels. Gene Expr Patterns 2012; 12:63-7. [DOI: 10.1016/j.gep.2011.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 10/18/2011] [Accepted: 11/07/2011] [Indexed: 12/20/2022]
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49
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Ligeti E, Welti S, Scheffzek K. Inhibition and Termination of Physiological Responses by GTPase Activating Proteins. Physiol Rev 2012; 92:237-72. [DOI: 10.1152/physrev.00045.2010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Physiological processes are strictly organized in space and time. However, in cell physiology research, more attention is given to the question of space rather than to time. To function as a signal, environmental changes must be restricted in time; they need not only be initiated but also terminated. In this review, we concentrate on the role of one specific protein family involved in biological signal termination. GTPase activating proteins (GAPs) accelerate the endogenously low GTP hydrolysis rate of monomeric guanine nucleotide-binding proteins (GNBPs), limiting thereby their prevalence in the active, GTP-bound form. We discuss cases where defective or excessive GAP activity of specific proteins causes significant alteration in the function of the nervous, endocrine, and hemopoietic systems, or contributes to development of infections and tumors. Biochemical and genetic data as well as observations from human pathology support the notion that GAPs represent vital elements in the spatiotemporal fine tuning of physiological processes.
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Affiliation(s)
- Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Stefan Welti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Klaus Scheffzek
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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Powell AD, Gill KK, Saintot PP, Jiruska P, Chelly J, Billuart P, Jefferys JGR. Rapid reversal of impaired inhibitory and excitatory transmission but not spine dysgenesis in a mouse model of mental retardation. J Physiol 2011; 590:763-76. [PMID: 22124149 DOI: 10.1113/jphysiol.2011.219907] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Intellectual disability affects 2-3% of the population: those due to mutations of the X-chromosome are a major cause of moderate to severe cases (1.8/1000 males). Established theories ascribe the cellular aetiology of intellectual disability to malformations of dendritic spines. Recent work has identified changes in synaptic physiology in some experimental models. Here, we investigated the pathophysiology of a mouse model of intellectual disability using electrophysiological recordings combined with confocal imaging of dentate gyrus granule neurons. Lack of oligophrenin-1 resulted in reductions in dendritic tree complexity and mature dendritic spine density and in evoked and spontaneous EPSCs and IPSCs. In the case of inhibitory transmission, the physiological change was associated with a reduction in the readily releasable pool and vesicle recycling which impaired the efficiency of inhibitory synaptic transmission. Acute inhibition of the downstream signalling pathway of oligophrenin-1 fully reversed the functional changes in synaptic transmission but not the dendritic abnormalities. The impaired inhibitory (as well as excitatory) synaptic transmission at frequencies associated with cognitive function suggests a cellular mechanism for the intellectual disability, because cortical oscillations associated with cognition normally depend on inhibitory neurons firing on every cycle.
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Affiliation(s)
- Andrew D Powell
- School of Clinical and Experimental Medicine (Neuronal Networks Group), College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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