1
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Torii T, Miyamoto Y, Yamauchi J. Myelination by signaling through Arf guanine nucleotide exchange factor. J Neurochem 2024. [PMID: 38894552 DOI: 10.1111/jnc.16141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/19/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024]
Abstract
During myelination, large quantities of proteins are synthesized and transported from the endoplasmic reticulum (ER)-trans-Golgi network (TGN) to their appropriate locations within the intracellular region and/or plasma membrane. It is widely believed that oligodendrocytes uptake neuronal signals from neurons to regulate the endocytosis- and exocytosis-mediated intracellular trafficking of major myelin proteins such as myelin-associated glycoprotein (MAG) and proteolipid protein 1 (PLP1). The small GTPases of the adenosine diphosphate (ADP) ribosylation factor (Arf) family constitute a large group of signal transduction molecules that act as regulators for intracellular signaling, vesicle sorting, or membrane trafficking in cells. Studies on mice deficient in Schwann cell-specific Arfs-related genes have revealed abnormal myelination formation in peripheral nerves, indicating that Arfs-mediated signaling transduction is required for myelination in Schwann cells. However, the complex roles in these events remain poorly understood. This review aims to provide an update on signal transduction, focusing on Arf and its activator ArfGEF (guanine nucleotide exchange factor for Arf) in oligodendrocytes and Schwann cells. Future studies are expected to provide important information regarding the cellular and physiological processes underlying the myelination of oligodendrocytes and Schwann cells and their function in modulating neural activity.
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Affiliation(s)
- Tomohiro Torii
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Yuki Miyamoto
- Department of Pharmacology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
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2
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Martinez-Garcia M, Naharro PR, Skinner MW, Baran KA, Lascarez-Lagunas LI, Nadarajan S, Shin N, Silva-García CG, Saito TT, Beese-Sims S, Diaz-Pacheco BN, Berson E, Castañer AB, Pacheco S, Martinez-Perez E, Jordan PW, Colaiácovo MP. GRAS-1 is a novel regulator of early meiotic chromosome dynamics in C. elegans. PLoS Genet 2023; 19:e1010666. [PMID: 36809245 PMCID: PMC9983901 DOI: 10.1371/journal.pgen.1010666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 03/03/2023] [Accepted: 02/13/2023] [Indexed: 02/23/2023] Open
Abstract
Chromosome movements and licensing of synapsis must be tightly regulated during early meiosis to ensure accurate chromosome segregation and avoid aneuploidy, although how these steps are coordinated is not fully understood. Here we show that GRAS-1, the worm homolog of mammalian GRASP/Tamalin and CYTIP, coordinates early meiotic events with cytoskeletal forces outside the nucleus. GRAS-1 localizes close to the nuclear envelope (NE) in early prophase I and interacts with NE and cytoskeleton proteins. Delayed homologous chromosome pairing, synaptonemal complex (SC) assembly, and DNA double-strand break repair progression are partially rescued by the expression of human CYTIP in gras-1 mutants, supporting functional conservation. However, Tamalin, Cytip double knockout mice do not exhibit obvious fertility or meiotic defects, suggesting evolutionary differences between mammals. gras-1 mutants show accelerated chromosome movement during early prophase I, implicating GRAS-1 in regulating chromosome dynamics. GRAS-1-mediated regulation of chromosome movement is DHC-1-dependent, placing it acting within the LINC-controlled pathway, and depends on GRAS-1 phosphorylation at a C-terminal S/T cluster. We propose that GRAS-1 coordinates the early steps of homology search and licensing of SC assembly by regulating the pace of chromosome movement in early prophase I.
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Affiliation(s)
- Marina Martinez-Garcia
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pedro Robles Naharro
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marnie W Skinner
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Kerstin A Baran
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Laura I Lascarez-Lagunas
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Saravanapriah Nadarajan
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nara Shin
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carlos G Silva-García
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Takamune T Saito
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sara Beese-Sims
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brianna N Diaz-Pacheco
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Elizaveta Berson
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ana B Castañer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarai Pacheco
- MRC London Institute of Medical Sciences, London, United Kingdom
| | | | - Philip W Jordan
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Monica P Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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3
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Tamalin Function Is Required for the Survival of Neurons and Oligodendrocytes in the CNS. Int J Mol Sci 2022; 23:ijms232113395. [PMID: 36362204 PMCID: PMC9654138 DOI: 10.3390/ijms232113395] [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: 09/06/2022] [Revised: 10/30/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Tamalin is a post-synaptic scaffolding protein that interacts with group 1 metabotropic glutamate receptors (mGluRs) and several other proteins involved in protein trafficking and cytoskeletal events, including neuronal growth and actin reorganization. It plays an important role in synaptic plasticity in vitro by controlling the ligand-dependent trafficking of group 1 mGluRs. Abnormal regulation of mGluRs in the central nervous system (CNS) is associated with glutamate-mediated neurodegenerative disorders. However, the pathological consequences of tamalin deficiency in the CNS are unclear. In this study, tamalin knockout (KO) zebrafish and mice exhibited neurodegeneration along with oligodendrocyte degeneration in the post-embryonic CNS to adulthood without any developmental defects, thus suggesting the function of tamalin is more important in the postnatal stage to adulthood than that in CNS development. Interestingly, hypomyelination was independent of axonal defects in the CNS of tamalin knockout zebrafish and mice. In addition, the loss of Arf6, a downstream signal of tamalin scaffolding protein, synergistically induced neurodegeneration in tamalin KO zebrafish even in the developing CNS. Furthermore, tamalin KO zebrafish displayed increased mGluR5 expression. Taken together, tamalin played an important role in neuronal and oligodendrocyte survival and myelination through the regulation of mGluR5 in the CNS.
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Ito A, Fukaya M, Okamoto H, Sakagami H. Physiological and Pathological Roles of the Cytohesin Family in Neurons. Int J Mol Sci 2022; 23:5087. [PMID: 35563476 PMCID: PMC9104363 DOI: 10.3390/ijms23095087] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 02/05/2023] Open
Abstract
The cytohesin proteins, consisting of four closely related members (cytohesins-1, -2, -3, and -4), are a subfamily of the Sec7 domain-containing guanine nucleotide exchange factors for ADP ribosylation factors (Arfs), which are critical regulators of membrane trafficking and actin cytoskeleton remodeling. Recent advances in molecular biological techniques and the development of a specific pharmacological inhibitor for cytohesins, SecinH3, have revealed the functional involvement of the cytohesin-Arf pathway in diverse neuronal functions from the formation of axons and dendrites, axonal pathfinding, and synaptic vesicle recycling, to pathophysiological processes including chronic pain and neurotoxicity induced by proteins related to neurodegenerative disorders, such as amyotrophic lateral sclerosis and Alzheimer's disease. Here, we review the physiological and pathological roles of the cytohesin-Arf pathway in neurons and discuss the future directions of this research field.
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Affiliation(s)
- Akiko Ito
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan; (A.I.); (H.O.)
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
| | - Hirotsugu Okamoto
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan; (A.I.); (H.O.)
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
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5
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Li J, Lambright DG, Hsu VW. Coordination of Grp1 recruitment mechanisms by its phosphorylation. Mol Biol Cell 2020; 31:2816-2825. [PMID: 33026967 PMCID: PMC7851867 DOI: 10.1091/mbc.e20-03-0173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The action of guanine nucleotide exchange factors (GEFs) on the ADP-ribosylation factor (ARF) family of small GTPases initiates intracellular transport pathways. This role requires ARF GEFs to be recruited from the cytosol to intracellular membrane compartments. An ARF GEF known as General receptor for 3-phosphoinositides 1 (Grp1) is recruited to the plasma membrane through its pleckstrin homology (PH) domain that recognizes phosphatidylinositol 3,4,5-trisphosphate (PIP3). Here, we find that the phosphorylation of Grp1 induces its PH domain to recognize instead phosphatidylinositol 4-phosphate (PI4P). This phosphorylation also releases an autoinhibitory mechanism that results in the coil–coil (CC) domain of Grp1 engaging two peripheral membrane proteins of the recycling endosome. Because the combination of these actions results in Grp1 being recruited preferentially to the recycling endosome rather than to the plasma membrane, our findings reveal the complexity of recruitment mechanisms that need to be coordinated in localizing an ARF GEF to an intracellular compartment to initiate a transport pathway. Our elucidation is also remarkable for having revealed that phosphoinositide recognition by a PH domain can be switched through its phosphorylation.
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Affiliation(s)
- Jian Li
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - David G Lambright
- Program in Molecular Medicine, Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Victor W Hsu
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115
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Schintu N, Zhang X, Stroth N, Mathé AA, Andrén PE, Svenningsson P. Non-dopaminergic Alterations in Depression-Like FSL Rats in Experimental Parkinsonism and L-DOPA Responses. Front Pharmacol 2020; 11:304. [PMID: 32265703 PMCID: PMC7099513 DOI: 10.3389/fphar.2020.00304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 02/28/2020] [Indexed: 12/16/2022] Open
Abstract
Depression is a common comorbid condition in Parkinson’s disease (PD). Patients with depression have a two-fold increased risk to develop PD. Further, depression symptoms often precede motor symptoms in PD and are frequent at all stages of the disease. However, the influence of a depressive state on the responses to antiparkinson treatments is largely unknown. In this study, the genetically inbred depression-like flinders sensitive line (FSL) rats and control flinders resistant line (FRL) rats were studied in models of experimental parkinsonism. FSL rats showed a potentiated tremorgenic response to tacrine, a cholinesterase inhibitor used experimentally to induce 6 Hz resting tremor reminiscent of parkinsonian tremor. We also studied rats lesioned with 6-OHDA to induce hemiparkinsonism. No baseline differences in dopaminergic response to acute apomorphine or L-DOPA was found. However, following chronic treatment with L-DOPA, FRL rats developed sensitization of turning and abnormal involuntary movements (AIMs); these effects were counteracted by the anti-dyskinetic 5-HT1A agonist/D2 partial agonist sarizotan. In contrast, FSL rats did not develop sensitization of turning and only minor AIMs in response to L-DOPA treatment. The roles of several non-dopamine systems underlying this discrepancy were studied. Unexpectedly, no differences of opioid neuropeptides or serotonin markers were found between FRL and FSL rats. The marked behavioral difference between the FRL and FSL rats was paralleled with the striatal expression of the established marker, c-fos, but also the GABAergic transporter (vGAT), and a hitherto unknown marker, tamalin, that is known to regulate mGluR5 receptor function and postsynaptic organization. This study demonstrates that behavioral and transcriptional responses of non-dopaminergic systems to experimental parkinsonism and L-DOPA are modified in a genetic rat model of depression.
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Affiliation(s)
- Nicoletta Schintu
- Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Xiaoqun Zhang
- Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Nikolas Stroth
- Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Aleksander A Mathé
- Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Per E Andrén
- Medical Mass Spectrometry Imaging, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.,Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
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7
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Zheng S, West JJ, Yu CG, Harris TJC. Arf-GEF localization and function at myosin-rich adherens junctions via coiled-coil heterodimerization with an adaptor protein. Mol Biol Cell 2019; 30:3090-3103. [PMID: 31693432 PMCID: PMC6938242 DOI: 10.1091/mbc.e19-10-0566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Tissue dynamics require regulated interactions between adherens junctions and cytoskeletal networks. For example, myosin-rich adherens junctions recruit the cytohesin Arf-GEF Steppke, which down-regulates junctional tension and facilitates tissue stretching. We dissected this recruitment mechanism with structure–function and other analyses of Steppke and Stepping stone, an implicated adaptor protein. During Drosophila dorsal closure, Steppke’s coiled-coil domain was necessary and sufficient for junctional recruitment. Purified coiled-coil domains of Steppke and Stepping stone heterodimerized through a hydrophobic surface of the Steppke domain. This mapped surface was required for Steppke’s junctional localization and tissue regulation. Stepping stone colocalized with Steppke at junctions, and was required for junctional Steppke localization and proper tissue stretching. A second conserved region of Stepping stone was necessary and largely sufficient for junctional localization. Remarkably, this region could substitute for the Steppke coiled-coil domain for junction localization and regulation, suggesting the main role of the Steppke coiled-coil domain is linkage to the junctional targeting region of Stepping stone. Thus, coiled-coil heterodimerization with Stepping stone normally recruits Step to junctions. Intriguingly, Stepping stone’s junctional localization also seems partly dependent on Steppke.
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Affiliation(s)
- Shiyu Zheng
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Junior J West
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Cao Guo Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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8
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Neyman S, Braunewell KH, O'Connell KE, Dev KK, Manahan-Vaughan D. Inhibition of the Interaction Between Group I Metabotropic Glutamate Receptors and PDZ-Domain Proteins Prevents Hippocampal Long-Term Depression, but Not Long-Term Potentiation. Front Synaptic Neurosci 2019; 11:13. [PMID: 31057390 PMCID: PMC6482240 DOI: 10.3389/fnsyn.2019.00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/04/2019] [Indexed: 01/07/2023] Open
Abstract
The group I metabotropic glutamate (mGlu) receptor subtypes, mGlu1 and mGlu5, strongly regulate hippocampal synaptic plasticity. Both harbor PSD-95/discs-large/ZO-1 (PDZ) motifs at their extreme carboxyl terminals, which allow interaction with the PDZ domain of Tamalin, regulate the cell surface expression of group I mGlu receptors, and may modulate their coupling to signaling proteins. We investigated the functional role of this interaction in hippocampal long-term depression (LTD). Acute intracerebral treatment of adult rats with a cell-permeable PDZ-blocking peptide (pep-mGluR-STL), designed to competitively inhibit the interaction between Tamalin and group 1 mGlu receptors, prevented expression of LTD in the hippocampal CA1 region without affecting long-term potentiation (LTP) or basal synaptic transmission. Pep-mGluR-STL prevented facilitation by the group I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), and the mGlu5 agonist, (R,S)-2-chloro-5-Hydroxyphenylglycine (CHPG), of short-term depression (STD) into LTD, suggesting that Tamalin preferentially acts by mediating signaling through mGlu5. These data support that Tamalin is essential for the persistent expression of LTD and that it subserves the effective signaling of group 1 mGlu receptors.
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Affiliation(s)
- Sergey Neyman
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Karl-Heinz Braunewell
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Kara E O'Connell
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - Kumlesh K Dev
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
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9
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Ito A, Fukaya M, Saegusa S, Kobayashi E, Sugawara T, Hara Y, Yamauchi J, Okamoto H, Sakagami H. Pallidin is a novel interacting protein for cytohesin-2 and regulates the early endosomal pathway and dendritic formation in neurons. J Neurochem 2018; 147:153-177. [PMID: 30151872 DOI: 10.1111/jnc.14579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 07/25/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Cytohesin-2 is a member of the guanine nucleotide exchange factors for ADP ribosylation factor 1 (Arf1) and Arf6, which are small GTPases that regulate membrane traffic and actin dynamics. In this study, we first demonstrated that cytohesin-2 localized to the plasma membrane and vesicles in various subcellular compartment in hippocampal neurons by immunoelectron microscopy. Next, to understand the molecular network of cytohesin-2 in neurons, we conducted yeast two-hybrid screening of brain cDNA libraries using cytohesin-2 as bait and isolated pallidin, a component of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) involved in endosomal trafficking. Pallidin interacted specifically with cytohesin-2 among cytohesin family members. Glutathione S-transferase pull-down and immunoprecipitation assays further confirmed the formation of a protein complex between cytohesin-2 and pallidin. Immunofluorescence demonstrated that cytohesin-2 and pallidin partially colocalized in various subsets of endosomes immunopositive for EEA1, syntaxin 12, and LAMP2 in hippocampal neurons. Knockdown of pallidin or cytohesin-2 reduced cytoplasmic EEA1-positive early endosomes. Furthermore, knockdown of pallidin increased the total dendritic length of cultured hippocampal neurons, which was rescued by co-expression of wild-type pallidin but not a mutant lacking the ability to interact with cytohesin-2. In contrast, knockdown of cytohesin-2 had the opposite effect on total dendritic length. The present results suggested that the interaction between pallidin and cytohesin-2 may participate in various neuronal functions such as endosomal trafficking and dendritic formation in hippocampal neurons. Cover Image for this issue: doi: 10.1111/jnc.14197.
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Affiliation(s)
- Akiko Ito
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.,Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Shintaro Saegusa
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Emi Kobayashi
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Takeyuki Sugawara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Yoshinobu Hara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neuroscience and Neurology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hirotsugu Okamoto
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
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10
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Interferon-β Inhibits Neurotrophin 3 Signalling and Pro-Survival Activity by Upregulating the Expression of Truncated TrkC-T1 Receptor. Mol Neurobiol 2016; 54:1825-1843. [PMID: 26887385 DOI: 10.1007/s12035-016-9789-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/11/2016] [Indexed: 12/17/2022]
Abstract
Although clinically useful for the treatment of various diseases, type I interferons (IFNs) have been implicated as causative factors of a number of neuroinflammatory disorders characterized by neuronal damage and altered CNS functions. As neurotrophin 3 (NT3) plays a critical role in neuroprotection, we examined the effects of IFN-β on the signalling and functional activity of the NT3/TrkC system. We found that prolonged exposure of differentiated human SH-SY5Y neuroblastoma cells to IFN-β impaired the ability of NT3 to induce transphosphorylation of the full-length TrkC receptor (TrkC-FL) and the phosphorylation of downstream signalling molecules, including PLCγ1, Akt, GSK-3β and ERK1/2. NT3 was effective in protecting the cells against apoptosis triggered by serum withdrawal or thapsigargin but not IFN-β. Prolonged exposure to the cytokine had little effects on TrkC-FL levels but markedly enhanced the messenger RNA (mRNA) and protein levels of the truncated isoform TrkC-T1, a dominant-negative receptor that inhibits TrkC-FL activity. Cell depletion of TrkC-T1 by small interfering RNA (siRNA) treatment enhanced NT3 signalling through TrkC-FL and allowed the neurotrophin to counteract IFN-β-induced apoptosis. Furthermore, the upregulation of TrkC-T1 by IFN-β was associated with the inhibition of NT3-induced recruitment of the scaffold protein tamalin to TrkC-T1 and tamalin tyrosine phosphorylation. These data indicate that IFN-β exerts a negative control on NT3 pro-survival signalling through a novel mechanism involving the upregulation of TrkC-T1.
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11
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Lee DM, Rodrigues FF, Yu CG, Swan M, Harris TJC. PH Domain-Arf G Protein Interactions Localize the Arf-GEF Steppke for Cleavage Furrow Regulation in Drosophila. PLoS One 2015; 10:e0142562. [PMID: 26556630 PMCID: PMC4640550 DOI: 10.1371/journal.pone.0142562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/23/2015] [Indexed: 11/18/2022] Open
Abstract
The recruitment of GDP/GTP exchange factors (GEFs) to specific subcellular sites dictates where they activate small G proteins for the regulation of various cellular processes. Cytohesins are a conserved family of plasma membrane GEFs for Arf small G proteins that regulate endocytosis. Analyses of mammalian cytohesins have identified a number of recruitment mechanisms for these multi-domain proteins, but the conservation and developmental roles for these mechanisms are unclear. Here, we report how the pleckstrin homology (PH) domain of the Drosophila cytohesin Steppke affects its localization and activity at cleavage furrows of the early embryo. We found that the PH domain is necessary for Steppke furrow localization, and for it to regulate furrow structure. However, the PH domain was not sufficient for the localization. Next, we examined the role of conserved PH domain amino acid residues that are required for mammalian cytohesins to bind PIP3 or GTP-bound Arf G proteins. We confirmed that the Steppke PH domain preferentially binds PIP3 in vitro through a conserved mechanism. However, disruption of residues for PIP3 binding had no apparent effect on GFP-Steppke localization and effects. Rather, residues for binding to GTP-bound Arf G proteins made major contributions to this Steppke localization and activity. By analyzing GFP-tagged Arf and Arf-like small G proteins, we found that Arf1-GFP, Arf6-GFP and Arl4-GFP, but not Arf4-GFP, localized to furrows. However, analyses of embryos depleted of Arf1, Arf6 or Arl4 revealed either earlier defects than occur in embryos depleted of Steppke, or no detectable furrow defects, possibly because of redundancies, and thus it was difficult to assess how individual Arf small G proteins affect Steppke. Nonetheless, our data show that the Steppke PH domain and its conserved residues for binding to GTP-bound Arf G proteins have substantial effects on Steppke localization and activity in early Drosophila embryos.
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Affiliation(s)
- Donghoon M. Lee
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | | | - Cao Guo Yu
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Michael Swan
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Tony J. C. Harris
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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12
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Shen J, LeFave C, Sirosh I, Siegel AB, Tycko B, Santella RM. Integrative epigenomic and genomic filtering for methylation markers in hepatocellular carcinomas. BMC Med Genomics 2015; 8:28. [PMID: 26059414 PMCID: PMC4460673 DOI: 10.1186/s12920-015-0105-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 06/01/2015] [Indexed: 02/05/2023] Open
Abstract
Background Epigenome-wide studies in hepatocellular carcinoma (HCC) have identified numerous genes with aberrant DNA methylation. However, methods for triaging functional candidate genes as useful biomarkers for epidemiological study have not yet been developed. Methods We conducted targeted next-generation bisulfite sequencing (bis-seq) to investigate associations of DNA methylation and mRNA expression in HCC. Integrative analyses of epigenetic profiles with DNA copy number analysis were used to pinpoint functional genes regulated mainly by altered DNA methylation. Results Significant differences between HCC tumor and adjacent non-tumor tissue were observed for 28 bis-seq amplicons, with methylation differences varying from 12% to 43%. Available mRNA expression data in Oncomine were evaluated. Two candidate genes (GRASP and TSPYL5) were significantly under-expressed in HCC tumors in comparison with precursor and normal liver tissues. The expression levels in tumor tissues were, respectively, 1.828 and − 0.148, significantly lower than those in both precursor and normal liver tissue. Validations in an additional 42 paired tissues showed consistent under-expression in tumor tissue for GRASP (−7.49) and TSPYL5 (−9.71). A highly consistent DNA hypermethylation and mRNA repression pattern was obtained for both GRASP (69%) and TSPYL5 (73%), suggesting that their biological function is regulated by DNA methylation. Another two genes (RGS17 and NR2E1) at Chr6q showed significantly decreased DNA methylation in tumors with loss of DNA copy number compared to those without, suggesting alternative roles of DNA copy number losses and hypermethylation in the regulation of RGS17 and NR2E1. Conclusions These results suggest that integrative analyses of epigenomic and genomic data provide an efficient way to filter functional biomarkers for future epidemiological studies in human cancers. Electronic supplementary material The online version of this article (doi:10.1186/s12920-015-0105-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jing Shen
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Clare LeFave
- Institute for Cancer Genetics, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Iryna Sirosh
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Abby B Siegel
- Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA.
| | - Benjamin Tycko
- Institute for Cancer Genetics, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA. .,Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, 10032, USA.
| | - Regina M Santella
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Center, New York, NY, 10032, USA.
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13
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Igartua C, Myers RA, Mathias RA, Pino-Yanes M, Eng C, Graves PE, Levin AM, Del-Rio-Navarro BE, Jackson DJ, Livne OE, Rafaels N, Edlund CK, Yang JJ, Huntsman S, Salam MT, Romieu I, Mourad R, Gern JE, Lemanske RF, Wyss A, Hoppin JA, Barnes KC, Burchard EG, Gauderman WJ, Martinez FD, Raby BA, Weiss ST, Williams LK, London SJ, Gilliland FD, Nicolae DL, Ober C. Ethnic-specific associations of rare and low-frequency DNA sequence variants with asthma. Nat Commun 2015; 6:5965. [PMID: 25591454 PMCID: PMC4309441 DOI: 10.1038/ncomms6965] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/25/2014] [Indexed: 12/11/2022] Open
Abstract
Common variants at many loci have been robustly associated with asthma but explain little of the overall genetic risk. Here we investigate the role of rare (<1%) and low-frequency (1-5%) variants using the Illumina HumanExome BeadChip array in 4,794 asthma cases, 4,707 non-asthmatic controls and 590 case-parent trios representing European Americans, African Americans/African Caribbeans and Latinos. Our study reveals one low-frequency missense mutation in the GRASP gene that is associated with asthma in the Latino sample (P=4.31 × 10(-6); OR=1.25; MAF=1.21%) and two genes harbouring functional variants that are associated with asthma in a gene-based analysis: GSDMB at the 17q12-21 asthma locus in the Latino and combined samples (P=7.81 × 10(-8) and 4.09 × 10(-8), respectively) and MTHFR in the African ancestry sample (P=1.72 × 10(-6)). Our results suggest that associations with rare and low-frequency variants are ethnic specific and not likely to explain a significant proportion of the 'missing heritability' of asthma.
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Affiliation(s)
- Catherine Igartua
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
| | - Rachel A. Myers
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
| | - Rasika A. Mathias
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224, USA
| | - Maria Pino-Yanes
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, USA
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Celeste Eng
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, USA
| | - Penelope E. Graves
- Arizona Respiratory Center and BIO5 Institute, University of Arizona, Tucson, Arizona 85721, USA
| | - Albert M. Levin
- Department of Public Health Science, Henry Ford Health System, Detroit, Michigan 48202, USA
| | | | - Daniel J. Jackson
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA
| | - Oren E. Livne
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
| | - Nicholas Rafaels
- Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland 21224, USA
| | - Christopher K. Edlund
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - James J. Yang
- School of Nursing, University of Michigan, Ann Arbor, Michigan 48202, USA
| | - Scott Huntsman
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, USA
| | - Muhammad T. Salam
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Isabelle Romieu
- International Agency for Research on Cancer, Lyon 69372, France
| | - Raphael Mourad
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
| | - James E. Gern
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA
- Department of Internal Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA
| | - Robert F. Lemanske
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53726, USA
| | - Annah Wyss
- Division of Intramural Research, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | - Jane A. Hoppin
- Division of Intramural Research, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27607, USA
| | - Kathleen C. Barnes
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21224, USA
| | - Esteban G. Burchard
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, USA
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California 94143, USA
| | - W. James Gauderman
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Fernando D. Martinez
- Arizona Respiratory Center and BIO5 Institute, University of Arizona, Tucson, Arizona 85721, USA
| | - Benjamin A. Raby
- Channing Division of Network Medicine, Harvard Medical School, Boston, Massachusetts 2115, USA
- Division of Pulmonary and Critical Care Medicine, Harvard Medical School, Boston, Massachusetts 2115, USA
| | - Scott T. Weiss
- Channing Division of Network Medicine, Harvard Medical School, Boston, Massachusetts 2115, USA
| | - L. Keoki Williams
- Center for Health Policy and Health Services Research, Henry Ford Health System, Detroit, Michigan 48202, USA
- Department of Internal Medicine, Henry Ford Health System, Detroit, Michigan 48202, USA
| | - Stephanie J. London
- Division of Intramural Research, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | - Frank D. Gilliland
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Dan L. Nicolae
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
- Departments of Medicine and Statistics, University of Chicago, Chicago, Illinois 60637, USA
| | - Carole Ober
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC 425, Chicago, Illinois 60637, USA
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Liu J, Lee DM, Yu CG, Angers S, Harris TJC. Stepping stone: a cytohesin adaptor for membrane cytoskeleton restraint in the syncytial Drosophila embryo. Mol Biol Cell 2014; 26:711-25. [PMID: 25540427 PMCID: PMC4325841 DOI: 10.1091/mbc.e14-11-1554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cytohesin Arf-GEFs are conserved plasma membrane regulators. The sole Drosophila cytohesin, Steppke, restrains Rho1-dependent membrane cytoskeleton activity at the base of plasma membrane furrows of the syncytial embryo. By mass spectrometry, we identified a single major Steppke-interacting protein from syncytial embryos, which we named Stepping stone (Sstn). By sequence, Sstn seems to be a divergent homologue of the mammalian cytohesin adaptor FRMD4A. Our experiments supported this relationship. Specifically, heterophilic coiled-coil interactions linked Sstn and Steppke in vivo and in vitro, whereas a separate C-terminal region was required for Sstn localization to furrows. Sstn mutant and RNAi embryos displayed abnormal, Rho1-dependent membrane cytoskeleton expansion from the base of pseudocleavage and cellularization furrows, closely mimicking Steppke loss-of-function embryos. Elevating Sstn furrow levels had no effect on the steppke phenotype, but elevating Steppke furrow levels reversed the sstn phenotype, suggesting that Steppke acts downstream of Sstn and that additional mechanisms can recruit Steppke to furrows. Finally, the coiled-coil domain of Steppke was required for Sstn binding and in addition homodimerization, and its removal disrupted Steppke furrow localization and activity in vivo. Overall we propose that Sstn acts as a cytohesin adaptor that promotes Steppke activity for localized membrane cytoskeleton restraint in the syncytial Drosophila embryo.
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Affiliation(s)
- Jiangshu Liu
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Donghoon M Lee
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Cao Guo Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3G5, Canada Department of Biochemistry, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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15
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The insulin/IGF signaling regulators cytohesin/GRP-1 and PIP5K/PPK-1 modulate susceptibility to excitotoxicity in C. elegans. PLoS One 2014; 9:e113060. [PMID: 25422944 PMCID: PMC4244091 DOI: 10.1371/journal.pone.0113060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 10/17/2014] [Indexed: 12/24/2022] Open
Abstract
During ischemic stroke, malfunction of excitatory amino acid transporters and reduced synaptic clearance causes accumulation of Glutamate (Glu) and excessive stimulation of postsynaptic neurons, which can lead to their degeneration by excitotoxicity. The balance between cell death-promoting (neurotoxic) and survival-promoting (neuroprotective) signaling cascades determines the fate of neurons exposed to the excitotoxic insult. The evolutionary conserved Insulin/IGF Signaling (IIS) cascade can participate in this balance, as it controls cell stress resistance in nematodes and mammals. Blocking the IIS cascade allows the transcription factor FoxO3/DAF-16 to accumulate in the nucleus and activate a transcriptional program that protects cells from a range of insults. We study the effect of IIS cascade on neurodegeneration in a C. elegans model of excitotoxicity, where a mutation in a central Glu transporter (glt-3) in a sensitizing background causes Glu-Receptor -dependent neuronal necrosis. We expand our studies on the role of the IIS cascade in determining susceptibility to excitotoxic necrosis by either blocking IIS at the level of PI3K/AGE-1 or stimulating it by removing the inhibitory effect of ZFP-1 on the expression of PDK-1. We further show that the components of the Cytohesin/GRP-1, Arf, and PIP5K/PPK-1 complex, known to regulate PIP2 production and the IIS cascade, modulate nematode excitotoxicity: mutations that are expected to reduce the complex's ability to produce PIP2 and inhibit the IIS cascade protect from excitotoxicity, while overstimulation of PIP2 production enhances neurodegeneration. Our observations therefore affirm the importance of the IIS cascade in determining the susceptibility to necrotic neurodegeneration in nematode excitotoxicity, and demonstrate the ability of Cytohesin/GRP-1, Arf, and PIP5K/PPK-1 complex to modulate neuroprotection.
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16
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Cytohesin 2/ARF6 regulates preadipocyte migration through the activation of ERK1/2. Biochem Pharmacol 2014; 92:651-60. [PMID: 25450674 DOI: 10.1016/j.bcp.2014.09.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/30/2014] [Accepted: 09/30/2014] [Indexed: 01/14/2023]
Abstract
Preadipocyte migration is vital for the development of adipose tissue, which plays a crucial role in lipid metabolism. ADP-ribosylation factor 6 (ARF6) small GTPase, which regulates membrane trafficking, is activated by GTP-exchange factors (GEFs) such as cytohesin 2. Cytohesin 2 and ARF6 have previously been implicated in the regulation of 3T3-L1 preadipocyte migration. We investigated here the molecular mechanism underlying the cytohesin 2 and ARF6 mediated regulation of preadipocyte migration. Preadipocyte migration and the activation of ARF6 and ERK1/2 were studied by using a number of approaches, including pharmacological inhibitors, siRNA and the inhibitory peptides. The siRNA mediated down regulation of ARF6 and cytohesin 2 expression confirmed the requirement of both for migration of preadipocytes. Phosphatidylinositol 3-kinase (PI3K) and PI 4,5-bisphosphate (PIP2) have also found to be essential for the cytohesin 2/ARF6 induced preadipocyte migration. Pharmacological inhibition of the activation of ARF6, ERK1/2 or dynamin led to significant reduction in migration of 3T3-L1 preadipocytes. Furthermore, our study revealed the activation of ARF6 and ERK1/2 during migration of preadipocytes. In the migrating preadipocytes, ARF6 activation was inhibited with SecinH3 (cytohesin inhibitor) and LY294002 (PI3K inhibitor) whereas the ERK1/2 phosphorylation was inhibited with SecinH3, LY294002, PBP10 (a PIP2 sequester peptide) and PD98059 (MAPKK inhibitor). However, dynosore (dynamin inhibitor) had inhibited neither ARF6 activation nor ERK1/2 phosphorylation during preadipocyte migration. These results together suggest that cytohesin 2 activates ARF6 in a PI3K dependent manner and then the active ARF6 causes phosphorylation of ERK1/2 during preadipocyte migration.
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17
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Tompkins N, MacNeil AJ, Pohajdak B. Cytohesin-associated scaffolding protein (CASP) is a substrate for granzyme B and ubiquitination. Biochem Biophys Res Commun 2014; 452:473-8. [DOI: 10.1016/j.bbrc.2014.08.088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 08/19/2014] [Indexed: 01/23/2023]
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18
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Venkataraman A, Coleman DJ, Nevrivy DJ, Long T, Kioussi C, Indra AK, Leid M. Grp1-associated scaffold protein regulates skin homeostasis after ultraviolet irradiation. Photochem Photobiol Sci 2014; 13:531-40. [PMID: 24407555 DOI: 10.1039/c3pp50351h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Grp1-associated scaffold protein (Grasp), the product of a retinoic acid-induced gene in P19 embryonal carcinoma cells, is expressed primarily in brain, heart, and lung of the mouse. We report herein that Grasp transcripts are also found in mouse skin in which the Grasp gene is robustly induced following acute ultraviolet-B (UVB) exposure. Grasp(-/-) mice were found to exhibit delayed epidermal proliferation and a blunted apoptotic response after acute UVB exposure. Immunohistochemical analyses revealed that the nuclear residence time of the tumor suppressor protein p53 was reduced in Grasp(-/-) mice after UVB exposure. Taken together, our results suggest that a physiological role of Grasp may be to regulate skin homeostasis after UVB exposure, potentially by influencing p53-mediated apoptotic responses in skin.
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Affiliation(s)
- Anand Venkataraman
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, Oregon 97331, USA.
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19
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Hiester KG, Santy LC. The cytohesin coiled-coil domain interacts with threonine 276 to control membrane association. PLoS One 2013; 8:e82084. [PMID: 24303080 PMCID: PMC3841123 DOI: 10.1371/journal.pone.0082084] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 10/30/2013] [Indexed: 01/08/2023] Open
Abstract
Cell migration is regulated by a number of small GTPases, including members of the Arf family. Cytohesins, a family of Arf-activating proteins, have been extensively implicated in the regulation of Arfs during migration and cell shape change. Membrane association of both the Arf and its activating protein is a prerequisite for Arf activation. Therefore regulating the extent of cytohesin membrane association is a mechanism for controlling the initiation of cell movement. We have discovered a novel intramolecular interaction that controls the association of cytohesins with membranes. The presence of the coiled-coil domain reduces the association of cytohesin 2 with membranes. We demonstrate that this domain interacts with more C-terminal regions of the protein. This interaction is independent of another previously identified autoinhibitory conformation. A threonine residue (T276) in the cytohesin 2 PH domain is a target for phosphorylation by Akt. Mutation of this threonine to aspartic acid, to mimic phosphorylation, disrupts the binding of the coiled-coil domain to c-terminal regions and promotes membrane association of cytohesin 2. The presence of a second autoinhibitory interaction in the cytohesins suggests that these proteins can act a signal integrators that stimulate migration only after receive multiple pro-migratory signals.
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Affiliation(s)
- Kevin G. Hiester
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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20
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Miyamoto Y, Torii T, Nakamura K, Takashima S, Sanbe A, Tanoue A, Yamauchi J. Signaling through Arf6 guanine-nucleotide exchange factor cytohesin-1 regulates migration in Schwann cells. Cell Signal 2013; 25:1379-87. [DOI: 10.1016/j.cellsig.2013.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 03/08/2013] [Indexed: 10/27/2022]
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21
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Grp1-associated scaffold protein (GRASP) is a regulator of the ADP ribosylation factor 6 (Arf6)-dependent membrane trafficking pathway. Cell Biol Int 2013; 36:1115-28. [PMID: 22931251 DOI: 10.1042/cbi20120221] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
GRASP interacts with Grp1 (general receptor for phosphoinositides 1; cytohesin 3), which catalyses nucleotide exchange on and activation of Arf6 (ADP-ribosylation factor-6). Arf6 is a low-molecular-mass GTPase that regulates key aspects of endocytic recycling pathways. Overexpressed GRASP accumulated in the juxtanuclear ERC (endocytic recycling compartment). GRASP co-localized with a constitutively inactive mutant of Arf6 in the ERC such that it was reversed by expression of wild-type Grp1. Co-expression of GRASP and Grp1 promoted membrane ruffling, a cellular hallmark of Arf6 activation. GRASP accumulation in ERC was found to block recycling of the MHC-I (major histocompatibility complex-I), which is trafficked by the Arf6-dependent pathway. In contrast, overexpression of GRASP had no effect on the recycling of transferrin receptors, which are trafficked by a clathrin-dependent pathway. The findings suggest that GRASP regulates the non-clathrin/Arf6-dependent, plasma membrane recycling and signalling pathways.
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22
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Attar MA, Santy LC. The scaffolding protein GRASP/Tamalin directly binds to Dock180 as well as to cytohesins facilitating GTPase crosstalk in epithelial cell migration. BMC Cell Biol 2013; 14:9. [PMID: 23441967 PMCID: PMC3599651 DOI: 10.1186/1471-2121-14-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 02/20/2013] [Indexed: 11/24/2022] Open
Abstract
Background The transition of epithelial cells from their normal non-motile state to a motile one requires the coordinated action of a number of small GTPases. We have previously shown that epithelial cell migration is stimulated by the coordinated activation of Arf and Rac GTPases. This crosstalk depends upon the assembly of a multi-protein complex that contains the Arf-activating protein cytohesin 2/ARNO and the Rac activating protein Dock180. Two scaffolding proteins that bind directly to cytohesin 2 organize this complex. Results We now have found that Rac activation in response to hepatocyte growth factor (HGF) requires cytohesin 2 and Dock180. GRASP/Tamalin is one of the scaffolds that builds the complex containing cytohesin 2 and Dock180. We determine here that the Ala/Pro rich region of GRASP directly interacts with the SH3 domain of Dock180. By binding to both cytohesin 2/ARNO and Dock180, GRASP bridges the guanine nucleotide exchange factors (GEFs) that activate Arf and Rac, thereby promoting Arf-to-Rac signaling. Furthermore, we find that knockdown of GRASP impairs hepatocyte growth factor (HGF)-stimulated Rac activation and HGF-stimulated epithelial migration. Conclusions GRASP binds directly both cytohesin 2 and Dock180 to coordinate their activities, and by doing so promotes crosstalk between Arf and Rac.
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Affiliation(s)
- Myriam A Attar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 208 Althouse Lab, University Park, PA 16802, USA
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Mo J, Choi S, Ahn PG, Sun W, Lee HW, Kim H. PDZ-scaffold protein, Tamalin promotes dendritic outgrowth and arborization in rat hippocampal neuron. Biochem Biophys Res Commun 2012; 422:250-5. [PMID: 22569042 DOI: 10.1016/j.bbrc.2012.04.136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 04/25/2012] [Indexed: 02/02/2023]
Abstract
Tamalin is a scaffold protein known to regulate membrane trafficking through its interaction with cytohesin-2/ARNO, guanine nucleotide exchange factor (GEF) on ADP-ribosylation factor (Arf) 1/6, and induces actin reorganization. However, the neuronal function of Tamalin is not well understood. Here, we report that Tamalin participates in neurite development through the association with exchange factor for Arf6 (EFA6A)/Arf6 signaling. In immature hippocampal neuron, Tamalin knockdown markedly reduced the dendritic outgrowth, the number of dendritic tips and the levels of filamentous actin (F-actin) and microtubule-associated protein 2 (MAP2) in dendrites. In addition, Tamalin colocalized with EFA6A and Arf6 in the dendritic shaft. Tamalin knockdown reduced the number, size, and intensity of endogenous EFA6A cluster, whereas overexpression of Tamalin showed opposite effects compared with those of knockdown. These results suggest that Tamalin is responsible for neuronal dendritic development via regulation of EFA6A/Arf6-mediated cytoskeleton dynamics.
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Affiliation(s)
- Jiwon Mo
- Department of Anatomy and Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, 126-1, 5-Ka, Anam-Dong, Seongbuk-Gu, Seoul 136-705, Republic of Korea
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Lewis AS, Estep CM, Chetkovich DM. The fast and slow ups and downs of HCN channel regulation. Channels (Austin) 2011; 4:215-31. [PMID: 20305382 DOI: 10.4161/chan.4.3.11630] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (h channels) form the molecular basis for the hyperpolarization-activated current, I(h), and modulation of h channels contributes to changes in cellular properties critical for normal functions in the mammalian brain and heart. Numerous mechanisms underlie h channel modulation during both physiological and pathological conditions, leading to distinct changes in gating, kinetics, surface expression, channel conductance or subunit composition of h channels. Here we provide a focused review examining mechanisms of h channel regulation, with an emphasis on recent findings regarding interacting proteins such as TRIP8b. This review is intended to serve as a comprehensive resource for physiologists to provide potential molecular mechanisms underlying functionally important changes in I(h) in different biological models, as well as for molecular biologists to delineate the predicted h channel changes associated with complex regulatory mechanisms in both normal function and in disease states.
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Affiliation(s)
- Alan S Lewis
- Davee Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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25
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Yang L, Matsuda T, Raviraj V, Ching YW, Braet F, Nagai T, Soon LL. Imaging the dynamics of intracellular protein translocation by photoconversion of phamret-cybr/ROM. J Microsc 2010; 242:250-61. [PMID: 21118394 DOI: 10.1111/j.1365-2818.2010.03463.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cybr/Reduced On-random Motile (ROM) is a scaffold protein, containing a postsynaptic density protein-95/discs-large/ZO-1 (PDZ) domain, a LEU region and a PDZ domain binding region at the C-terminus. In the immune system, Cybr/ROM was found to localize in vesicles and at the plasma membrane, through interactions with cytohesin-1. In this investigation, we reported Cybr/ROM as occurring in vesicles, the cytoplasm and at membrane ruffles of H1299 lung cancer cells. Its localization at the ruffles was dependent on intact actin structures as indicated by latrunculin A treatment, which abrogated ruffle formation and staining of Cybr/ROM at the cells' periphery. Transfection of truncation mutants consisting of either the PDZ or LEU domain showed that the LEU domain of ROM was localized to membrane ruffles, vesicles and the cytoplasm, whereas, the PDZ domain localized to the membrane ruffles and cytoplasm only. There was therefore, domain/molecular segregation of Cybr/ROM in different cellular compartments. Cybr/ROM was subcloned into a plasmid carrying the photoactivation-mediated resonance energy transfer (Phamret) protein. The photoconversion experiments demonstrated the diffusion of ROM from the cytoplasm to the membrane ruffling sites and conversely from membrane ruffles to the cytoplasm. Large variances in the transport velocity of Cybr/ROM in the cytoplasm suggested that its movements were facilitated by other mechanisms in addition to diffusion.
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Affiliation(s)
- L Yang
- Australian Centre for Microscopy and Microanalysis (ACMM), Australian Microscopy and Microanalysis Research Facility (AMMRF), University of Sydney, Australia
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26
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Stalder D, Barelli H, Gautier R, Macia E, Jackson CL, Antonny B. Kinetic studies of the Arf activator Arno on model membranes in the presence of Arf effectors suggest control by a positive feedback loop. J Biol Chem 2010; 286:3873-83. [PMID: 21118813 DOI: 10.1074/jbc.m110.145532] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins of the cytohesin/Arno/Grp1 family of Arf activators are positive regulators of the insulin-signaling pathway and control various remodeling events at the plasma membrane. Arno has a catalytic Sec7 domain, which promotes GDP to GTP exchange on Arf, followed by a pleckstrin homology (PH) domain. Previous studies have revealed two functions of the PH domain: inhibition of the Sec7 domain and membrane targeting. Interestingly, the Arno PH domain interacts not only with a phosphoinositide (phosphatidylinositol 4,5-bisphosphate or phosphatidylinositol 3,4,5-trisphosphate) but also with an activating Arf family member, such as Arf6 or Arl4. Using the full-length membrane-bound forms of Arf1 and Arf6 instead of soluble forms, we show here that the membrane environment dramatically affects the mechanism of Arno activation. First, Arf6-GTP stimulates Arno at nanomolar concentrations on liposomes compared with micromolar concentrations in solution. Second, mutations in the PH domain that abolish interaction with Arf6-GTP render Arno completely inactive when exchange reactions are reconstituted on liposomes but have no effect on Arno activity in solution. Third, Arno is activated by its own product Arf1-GTP in addition to a distinct activating Arf isoform. Consequently, Arno activity is strongly modulated by competition with Arf effectors. These results show that Arno behaves as a bistable switch, having an absolute requirement for activation by an Arf protein but, once triggered, becoming highly active through the positive feedback effect of Arf1-GTP. This property of Arno might provide an explanation for its function in signaling pathways that, once triggered, must move forward decisively.
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Affiliation(s)
- Danièle Stalder
- Institut de Pharmacologie Moléculaire et Cellulaire, Université de Nice Sophia Antipolis et CNRS, 06560 Valbonne, France
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27
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DiNitto JP, Lee MT, Malaby AW, Lambright DG. Specificity and membrane partitioning of Grsp1 signaling complexes with Grp1 family Arf exchange factors. Biochemistry 2010; 49:6083-92. [PMID: 20527794 DOI: 10.1021/bi1000454] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Arf exchange factor Grp1 selectively binds phosphatidylinositol 3,4,5-triphosphate [PtdIns(3,4,5)P(3)], which is required for recruitment to the plasma membrane in stimulated cells. The mechanisms for phosphoinositide recognition by the PH domain, catalysis of nucleotide exchange by the Sec7 domain, and autoinhibition by elements proximal to the PH domain are well-characterized. The N-terminal heptad repeats in Grp1 have also been shown to mediate homodimerization in vitro as well as heteromeric interactions with heptad repeats in the FERM domain-containing protein Grsp1 both in vitro and in cells [Klarlund, J. K., et al. (2001) J. Biol. Chem. 276, 40065-40070]. Here, we have characterized the oligomeric state of Grsp1 and Grp1 family proteins (Grp1, ARNO, and Cytohesin-1) as well as the oligomeric state, stoichiometry, and specificity of Grsp1 complexes with Grp1, ARNO, and Cytohesin-1. At low micromolar concentrations, Grp1 and ARNO are homodimeric whereas Cytohesin-1 and Grsp1 are monomeric. When mixed with Grsp1, Grp1 homodimers and Cytohesin-1 monomers spontaneously re-equilibrate to form heterodimers, whereas approximately 50% of ARNO remains homodimeric under the same conditions. Fluorescence resonance energy transfer experiments suggest that the Grsp1 heterodimers with Grp1 and Cytohesin-1 adopt a largely antiparallel orientation. Finally, formation of Grsp1-Grp1 heterodimers does not substantially influence the binding of Grp1 to the headgroups of PtdIns(3,4,5)P(3) or PtdIns(4,5)P(2), nor does it influence partitioning with liposomes containing PtdIns(3,4,5)P(3), PtdIns(4,5)P(2), and/or phosphatidylserine.
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Affiliation(s)
- Jonathan P DiNitto
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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Lim J, Zhou M, Veenstra TD, Morrison DK. The CNK1 scaffold binds cytohesins and promotes insulin pathway signaling. Genes Dev 2010; 24:1496-506. [PMID: 20634316 DOI: 10.1101/gad.1904610] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Protein scaffolds play an important role in signal transduction, regulating the localization of signaling components and mediating key protein interactions. Here, we report that the major binding partners of the Connector Enhancer of KSR 1 (CNK1) scaffold are members of the cytohesin family of Arf guanine nucleotide exchange factors, and that the CNK1/cytohesin interaction is critical for activation of the PI3K/AKT cascade downstream from insulin and insulin-like growth factor 1 (IGF-1) receptors. We identified a domain located in the C-terminal region of CNK1 that interacts constitutively with the coiled-coil domain of the cytohesins, and found that CNK1 facilitates the membrane recruitment of cytohesin-2 following insulin stimulation. Moreover, through protein depletion and rescue experiments, we found that the CNK1/cytohesin interaction promotes signaling from plasma membrane-bound Arf GTPases to the phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) to generate a PIP(2)-rich microenvironment that is critical for the membrane recruitment of insulin receptor substrate 1 (IRS1) and signal transmission to the PI3K/AKT cascade. These findings identify CNK1 as a new positive regulator of insulin signaling.
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Affiliation(s)
- Junghwa Lim
- Laboratory of Cell and Developmental Signaling, National Cancer Institute-Frederick, Frederick, Maryland 21702, USA
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29
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Torii T, Miyamoto Y, Sanbe A, Nishimura K, Yamauchi J, Tanoue A. Cytohesin-2/ARNO, through its interaction with focal adhesion adaptor protein paxillin, regulates preadipocyte migration via the downstream activation of Arf6. J Biol Chem 2010; 285:24270-81. [PMID: 20525696 DOI: 10.1074/jbc.m110.125658] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The formation of primitive adipose tissue is the initial process in adipose tissue development followed by the migration of preadipocytes into adipocyte clusters. Comparatively little is known about the molecular mechanism controlling preadipocyte migration. Here, we show that cytohesin-2, the guanine-nucleotide exchange factor for the Arf family GTP-binding proteins, regulates migration of mouse preadipocyte 3T3-L1 cells through Arf6. SecinH3, a specific inhibitor of the cytohesin family, markedly inhibits migration of 3T3-L1 cells. 3T3-L1 cells express cytohesin-2 and cytohesin-3, and knockdown of cytohesin-2 with its small interfering RNA effectively decreases cell migration. Cytohesin-2 preferentially acts upstream of Arf6 in this signaling pathway. Furthermore, we find that the focal adhesion protein paxillin forms a complex with cytohesin-2. Paxillin colocalizes with cytohesin-2 at the leading edges of migrating cells. This interaction is mediated by the LIM2 domain of paxillin and the isolated polybasic region of cytohesin-2. Importantly, migration is inhibited by expression of the constructs containing these regions. These results suggest that cytohesin-2, through a previously unexplored complex formation with paxillin, regulates preadipocyte migration and that paxillin plays a previously unknown role as a scaffold protein of Arf guanine-nucleotide exchange factor.
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Affiliation(s)
- Tomohiro Torii
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Okura, Tokyo 157-8535, Japan
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Lee HJ, Zheng JJ. PDZ domains and their binding partners: structure, specificity, and modification. Cell Commun Signal 2010; 8:8. [PMID: 20509869 PMCID: PMC2891790 DOI: 10.1186/1478-811x-8-8] [Citation(s) in RCA: 390] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2009] [Accepted: 05/28/2010] [Indexed: 02/07/2023] Open
Abstract
PDZ domains are abundant protein interaction modules that often recognize short amino acid motifs at the C-termini of target proteins. They regulate multiple biological processes such as transport, ion channel signaling, and other signal transduction systems. This review discusses the structural characterization of PDZ domains and the use of recently emerging technologies such as proteomic arrays and peptide libraries to study the binding properties of PDZ-mediated interactions. Regulatory mechanisms responsible for PDZ-mediated interactions, such as phosphorylation in the PDZ ligands or PDZ domains, are also discussed. A better understanding of PDZ protein-protein interaction networks and regulatory mechanisms will improve our knowledge of many cellular and biological processes.
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Affiliation(s)
- Ho-Jin Lee
- Department of Structural Biology, St, Jude Children's Research Hospital, Memphis, TN 38105, USA.
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31
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Oh SJ, Santy LC. Differential effects of cytohesins 2 and 3 on beta1 integrin recycling. J Biol Chem 2010; 285:14610-6. [PMID: 20223830 DOI: 10.1074/jbc.m109.043935] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
ADP-ribosylation actor 6 (ARF6) regulates the endocytosis and recycling of a variety of proteins and also promotes peripheral actin rearrangements and cell motility. ARF6 is activated by a large number of guanine nucleotide exchange factors, which likely regulate ARF6 at different locations and during different processes. In this study we investigate the roles of the cytohesin ADP-ribosylation factor (ARF)-guanine nucleotide exchange factors during the recycling of integrin beta1. Intriguingly, we find that knockdown and overexpression of ARNO/cytohesin 2 and GRP1/cytohesin 3 have opposing effects on cell adhesion and spreading on fibronectin and on cell migration. We find that ARNO/cytohesin 2 is required for integrin beta1 recycling, whereas GRP1/cytohesin 3 is dispensable for this process. This is the first demonstration of unique roles for these proteins.
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Affiliation(s)
- Seung Ja Oh
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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32
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White DT, McShea KM, Attar MA, Santy LC. GRASP and IPCEF promote ARF-to-Rac signaling and cell migration by coordinating the association of ARNO/cytohesin 2 with Dock180. Mol Biol Cell 2009; 21:562-71. [PMID: 20016009 PMCID: PMC2820421 DOI: 10.1091/mbc.e09-03-0217] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ARF-GEF ARNO promotes motility by activating ARF6 and a subsequent downstream activation of Rac. ARNO is shown to associate with the Rac GEF Dock180 via its coiled-coil domain. Knockdown of scaffold proteins that bind ARNO disrupts the formation of this complex and disrupts ARF-to-Rac signaling. ARFs are small GTPases that regulate vesicular trafficking, cell shape, and movement. ARFs are subject to extensive regulation by a large number of accessory proteins. The many different accessory proteins are likely specialized to regulate ARF signaling during particular processes. ARNO/cytohesin 2 is an ARF-activating protein that promotes cell migration and cell shape changes. We report here that protein–protein interactions mediated by the coiled-coil domain of ARNO are required for ARNO induced motility. ARNO lacking the coiled-coil domain does not promote migration and does not induce ARF-dependent Rac activation. We find that the coiled-coil domain promotes the assembly of a multiprotein complex containing both ARNO and the Rac-activating protein Dock180. Knockdown of either GRASP/Tamalin or IPCEF, two proteins known to bind to the coiled-coil of ARNO, prevents the association of ARNO and Dock180 and prevents ARNO-induced Rac activation. These data suggest that scaffold proteins can regulate ARF dependent processes by biasing ARF signaling toward particular outputs.
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Affiliation(s)
- David T White
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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MacNeil AJ, Pohajdak B. Getting aGRASPon CASP: properties and role of the cytohesin‐associated scaffolding protein in immunity. Immunol Cell Biol 2008; 87:72-80. [DOI: 10.1038/icb.2008.71] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Adam J MacNeil
- Department of Biology, Dalhousie University Nova Scotia Halifax Canada
| | - Bill Pohajdak
- Department of Biology, Dalhousie University Nova Scotia Halifax Canada
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34
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Gene duplication in early vertebrates results in tissue-specific subfunctionalized adaptor proteins: CASP and GRASP. J Mol Evol 2008; 67:168-78. [PMID: 18600293 DOI: 10.1007/s00239-008-9136-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 05/22/2008] [Accepted: 06/09/2008] [Indexed: 01/12/2023]
Abstract
CASP and GRASP are small cytoplasmic adaptor proteins that share highly similar protein structures as well as an association with the cytohesin/ARNO family of guanine nucleotide exchange factors within the immune and nervous systems respectively. Each contains an N-terminal PDZ domain, a central coiled-coil motif, and a carboxy-terminal PDZ-binding motif (PDZbm). We set out to further characterize the relationship between CASP and GRASP by comparing both their gene structures and their functional motifs across several vertebrate organisms. CASP and GRASP not only share significant protein structure but also share remarkably similar gene structure, with six of eight exons of equal length and relative position. We report on the addition of a unique amino acid within the coiled-coil motif of CASP proteins in several species. We also examine the Class I PDZbm, which is highly conserved across all classes of vertebrates but shows a functionally relevant mutation in the CASP proteins of several species of fish. Further, we determine the evolutionary relationship of these proteins both by use of phylogenetics and by comparative analysis of the conservation of genes near each locus in various chordates including amphioxus. We conclude that CASP and GRASP are the products of a relatively recent gene duplication event in early vertebrate organisms and that the evolution of the adaptive immune system and complex brain most likely contributed to the apparent subfunctionalization of these proteins into tissue-specific roles.
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35
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Kolanus W. Guanine nucleotide exchange factors of the cytohesin family and their roles in signal transduction. Immunol Rev 2007; 218:102-13. [PMID: 17624947 DOI: 10.1111/j.1600-065x.2007.00542.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Members of the cytohesin protein family, a group of guanine nucleotide exchange factors for adenosine diphosphate ribosylation factor (ARF) guanosine triphosphatases, have recently emerged as important regulators of signal transduction in vertebrate and invertebrate biology. These proteins share a modular domain structure, comprising carboxy-terminal membrane recruitment elements, a Sec7 homology effector domain, and an amino-terminal coiled-coil domain that serve as a platform for their integration into larger signaling complexes. Although these proteins have a highly similar overall build, their individual biological functions appear to be at least partly specific. Cytohesin-1 had been identified as a regulator of beta2 integrin inside-out regulation in immune cells and was subsequently shown to be involved in mitogen-associated protein kinase signaling in tumor cell proliferation as well as in T-helper cell activation and differentiation. Cytohesin-3, which had been discovered to be strongly associated with T-cell anergy, was very recently described as an essential component of insulin signal transduction in Drosophila and in human and murine liver cells. Future work will aim to dissect the mechanistic details of the modes of action of the cytohesins as well as to define the precise roles of these versatile proteins in vertebrates at the genetic level.
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Affiliation(s)
- Waldemar Kolanus
- Laboratory of Molecular Immunology, Program Unit Molecular Immune and Cell Biology, LIMES (Life and Medical Sciences Bonn), University of Bonn, Bonn, Germany.
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36
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Ogawa M, Miyakawa T, Nakamura K, Kitano J, Furushima K, Kiyonari H, Nakayama R, Nakao K, Moriyoshi K, Nakanishi S. Altered sensitivities to morphine and cocaine in scaffold protein tamalin knockout mice. Proc Natl Acad Sci U S A 2007; 104:14789-94. [PMID: 17766434 PMCID: PMC1976212 DOI: 10.1073/pnas.0706945104] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tamalin is a scaffold protein that interacts with metabotropic glutamate receptors and the kinase-deficient neurotrophin TrkCT1 receptor and forms a protein complex with multiple protein-trafficking and intracellular signaling molecules. In culture, tamalin promotes intracellular trafficking of group 1 metabotropic glutamate receptors through its interaction with guanine nucleotide exchange factor cytohesins and causes actin reorganization and membrane ruffling via the TrkCT1/cytohesin-2 signaling mechanism. However, how tamalin serves its physiological function in vivo has remained elusive. In this study, we generated tamalin knockout (Tam(-/-) KO) mice and investigated behavioral alterations resulting from their deficiency in functional tamalin. Targeted deletion of functional tamalin altered neither the overall brain architecture nor the general behavior of the mice under ordinary conditions. However, Tam(-/-) KO mice showed a decrease in sensitivity to acute morphine-induced hyperlocomotion and morphine analgesic effects in the hot-plate test. Furthermore, tamalin deficiency impaired the ability of the animals to show conditioned place preference after repeated morphine administration and to display locomotor sensitization by chronic cocaine treatment. Upon in vivo microdialysis analysis of the nucleus accumbens, Tam(-/-) KO and wild-type mice showed no genotypic differences in their response patterns of extracellular dopamine and glutamate before or after morphine administration. These results demonstrate that the tamalin scaffold protein plays a unique role in both acute and adaptive behavioral responses to morphine and cocaine and could regulate common neural substrates implicated in drugs of abuse.
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Affiliation(s)
- Masaaki Ogawa
- *Department of Systems Biology, Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan
- Department of Biological Sciences and
| | | | - Kenji Nakamura
- Mouse Genome Technology Laboratory, Mitsubishi Kagaku Institute of Life Sciences, Machida, Tokyo 194-8511, Japan; and
| | | | - Kenryo Furushima
- **Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Hiroshi Kiyonari
- **Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Rika Nakayama
- **Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Kazuki Nakao
- **Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Developmental Biology, Chuo-ku, Kobe, Hyogo 650-0046, Japan
| | - Koki Moriyoshi
- Department of Molecular and System Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shigetada Nakanishi
- *Department of Systems Biology, Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan
- Department of Biological Sciences and
- Department of Molecular and System Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
- To whom correspondence should be addressed. E-mail:
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MacNeil AJ, Mansour M, Pohajdak B. Sorting nexin 27 interacts with the Cytohesin associated scaffolding protein (CASP) in lymphocytes. Biochem Biophys Res Commun 2007; 359:848-53. [PMID: 17577583 DOI: 10.1016/j.bbrc.2007.05.162] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 05/21/2007] [Indexed: 10/23/2022]
Abstract
CASP is a small cytokine-inducible protein, primarily expressed in hematopoetic cells, which associates with members of the Cytohesin/ARNO family of guanine nucleotide-exchange factors. Cytohesins activate ARFs, a group of GTPases involved in vesicular initiation. Functionally, CASP is an adaptor protein containing a PDZ domain, a coiled-coil, and a potential carboxy terminal PDZ-binding motif that we sought to characterize here. Using GST pulldowns and mass spectrometry we identified the novel interaction of CASP and sorting nexin 27 (SNX27). In lymphocytes, CASP's PDZ-binding motif interacts with the PDZ domain of SNX27. This protein is a unique member of the sorting nexin family of proteins, a group generally involved in the endocytic and intracellular sorting machinery. Endogenous SNX27 and CASP co-localize at the early endosomal compartment in lymphocytes and also in transfection studies. These results suggest that endosomal SNX27 may recruit CASP to orchestrate intracellular trafficking and/or signaling complexes.
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Affiliation(s)
- Adam J MacNeil
- Department of Biology, Dalhousie University, Halifax, NS, Canada B3H 4J1
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38
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Akamine R, Yamamoto T, Watanabe M, Yamazaki N, Kataoka M, Ishikawa M, Ooie T, Baba Y, Shinohara Y. Usefulness of the 5′ region of the cDNA encoding acidic ribosomal phosphoprotein P0 conserved among rats, mice, and humans as a standard probe for gene expression analysis in different tissues and animal species. ACTA ACUST UNITED AC 2007; 70:481-6. [PMID: 17196660 DOI: 10.1016/j.jbbm.2006.11.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 11/22/2006] [Accepted: 11/22/2006] [Indexed: 11/30/2022]
Abstract
Housekeeping genes are often used as internal standards for gene expression analysis. When steady-state transcript levels of 4 typically used housekeeping genes, i.e., beta-actin, glyceraldehyde 3-phosphate dehydrogenase, cyclophilin, and acidic ribosomal phosphoprotein P0 (36B4), were evaluated in various rat tissues, the 36B4 gene seemed to be the most suitable as a standard to compare the expression levels of genes among different tissues. Next, for possible quantitative comparison of the expression level of this gene among different animal species, we compared the nucleotide sequence of the cDNA of 36B4 among rats, mice, and humans. As a result, highly conserved regions showing more than 97.5% identities were observed in the 5' portion of its open reading frame. When samples of synthesized mRNA encoding rat, mouse, and human 36B4 were hybridized with the entire cDNA encoding rat 36B4 as a probe, hybridization signals of mRNAs of mouse and human 36B4 were much weaker than those of mRNA encoding rat 36B4. However, when they were hybridized with an oligonucleotide probe corresponding to the highly conserved regions, they showed similar signal intensities. Thus, these highly conserved regions of the cDNA encoding 36B4 were concluded to be an effective standard for use in gene expression analysis.
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Affiliation(s)
- Rie Akamine
- Institute for Genome Research, Faculty of Pharmaceutical Sciences, University of Tokushima, Kuramotocho-3, Tokushima 770-8503, Japan
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Sugi T, Oyama T, Muto T, Nakanishi S, Morikawa K, Jingami H. Crystal structures of autoinhibitory PDZ domain of Tamalin: implications for metabotropic glutamate receptor trafficking regulation. EMBO J 2007; 26:2192-205. [PMID: 17396155 PMCID: PMC1852777 DOI: 10.1038/sj.emboj.7601651] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 02/23/2007] [Indexed: 11/09/2022] Open
Abstract
Metabotropic glutamate receptors (mGluRs) function as neuronal G-protein-coupled receptors and this requires efficient membrane targeting through associations with cytoplasmic proteins. However, the molecular mechanism regulating mGluR cell-surface trafficking remains unknown. We report here that mGluR trafficking is controlled by the autoregulatory assembly of a scaffold protein Tamalin. In the absence of mGluR, Tamalin self-assembles into autoinhibited conformations, through its PDZ domain and C-terminal intrinsic ligand motif. X-ray crystallographic analyses visualized integral parts of the oligomeric self-assemblies of Tamalin, which require not only the novel hydrophobic dimerization interface but also canonical and noncanonical PDZ/ligand autoinhibitory interactions. The mGluR cytoplasmic region can competitively bind to Tamalin at a higher concentration, disrupting weak inhibitory interactions. The atomic view of mGluR association suggests that this rearrangement is dominated by electrostatic attraction and repulsion. We also observed in mammalian cells that the association liberates the intrinsic ligand toward a motor protein receptor, thereby facilitating mGluR cell-surface trafficking. Our study suggests a novel regulatory mechanism of the PDZ domain, by which Tamalin switches between the trafficking-inhibited and -active forms depending on mGluR association.
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Affiliation(s)
- Takuma Sugi
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
| | - Takuji Oyama
- Department of Structural Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
| | - Takanori Muto
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Fuji Gotemba Research Laboratories, Chugai Pharmaceutical Co., Ltd, 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan
| | | | - Kosuke Morikawa
- Department of Structural Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan
- Institute for Protein Research, Open Laboratories of Advanced Bioscience and Biotechnology (OLABB), Osaka University, 6-2-3, Furuedai, Suita, Osaka 565-0874, Japan. Tel.: +81 6 6872 8201; Fax: +81 6 6872 19. E-mail:
| | - Hisato Jingami
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), Suita, Osaka, Japan
- Present address: Office of Graduate Courses for Integrated Research Training, Kyoto University Faculty of Medicine, Yoshida, Sakyo-Ku, Kyoto 606-8501, Japan
- Office of Graduate Courses for Integrated Research Training, Kyoto University, Yoshida-Konoe, Sakyo-Ku, Kyoto 606-8501, Japan. Tel.: +81 75 753 9493; Fax: +81 75 753 9495. E-mail:
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40
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Enz R. The trick of the tail: protein-protein interactions of metabotropic glutamate receptors. Bioessays 2007; 29:60-73. [PMID: 17187376 DOI: 10.1002/bies.20518] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It was initially believed that G-protein-coupled receptors, such as metabotropic glutamate receptors, could simply be described as individual proteins that are associated with intracellular signal cascades via G-proteins. This view is no longer tenable. Today we know that metabotropic glutamate receptors (mGluRs) can dimerize and bind to a variety of proteins in addition to trimeric G-proteins. These newly identified protein interactions led to the discovery of new regulatory mechanisms that are independent of and sometimes synergistic with the classical G-protein-coupled second messenger pathways. Notably, several of these mechanisms connect mGluR-mediated signaling to other receptor classes, thereby creating a network of different receptor types and associated signal cascades. The intracellular C-termini of mGluRs play a key role in the regulation of these networks, and various new protein interactions of these domains were described recently. Because mGluRs are involved in a variety of physiological and pathophysiological processes, some of the proteins interacting with this receptor class have potential as valuable pharmaceutical targets. This review will give a comprehensive overview of proteins interacting with mGluR C-termini, highlight new evolving regulatory mechanisms for glutamatergic signal transduction and discuss possibilities for future drug development.
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Affiliation(s)
- Ralf Enz
- Emil-Fischer-Zentrum, Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany.
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41
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Watford WT, Li D, Agnello D, Durant L, Yamaoka K, Yao ZJ, Ahn HJ, Cheng TP, Hofmann SR, Cogliati T, Chen A, Hissong BD, Husa MR, Schwartzberg P, O'Shea JJ, Gadina M. Cytohesin binder and regulator (cybr) is not essential for T- and dendritic-cell activation and differentiation. Mol Cell Biol 2006; 26:6623-32. [PMID: 16914744 PMCID: PMC1592848 DOI: 10.1128/mcb.02460-05] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cybr (also known as Cytip, CASP, and PSCDBP) is an interleukin-12-induced gene expressed exclusively in hematopoietic cells and tissues that associates with Arf guanine nucleotide exchange factors known as cytohesins. Cybr levels are dynamically regulated during T-cell development in the thymus and upon activation of peripheral T cells. In addition, Cybr is induced in activated dendritic cells and has been reported to regulate dendritic cell (DC)-T-cell adhesion. Here we report the generation and characterization of Cybr-deficient mice. Despite the selective expression in hematopoietic cells, there was no intrinsic defect in T- or B-cell development or function in Cybr-deficient mice. The adoptive transfer of Cybr-deficient DCs showed that they migrated efficiently and stimulated proliferation and cytokine production by T cells in vivo. However, competitive stem cell repopulation experiments showed a defect in the abilities of Cybr-deficient T cells to develop in the presence of wild-type precursors. These data suggest that Cybr is not absolutely required for hematopoietic cell development or function, but stem cells lacking Cybr are at a developmental disadvantage compared to wild-type cells. Collectively, these data demonstrate that despite its selective expression in hematopoietic cells, the role of Cybr is limited or largely redundant. Previous in vitro studies using overexpression or short interfering RNA inhibition of the levels of Cybr protein appear to have overestimated its immunological role.
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Affiliation(s)
- Wendy T Watford
- LCBS-MIIB-NIAMS-NIH, Bldg. 10, Room 9N256, MSC-1820, 10 Center Dr., Bethesda, MD 20892-1820, USA.
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42
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Coppola V, Barrick CA, Bobisse S, Rodriguez-Galan MC, Pivetta M, Reynolds D, Howard OMZ, Palko ME, Esteban PF, Young HA, Rosato A, Tessarollo L. The scaffold protein Cybr is required for cytokine-modulated trafficking of leukocytes in vivo. Mol Cell Biol 2006; 26:5249-58. [PMID: 16809763 PMCID: PMC1592701 DOI: 10.1128/mcb.02473-05] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Trafficking and cell adhesion are key properties of cells of the immune system. However, the molecular pathways that control these cellular behaviors are still poorly understood. Cybr is a scaffold protein highly expressed in the hematopoietic/immune system whose physiological role is still unknown. In vitro studies have shown it regulates LFA-1, a crucial molecule in lymphocyte attachment and migration. Cybr also binds cytohesin-1, a guanine nucleotide exchange factor for the ARF GTPases, which affects actin cytoskeleton remodeling during cell migration. Here we show that expression of Cybr in vivo is differentially modulated by type 1 cytokines during lymphocyte maturation. In mice, Cybr deficiency negatively affects leukocytes circulating in blood and lymphocytes present in the lymph nodes. Moreover, in a Th1-polarized mouse model, lymphocyte trafficking is impaired by loss of Cybr, and Cybr-deficient mice with aseptic peritonitis have fewer cells than controls present in the peritoneal cavity, as well as fewer leukocytes leaving the bloodstream. Mutant mice injected with Moloney murine sarcoma/leukemia virus develop significantly larger tumors than wild-type mice and have reduced lymph node enlargement, suggesting reduced cytotoxic T-lymphocyte migration. Taken together, these data support a role for Cybr in leukocyte trafficking, especially in response to proinflammatory cytokines in stress conditions.
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Affiliation(s)
- Vincenzo Coppola
- Neural Development Group, Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD, USA.
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43
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Rogelj B, Mitchell JC, Miller CCJ, McLoughlin DM. The X11/Mint family of adaptor proteins. ACTA ACUST UNITED AC 2006; 52:305-15. [PMID: 16764936 DOI: 10.1016/j.brainresrev.2006.04.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 03/27/2006] [Accepted: 04/16/2006] [Indexed: 12/25/2022]
Abstract
The X11 protein family are multidomain proteins composed of a conserved PTB domain and two C-terminal PDZ domains. They are involved in formation of multiprotein complexes and two of the family members, X11alpha and X11beta, are expressed primarily in neurones. Not much is known about the principal function of X11s, but through interactions with other neuronal proteins, they are believed to be involved in regulating neuronal signaling, trafficking and plasticity. Furthermore, they have been shown to modulate processing of APP and accumulation of Abeta, making them potential therapeutic targets for Alzheimer's disease. This article reviews the known interactions of the different X11s and their involvement in Alzheimer's disease.
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Affiliation(s)
- Boris Rogelj
- King's College London, MRC Centre for Neurodegeneration Research, Department of Neuroscience, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
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44
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Esteban PF, Yoon HY, Becker J, Dorsey SG, Caprari P, Palko ME, Coppola V, Saragovi HU, Randazzo PA, Tessarollo L. A kinase-deficient TrkC receptor isoform activates Arf6-Rac1 signaling through the scaffold protein tamalin. ACTA ACUST UNITED AC 2006; 173:291-9. [PMID: 16636148 PMCID: PMC2063819 DOI: 10.1083/jcb.200512013] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurotrophins play an essential role in mammalian development. Most of their functions have been attributed to activation of the kinase-active Trk receptors and the p75 neurotrophin receptor. Truncated Trk receptor isoforms lacking the kinase domain are abundantly expressed during development and in the adult; however, their function and signaling capacity is largely unknown. We show that the neurotrophin-3 (NT3) TrkCT1-truncated receptor binds to the scaffold protein tamalin in a ligand-dependent manner. Moreover, NT3 initiation of this complex leads to activation of the Rac1 GTPase through adenosine diphosphate-ribosylation factor 6 (Arf6). At the cellular level, NT3 binding to TrkCT1–tamalin induces Arf6 translocation to the membrane, which in turn causes membrane ruffling and the formation of cellular protrusions. Thus, our data identify a new signaling pathway elicited by the kinase-deficient TrkCT1 receptor. Moreover, we establish NT3 as an upstream regulator of Arf6.
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Affiliation(s)
- Pedro F Esteban
- Neural Development Group, Mouse Cancer Genetics Program, National Cancer Institute, Frederick, MD 21702, USA
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45
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Abstract
The ADP-ribosylation factor (ARF) small GTPases regulate vesicular traffic and organelle structure by recruiting coat proteins, regulating phospholipid metabolism and modulating the structure of actin at membrane surfaces. Recent advances in our understanding of the signalling pathways that are regulated by ARF1 and ARF6, two of the best characterized ARF proteins, provide a molecular context for ARF protein function in fundamental biological processes, such as secretion, endocytosis, phagocytosis, cytokinesis, cell adhesion and tumour-cell invasion.
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Affiliation(s)
- Crislyn D'Souza-Schorey
- Department of Biological Sciences and the Walther Cancer Institute, University of Notre Dame, Notre Dame, Indiana, USA.
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46
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Shmuel M, Santy LC, Frank S, Avrahami D, Casanova JE, Altschuler Y. ARNO through its coiled-coil domain regulates endocytosis at the apical surface of polarized epithelial cells. J Biol Chem 2006; 281:13300-13308. [PMID: 16484220 DOI: 10.1074/jbc.m513723200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
ARNO is a guanine-nucleotide exchange protein for the ARF family of GTPases. Here we show that in polarized epithelial cells, ARNO is localized exclusively to the apical plasma membrane, where it regulates endocytosis. Expression of ARNO stimulates apical endocytosis of the polymeric immunoglobulin receptor, and coexpression of ARF6 with ARNO leads to a synergistic stimulation of apical endocytosis. Expression of a dominant negative ARF6 mutant, ARF6-T27N, antagonizes this stimulatory effect. Deletion of the N-terminal coiled-coil (CC) domain of ARNO causes the mutant ARNO to localize to both the apical and basolateral plasma membranes. Expression of the CC domain alone abolishes ARNO-induced apical endocytosis as well as co-localization of IgA-receptor complexes with ARNO and clathrin. These results suggest that the CC domain contributes to the specificity of apical localization of ARNO through association with components of the apical plasma membrane. We conclude that ARNO acts together with ARF6 to regulate apical endocytosis.
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Affiliation(s)
- Miriam Shmuel
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Lorraine C Santy
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Scott Frank
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Dana Avrahami
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - James E Casanova
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, Virginia 22908
| | - Yoram Altschuler
- Department of Pharmacology, School of Pharmacy, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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47
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Kellersch B, Kolanus W. Membrane-proximal signaling events in beta-2 integrin activation. Results Probl Cell Differ 2006; 43:245-57. [PMID: 17068975 DOI: 10.1007/400_024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In the immune system, integrins have essential roles in leukocyte trafficking and function. These include immune cell attachment to endothelial and antigen-presenting cells, cytotoxicity, and extravasation into tissues. The integrin leukocyte function-associated antigen-1 (LFA-1), which is exclusively expressed on hematopoietic cells, has been intensely studied since this receptor is important for many functions of the immune system. LFA-1 is involved in a) the interaction between T-cells and antigen presenting cells, b) the adhesion of cells to post-capillary high endothelial venules or to activated endothelium at sites of inflammation (extravasation), c) the control of cell differentiation and proliferation, and d) the regulation of T-cell effector functions. Therefore, a precise understanding of the spatial and temporal control of LFA-1 interaction with its cellular counter-receptors, the intercellular adhesion molecules (ICAM) -1, -2 and -3, in the various contexts, is of high interest. LFA-1 mediated adhesion is induced by several extracellular stimuli in different cell types. In T-cells, LFA-1 becomes activated upon signaling from the T-cell receptor (TCR), and upon cytokine and chemokine sensing. Adhesion of monocytes to ICAM-1 is induced by lipopolysaccharide (LPS), a component of the bacterial cell wall. To investigate the regulation of LFA-1 adhesiveness, research has focused on the identification of interaction partners of the intracellular portions of the integrin alpha and beta subunits. This review will highlight recent developments on transmembrane and intracellular signaling proteins, which have been implicated in beta-2 integrin activation.
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Affiliation(s)
- Bettina Kellersch
- Life and Medical Sciences Institute (LIMES), Molecular Immune and Cell Biology Program Unit, Laboratory of Molecular Immunology, University of Bonn, Germany
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Fodor S, Jakus Z, Mócsai A. ITAM-based signaling beyond the adaptive immune response. Immunol Lett 2005; 104:29-37. [PMID: 16332394 DOI: 10.1016/j.imlet.2005.11.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 10/29/2005] [Accepted: 11/08/2005] [Indexed: 01/26/2023]
Abstract
Classical immunoreceptors like lymphocyte antigen receptors and Fc-receptors (FcR) are central players of the adaptive immune response. These receptors utilize a common signal transduction mechanism, which relies on immunoreceptor tyrosine-based activation motifs (ITAMs) present in the receptor complex. Upon ligand binding to the receptors, tyrosines within the ITAM sequence are phosphorylated by Src-family kinases, leading to an SH2-domain mediated recruitment and activation of the Syk or the related ZAP-70 tyrosine kinase. These kinases then initiate further downstream signaling events. Here we review recent evidence indicating that components of this ITAM-based signaling machinery are also present in a number of non-lymphoid or even non-immune cell types and they participate in diverse biological functions beyond the adaptive immune response, including innate immune mechanisms, platelet activation, bone resorption or tumor development. These results suggest that the ITAM-based signaling paradigm has much wider implications than previously anticipated.
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Affiliation(s)
- Szabina Fodor
- Department of Computer Science, Corvinus University, Budapest, Hungary
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49
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Poirier MB, Hamann G, Domingue ME, Roy M, Bardati T, Langlois MF. General Receptor for Phosphoinositides 1, a Novel Repressor of Thyroid Hormone Receptor Action that Prevents Deoxyribonucleic Acid Binding. Mol Endocrinol 2005; 19:1991-2005. [PMID: 15878955 DOI: 10.1210/me.2004-0449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Thyroid hormone receptors (TRs) bind to response elements (TREs) located in the promoter region of target genes and modulate their transcription. The effects of TRs require the presence of coregulators that act as adaptor molecules between TRs and complexes that are involved in chromatin remodeling or that directly contact the basal transcription machinery. Using the yeast two-hybrid system, we identified a new interacting partner for TRs: GRP1 (general receptor for phosphoinositides-1), a nucleotide exchange factor, which had never been shown to interact with nuclear receptors. We reconfirmed the interaction between TRs and GRP1 in yeast and glutathione-S-transferase pull-down assays, and determined the areas of TRs and GRP1 involved in the interaction. Coimmunoprecipitation studies demonstrated that the interaction between GRP1 and TRs takes place in the cytoplasm and the nucleus of mammalian cells. To assess functional consequences of the interaction, we used transient transfection of CV-1 cells with TR and GRP1 expression vectors and luciferase reporter genes. On positive TREs, GRP1 decreased activation by 45-60%. On the negative TREs it increased repression by blunting the activation in the absence of T3, except for TRbeta2, which was not affected. Using EMSA, we have determined that addition of GRP1 diminishes the formation of TR/TR homodimers and TR/retinoid X receptor heterodimers on TREs, which could explain the effect of GRP1 on transcription. Furthermore, protein interaction assays using increasing concentrations of double-stranded TREs show a dose-dependent decrease of the interaction between GRP1 and TRs. The homo/heterodimers formed by TRs and retinoic X receptor-alpha were not influenced by the presence of GRP1, also suggesting that GRP1 interferes directly with DNA binding. Taken together, these data provide evidence that GRP1 is a new corepressor for TRs, which modulates both positive and negative regulation by T3 by decreasing TR-complex formation on TREs.
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Affiliation(s)
- Marie-Belle Poirier
- Department of Medicine and Physiology, Division of Endocrinology, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada J1H 5N4
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50
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Senawong T, Peterson VJ, Leid M. BCL11A-dependent recruitment of SIRT1 to a promoter template in mammalian cells results in histone deacetylation and transcriptional repression. Arch Biochem Biophys 2005; 434:316-25. [PMID: 15639232 PMCID: PMC2819353 DOI: 10.1016/j.abb.2004.10.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 10/22/2004] [Indexed: 11/21/2022]
Abstract
The B cell leukemia 11A protein (BCL11A/Evi9/CTIP1) has been implicated in hematopoietic cell development and malignancies. BCL11A is a transcriptional repressor that binds directly to a GC-rich motif and is also recruited to a promoter template via interaction with the orphan nuclear receptor, chicken ovalbumin upstream promoter transcription factor II. In both cases, BCL11A-mediated transcriptional repression is only minimally reversed by trichostatin A, suggesting the possible lack of involvement of class I or II histone deacetylases. Nonetheless, chromatin immunoprecipitation assays revealed that expression of BCL11A in mammalian cells resulted in deacetylation of histones H3 and/or H4 that were associated with the promoter region of a reporter gene. BCL11A-mediated transcriptional repression, as well as deacetylation of histone H3/H4 in BCL11A-transfected cells, was partially reversed by nicotinamide, an inhibitor of class III histone deacetylases such as SIRT1. SIRT1 was found to interact directly with BCL11A and was recruited to the promoter template in a BCL11A-dependent manner leading to transcriptional repression. These findings define a role for SIRT1 in transcriptional repression mediated by BCL11A in mammalian cells.
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Affiliation(s)
- Thanaset Senawong
- Program in Molecular and Cellular Biology, Oregon State University, Corvallis, OR 97331, USA
- Laboratory of Molecular Pharmacology, Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
| | - Valerie J. Peterson
- Laboratory of Molecular Pharmacology, Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
| | - Mark Leid
- Program in Molecular and Cellular Biology, Oregon State University, Corvallis, OR 97331, USA
- Laboratory of Molecular Pharmacology, Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
- Environmental Health Sciences Center, Oregon State University, Corvallis, OR 97331, USA
- Corresponding author. Fax: +1 541 737 3999. (M. Leid)
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