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Ramachandran RP, Nandi I, Haritan N, Zlotkin-Rivkin E, Keren Y, Danieli T, Lebendiker M, Melamed-Book N, Breuer W, Reichmann D, Aroeti B. EspH interacts with the host active Bcr related (ABR) protein to suppress RhoGTPases. Gut Microbes 2022; 14:2130657. [PMID: 36219160 PMCID: PMC9559323 DOI: 10.1080/19490976.2022.2130657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enteropathogenic Escherichia coli are bacterial pathogens that colonize the gut and cause severe diarrhea in humans. Upon intimate attachment to the intestinal epithelium, these pathogens translocate via a type III secretion system virulent proteins, termed effectors, into the host cells. These effectors manipulate diverse host cell organelles and functions for the pathogen's benefit. However, the precise mechanisms underlying their activities are not fully understood despite intensive research. EspH, a critical effector protein, has been previously reported to disrupt the host cell actin cytoskeleton by suppressing RhoGTPase guanine exchange factors. However, native host proteins targeted by EspH to mediate these activities remained unknown. Here, we identified the active Bcr related (ABR), a protein previously characterized to possess dual Rho guanine nucleotide exchange factor and GTPase activating protein (GAP) domains, as a native EspH interacting partner. These interactions are mediated by the effector protein's C-terminal 38 amino acid segment. The effector primarily targets the GAP domain of ABR to suppress Rac1 and Cdc42, host cell cytotoxicity, bacterial invasion, and filopodium formation at infection sites. Knockdown of ABR expression abolished the ability of EspH to suppress Rac1, Cdc42. Our studies unravel a novel mechanism by which host RhoGTPases are hijacked by bacterial effectors.
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Affiliation(s)
- Rachana Pattani Ramachandran
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ipsita Nandi
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nir Haritan
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yael Keren
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tsafi Danieli
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mario Lebendiker
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naomi Melamed-Book
- Bioimaging Unit, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - William Breuer
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dana Reichmann
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,CONTACT Benjamin Aroeti Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem91904, Israel
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2
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Rac-deficient cerebellar granule neurons die before they migrate to the internal granule layer. Sci Rep 2022; 12:14848. [PMID: 36050459 PMCID: PMC9436960 DOI: 10.1038/s41598-022-19252-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 08/26/2022] [Indexed: 11/23/2022] Open
Abstract
Granule neurons are the most common cell type in the cerebellum. They are generated in the external granule layer and migrate inwardly, forming the internal granule layer. Small Rho GTPases play various roles during development of the nervous system and may be involved in generation, differentiation and migration of granule neurons. We deleted Rac1, a member of small Rho GTPases, by GFAP-Cre driver in cerebellar granule neurons and Bergmann glial cells. Rac1flox/flox; Cre mice showed impaired migration and slight reduction in the number of granule neurons in the internal granule layer. Deletion of both Rac1 and Rac3 resulted in almost complete absence of granule neurons. Rac-deficient granule neurons differentiated into p27 and NeuN-expressing post mitotic neurons, but died before migration to the internal granule layer. Loss of Rac3 has little effect on granule neuron development. Rac1flox/flox; Rac3+/−; Cre mice showed intermediate phenotype between Rac1flox/flox; Cre and Rac1flox/flox; Rac3−/−; Cre mice in both survival and migration of granule neurons. Rac3 itself seems to be unimportant in the development of the cerebellum, but has some roles in Rac1-deleted granule neurons. Conversely, overall morphology of Rac1+/flox; Rac3−/−; Cre cerebella was normal. One allele of Rac1 is therefore thought to be sufficient to promote development of cerebellar granule neurons.
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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Xiao Y, Sun Y, Lu Y, Du J, Tian X, Cai W, Wang Y. Loss function of Bcr mutation causes gastrointestinal dysmotility and brain developmental defects. Neurogastroenterol Motil 2021; 33:e14190. [PMID: 34190380 DOI: 10.1111/nmo.14190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/25/2021] [Accepted: 05/11/2021] [Indexed: 12/29/2022]
Abstract
BACKGROUND The breakpoint cluster region (BCR) is a protein that originally forms a fusion protein with c-Abl tyrosine kinase and induces leukemia. Researchers have shown that BCR is enriched in the central nervous system and may contribute to neurological disorders. We aimed to investigate the physiological function of BCR in neural development in the gastrointestinal (GI) tract and brain. METHODS Whole-exome sequencing was used to screen for mutations in the BCR. Bcr knockout mice (Bcr-/- , ΔExon 2-22) were generated using the CRISPR/Cas9 system. Transit of carmine red dye and glass bead expulsion assays were used to record total and proximal GI transit and distal colonic transit. KEY RESULTS In an infant with pediatric intestinal pseudo-obstruction, we found a heterozygous de novo mutation (NM_004327.3:c.3072+1G>A) in BCR. Bcr deficiency mice (Bcr-/- ) exhibited growth retardation and impaired gastrointestinal motility. Bcr-/- mice had a prolonged average total GI transit time with increased distal colonic transit and proximal GI transit in isolation. Morphology analysis indicated that Bcr-/- mice had a less number of neurons in the submucosal plexus and myenteric plexus. Bcr-/- mice exhibited apparent structural defects in the brain, particularly in the cortex. Additionally, Bcr- depletion in the mouse cortex altered the expression of Ras homologous (Rho) family small GTPases. CONCLUSIONS AND INFERENCES BCR mutations are associated with intestinal obstruction in children. Loss of Bcr can cause intestinal dysmotility and brain developmental defects may via regulation of Rho GTPases.
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Affiliation(s)
- Yongtao Xiao
- Shanghai Institute of Pediatric Research, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Yu Sun
- Shanghai Institute of Pediatric Research, Shanghai, China
| | - Ying Lu
- Shanghai Institute of Pediatric Research, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Jun Du
- Shanghai Institute of Pediatric Research, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China
| | - Xinbei Tian
- Shanghai Institute of Pediatric Research, Shanghai, China
| | - Wei Cai
- Shanghai Institute of Pediatric Research, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Division of Pediatric Gastroenterology and Nutrition, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Department of Pediatric Surgery, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Wang
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Division of Pediatric Gastroenterology and Nutrition, Xin Hua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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5
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BCR: a promiscuous fusion partner in hematopoietic disorders. Oncotarget 2019; 10:2738-2754. [PMID: 31105873 PMCID: PMC6505627 DOI: 10.18632/oncotarget.26837] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/23/2019] [Indexed: 12/23/2022] Open
Abstract
Considerable advances have been made in our understanding of the molecular basis of hematopoietic cancers. The discovery of the BCR-ABL fusion protein over 50 years ago has brought about a new era of therapeutic progress and overall improvement in patient care, mainly due to the development and use of personalized medicine and tyrosine kinase inhibitors (TKIs). However, since the detection of BCR-ABL, BCR has been identified as a commonly occurring fusion partner in hematopoietic disorders. BCR has been discovered fused to additional tyrosine kinases, including: Fibroblast Growth Factor Receptor 1 (FGFR1), Platelet-derived Growth Factor Receptor Alpha (PDGFRA), Ret Proto-Oncogene (RET), and Janus Kinase 2 (JAK2). While BCR translocations are infrequent in hematopoietic malignancies, clinical evidence suggests that patients who harbor these mutations benefit from TKIs and additional personalized therapies. The improvement of further methodologies for characterization of these fusions is crucial to determine a patient’s treatment regimen, and optimal outcome. However, potential relapse and drug resistance among patients’ highlights the need for additional treatment options and further understanding of these oncogenic fusion proteins. This review explores the mechanisms behind cancer progression of these BCR oncogenic fusion proteins, comparing their similarities and differences, examining the significance of BCR as a partner gene, and discussing current treatment options for these translocation-induced hematopoietic malignancies.
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6
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The Molecular Pathway Regulating Bergmann Glia and Folia Generation in the Cerebellum. THE CEREBELLUM 2019; 17:42-48. [PMID: 29218544 DOI: 10.1007/s12311-017-0904-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Evolution of complex behaviors in higher vertebrates and primates require the development of sophisticated neuronal circuitry and the expansion of brain surface area to accommodate the vast number of neuronal and glial populations. To achieve these goals, the neocortex in primates and the cerebellum in amniotes have developed specialized types of basal progenitors to aid the folding of their cortices. In the cerebellum, Bergmann glia constitute such a basal progenitor population, having a distinctive morphology and playing a critical role in cerebellar corticogenesis. Here, we review recent studies on the induction of Bergmann glia and their crucial role in mediating folding of the cerebellar cortex. These studies uncover a key function of FGF-ERK-ETV signaling cascade in the transformation of Bergmann glia from radial glia in the ventricular zone. Remarkably, in the neocortex, the same signaling axis operates to facilitate the transformation of ventricular radial glia into basal radial glia, a Bergmann glia-like basal progenitor population, which have been implicated in the establishment of neocortical gyri. These new findings draw a striking similarity in the function and ontogeny of the two basal progenitor populations born in distinct brain compartments.
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7
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The RacGAP β-Chimaerin is essential for cerebellar granule cell migration. Sci Rep 2018; 8:680. [PMID: 29330522 PMCID: PMC5766509 DOI: 10.1038/s41598-017-19116-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 12/21/2017] [Indexed: 11/08/2022] Open
Abstract
During mammalian cerebellar development, postnatal granule cell progenitors proliferate in the outer part of the External Granule Layer (EGL). Postmitotic granule progenitors migrate tangentially in the inner EGL before switching to migrate radially inward, past the Purkinje cell layer, to achieve their final position in the mature Granule Cell Layer (GCL). Here, we show that the RacGAP β-chimaerin is expressed by a small population of late-born, premigratory granule cells. β-chimaerin deficiency causes a subset of granule cells to become arrested in the EGL, where they differentiate and form ectopic neuronal clusters. These clusters of granule cells are able to recruit aberrantly projecting mossy fibers. Collectively, these data suggest a role for β-chimaerin as an intracellular mediator of Cerebellar Granule Cell radial migration.
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Sakamoto I, Ueyama T, Hayashibe M, Nakamura T, Mohri H, Kiyonari H, Shigyo M, Tohda C, Saito N. Roles of Cdc42 and Rac in Bergmann glia during cerebellar corticogenesis. Exp Neurol 2017; 302:57-67. [PMID: 29253508 DOI: 10.1016/j.expneurol.2017.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 11/18/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
Bergmann glia (BG) are important in the inward type of radial migration of cerebellar granule neurons (CGNs). However, details regarding the functions of Cdc42 and Rac in BG for radial migration of CGN are unknown. To examine the roles of Cdc42 and Rac in BG during cerebellar corticogenesis, mice with a single deletion of Cdc42 or Rac1 and those with double deletions of Cdc42 and Rac1 under control of the glial fibrillary acidic protein (GFAP) promoter: GFAP-Cre;Cdc42flox/flox (Cdc42-KO), GFAP-Cre;Rac1flox/flox (Rac1-KO), and GFAP-Cre; Cdc42flox/flox;Rac1flox/flox (Cdc42/Rac1-DKO) mice, were generated. Both Cdc42-KO and Rac1-KO mice, but more obviously Cdc42-KO mice, had disturbed alignment of BG in the Purkinje cell layer (PCL). We found that Cdc42-KO, but not Rac1-KO, induced impaired radial migration of CGNs in the late phase of radial migration, leading to retention of CGNs in the lower half of the molecular layer (ML). Cdc42-KO, but not Rac1-KO, mice also showed aberrantly aligned Purkinje cells (PCs). These phenotypes were exacerbated in Cdc42/Rac1-DKO mice. Alignment of BG radial fibers in the ML and BG endfeet at the pial surface of the cerebellum evaluated by GFAP staining was disturbed and weak in Cdc42/Rac1-DKO mice, respectively. Our data indicate that Cdc42 and Rac, but predominantly Cdc42, in BG play important roles during the late phase of radial migration of CGNs. We also report here that Cdc42 is involved in gliophilic migration of CGNs, in contrast to Rac, which is more closely connected to regulating neurophilic migration.
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Affiliation(s)
- Isao Sakamoto
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan.
| | - Masakazu Hayashibe
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Takashi Nakamura
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Hiroaki Mohri
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit and Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | - Michiko Shigyo
- Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, Toyama 930-0194, Japan
| | - Chihiro Tohda
- Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, Toyama 930-0194, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan.
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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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10
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Torchia J, Golbourn B, Feng S, Ho KC, Sin-Chan P, Vasiljevic A, Norman JD, Guilhamon P, Garzia L, Agamez NR, Lu M, Chan TS, Picard D, de Antonellis P, Khuong-Quang DA, Planello AC, Zeller C, Barsyte-Lovejoy D, Lafay-Cousin L, Letourneau L, Bourgey M, Yu M, Gendoo DMA, Dzamba M, Barszczyk M, Medina T, Riemenschneider AN, Morrissy AS, Ra YS, Ramaswamy V, Remke M, Dunham CP, Yip S, Ng HK, Lu JQ, Mehta V, Albrecht S, Pimentel J, Chan JA, Somers GR, Faria CC, Roque L, Fouladi M, Hoffman LM, Moore AS, Wang Y, Choi SA, Hansford JR, Catchpoole D, Birks DK, Foreman NK, Strother D, Klekner A, Bognár L, Garami M, Hauser P, Hortobágyi T, Wilson B, Hukin J, Carret AS, Van Meter TE, Hwang EI, Gajjar A, Chiou SH, Nakamura H, Toledano H, Fried I, Fults D, Wataya T, Fryer C, Eisenstat DD, Scheinemann K, Fleming AJ, Johnston DL, Michaud J, Zelcer S, Hammond R, Afzal S, Ramsay DA, Sirachainan N, Hongeng S, Larbcharoensub N, Grundy RG, Lulla RR, Fangusaro JR, Druker H, Bartels U, Grant R, Malkin D, McGlade CJ, Nicolaides T, Tihan T, Phillips J, Majewski J, Montpetit A, Bourque G, Bader GD, Reddy AT, Gillespie GY, Warmuth-Metz M, Rutkowski S, Tabori U, Lupien M, Brudno M, Schüller U, Pietsch T, Judkins AR, Hawkins CE, Bouffet E, Kim SK, Dirks PB, Taylor MD, Erdreich-Epstein A, Arrowsmith CH, De Carvalho DD, Rutka JT, Jabado N, Huang A. Integrated (epi)-Genomic Analyses Identify Subgroup-Specific Therapeutic Targets in CNS Rhabdoid Tumors. Cancer Cell 2016; 30:891-908. [PMID: 27960086 PMCID: PMC5500911 DOI: 10.1016/j.ccell.2016.11.003] [Citation(s) in RCA: 169] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 09/19/2016] [Accepted: 10/31/2016] [Indexed: 02/07/2023]
Abstract
We recently reported that atypical teratoid rhabdoid tumors (ATRTs) comprise at least two transcriptional subtypes with different clinical outcomes; however, the mechanisms underlying therapeutic heterogeneity remained unclear. In this study, we analyzed 191 primary ATRTs and 10 ATRT cell lines to define the genomic and epigenomic landscape of ATRTs and identify subgroup-specific therapeutic targets. We found ATRTs segregated into three epigenetic subgroups with distinct genomic profiles, SMARCB1 genotypes, and chromatin landscape that correlated with differential cellular responses to a panel of signaling and epigenetic inhibitors. Significantly, we discovered that differential methylation of a PDGFRB-associated enhancer confers specific sensitivity of group 2 ATRT cells to dasatinib and nilotinib, and suggest that these are promising therapies for this highly lethal ATRT subtype.
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Affiliation(s)
- Jonathon Torchia
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Department of Paediatrics, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Brian Golbourn
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Neurosurgery, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Shengrui Feng
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G0A4, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - King Ching Ho
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Patrick Sin-Chan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Department of Paediatrics, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Alexandre Vasiljevic
- Department of Pathology, Groupement Hospitalier Est, CHU de Lyon, Lyon-Bron 69677, France
| | - Joseph D Norman
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Paul Guilhamon
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Livia Garzia
- Program in Developmental & Stem Cell Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Natalia R Agamez
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Mei Lu
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Tiffany S Chan
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Department of Paediatrics, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Daniel Picard
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Pasqualino de Antonellis
- Program in Developmental & Stem Cell Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Dong-Anh Khuong-Quang
- Department of Pediatrics, McGill University, Montreal, QC H3Z2Z3, Canada; Department of Human Genetics, McGill University, Montreal, QC H3Z2Z3, Canada
| | - Aline C Planello
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Constanze Zeller
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Dalia Barsyte-Lovejoy
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Lucie Lafay-Cousin
- Division of Pediatric Hematology/Oncology, Alberta Children's Hospital, AB T3B6A8, Canada
| | - Louis Letourneau
- Genome Quebec Innovation Centre, McGill University, Montreal, QC H3A1A4, Canada
| | - Mathieu Bourgey
- Genome Quebec Innovation Centre, McGill University, Montreal, QC H3A1A4, Canada
| | - Man Yu
- Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Deena M A Gendoo
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Misko Dzamba
- Department of Computer Science, University of Toronto, Toronto, ON M5G0A4, Canada
| | - Mark Barszczyk
- Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Tiago Medina
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Alexandra N Riemenschneider
- Division of Neurosurgery, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - A Sorana Morrissy
- Program in Developmental & Stem Cell Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Young-Shin Ra
- Department of Neurosurgery, Asan Medical Center, Seoul 138-736, Korea
| | - Vijay Ramaswamy
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Marc Remke
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Christopher P Dunham
- Division of Anatomic Pathology, Children's and Women's Health Centre of B.C, University of British Columbia, Vancouver, BC V6H3N1, Canada
| | - Stephen Yip
- Department of Pathology & Laboratory Medicine, University of British Columbia, V6T1Z3, Canada
| | - Ho-Keung Ng
- Department of Anatomical and Cellular Pathology, Chinese University of Hong Kong, Hong Kong, China
| | - Jian-Qiang Lu
- Laboratory Medicine and Pathology, Stollery Children's Hospital, University of Alberta, Edmonton, AB T2W3N2, Canada
| | - Vivek Mehta
- Division of Neurosurgery, Stollery Children's Hospital, University of Alberta, Edmonton, AB T2W3N2, Canada
| | - Steffen Albrecht
- Department of Pathology, McGill University, Montreal, QC H3Z2Z3, Canada
| | - Jose Pimentel
- Divison of Pathology, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Lisbon 1649-035, Portugal
| | - Jennifer A Chan
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB T2N1N4, Canada
| | - Gino R Somers
- Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Claudia C Faria
- Department of Neurosurgery, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Lisbon 1649-035, Portugal
| | - Lucia Roque
- Cytometry and Cytogenetic Laboratory, CIPM, Portuguese Cancer Institute, Lisbon 1099-023, Portugal
| | - Maryam Fouladi
- Division of Oncology, Department of Cancer and Blood Diseases, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA
| | - Lindsey M Hoffman
- Department of Pediatrics, University of Colorado, Denver, CO 80045, USA
| | - Andrew S Moore
- Oncology Service, Children's Health Queensland Hospital; University of Queensland Diamantina Institute, Brisbane, QLD 4102, Australia
| | - Yin Wang
- Research Institute of Health Development Strategies, Fudan University, Shanghai 200032, China
| | - Seung Ah Choi
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul 03080, Korea
| | - Jordan R Hansford
- Royal Children's Hospital, Murdoch Children's Research Institute, Melbourne, VIC 3052, Australia
| | - Daniel Catchpoole
- Children's Cancer Research Unit, Children's Hospital at Westmead, Westmead, NSW 2145, Australia
| | - Diane K Birks
- Department of Pediatrics, University of Colorado, Denver, CO 80045, USA
| | | | - Doug Strother
- Division of Pediatric Hematology/Oncology, Stollery Children's Hospital, University of Alberta, Edmonton, AB T2W3N2, Canada
| | - Almos Klekner
- Department of Neurosurgery, University of Debrecen, Debrecen 4032, Hungary
| | - Laszló Bognár
- Department of Neurosurgery, University of Debrecen, Debrecen 4032, Hungary
| | - Miklós Garami
- Second Department of Pediatrics, Semmelweis University, Budapest 1094, Hungary
| | - Péter Hauser
- Second Department of Pediatrics, Semmelweis University, Budapest 1094, Hungary
| | - Tibor Hortobágyi
- Department of Histopathology, University of Szeged, Szeged 6720, Hungary
| | - Beverly Wilson
- Division of Pediatric Hematology/Oncology, Stollery Children's Hospital, University of Alberta, Edmonton, AB T2W3N2, Canada
| | - Juliette Hukin
- Division of Hematology and Oncology, Children's and Women's Health Centre of B.C, University of British Columbia, Vancouver, BC V6H3N1, Canada
| | - Anne-Sophie Carret
- Department of Pediatrics, Division of Hematology-Oncology, Université de Montréal/CHU Sainte-Justine, Montreal, QC H3T1C5, Canada
| | - Timothy E Van Meter
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA 23298-0631, USA
| | - Eugene I Hwang
- Department of Oncology, Children's National Medical Center, Washington, DC 20010, USA
| | - Amar Gajjar
- Division of Neuro-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shih-Hwa Chiou
- Department of Medical Research, Taipei Veterans General Hospital and National Yang-Ming University, Taipei 112, Taiwan
| | - Hideo Nakamura
- Department of Neurosurgery, Kumamoto University, Kumamoto 860-8556, Japan
| | - Helen Toledano
- Department of Pediatric Hematology Oncology, Children's Medical Center of Israel, Petach Tikva 49202, Isreal
| | - Iris Fried
- Department of Pediatric Hematology-Oncology, Hadassah Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Daniel Fults
- Department of Neurosurgery, University of Utah, School of Medicine, Salt Lake City, UT 84132, USA
| | - Takafumi Wataya
- Department of Neurosurgery, Shizuoka Children's Hospital, Shizuoka 420-8660, Japan
| | - Chris Fryer
- Division of Hematology and Oncology, Children's and Women's Health Centre of B.C, University of British Columbia, Vancouver, BC V6H3N1, Canada
| | - David D Eisenstat
- Division of Pediatric Hematology/Oncology, Stollery Children's Hospital, University of Alberta, Edmonton, AB T2W3N2, Canada
| | - Katrin Scheinemann
- Department of Pediatrics, McMaster University, Hamilton, ON L8S4K1, Canada
| | - Adam J Fleming
- Department of Pediatrics, McMaster University, Hamilton, ON L8S4K1, Canada
| | - Donna L Johnston
- Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON K1H8L1, Canada
| | - Jean Michaud
- Pathology and Laboratory Medicine, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON K1H8L1, Canada
| | - Shayna Zelcer
- Division of Pediatric Hematology/Oncology, Children's Hospital, London Health Sciences Center, London, ON N6A5A5, Canada
| | - Robert Hammond
- Department of Pathology and Laboratory Medicine, Children's Hospital of Western Ontario, University of Western Ontario, London, ON N6A5W9, Canada
| | - Samina Afzal
- Department of Pediatrics, Dalhousie University, Halifax, NS B3H4R2, Canada
| | - David A Ramsay
- Department of Pathology and Laboratory Medicine, Children's Hospital of Western Ontario, University of Western Ontario, London, ON N6A5W9, Canada
| | - Nongnuch Sirachainan
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10300, Thailand
| | - Suradej Hongeng
- Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10300, Thailand
| | - Noppadol Larbcharoensub
- Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Richard G Grundy
- Children's Brain Tumour Research Centre, University of Nottingham, Nottingham NG72RD, England
| | - Rishi R Lulla
- Division of Pediatric Hematology-Oncology and Stem Cell Transplantation, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Jason R Fangusaro
- Division of Pediatric Hematology-Oncology and Stem Cell Transplantation, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Harriet Druker
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Ute Bartels
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Ronald Grant
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - David Malkin
- Department of Paediatrics, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Program in Genetics & Genome Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - C Jane McGlade
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G0A4, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Theodore Nicolaides
- Department of Pediatrics (Hematology/Oncology), University of California, San Francisco, San Francisco, CA 94143-0112, USA
| | - Tarik Tihan
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143-0112, USA
| | - Joanna Phillips
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA 94143-0112, USA
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC H3Z2Z3, Canada; Genome Quebec Innovation Centre, McGill University, Montreal, QC H3A1A4, Canada
| | - Alexandre Montpetit
- Genome Quebec Innovation Centre, McGill University, Montreal, QC H3A1A4, Canada
| | - Guillaume Bourque
- Department of Human Genetics, McGill University, Montreal, QC H3Z2Z3, Canada; Genome Quebec Innovation Centre, McGill University, Montreal, QC H3A1A4, Canada
| | - Gary D Bader
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G0A4, Canada
| | - Alyssa T Reddy
- Department of Pediatric Hematology and Oncology, University of Alabama, Birmingham, AL 35233, USA
| | - G Yancey Gillespie
- Department of Neurosurgery, University of Alabama, Birmingham, AL 35233, USA
| | - Monika Warmuth-Metz
- Department of Neuroradiology, University of Würzburg, Würzburg 97070, Germany
| | - Stefan Rutkowski
- Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - Uri Tabori
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Program in Genetics & Genome Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Mathieu Lupien
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G0A4, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Michael Brudno
- Department of Computer Science, University of Toronto, Toronto, ON M5G0A4, Canada; Program in Genetics & Genome Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Ulrich Schüller
- Department of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg 20246, Germany
| | - Torsten Pietsch
- Institute for Neuropathology, University of Bonn Medical Center, Bonn 53105, Germany
| | - Alexander R Judkins
- Department of Pathology & Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA 90027, USA
| | - Cynthia E Hawkins
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Pathology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Eric Bouffet
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Seung-Ki Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul 03080, Korea
| | - Peter B Dirks
- Division of Neurosurgery, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Michael D Taylor
- Division of Neurosurgery, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Program in Developmental & Stem Cell Biology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada
| | - Anat Erdreich-Epstein
- Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027, USA
| | - Cheryl H Arrowsmith
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada
| | - Daniel D De Carvalho
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G0A4, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G1L7, Canada.
| | - James T Rutka
- Department of Surgery, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Neurosurgery, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada.
| | - Nada Jabado
- Department of Pediatrics, McGill University, Montreal, QC H3Z2Z3, Canada; Department of Human Genetics, McGill University, Montreal, QC H3Z2Z3, Canada.
| | - Annie Huang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5G0A4, Canada; Department of Paediatrics, University of Toronto, Toronto, ON M5G0A4, Canada; Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON M5G1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, Hospital for Sick Children, Toronto, ON M5G1X8, Canada.
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11
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Hollstein R, Parry DA, Nalbach L, Logan CV, Strom TM, Hartill VL, Carr IM, Korenke GC, Uppal S, Ahmed M, Wieland T, Markham AF, Bennett CP, Gillessen-Kaesbach G, Sheridan EG, Kaiser FJ, Bonthron DT. HACE1 deficiency causes an autosomal recessive neurodevelopmental syndrome. J Med Genet 2015; 52:797-803. [PMID: 26424145 PMCID: PMC4717446 DOI: 10.1136/jmedgenet-2015-103344] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 07/23/2015] [Indexed: 01/05/2023]
Abstract
Background The genetic aetiology of neurodevelopmental defects is extremely diverse, and the lack of distinctive phenotypic features means that genetic criteria are often required for accurate diagnostic classification. We aimed to identify the causative genetic lesions in two families in which eight affected individuals displayed variable learning disability, spasticity and abnormal gait. Methods Autosomal recessive inheritance was suggested by consanguinity in one family and by sibling recurrences with normal parents in the second. Autozygosity mapping and exome sequencing, respectively, were used to identify the causative gene. Results In both families, biallelic loss-of-function mutations in HACE1 were identified. HACE1 is an E3 ubiquitin ligase that regulates the activity of cellular GTPases, including Rac1 and members of the Rab family. In the consanguineous family, a homozygous mutation p.R219* predicted a truncated protein entirely lacking its catalytic domain. In the other family, compound heterozygosity for nonsense mutation p.R748* and a 20-nt insertion interrupting the catalytic homologous to the E6-AP carboxyl terminus (HECT) domain was present; western blot analysis of patient cells revealed an absence of detectable HACE1 protein. Conclusion HACE1 mutations underlie a new autosomal recessive neurodevelopmental disorder. Previous studies have implicated HACE1 as a tumour suppressor gene; however, since cancer predisposition was not observed either in homozygous or heterozygous mutation carriers, this concept may require re-evaluation.
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Affiliation(s)
- Ronja Hollstein
- Sektion für Funktionelle Genetik am Institut für Humangenetik, Universität zu Lübeck, Lübeck, Germany
| | - David A Parry
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK
| | - Lisa Nalbach
- Sektion für Funktionelle Genetik am Institut für Humangenetik, Universität zu Lübeck, Lübeck, Germany
| | - Clare V Logan
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK
| | - Tim M Strom
- Institute of Human Genetics, Technische Universität München, Munich, Germany Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Verity L Hartill
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK Yorkshire Regional Genetics Service, Leeds, UK
| | - Ian M Carr
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK
| | - Georg C Korenke
- Zentrum für Kinder- und Jugendmedizin, Neuropädiatrie, Klinikum Oldenburg, Oldenburg, Germany
| | - Sandeep Uppal
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK
| | | | - Thomas Wieland
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | | | | | - Eamonn G Sheridan
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK Yorkshire Regional Genetics Service, Leeds, UK
| | - Frank J Kaiser
- Sektion für Funktionelle Genetik am Institut für Humangenetik, Universität zu Lübeck, Lübeck, Germany
| | - David T Bonthron
- Section of Genetics, School of Medicine, University of Leeds, Leeds, UK Yorkshire Regional Genetics Service, Leeds, UK
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12
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Regeneration, Plasticity, and Induced Molecular Programs in Adult Zebrafish Brain. BIOMED RESEARCH INTERNATIONAL 2015; 2015:769763. [PMID: 26417601 PMCID: PMC4568348 DOI: 10.1155/2015/769763] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/25/2014] [Accepted: 09/25/2014] [Indexed: 12/20/2022]
Abstract
Regenerative capacity of the brain is a variable trait within animals. Aquatic vertebrates such as zebrafish have widespread ability to renew their brains upon damage, while mammals have—if not none—very limited overall regenerative competence. Underlying cause of such a disparity is not fully evident; however, one of the reasons could be activation of peculiar molecular programs, which might have specific roles after injury or damage, by the organisms that regenerate. If this hypothesis is correct, then there must be genes and pathways that (a) are expressed only after injury or damage in tissues, (b) are biologically and functionally relevant to restoration of neural tissue, and (c) are not detected in regenerating organisms. Presence of such programs might circumvent the initial detrimental effects of the damage and subsequently set up the stage for tissue redevelopment to take place by modulating the plasticity of the neural stem/progenitor cells. Additionally, if transferable, those “molecular mechanisms of regeneration” could open up new avenues for regenerative therapies of humans in clinical settings. This review focuses on the recent studies addressing injury/damage-induced molecular programs in zebrafish brain, underscoring the possibility of the presence of genes that could be used as biomarkers of neural plasticity and regeneration.
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13
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Duman JG, Mulherkar S, Tu YK, X Cheng J, Tolias KF. Mechanisms for spatiotemporal regulation of Rho-GTPase signaling at synapses. Neurosci Lett 2015; 601:4-10. [PMID: 26003445 DOI: 10.1016/j.neulet.2015.05.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/16/2015] [Accepted: 05/18/2015] [Indexed: 01/16/2023]
Abstract
Synapses mediate information flow between neurons and undergo plastic changes in response to experience, which is critical for learning and memory. Conversely, synaptic defects impair information processing and underlie many brain pathologies. Rho-family GTPases control synaptogenesis by transducing signals from extracellular stimuli to the cytoskeleton and nucleus. The Rho-GTPases Rac1 and Cdc42 promote synapse development and the growth of axons and dendrites, while RhoA antagonizes these processes. Despite its importance, many aspects of Rho-GTPase signaling remain relatively unknown. Rho-GTPases are activated by guanine nucleotide exchange factors (GEFs) and inhibited by GTPase-activating proteins (GAPs). Though the number of both GEFs and GAPs greatly exceeds that of Rho-GTPases, loss of even a single GEF or GAP often has profound effects on cognition and behavior. Here, we explore how the actions of specific GEFs and GAPs give rise to the precise spatiotemporal activation patterns of Rho-GTPases in neurons. We consider the effects of coupling GEFs and GAPs targeting the same Rho-GTPase and the modular pathways that connect specific cellular stimuli with a given Rho-GTPase via different GEFs. We discuss how the creation of sharp borders between Rho-GTPase activation zones is achieved by pairing a GEF for one Rho-GTPase with a GAP for another and the extensive crosstalk between different Rho-GTPases. Given the importance of synapses for cognition and the fundamental roles that Rho-GTPases play in regulating them, a detailed understanding of Rho-GTPase signaling is essential to the progress of neuroscience.
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Affiliation(s)
- Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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14
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Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:632450. [PMID: 25879033 PMCID: PMC4388020 DOI: 10.1155/2015/632450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.
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15
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Gray EJ, Petsalaki E, James DA, Bagshaw RD, Stacey MM, Rocks O, Gingras AC, Pawson T. Src homology 2 domain containing protein 5 (SH2D5) binds the breakpoint cluster region protein, BCR, and regulates levels of Rac1-GTP. J Biol Chem 2014; 289:35397-408. [PMID: 25331951 DOI: 10.1074/jbc.m114.615112] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SH2D5 is a mammalian-specific, uncharacterized adaptor-like protein that contains an N-terminal phosphotyrosine-binding domain and a C-terminal Src homology 2 (SH2) domain. We show that SH2D5 is highly enriched in adult mouse brain, particularly in Purkinjie cells in the cerebellum and the cornu ammonis of the hippocampus. Despite harboring two potential phosphotyrosine (Tyr(P)) recognition domains, SH2D5 binds minimally to Tyr(P) ligands, consistent with the absence of a conserved Tyr(P)-binding arginine residue in the SH2 domain. Immunoprecipitation coupled to mass spectrometry (IP-MS) from cultured cells revealed a prominent association of SH2D5 with breakpoint cluster region protein, a RacGAP that is also highly expressed in brain. This interaction occurred between the phosphotyrosine-binding domain of SH2D5 and an NxxF motif located within the N-terminal region of the breakpoint cluster region. siRNA-mediated depletion of SH2D5 in a neuroblastoma cell line, B35, induced a cell rounding phenotype correlated with low levels of activated Rac1-GTP, suggesting that SH2D5 affects Rac1-GTP levels. Taken together, our data provide the first characterization of the SH2D5 signaling protein.
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Affiliation(s)
- Elizabeth J Gray
- From the Department of Molecular Genetics, University of Toronto, Ontario M5S1A8, Canada, the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada,
| | - Evangelia Petsalaki
- the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada
| | - D Andrew James
- the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada, Sanofi Pasteur, Toronto, Ontario M2R3T4, Canada, and
| | - Richard D Bagshaw
- the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada
| | - Melissa M Stacey
- the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada
| | - Oliver Rocks
- the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada, the Max Delbrück Center for Molecular Medicine Berlin-Buch, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Anne-Claude Gingras
- From the Department of Molecular Genetics, University of Toronto, Ontario M5S1A8, Canada, the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada,
| | - Tony Pawson
- From the Department of Molecular Genetics, University of Toronto, Ontario M5S1A8, Canada, the Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G1X5, Canada
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16
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Um K, Niu S, Duman JG, Cheng JX, Tu YK, Schwechter B, Liu F, Hiles L, Narayanan AS, Ash RT, Mulherkar S, Alpadi K, Smirnakis SM, Tolias KF. Dynamic control of excitatory synapse development by a Rac1 GEF/GAP regulatory complex. Dev Cell 2014; 29:701-15. [PMID: 24960694 DOI: 10.1016/j.devcel.2014.05.011] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 04/23/2014] [Accepted: 05/14/2014] [Indexed: 11/18/2022]
Abstract
The small GTPase Rac1 orchestrates actin-dependent remodeling essential for numerous cellular processes including synapse development. While precise spatiotemporal regulation of Rac1 is necessary for its function, little is known about the mechanisms that enable Rac1 activators (GEFs) and inhibitors (GAPs) to act in concert to regulate Rac1 signaling. Here, we identify a regulatory complex composed of a Rac-GEF (Tiam1) and a Rac-GAP (Bcr) that cooperate to control excitatory synapse development. Disruption of Bcr function within this complex increases Rac1 activity and dendritic spine remodeling, resulting in excessive synaptic growth that is rescued by Tiam1 inhibition. Notably, EphB receptors utilize the Tiam1-Bcr complex to control synaptogenesis. Following EphB activation, Tiam1 induces Rac1-dependent spine formation, whereas Bcr prevents Rac1-mediated receptor internalization, promoting spine growth over retraction. The finding that a Rac-specific GEF/GAP complex is required to maintain optimal levels of Rac1 signaling provides an important insight into the regulation of small GTPases.
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Affiliation(s)
- Kyongmi Um
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Sanyong Niu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Brandon Schwechter
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Feng Liu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Laura Hiles
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Anjana S Narayanan
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ryan T Ash
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kannan Alpadi
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Stelios M Smirnakis
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Mulherkar S, Uddin MD, Couvillon AD, Sillitoe RV, Tolias KF. The small GTPases RhoA and Rac1 regulate cerebellar development by controlling cell morphogenesis, migration and foliation. Dev Biol 2014; 394:39-53. [PMID: 25128586 DOI: 10.1016/j.ydbio.2014.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
The small GTPases RhoA and Rac1 are key cytoskeletal regulators that function in a mutually antagonistic manner to control the migration and morphogenesis of a broad range of cell types. However, their role in shaping the cerebellum, a unique brain structure composed of an elaborate set of folia separated by fissures of different lengths, remains largely unexplored. Here we show that dysregulation of both RhoA and Rac1 signaling results in abnormal cerebellar ontogenesis. Ablation of RhoA from neuroprogenitor cells drastically alters the timing and placement of fissure formation, the migration and positioning of granule and Purkinje cells, the alignment of Bergmann glia, and the integrity of the basement membrane, primarily in the anterior lobules. Furthermore, in the absence of RhoA, granule cell precursors located at the base of fissures fail to undergo cell shape changes required for fissure initiation. Many of these abnormalities can be recapitulated by deleting RhoA specifically from granule cell precursors but not postnatal glia, indicating that RhoA functions in granule cell precursors to control cerebellar morphogenesis. Notably, mice with elevated Rac1 activity due to loss of the Rac1 inhibitors Bcr and Abr show similar anterior cerebellar deficits, including ectopic neurons and defects in fissure formation, Bergmann glia organization and basement membrane integrity. Together, our results suggest that RhoA and Rac1 play indispensable roles in patterning cerebellar morphology.
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Affiliation(s)
- Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Anthony D Couvillon
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Roy V Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children׳s Hospital, Houston, TX 77030, USA; Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, M.S. BCM 295, Houston, TX 77030, USA.
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18
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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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19
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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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20
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Ibitoye RM, Roberts J, Goodacre T, Kini U. 17p13.3 microduplication, a potential novel genetic locus for nonsyndromic bilateral cleft lip and palate. Cleft Palate Craniofac J 2014; 52:359-62. [PMID: 24625222 DOI: 10.1597/13-113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cleft lip and palate (CLP) is a relatively common congenital malformation. The etiology is complex and postulated to be a combination of genetic and environmental factors. The genetic loci for nonsyndromic CLP remain poorly characterized. Two families have recently been reported with a chromosome 17p13.3 microduplication and CLP. We report a third family with four individuals affected by nonsyndromic bilateral CLP and a 350-kb chromosome 17p13.3 microduplication (17:1,113,102-1,461,838). Our family possesses the smallest overlapping chromosome 17p13.3 microduplication associated with CLP, narrowing down the critical region for this potential new genetic locus for CLP.
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21
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Gong D, Fei F, Lim M, Yu M, Groffen J, Heisterkamp N. Abr, a negative regulator of Rac, attenuates cockroach allergen-induced asthma in a mouse model. THE JOURNAL OF IMMUNOLOGY 2013; 191:4514-20. [PMID: 24058174 DOI: 10.4049/jimmunol.1202603] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Abr deactivates Ras-related C3 botulinum toxin substrate (Rac), a master molecular switch that positively regulates many immune cell functions, by converting it to its GDP-bound conformation. In this article, we report that, in the absence of Abr function, cockroach allergen (CRA)-immunized mice experienced a fatal asthma attack when challenged with CRA. The asthma in abr(-/-) mice was characterized by increased pulmonary mucus production, elevated serum IgE, and leukocyte airway infiltration. Decreased pulmonary compliance was further documented by increased airway resistance upon methacholine challenge. Peribronchial and bronchoalveolar lavage eosinophils, key cells associated with allergic asthma, were increased in abr(-/-) mice, but adoptive transfer of this cell type from immunized mice to naive controls, followed by CRA challenge, showed that eosinophils are not primarily responsible for differences in airway resistance between controls and abr-null mutants. CD4(+) T cell numbers in the airways of CRA-challenged abr(-/-) mice also were significantly increased compared with controls, as were the Th2 T cell-secreted cytokines IL-4 and IL-5 in total lung. Interestingly, when control and abr(-/-) CD4(+) T cells from CRA-immunized mice were transferred to wild-type animals, airway resistance upon challenge with CRA was significantly higher in mice transplanted with T cells lacking Abr function. CD4(+) T cells from CRA-immunized and challenged abr(-/-) mice contained elevated levels of activated GTP-bound Rac compared with wild-type controls. Functionally, abr(-/-) CD4(+) T cells from CRA-exposed mice showed significantly enhanced chemotaxis toward CCL21. These results identify Abr-regulated CD4(+) T cell migration as an important component of severe CRA-evoked allergic asthma in mice.
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Affiliation(s)
- Dapeng Gong
- Division of Hematology and Oncology, Children's Hospital Los Angeles, Los Angeles, CA 90027
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22
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Cook DR, Rossman KL, Der CJ. Rho guanine nucleotide exchange factors: regulators of Rho GTPase activity in development and disease. Oncogene 2013; 33:4021-35. [PMID: 24037532 DOI: 10.1038/onc.2013.362] [Citation(s) in RCA: 286] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/25/2013] [Accepted: 06/26/2013] [Indexed: 12/16/2022]
Abstract
The aberrant activity of Ras homologous (Rho) family small GTPases (20 human members) has been implicated in cancer and other human diseases. However, in contrast to the direct mutational activation of Ras found in cancer and developmental disorders, Rho GTPases are activated most commonly in disease by indirect mechanisms. One prevalent mechanism involves aberrant Rho activation via the deregulated expression and/or activity of Rho family guanine nucleotide exchange factors (RhoGEFs). RhoGEFs promote formation of the active GTP-bound state of Rho GTPases. The largest family of RhoGEFs is comprised of the Dbl family RhoGEFs with 70 human members. The multitude of RhoGEFs that activate a single Rho GTPase reflects the very specific role of each RhoGEF in controlling distinct signaling mechanisms involved in Rho activation. In this review, we summarize the role of Dbl RhoGEFs in development and disease, with a focus on Ect2 (epithelial cell transforming squence 2), Tiam1 (T-cell lymphoma invasion and metastasis 1), Vav and P-Rex1/2 (PtdIns(3,4,5)P3 (phosphatidylinositol (3,4,5)-triphosphate)-dependent Rac exchanger).
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Affiliation(s)
- D R Cook
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Chapel Hill, NC, USA
| | - K L Rossman
- 1] Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [2] Lineberger Comprehensive Cancer Center, Chapel Hill, NC, USA
| | - C J Der
- 1] Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill, Lineberger Comprehensive Cancer Center, Chapel Hill, NC, USA [2] Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [3] Lineberger Comprehensive Cancer Center, Chapel Hill, NC, USA
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23
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Curry CJ, Rosenfeld JA, Grant E, Gripp KW, Anderson C, Aylsworth AS, Saad TB, Chizhikov VV, Dybose G, Fagerberg C, Falco M, Fels C, Fichera M, Graakjaer J, Greco D, Hair J, Hopkins E, Huggins M, Ladda R, Li C, Moeschler J, Nowaczyk MJM, Ozmore JR, Reitano S, Romano C, Roos L, Schnur RE, Sell S, Suwannarat P, Svaneby D, Szybowska M, Tarnopolsky M, Tervo R, Tsai ACH, Tucker M, Vallee S, Wheeler FC, Zand DJ, Barkovich AJ, Aradhya S, Shaffer LG, Dobyns WB. The duplication 17p13.3 phenotype: analysis of 21 families delineates developmental, behavioral and brain abnormalities, and rare variant phenotypes. Am J Med Genet A 2013; 161A:1833-52. [PMID: 23813913 DOI: 10.1002/ajmg.a.35996] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 03/31/2013] [Indexed: 11/11/2022]
Abstract
Chromosome 17p13.3 is a gene rich region that when deleted is associated with the well-known Miller-Dieker syndrome. A recently described duplication syndrome involving this region has been associated with intellectual impairment, autism and occasional brain MRI abnormalities. We report 34 additional patients from 21 families to further delineate the clinical, neurological, behavioral, and brain imaging findings. We found a highly diverse phenotype with inter- and intrafamilial variability, especially in cognitive development. The most specific phenotype occurred in individuals with large duplications that include both the YWHAE and LIS1 genes. These patients had a relatively distinct facial phenotype and frequent structural brain abnormalities involving the corpus callosum, cerebellar vermis, and cranial base. Autism spectrum disorders were seen in a third of duplication probands, most commonly in those with duplications of YWHAE and flanking genes such as CRK. The typical neurobehavioral phenotype was usually seen in those with the larger duplications. We did not confirm the association of early overgrowth with involvement of YWHAE and CRK, or growth failure with duplications of LIS1. Older patients were often overweight. Three variant phenotypes included cleft lip/palate (CLP), split hand/foot with long bone deficiency (SHFLD), and a connective tissue phenotype resembling Marfan syndrome. The duplications in patients with clefts appear to disrupt ABR, while the SHFLD phenotype was associated with duplication of BHLHA9 as noted in two recent reports. The connective tissue phenotype did not have a convincing critical region. Our experience with this large cohort expands knowledge of this diverse duplication syndrome.
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24
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Wegiel J, Kuchna I, Nowicki K, Imaki H, Wegiel J, Ma SY, Azmitia EC, Banerjee P, Flory M, Cohen IL, London E, Brown WT, Komich Hare C, Wisniewski T. Contribution of olivofloccular circuitry developmental defects to atypical gaze in autism. Brain Res 2013; 1512:106-22. [PMID: 23558308 DOI: 10.1016/j.brainres.2013.03.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 02/11/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
Abstract
Individuals with autism demonstrate atypical gaze, impairments in smooth pursuit, altered movement perception and deficits in facial perception. The olivofloccular neuronal circuit is a major contributor to eye movement control. This study of the cerebellum in 12 autistic and 10 control subjects revealed dysplastic changes in the flocculus of eight autistic (67%) and two control (20%) subjects. Defects of the oculomotor system, including avoidance of eye contact and poor or no eye contact, were reported in 88% of autistic subjects with postmortem-detected floccular dysplasia. Focal disorganization of the flocculus cytoarchitecture with deficit, altered morphology, and spatial disorientation of Purkinje cells (PCs); deficit and abnormalities of granule, basket, stellate and unipolar brush cells; and structural defects and abnormal orientation of Bergmann glia are indicators of profound disruption of flocculus circuitry in a dysplastic area. The average volume of PCs was 26% less in the dysplastic region than in the unaffected region of the flocculus (p<0.01) in autistic subjects. Moreover, the average volume of PCs in the entire cerebellum was 25% less in the autistic subjects than in the control subjects (p<0.001). Findings from this study and a parallel study of the inferior olive (IO) suggest that focal floccular dysplasia combined with IO neurons and PC developmental defects may contribute to oculomotor system dysfunction and atypical gaze in autistic subjects.
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Affiliation(s)
- Jerzy Wegiel
- Department of Developmental Neurobiology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, United States.
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25
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Yu M, Gong D, Lim M, Arutyunyan A, Groffen J, Heisterkamp N. Lack of bcr and abr promotes hypoxia-induced pulmonary hypertension in mice. PLoS One 2012; 7:e49756. [PMID: 23152932 PMCID: PMC3495860 DOI: 10.1371/journal.pone.0049756] [Citation(s) in RCA: 10] [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: 12/19/2011] [Accepted: 10/16/2012] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Bcr and Abr are GTPase activating proteins that specifically downregulate activity of the small GTPase Rac in restricted cell types in vivo. Rac1 is expressed in smooth muscle cells, a critical cell type involved in the pathogenesis of pulmonary hypertension. The molecular mechanisms that underlie hypoxia-associated pulmonary hypertension are not well-defined. METHODOLOGY/PRINCIPAL FINDINGS Bcr and abr null mutant mice were compared to wild type controls for the development of pulmonary hypertension after exposure to hypoxia. Also, pulmonary arterial smooth muscle cells from those mice were cultured in hypoxia and examined for proliferation, p38 activation and IL-6 production. Mice lacking Bcr or Abr exposed to hypoxia developed increased right ventricular pressure, hypertrophy and pulmonary vascular remodeling. Perivascular leukocyte infiltration in the lungs was increased, and under hypoxia bcr-/- and abr-/- macrophages generated more reactive oxygen species. Consistent with a contribution of inflammation and oxidative stress in pulmonary hypertension-associated vascular damage, Bcr and Abr-deficient animals showed elevated endothelial leakage after hypoxia exposure. Hypoxia-treated pulmonary arterial smooth muscle cells from Bcr- or Abr-deficient mice also proliferated faster than those of wild type mice. Moreover, activated Rac1, phosphorylated p38 and interleukin 6 were increased in these cells in the absence of Bcr or Abr. Inhibition of Rac1 activation with Z62954982, a novel Rac inhibitor, decreased proliferation, p38 phosphorylation and IL-6 levels in pulmonary arterial smooth muscle cells exposed to hypoxia. CONCLUSIONS Bcr and Abr play a critical role in down-regulating hypoxia-induced pulmonary hypertension by deactivating Rac1 and, through this, reducing both oxidative stress generated by leukocytes as well as p38 phosphorylation, IL-6 production and proliferation of pulmonary arterial smooth muscle cells.
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Affiliation(s)
- Min Yu
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - Dapeng Gong
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - Min Lim
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Anna Arutyunyan
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
| | - John Groffen
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Nora Heisterkamp
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, and The Saban Research Institute of Children’s Hospital, Los Angeles, California, United States of America
- Departments of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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26
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Miller NLG, Lawson C, Chen XL, Lim ST, Schlaepfer DD. Rgnef (p190RhoGEF) knockout inhibits RhoA activity, focal adhesion establishment, and cell motility downstream of integrins. PLoS One 2012; 7:e37830. [PMID: 22649559 PMCID: PMC3359313 DOI: 10.1371/journal.pone.0037830] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/24/2012] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Cell migration is a highly regulated process that involves the formation and turnover of cell-matrix contact sites termed focal adhesions. Rho-family GTPases are molecular switches that regulate actin and focal adhesion dynamics in cells. Guanine nucleotide exchange factors (GEFs) activate Rho-family GTPases. Rgnef (p190RhoGEF) is a ubiquitous 190 kDa GEF implicated in the control of colon carcinoma and fibroblast cell motility. PRINCIPAL FINDINGS Rgnef exon 24 floxed mice (Rgnef(flox)) were created and crossed with cytomegalovirus (CMV)-driven Cre recombinase transgenic mice to inactivate Rgnef expression in all tissues during early development. Heterozygous Rgnef(WT/flox) (Cre+) crosses yielded normal Mendelian ratios at embryonic day 13.5, but Rgnef(flox/flox) (Cre+) mice numbers at 3 weeks of age were significantly less than expected. Rgnef(flox/flox) (Cre+) (Rgnef-/-) embryos and primary mouse embryo fibroblasts (MEFs) were isolated and verified to lack Rgnef protein expression. When compared to wildtype (WT) littermate MEFs, loss of Rgnef significantly inhibited haptotaxis migration, wound closure motility, focal adhesion number, and RhoA GTPase activation after fibronectin-integrin stimulation. In WT MEFs, Rgnef activation occurs within 60 minutes upon fibronectin plating of cells associated with RhoA activation. Rgnef-/- MEF phenotypes were rescued by epitope-tagged Rgnef re-expression. CONCLUSIONS Rgnef-/- MEF phenotypes were due to Rgnef loss and support an essential role for Rgnef in RhoA regulation downstream of integrins in control of cell migration.
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Affiliation(s)
| | | | | | | | - David D. Schlaepfer
- Moores Cancer Center, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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27
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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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28
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Pham MH, Zada G, Mosich GM, Chen TC, Giannotta SL, Wang K, Mack WJ. Molecular genetics of meningiomas: a systematic review of the current literature and potential basis for future treatment paradigms. Neurosurg Focus 2011; 30:E7. [PMID: 21529178 DOI: 10.3171/2011.2.focus1117] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although a majority of meningiomas are benign neoplasms, those occurring at the cranial base may be challenging tumors to treat because of extensive tissue invasion, an inability to achieve gross-total microscopic resection, and local tumor recurrence and/or progression. A more comprehensive understanding of the genetic abnormalities associated with meningioma tumorigenesis, growth, and invasion may provide novel targets for grading assessments and individualizing molecular therapies for skull base meningiomas. The authors performed a review of the current literature to identify genes that have been associated with the formation and/or progression of meningiomas. Mutations in the NF2 gene have been most commonly implicated in the formation of the majority of meningiomas. Inactivation of other tumor suppressor genes, including DAL-1 and various tissue inhibitors of matrix metalloproteinases, upregulation of several oncogenes including c-sis and STAT3, and signaling dysregulation of pathways such as the Wnt pathway, have each been found to play important, and perhaps, complementary roles in meningioma development, progression, and recurrence. Identification of these genetic factors using genome-wide association studies and high-throughput genomics may provide data for future individualized treatment strategies.
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Affiliation(s)
- Martin H Pham
- Department of Neurosurgery, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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29
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Tolias KF, Duman JG, Um K. Control of synapse development and plasticity by Rho GTPase regulatory proteins. Prog Neurobiol 2011; 94:133-48. [PMID: 21530608 DOI: 10.1016/j.pneurobio.2011.04.011] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/13/2011] [Accepted: 04/15/2011] [Indexed: 12/21/2022]
Abstract
Synapses are specialized cell-cell contacts that mediate communication between neurons. Most excitatory synapses in the brain are housed on dendritic spines, small actin-rich protrusions extending from dendrites. During development and in response to environmental stimuli, spines undergo marked changes in shape and number thought to underlie processes like learning and memory. Improper spine development, in contrast, likely impedes information processing in the brain, since spine abnormalities are associated with numerous brain disorders. Elucidating the mechanisms that regulate the formation and plasticity of spines and their resident synapses is therefore crucial to our understanding of cognition and disease. Rho-family GTPases, key regulators of the actin cytoskeleton, play essential roles in orchestrating the development and remodeling of spines and synapses. Precise spatio-temporal regulation of Rho GTPase activity is critical for their function, since aberrant Rho GTPase signaling can cause spine and synapse defects as well as cognitive impairments. Rho GTPases are activated by guanine nucleotide exchange factors (GEFs) and inhibited by GTPase-activating proteins (GAPs). We propose that Rho-family GEFs and GAPs provide the spatiotemporal regulation and signaling specificity necessary for proper Rho GTPase function based on the following features they possess: (i) existence of multiple GEFs and GAPs per Rho GTPase, (ii) developmentally regulated expression, (iii) discrete localization, (iv) ability to bind to and organize specific signaling networks, and (v) tightly regulated activity, perhaps involving GEF/GAP interactions. Recent studies describe several Rho-family GEFs and GAPs that uniquely contribute to spinogenesis and synaptogenesis. Here, we highlight several of these proteins and discuss how they occupy distinct biochemical niches critical for synaptic development.
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Affiliation(s)
- Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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Kiraly DD, Eipper-Mains JE, Mains RE, Eipper BA. Synaptic plasticity, a symphony in GEF. ACS Chem Neurosci 2010; 1:348-365. [PMID: 20543890 DOI: 10.1021/cn100012x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Dendritic spines are the postsynaptic sites for the majority of excitatory synapses in the mammalian forebrain. While many spines display great stability, others change shape in a matter of seconds to minutes. These rapid alterations in dendritic spine number and size require tight control of the actin cytoskeleton, the main structural component of dendritic spines. The ability of neurons to alter spine number and size is essential for the expression of neuronal plasticity. Within spines, guanine nucleotide exchange factors (GEFs) act as critical regulators of the actin cytoskeleton by controlling the activity of Rho-GTPases. In this review we focus on the Rho-GEFs expressed in the nucleus accumbens and localized to the postsynaptic density, and thus positioned to effect rapid alterations in the structure of dendritic spines. We review literature that ties these GEFs to different receptor systems and intracellular signaling cascades and discuss the effects these interactions are likely to have on synaptic plasticity.
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Affiliation(s)
- Drew D. Kiraly
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut
| | - Jodi E. Eipper-Mains
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, Connecticut
| | - Richard E. Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut
| | - Betty A. Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut
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Olk S, Turchinovich A, Grzendowski M, Stühler K, Meyer HE, Zoidl G, Dermietzel R. Proteomic analysis of astroglial connexin43 silencing uncovers a cytoskeletal platform involved in process formation and migration. Glia 2010; 58:494-505. [PMID: 19795503 DOI: 10.1002/glia.20942] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Connexin43 (Cx43) is the most abundant gap junction protein of the brain, where it is predominantly expressed in astrocytes. Recent studies imply a role of Cx43 in the regulation of important cellular processes, including migration, proliferation, and shape formation. These processes are assumed to be reflected by the proteome of the Cx43 expressing cells. To analyze the influence of Cx43 on the astrocytic proteome, we used RNA interference to downregulate the expression of this connexin in cultures of mouse astrocytes. We applied difference gel electrophoresis (DIGE) to compare silenced astrocytes with control cells. The differential proteome analysis revealed 15 significantly regulated proteins (between 1.2- and 1.6-fold), of which six are known to belong to a group of cytoskeletal proteins involved in cortical platform formation. Astrocytes treated with Cx43 small interfering (si)RNA showed an increased expression of the cytoskeletal proteins: actin, tropomyosin, microtubule-associated protein RP/EB1, transgelin, and GFAP, and a decreased expression of cofilin-1. Quantitative immunocytochemistry and Western blotting revealed similar results showing an upregulation of actin, tubulin, tropomyosin, EB1, transgelin and GFAP, and a downregulation of Ser-3-phosphorylated cofilin. Furthermore, Cx43 silencing led to phenotypical changes in cell morphology, migratory activity, and cell adhesion. Our results provide mechanistic clues for an understanding of Cx43 interaction with cellular motor activities such as migration and process formation in astrocytes.
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Affiliation(s)
- Stephan Olk
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, Germany
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Cerri S, Piccolini VM, Bernocchi G. Postnatal Development of the Central Nervous System: Anomalies in the Formation of Cerebellum Fissures. Anat Rec (Hoboken) 2010; 293:492-501. [DOI: 10.1002/ar.21082] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yi SJ, Groffen J, Heisterkamp N. Transglutaminase 2 regulates the GTPase-activating activity of Bcr. J Biol Chem 2010; 284:35645-51. [PMID: 19840940 DOI: 10.1074/jbc.m109.062240] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Transglutaminase 2 (TG2) is a multifunctional protein that has been implicated in numerous pathologies including that of neurodegeneration and celiac disease, but the molecular interactions that mediate its diverse activities are largely unknown. Bcr and the closely related Abr negatively regulate the small G-protein Rac: loss of their combined function in vivo results in increased reactivity of innate immune cells. Bcr and Abr are GTPase-activating proteins that catalyze the hydrolysis of the GTP bound to Rac. However, how the Bcr and Abr GTPase-activating activity is regulated is not precisely understood. We here report a novel mechanism of regulation through direct protein-protein interaction with TG2. TG2 bound to the Rac-binding pocket in the GTPase-activating domains of Bcr and Abr, blocked Bcr activity and, through this mechanism, increased levels of active GTP-bound Rac and EGF-stimulated membrane ruffling. TG2 exists in at least two different conformations. Interestingly, experiments using TG2 mutants showed that Bcr exhibits preferential binding to the non-compacted conformation of TG2, in which its catalytic domain is exposed, but transamidation is not needed for the interaction. Thus, TG2 regulates levels of cellular GTP-bound Rac and actin cytoskeletal reorganization through a new mechanism involving direct inhibition of Bcr GTPase-activating activity.
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Affiliation(s)
- Sun-Ju Yi
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, Childrens Hospital Los Angeles and the Saban Research Institute of Childrens Hospital, Los Angeles, California 90027, USA
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Negative regulators of insulin signaling revealed in a genome-wide functional screen. PLoS One 2009; 4:e6871. [PMID: 19727444 PMCID: PMC2731165 DOI: 10.1371/journal.pone.0006871] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 08/03/2009] [Indexed: 12/30/2022] Open
Abstract
Background Type 2 diabetes develops due to a combination of insulin resistance and β-cell failure and current therapeutics aim at both of these underlying causes. Several negative regulators of insulin signaling are known and are the subject of drug discovery efforts. We sought to identify novel contributors to insulin resistance and hence potentially novel targets for therapeutic intervention. Methodology An arrayed cDNA library encoding 18,441 human transcripts was screened for inhibitors of insulin signaling and revealed known inhibitors and numerous potential novel regulators. The novel hits included proteins of various functional classes such as kinases, phosphatases, transcription factors, and GTPase associated proteins. A series of secondary assays confirmed the relevance of the primary screen hits to insulin signaling and provided further insight into their modes of action. Conclusion/Significance Among the novel hits was PALD (KIAA1274, paladin), a previously uncharacterized protein that when overexpressed led to inhibition of insulin's ability to down regulate a FOXO1A-driven reporter gene, reduced upstream insulin-stimulated AKT phosphorylation, and decreased insulin receptor (IR) abundance. Conversely, knockdown of PALD gene expression resulted in increased IR abundance, enhanced insulin-stimulated AKT phosphorylation, and an improvement in insulin's ability to suppress FOXO1A-driven reporter gene activity. The present data demonstrate that the application of arrayed genome-wide screening technologies to insulin signaling is fruitful and is likely to reveal novel drug targets for insulin resistance and the metabolic syndrome.
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35
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Bcr and Abr cooperate in negatively regulating acute inflammatory responses. Mol Cell Biol 2009; 29:5742-50. [PMID: 19703997 DOI: 10.1128/mcb.00357-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bcr and Abr are GTPase-activating proteins for the small GTPase Rac. Both proteins are expressed in cells of the innate immune system, including neutrophils and macrophages. The function of Bcr has been linked to the negative regulation of neutrophil reactive oxygen species (ROS) production, but the function of Abr in the innate immune system was unknown. Here, we report that mice lacking both proteins are severely affected in two models of experimental endotoxemia, including exposure to Escherichia coli lipopolysaccharide and polymicrobial sepsis, with extensive microvascular leakage, resulting in severe pulmonary edema and hemorrhage. Additionally, in vivo-activated neutrophils of abr and bcr null mutant mice produced excessive tissue-damaging myeloperoxidase (MPO), elastase, and ROS. Moreover, the secretion of the tissue metalloproteinase MMP9 by monocytes and ROS by elicited macrophages was abnormally high. In comparison, ROS production from bone marrow monocytes was not significantly different from that of controls, and the exocytosis of neutrophil secondary and tertiary granule products, including lactoferrin, was normal. These data show that Abr and Bcr normally curb very specific functions of mature tissue innate immune cells, and that each protein has distinct as well as partly overlapping functions in the downregulation of inflammatory processes.
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Wozniak K, Piaskowski S, Gresner SM, Golanska E, Bieniek E, Bigoszewska K, Sikorska B, Szybka M, Kulczycka-Wojdala D, Zakrzewska M, Zawlik I, Papierz W, Stawski R, Jaskolski DJ, Och W, Sieruta M, Liberski PP, Rieske P. BCR expression is decreased in meningiomas showing loss of heterozygosity of 22q within a new minimal deletion region. ACTA ACUST UNITED AC 2008; 183:14-20. [PMID: 18474292 DOI: 10.1016/j.cancergencyto.2008.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 01/14/2008] [Accepted: 01/30/2008] [Indexed: 11/18/2022]
Abstract
Neurofibromin 2 (NF2), located on chromosome arm 22q, has been established as a tumor suppressor gene involved in meningioma pathogenesis. In our study, we investigated 149 meningiomas to determine whether there are additional tumor suppressor genes localized on chromosome 22q, apart from NF2, that might be involved in meningioma pathogenesis. The LOH analysis on chromosome 22q identified two regions of deletion: the first one, which is limited to the NF2 gene locus, and the second one, which is outside this location. The new minimal deletion region (MDR) included the following genes: BCR (breakpoint cluster region), RAB36 (a member of RAS oncogene family), GNAZ [guanine nucleotide binding protein (G protein), alpha-z polypeptide], and RTDR1 (rhabdoid tumor deletion region gene 1). The expression levels of all these genes, including NF2, were subsequently analyzed by quantitative real-time polymerase chain reaction. We observed a significantly lowered expression level of NF2 in meningiomas with 22q loss of heterozygosity (LOH) within NF2 region compared to the one in meningiomas with 22q retention of heterozygosity (ROH, P<0.05). Similarly, BCR showed a significantly lowered expression in meningiomas with 22q LOH within the new MDR compared to cases with 22q ROH (P<0.05). Our data, together with the already published information considering BCR function suggest that BCR can be considered as a candidate tumor suppressor gene localized on chromosome 22q which may be involved in meningioma pathogenesis.
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Affiliation(s)
- K Wozniak
- Department of Molecular Pathology and Neuropathology, Medical University of Lodz, Czechoslowacka 8/10, 92-216 Lodz, Poland
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Kweon SM, Cho YJ, Minoo P, Groffen J, Heisterkamp N. Activity of the Bcr GTPase-activating domain is regulated through direct protein/protein interaction with the Rho guanine nucleotide dissociation inhibitor. J Biol Chem 2007; 283:3023-3030. [PMID: 18070886 DOI: 10.1074/jbc.m705513200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cycling of Rac GTPases, alternating between an active GTP- and an inactive GDP-bound state, is controlled by guanine nucleotide exchange factors, GTPase-activating proteins (GAPs), and guanine nucleotide dissociation inhibitors (GDIs). Little is known about how these controlling activities are coordinated. Studies using null mutant mice have demonstrated that Bcr and Abr are two physiologically important GAPs for Rac. Here, we report that in the presence of RhoGDIalpha, Bcr is unable to convert Rac-GTP to Rac-GDP because RhoGDI forms a direct protein complex with Bcr. Interestingly, RhoGDIalpha binds to the GAP domain in Bcr and Abr, a domain that also binds to Rac-GTP and catalyzes conversion of the bound GTP to GDP on Rac. The presence of activated Rac diminished the Bcr/RhoGDIalpha interaction. Moreover, a Bcr mutant that lacks the ability to promote hydrolysis of Rac-GTP bound to its GAP domain did not bind to RhoGDIalpha in cell lysates, indicating that binding of RhoGDIalpha and Rac-GTP to the Bcr GAP domain is mutually exclusive. Our results provide the first identification of a protein that regulates BcrGAP activity.
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Affiliation(s)
- Soo-Mi Kweon
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California 90027
| | - Young Jin Cho
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California 90027
| | - Parviz Minoo
- Department of Pediatrics, University of Southern California, Los Angeles, California 90033
| | - John Groffen
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California 90027; Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033
| | - Nora Heisterkamp
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California 90027; Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033.
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Namiki K, Nakamura A, Furuya M, Mizuhashi S, Matsuo Y, Tokuhara N, Sudo T, Hama H, Kuwaki T, Yano S, Kimura S, Kasuya Y. Involvement of p38alpha in kainate-induced seizure and neuronal cell damage. J Recept Signal Transduct Res 2007; 27:99-111. [PMID: 17613723 DOI: 10.1080/10799890701357855] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated how p38alpha mitogen-activated protein kinase (p38) is related to kainate-induced epilepsy and neuronal damages, by using the mice with a single copy disruption of the p38 alpha gene (p38alpha(+/-)). Mortality rate and seizure score of p38alpha(+/-) mice administered with kainate were significantly reduced compared with the case of wild-type (WT) mice. This was clearly supported by the electroencephalography data in which kainate-induced seizure duration and frequency in the brain of p38alpha(+/-) mice were significantly suppressed compared to those of WT mice. As a consequence of seizure, kainate induced delayed neuronal damages in parallel with astrocytic growth in the hippocampus and ectopic innervation of the mossy fibers into the stratum oriens in the CA3 region of hippocampus in WT mice, whose changes were moderate in p38alpha(+/-) mice. Likewise, kainate-induced phosphorylation of calcium/calmodulin-dependent kinase II in the hippocampus of p38alpha (+/-) mice was significantly decreased compared to that of WT mice. These results suggest that p38alpha signaling pathway plays an important role in epileptic seizure and excitotoxicity.
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Affiliation(s)
- Kana Namiki
- Department of Biochemistry and Molecular Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
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Wiencken-Barger AE, Djukic B, Casper KB, McCarthy KD. A role for Connexin43 during neurodevelopment. Glia 2007; 55:675-86. [PMID: 17311295 DOI: 10.1002/glia.20484] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Connexin43 (Cx43) is the predominant gap junction protein expressed in premitotic radial glial cells and mature astrocytes. It is thought to play a role in many aspects of brain development and physiology, including intercellular communication, the release of neuroactive substances, and neural and glial proliferation and migration. To investigate the role of Cx43 in brain physiology, we generated a conditional knockout (cKO) mouse expressing Cre recombinase driven by the human GFAP promoter and a floxed Cx43 gene. The removal of Cx43 from GFAP-expressing cells affects the behavior of the mice and the development of several brain structures; however, the severity of the phenotype varies depending on the mouse background. One mouse subline, hereafter termed Shuffler, exhibits cellular disorganization of the cortex, hippocampus, and cerebellum, accompanied by ataxia and motor deficits. The Shuffler cerebellum is most affected and displays altered distribution and lamination of glia and neurons suggestive of cell migration defects. In all Shuffler mice by postnatal day two (P2), the hippocampus, cortex, and cerebellum are smaller. Disorganization of the ventricular and subventricular zone of the cortex is also evident. Given that these are sites of early progenitor cell proliferation, we suspect production and migration of neural progenitors may be altered. In conclusion, neurodevelopment of Shuffler/Cx43 cKO mice is abnormal, and the observed cellular phenotype may explain behavioral disturbances seen in these animals as well as in humans carrying Cx43 mutations.
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Affiliation(s)
- Amy E Wiencken-Barger
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
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Correa-Cerro LS, Mandell JW. Molecular mechanisms of astrogliosis: new approaches with mouse genetics. J Neuropathol Exp Neurol 2007; 66:169-76. [PMID: 17356378 DOI: 10.1097/01.jnen.0000248555.53079.d5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Astrocytes are increasingly being recognized as dynamic participants in many aspects of normal central nervous system function. In disease states, reactive astrocytes undergo complex phenotypic changes, generically referred to as astrogliosis. Unraveling the functions of reactive astrocytes and underlying molecular mechanisms is a difficult problem. The use of genetically modified mice is beginning to yield some answers to long-standing questions in the field. What are the functions of reactive astrocytes? What extracellular factors and intracellular signaling mechanisms are responsible for astrocyte activation in various forms of neural injury? In this review we will highlight studies using astrocyte reporter lines for cellular imaging and lineage tracing, as well as gain- and loss-of-function mutations that have begun to shed light on mechanisms of astrogliosis.
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Affiliation(s)
- Lina S Correa-Cerro
- Department of Pathology, Division of Neuropathology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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Samson T, Will C, Knoblauch A, Sharek L, von der Mark K, Burridge K, Wixler V. Def-6, a guanine nucleotide exchange factor for Rac1, interacts with the skeletal muscle integrin chain alpha7A and influences myoblast differentiation. J Biol Chem 2007; 282:15730-42. [PMID: 17403664 DOI: 10.1074/jbc.m611197200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Integrin alpha7beta1 is the major laminin binding integrin receptor of muscle cells. The alpha7 chain occurs in several splice isoforms, of which alpha7A and alpha7B differ in their intracellular domains only. The fact that the expression of alpha7A and alpha7B is tightly regulated during skeletal muscle development suggests different and distinct roles for both isoforms. However, so far, functional properties and interacting proteins were described for the alpha7B chain only. Using a yeast two-hybrid screen, we have found that Def-6, a guanine nucleotide exchange factor for Rac1, binds to the intracellular domain of the alpha7A subunit. The specificity of the Def-6-alpha7A interaction has been shown by direct yeast two-hybrid binding assays and coprecipitation experiments. This is the first description of an alpha7A-specific and -exclusive interaction, because Def-6 did not bind to any other tested integrin cytoplasmic domain. Interestingly, the binding of Def-6 to alpha7A was abolished, when cells were cotransfected with an Src-related kinase, which is known to phosphorylate Def-6 and stimulate its exchange activity. We found expression of Def-6 was not only restricted to T-lymphocytes as described thus far but in a more widespread manner, including different muscle tissues. In cells, Def-6 is seen in newly forming cell protrusions and focal adhesions, and its localization partially overlaps with the alpha7A integrin receptor. C2C12 myoblasts overexpressing Def-6 show a delay of Rac1 inactivation during myogenic differentiation and abnormal myotube formation. Thus, our data suggest a role for Def-6 in the fine regulation of Rac1 during myogenesis with the integrin alpha7A chain guiding this regulation in a spatio-temporal manner.
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Affiliation(s)
- Thomas Samson
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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Cho YJ, Cunnick JM, Yi SJ, Kaartinen V, Groffen J, Heisterkamp N. Abr and Bcr, two homologous Rac GTPase-activating proteins, control multiple cellular functions of murine macrophages. Mol Cell Biol 2006; 27:899-911. [PMID: 17116687 PMCID: PMC1800684 DOI: 10.1128/mcb.00756-06] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Small GTPases of the Rho family are key regulators of phagocytic leukocyte function. Abr and Bcr are homologous, multidomain proteins. Their C-terminal domain has GTPase-activating protein (GAP) activity that, in vitro, is specific for Rac and Cdc42. To address the in vivo relevance of these entire proteins, of which little is known, the current study examined the effect of the genetic ablation of Abr and Bcr in murine macrophages. The concomitant loss of Abr and Bcr induced multiple alterations of macrophage cellular behavior known to be under the control of Rac. Macrophages lacking both Abr and Bcr exhibited an atypical, elongated morphology that was reproduced by the ectopic expression of GAP domain mutant Abr and Bcr in a macrophage cell line and of constitutively active Rac in primary macrophages. A robust increase in colony-stimulating factor 1 (CSF-1)-directed motility was observed in macrophages deficient for both proteins and, in response to CSF-1 stimulation, Abr and Bcr transiently translocated to the plasma membrane. Phagocytosis of opsonized particles was also increased in macrophages lacking both proteins and correlated with sustained Rac activation. Bcr and Abr GAP mutant proteins localized around phagosomes and induced distinct phagocytic cup formation. These results identify Abr and Bcr as the only GAPs to date that specifically negatively regulate Rac function in vivo in primary macrophages.
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Affiliation(s)
- Young Jin Cho
- Division of Hematology/Oncology Ms#54, Children's Hospital Los Angeles, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA
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Olabisi OO, Mahon GM, Kostenko EV, Liu Z, Ozer HL, Whitehead IP. Bcr interacts with components of the endosomal sorting complex required for transport-I and is required for epidermal growth factor receptor turnover. Cancer Res 2006; 66:6250-7. [PMID: 16778200 DOI: 10.1158/0008-5472.can-06-0536] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Virtually all patients with chronic myelogenous leukemia (CML) express an aberrant protein (p210 Bcr-Abl) that contains NH2-terminal sequences from Bcr fused to COOH-terminal sequences from Abl. In a yeast two-hybrid screen, we have identified TSG101 as a binding partner for Bcr. Because TSG101 is a subunit of the mammalian endosomal sorting complex required for transport (ESCRT), which regulates protein sorting during endosomal trafficking, this association suggests that Bcr may have a related cellular function. The docking site for TSG101 has been mapped to the COOH terminus of Bcr, indicating that this interaction may be disrupted in CML. Overexpression studies with full-length TSG101 and Bcr reveal that this interaction can be recapitulated in mammalian cells. The association can also be observed between natively expressed proteins in a panel of hematopoietic and nonhematopoietic cell lines, where a second subunit of the ESCRT complex, vacuolar sorting protein 28 (Vps28), was also found to interact with Bcr. Both Bcr and TSG101 exhibit a punctate cytoplasmic distribution and seem to colocalize in HeLa cells, which would be consistent with an in vivo association. Bacterially purified Bcr and TSG101 also bind, suggesting that the interaction is direct and is not dependent on ubiquitination. Disruption of the endosomal pathway with an ATPase-defective Vps4 mutant results in the cellular redistribution of Bcr, and suppression of Bcr in HeLa cells by small interfering RNA impairs epidermal growth factor receptor turnover. Taken together, these observations suggest that Bcr is a component of the mammalian ESCRT complexes and plays an important role in cellular trafficking of growth factor receptors.
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Affiliation(s)
- Oyenike O Olabisi
- Department of Microbiology and Molecular Genetics and University Hospital Cancer Center, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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Tanaka M, Marunouchi T. Abnormality in the cerebellar folial pattern of C57BL/6J mice. Neurosci Lett 2005; 390:182-6. [PMID: 16139954 DOI: 10.1016/j.neulet.2005.08.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 07/31/2005] [Accepted: 08/04/2005] [Indexed: 11/15/2022]
Abstract
The characteristic folial pattern of the mouse cerebellum is formed during postnatal development. We observed this process in C57BL/6J (B6) mice in detail, and found an abnormal folial pattern in a specific region (lobules VIII and IX of the vermis) in a substantial number of B6 mice. The frequency of this abnormality increased during postnatal development and reached 55% in the adult. Thus, the present study showed an abnormality in the cerebellar folial pattern of B6 mice, a mouse widely used in knockout studies, and called for caution in the phenotypic analysis of knockout mice of the B6 genetic background.
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Affiliation(s)
- Masahiko Tanaka
- Division of Cell Biology, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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Cho YJ, Zhang B, Kaartinen V, Haataja L, de Curtis I, Groffen J, Heisterkamp N. Generation of rac3 null mutant mice: role of Rac3 in Bcr/Abl-caused lymphoblastic leukemia. Mol Cell Biol 2005; 25:5777-85. [PMID: 15964830 PMCID: PMC1157002 DOI: 10.1128/mcb.25.13.5777-5785.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous studies indirectly implicate Rac GTPases in cancer. To investigate if Rac3 contributes to normal or malignant cell function, we generated rac3 null mutants through gene targeting. These mice were viable, fertile, and lacked an obvious external phenotype. This shows Rac3 function is dispensable for embryonic development. Bcr/Abl is a deregulated tyrosine kinase that causes chronic myelogenous leukemia and Ph-positive acute lymphoblastic leukemia in humans. Vav1, a hematopoiesis-specific exchange factor for Rac, was constitutively tyrosine phosphorylated in primary lymphomas from Bcr/Abl P190 transgenic mice, suggesting inappropriate Rac activation. rac3 is expressed in these malignant hematopoietic cells. Using lysates from BCR/ABL transgenic mice that express or lack rac3, we detected the presence of activated Rac3 but not Rac1 or Rac2 in the malignant precursor B-lineage lymphoblasts. In addition, in female P190 BCR/ABL transgenic mice, lack of rac3 was associated with a longer average survival. These data are the first to directly show a stimulatory role for Rac in leukemia in vivo. Moreover, our data suggest that interference with Rac3 activity, for example, by using geranyl-geranyltransferase inhibitors, may provide a positive clinical benefit for patients with Ph-positive acute lymphoblastic leukemia.
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Affiliation(s)
- Young Jin Cho
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology Ms#54, Childrens Hospital Los Angeles, University of Southern California 4650 Sunset Boulevard, Los Angeles, California 90027, USA
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46
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Rossman KL, Der CJ, Sondek J. GEF means go: turning on RHO GTPases with guanine nucleotide-exchange factors. Nat Rev Mol Cell Biol 2005; 6:167-80. [PMID: 15688002 DOI: 10.1038/nrm1587] [Citation(s) in RCA: 1322] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Guanine nucleotide-exchange factors (GEFs) are directly responsible for the activation of Rho-family GTPases in response to diverse extracellular stimuli, and ultimately regulate numerous cellular responses such as proliferation, differentiation and movement. With 69 distinct homologues, Dbl-related GEFs represent the largest family of direct activators of Rho GTPases in humans, and they activate Rho GTPases within particular spatio-temporal contexts. The failure to do so can have significant consequences and is reflected in the aberrant function of Dbl-family GEFs in some human diseases.
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Affiliation(s)
- Kent L Rossman
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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47
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Santos-Bredariol AS, Belmonte MA, Kihara AH, Santos MF, Hamassaki DE. Small GTP-binding protein RhoB is expressed in glial müller cells in the vertebrate retina. J Comp Neurol 2005; 494:976-85. [PMID: 16385489 DOI: 10.1002/cne.20861] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Among several small Rho GTPases observed in the chick retina, RhoB was transiently expressed during development and mainly present in glial Müller cells in the adult. The aim of this study was to compare the distribution of RhoB in the chick and mouse adult retinas and to study its potential role in the maintenance of cell morphology. The distribution of RhoB was studied in situ and pure Müller cell cultures were submitted to Clostridium difficile toxin A and lysophosphatidic acid (LPA) treatment in order to inactivate and activate Rho proteins, respectively. Cell morphology, F-actin arrangement, RhoB, and vimentin distribution were studied by immunofluorescence and confocal microscopy. The results showed that, in both species, all vimentin-containing cells also expressed RhoB in situ and in vitro. Toxin A promoted cell rounding and detachment due to actin depolymerization, changing the distribution of RhoB only in chick cells. In serum-starved cells LPA stimulated actin polymerization and cell spreading, but only in chick cells was RhoB distribution recruited to expanding cellular processes and newly formed focal adhesions. These data suggest that, although RhoB is expressed by Müller cells in chick and mouse, its role in the maintenance of cellular morphology and regulation may be different. In addition, we show that RhoB may be an interesting Müller cell marker in the adult retina.
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Affiliation(s)
- Andréa Silveira Santos-Bredariol
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP 05508-900, Brazil
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48
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Xiao J, Neylon CB, Nicholson GA, Furness JB. Evidence that a major site of expression of the RHO-GTPASE activating protein, oligophrenin-1, is peripheral myelin. Neuroscience 2004; 124:781-7. [PMID: 15026118 DOI: 10.1016/j.neuroscience.2004.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2004] [Indexed: 10/26/2022]
Abstract
Oligophrenin-1 is a recently discovered Rho-GTPase activating protein, mutation of which is associated with X-linked mental retardation. Since little is known about the cellular localization of oligophrenin-1 in central and peripheral neurons, we investigated its expression by RT-PCR and immunochemical analysis. Oligophrenin-1 immunoreactivity was found in glial cells forming myelin sheaths in the vagus nerve, sciatic nerve and dorsal roots of guinea-pig, rat and human, in chromaffin cells of the adrenal medulla, and in chromaffin cells associated with sympathetic ganglia. No immunoreactivity was detected in sympathetic neurons, in glial cells surrounding these neurons, in optic nerve or in spinal cord myelin. The full length cDNA sequence was determined from guinea-pig sciatic nerve. The translated amino acid sequence was 99% identical to the published human oligophrenin-1 sequence. Western blotting revealed two protein forms which were expressed to different relative extents in different tissues. A 91 kDa form was predominant in extracts of sciatic nerve whereas a 36 kDa form was relatively more abundant in adrenal medulla and brain. Greater amounts of the full length oligophrenin-1 protein occurred in the sciatic nerve of adult rats, compared with P2 rats, which reflects the development of myelination. The presence of multiple forms does not appear to be due to alternative mRNA splicing since RT-PCR products amplified from a variety of tissues were identical and only a single mRNA transcript of 7.4 kb was identified by Northern analysis. These findings demonstrate that a major site of oligophrenin-1 expression is peripheral myelin.
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Affiliation(s)
- J Xiao
- Department of Anatomy and Cell Biology and Centre for Neuroscience, University of Melbourne, Parkville, Victoria 3010, Australia
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49
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Mishra S, Reichert A, Cunnick J, Senadheera D, Hemmeryckx B, Heisterkamp N, Groffen J. Protein kinase CKIIalpha interacts with the Bcr moiety of Bcr/Abl and mediates proliferation of Bcr/Abl-expressing cells. Oncogene 2004; 22:8255-62. [PMID: 14614449 DOI: 10.1038/sj.onc.1207156] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Bcr protein was originally identified because of its fusion to Abl as a consequence of the Philadelphia chromosome translocation found in chronic myelogenous and acute lymphoblastic leukemias. The Bcr moiety is essential for the transforming activity of the Bcr/Abl oncogene. In search of physiologically relevant Bcr and Bcr/Abl-interacting proteins, we performed an interaction screen in yeast using the entire Bcr protein as bait. We here report that the alpha catalytic subunit of protein kinase CKII strongly and specifically forms a complex with Bcr in yeast in mouse lysates. The region in Bcr responsible for CKIIalpha binding was localized to residues 242-413. CKIIalpha was previously shown to be involved in leukemogenesis and tumorigenesis using different experimental approaches including mouse models. Inhibition of Bcr/Abl P190 in lymphoma cells from Bcr/Abl transgenic mice using imatinib reduced CKIIalpha activity. A highly selective inhibitor of CKIIalpha, 4,5,6,7-tetrabromo-2-benzotriazole, inhibited the growth of murine lymphoid cells with induced P210 Bcr/Abl expression and of P190 lymphoma cells. Our results demonstrate that CKIIalpha plays an important role in the proliferation of Bcr/Abl expressing cells, and suggests that inhibitors of CKIIalpha may have therapeutic potential in the treatment of Bcr/Abl-positive leukemia patients.
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Affiliation(s)
- Suparna Mishra
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, Ms#54, Childrens Hospital of Los Angeles Research Institute 4650 Sunset Boulevard, Los Angeles, CA 90027, USA
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50
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Yingling J, Toyo-Oka K, Wynshaw-Boris A. Miller-Dieker syndrome: analysis of a human contiguous gene syndrome in the mouse. Am J Hum Genet 2003; 73:475-88. [PMID: 12905154 PMCID: PMC1180674 DOI: 10.1086/378096] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2002] [Accepted: 06/30/2003] [Indexed: 11/03/2022] Open
Affiliation(s)
- Jessica Yingling
- Departments of Pediatrics and Medicine, University of California at San Diego School of Medicine, La Jolla, CA, 92093, USA
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