1
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Mutations in DISC1 alter IP 3R and voltage-gated Ca 2+ channel functioning, implications for major mental illness. Neuronal Signal 2021; 5:NS20180122. [PMID: 34956649 PMCID: PMC8663806 DOI: 10.1042/ns20180122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/26/2021] [Accepted: 11/08/2021] [Indexed: 12/16/2022] Open
Abstract
Disrupted in Schizophrenia 1 (DISC1) participates in a wide variety of
developmental processes of central neurons. It also serves critical roles that
underlie cognitive functioning in adult central neurons. Here we summarize
DISC1’s general properties and discuss its use as a model system for
understanding major mental illnesses (MMIs). We then discuss the cellular
actions of DISC1 that involve or regulate Ca2+ signaling in adult
central neurons. In particular, we focus on the tethering role DISC1 plays in
transporting RNA particles containing Ca2+ channel subunit RNAs,
including IP3R1, CACNA1C and CACNA2D1, and in transporting mitochondria into
dendritic and axonal processes. We also review DISC1’s role in modulating
IP3R1 activity within mitochondria-associated ER membrane (MAM).
Finally, we discuss DISC1-glycogen synthase kinase 3β (GSK3β)
signaling that regulates functional expression of voltage-gated Ca2+
channels (VGCCs) at central synapses. In each case, DISC1 regulates the movement
of molecules that impact Ca2+ signaling in neurons.
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2
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Suh BK, Lee SA, Park C, Suh Y, Kim SJ, Woo Y, Nhung TTM, Lee SB, Mun DJ, Goo BS, Choi HS, Kim SJ, Park SK. Schizophrenia-associated dysbindin modulates axonal mitochondrial movement in cooperation with p150 glued. Mol Brain 2021; 14:14. [PMID: 33461576 PMCID: PMC7814725 DOI: 10.1186/s13041-020-00720-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/23/2020] [Indexed: 11/10/2022] Open
Abstract
Mitochondrial movement in neurons is finely regulated to meet the local demand for energy and calcium buffering. Elaborate transport machinery including motor complexes is required to deliver and localize mitochondria to appropriate positions. Defects in mitochondrial transport are associated with various neurological disorders without a detailed mechanistic information. In this study, we present evidence that dystrobrevin-binding protein 1 (dysbindin), a schizophrenia-associated factor, plays a critical role in axonal mitochondrial movement. We observed that mitochondrial movement was impaired in dysbindin knockout mouse neurons. Reduced mitochondrial motility caused by dysbindin deficiency decreased the density of mitochondria in the distal part of axons. Moreover, the transport and distribution of mitochondria were regulated by the association between dysbindin and p150glued. Furthermore, altered mitochondrial distribution in axons led to disrupted calcium dynamics, showing abnormal calcium influx in presynaptic terminals. These data collectively suggest that dysbindin forms a functional complex with p150glued that regulates axonal mitochondrial transport, thereby affecting presynaptic calcium homeostasis.
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Affiliation(s)
- Bo Kyoung Suh
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Seol-Ae Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Cana Park
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
- Weill Institute of Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, USA
| | - Yeongjun Suh
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Soo Jeong Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Youngsik Woo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Truong Thi My Nhung
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Su Been Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Dong Jin Mun
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Bon Seong Goo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Hyun Sun Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - So Jung Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Sang Ki Park
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.
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3
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Lv X, Guo X, Ru Y, Zhou F, Yang X, Ge J, Li J, Liu S, Jiang K, Chen B. Dysbindin facilitates invasion and metastasis by promoting phosphorylation of ERK in epithelial ovarian cancer. J Cancer 2020; 11:2821-2829. [PMID: 32226500 PMCID: PMC7086264 DOI: 10.7150/jca.39269] [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: 08/13/2019] [Accepted: 01/19/2020] [Indexed: 12/11/2022] Open
Abstract
Dysbindin has been reported to be correlated with several malignancies. However, the clinical significance and biological role of dysbindin in epithelial ovarian cancer remains largely unknown. Here we demonstrated that the mRNA and protein levels of dysbindin were significantly upregulated in EOC tissues compared with normal ovarian tissues. High levels of dysbindin were significantly correlated with worse clinicopathological characteristics and poor prognosis in EOC patients. Overexpression and silencing of dysbindin promoted and inhibited, respectively, invasion and metastasis of EOC cells in vitro and in vivo. Mechanistically, dysbindin activates phosphorylation of ERK to promote the epithelial-mesenchymal transition and to mediate the invasive and metastatic ability of EOC cells. Our findings suggest that dysbindin facilitates invasion and metastasis by promoting the EMT of EOC cells and may serve as a potential therapeutic target in EOC.
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Affiliation(s)
- Xiaohui Lv
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xin Guo
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing 100853, China.,Department of Endoscopic Surgery, Chinese People's Liberation Army 986 th Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710054, China
| | - Yi Ru
- Department of biochemistry and molecular biology, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Fuxing Zhou
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xiaoshan Yang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi International Joint Research Center for Oral Diseases, Center for Tissue Engineering, School of Stomatology, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Junli Ge
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jia Li
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Shujuan Liu
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Kuo Jiang
- Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710054, China
| | - Biliang Chen
- Department of Gynecology and Obstetrics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
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4
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Alexander CJ, Wagner W, Copeland NG, Jenkins NA, Hammer JA. Creation of a myosin Va-TAP-tagged mouse and identification of potential myosin Va-interacting proteins in the cerebellum. Cytoskeleton (Hoboken) 2019; 75:395-409. [PMID: 29979496 DOI: 10.1002/cm.21474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/19/2018] [Accepted: 06/27/2018] [Indexed: 12/29/2022]
Abstract
The actin-based motor myosin Va transports numerous cargos, including the smooth endoplasmic reticulum (SER) in cerebellar Purkinje neurons (PNs) and melanosomes in melanocytes. Identifying proteins that interact with this myosin is key to understanding its cellular functions. Toward that end, we used recombineering to insert via homologous recombination a tandem affinity purification (TAP) tag composed of the immunoglobulin G-binding domain of protein A, a tobacco etch virus cleavage site, and a FLAG tag into the mouse MYO5A locus immediately after the initiation codon. Importantly, we provide evidence that the TAP-tagged version of myosin Va (TAP-MyoVa) functions normally in terms of SER transport in PNs and melanosome positioning in melanocytes. Given this and other evidence that TAP-MyoVa is fully functional, we purified it together with associated proteins directly from juvenile mouse cerebella and subjected the samples to mass spectroscopic analyses. As expected, known myosin Va-binding partners like dynein light chain were identified. Importantly, numerous novel interacting proteins were also tentatively identified, including guanine nucleotide-binding protein G(o) subunit alpha (Gnao1), a biomarker for schizophrenia. Consistently, an antibody to Gnao1 immunoprecipitates myosin Va, and Gnao1's localization to PN dendritic spines depends on myosin Va. The mouse model created here should facilitate the identification of novel myosin Va-binding partners, which in turn should advance our understanding of the roles played by this important myosin in vivo.
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Affiliation(s)
- Christopher J Alexander
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Wolfgang Wagner
- Center for Molecular Neurobiology (ZMNH), Department of Molecular Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Neal G Copeland
- The University of Texas MD Anderson, Department of Genetics, Cancer Center, Houston, Texas
| | - Nancy A Jenkins
- The University of Texas MD Anderson, Department of Genetics, Cancer Center, Houston, Texas
| | - John A Hammer
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
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5
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Sharma S, Carmona A, Skowronek A, Yu F, Collins MO, Naik S, Murzeau CM, Tseng PL, Erdmann KS. Apoptotic signalling targets the post-endocytic sorting machinery of the death receptor Fas/CD95. Nat Commun 2019; 10:3105. [PMID: 31308371 PMCID: PMC6629679 DOI: 10.1038/s41467-019-11025-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 06/12/2019] [Indexed: 02/07/2023] Open
Abstract
Fas plays a major role in regulating ligand-induced apoptosis in many cell types. It is well known that several cancers demonstrate reduced cell surface levels of Fas and thus escape a potential control system via ligand-induced apoptosis, although underlying mechanisms are unclear. Here we report that the endosome associated trafficking regulator 1 (ENTR1), controls cell surface levels of Fas and Fas-mediated apoptotic signalling. ENTR1 regulates, via binding to the coiled coil domain protein Dysbindin, the delivery of Fas from endosomes to lysosomes thereby controlling termination of Fas signal transduction. We demonstrate that ENTR1 is cleaved during Fas-induced apoptosis in a caspase-dependent manner revealing an unexpected interplay of apoptotic signalling and regulation of endolysosomal trafficking resulting in a positive feedback signalling-loop. Our data provide insights into the molecular mechanism of Fas post-endocytic trafficking and signalling, opening possible explanations on how cancer cells regulate cell surface levels of death receptors. Fas is a death receptor that regulates apoptosis in many cell types and is downregulated on the cell surface in many cancers. Here, Sharma et al. show that endosome associated trafficking regulator ENTR1 regulates delivery of Fas to lysosomes, thereby controlling its degradation and signalling.
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Affiliation(s)
- Shruti Sharma
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Antonio Carmona
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Agnieszka Skowronek
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Fangyan Yu
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK.,Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Mark O Collins
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Sindhu Naik
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Claire M Murzeau
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Pei-Li Tseng
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK
| | - Kai S Erdmann
- Department of Biomedical Science & Centre of Membrane Interactions and Dynamics, University of Sheffield, Sheffield, S10 2TN, UK.
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6
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The interaction between SPARC and GRP78 interferes with ER stress signaling and potentiates apoptosis via PERK/eIF2α and IRE1α/XBP-1 in colorectal cancer. Cell Death Dis 2019; 10:504. [PMID: 31243264 PMCID: PMC6594974 DOI: 10.1038/s41419-019-1687-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 02/06/2023]
Abstract
Therapy-refractory disease is one of the main contributors of treatment failure in cancer. In colorectal cancer (CRC), SPARC can function as a sensitizer to conventional chemotherapy by enhancing apoptosis by interfering with the activity of Bcl-2. Here, we examine a novel mechanism by which SPARC further potentiates apoptosis via its modulation of the unfolded protein response (UPR). Using mass spectrometry to identify SPARC-associated proteins, GRP78 was identified as a protein partner for SPARC in CRC. In vitro studies conducted to assess the signaling events resulting from this interaction, included induction of ER stress with tunicamycin, 5-fluorouracil (5-FU), and irinotecan (CPT-11). We found that the interaction between GRP78 and SPARC increased during exposure to 5-FU, CPT-11, and tunicamycin, resulting in an attenuation of GRP78’s inhibition of apoptosis. In addition, we also show that SPARC can sensitize CRC cells to PERK/eIF2α and IRE1α/XBP-1 UPR signaling by interfering with ER stress following binding to GRP78, which leads to ER stress-associated cell death in CRC cells. In line with these findings, a lower expression of GRP78 relative to SPARC in CRC is associated with a lower IC50 for 5-FU in either sensitive or therapy-refractory CRC cells. Interestingly, this observation correlates with tissue microarray analysis of 143 human CRC, where low GRP78 to SPARC expression level was prognostic of higher survival rate (P = 0.01) in individuals with CRC. This study demonstrates that modulation of UPR signaling by SPARC promotes ER stress-associated death and potentiates apoptosis. This may be an effective strategy that can be combined with current treatment options to improve therapeutic efficacy in CRC.
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7
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Weng YT, Chien T, Kuan II, Chern Y. The TRAX, DISC1, and GSK3 complex in mental disorders and therapeutic interventions. J Biomed Sci 2018; 25:71. [PMID: 30285728 PMCID: PMC6171312 DOI: 10.1186/s12929-018-0473-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/25/2018] [Indexed: 01/15/2023] Open
Abstract
Psychiatric disorders (such as bipolar disorder, depression, and schizophrenia) affect the lives of millions of individuals worldwide. Despite the tremendous efforts devoted to various types of psychiatric studies and rapidly accumulating genetic information, the molecular mechanisms underlying psychiatric disorder development remain elusive. Among the genes that have been implicated in schizophrenia and other mental disorders, disrupted in schizophrenia 1 (DISC1) and glycogen synthase kinase 3 (GSK3) have been intensively investigated. DISC1 binds directly to GSK3 and modulates many cellular functions by negatively inhibiting GSK3 activity. The human DISC1 gene is located on chromosome 1 and is highly associated with schizophrenia and other mental disorders. A recent study demonstrated that a neighboring gene of DISC1, translin-associated factor X (TRAX), binds to the DISC1/GSK3β complex and at least partly mediates the actions of the DISC1/GSK3β complex. Previous studies also demonstrate that TRAX and most of its interacting proteins that have been identified so far are risk genes and/or markers of mental disorders. In the present review, we will focus on the emerging roles of TRAX and its interacting proteins (including DISC1 and GSK3β) in psychiatric disorders and the potential implications for developing therapeutic interventions.
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Affiliation(s)
- Yu-Ting Weng
- Institute of Biomedical Sciences, Academia Sinica, 128 Sec. 2, Academia Rd. Nankang, Taipei, 115, Taiwan, Republic of China.,Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, No.155, Sec.2, Linong Street, Taipei, 112, Taiwan, Republic of China
| | - Ting Chien
- Institute of Biomedical Sciences, Academia Sinica, 128 Sec. 2, Academia Rd. Nankang, Taipei, 115, Taiwan, Republic of China
| | - I-I Kuan
- Institute of Biomedical Sciences, Academia Sinica, 128 Sec. 2, Academia Rd. Nankang, Taipei, 115, Taiwan, Republic of China
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, 128 Sec. 2, Academia Rd. Nankang, Taipei, 115, Taiwan, Republic of China. .,Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, No.155, Sec.2, Linong Street, Taipei, 112, Taiwan, Republic of China.
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8
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Hartwig C, Monis WJ, Chen X, Dickman DK, Pazour GJ, Faundez V. Neurodevelopmental disease mechanisms, primary cilia, and endosomes converge on the BLOC-1 and BORC complexes. Dev Neurobiol 2017; 78:311-330. [PMID: 28986965 DOI: 10.1002/dneu.22542] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/08/2017] [Accepted: 09/15/2017] [Indexed: 12/12/2022]
Abstract
The biogenesis of lysosome-related organelles complex-1 (BLOC-1) and the bloc-one-related complex (BORC) are the cytosolic protein complexes required for specialized membrane protein traffic along the endocytic route and the spatial distribution of endosome-derived compartments, respectively. BLOC-1 and BORC complex subunits and components of their interactomes have been associated with the risk and/or pathomechanisms of neurodevelopmental disorders. Thus, cellular processes requiring BLOC-1 and BORC interactomes have the potential to offer novel insight into mechanisms underlying behavioral defects. We focus on interactions between BLOC-1 or BORC subunits with the actin and microtubule cytoskeleton, membrane tethers, and SNAREs. These interactions highlight requirements for BLOC-1 and BORC in membrane movement by motors, control of actin polymerization, and targeting of membrane proteins to specialized cellular domains such as the nerve terminal and the primary cilium. We propose that the endosome-primary cilia pathway is an underappreciated hub in the genesis and mechanisms of neurodevelopmental disorders. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 311-330, 2018.
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Affiliation(s)
- Cortnie Hartwig
- Department of Cell Biology, Emory University, Atlanta, Georgia, 30322
| | - William J Monis
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Worcester, Massachusetts, 01605
| | - Xun Chen
- Department of Biology, Neurobiology Section, University of Southern California, Los Angeles, California, 90089
| | - Dion K Dickman
- Department of Biology, Neurobiology Section, University of Southern California, Los Angeles, California, 90089
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Biotech II, Worcester, Massachusetts, 01605
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, Georgia, 30322
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9
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Dysbindin-1 Involvement in the Etiology of Schizophrenia. Int J Mol Sci 2017; 18:ijms18102044. [PMID: 28937620 PMCID: PMC5666726 DOI: 10.3390/ijms18102044] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/13/2022] Open
Abstract
Schizophrenia is a major psychiatric disorder that afflicts about 1% of the world’s population, falling into the top 10 medical disorders causing disability. Existing therapeutic strategies have had limited success on cognitive impairment and long-term disability and are burdened by side effects. Although new antipsychotic medications have been launched in the past decades, there has been a general lack of significant innovation. This lack of significant progress in the pharmacotherapy of schizophrenia is a reflection of the complexity and heterogeneity of the disease. To date, many susceptibility genes have been identified to be associated with schizophrenia. DTNBP1 gene, which encodes dysbindin-1, has been linked to schizophrenia in multiple populations. Studies on genetic variations show that DTNBP1 modulate prefrontal brain functions and psychiatric phenotypes. Dysbindin-1 is enriched in the dorsolateral prefrontal cortex and hippocampus, while postmortem brain studies of individuals with schizophrenia show decreased levels of dysbindin-1 mRNA and protein in these brain regions. These studies proposed a strong connection between dysbindin-1 function and the pathogenesis of disease. Dysbindin-1 protein was localized at both pre- and post-synaptic sites, where it regulates neurotransmitter release and receptors signaling. Moreover, dysbindin-1 has also been found to be involved in neuronal development. Reduced expression levels of dysbindin-1 mRNA and protein appear to be common in dysfunctional brain areas of schizophrenic patients. The present review addresses our current knowledge of dysbindin-1 with emphasis on its potential role in the schizophrenia pathology. We propose that dysbindin-1 and its signaling pathways may constitute potential therapeutic targets in the therapy of schizophrenia.
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10
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Devine MJ, Norkett R, Kittler JT. DISC1 is a coordinator of intracellular trafficking to shape neuronal development and connectivity. J Physiol 2016; 594:5459-69. [PMID: 27121900 DOI: 10.1113/jp272187] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/31/2016] [Indexed: 01/14/2023] Open
Abstract
The long, asymmetric and specialised architecture of neuronal processes necessitates a properly regulated transport network of molecular motors and cytoskeletal tracks. This allows appropriate distribution of cargo for correct formation and activity of the synapse, and thus normal neuronal communication. This communication is impaired in psychiatric disease, and ongoing studies have proposed that Disrupted in schizophrenia 1 (DISC1) is an important genetic risk factor for these disorders. The mechanisms by which DISC1 dysfunction might increase propensity to psychiatric disease are not completely understood; however, an emerging theme is that DISC1 can function as a key regulator of neuronal intracellular trafficking. Transport of a wide range of potential cargoes - including mRNAs, neurotransmitter receptors, vesicles and mitochondria - can be modulated by DISC1, and therefore is susceptible to DISC1 dysfunction. This theme highlights the importance of understanding precisely how DISC1 can regulate intracellular trafficking, and suggests that a novel approach to the treatment of psychiatric disorders could be provided by targeting this protein and the trafficking machinery with which it interacts.
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Affiliation(s)
- M J Devine
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
| | - R Norkett
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
| | - J T Kittler
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.
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11
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Rodriguez-Fernandez IA, Dell’Angelica EC. Identification of Atg2 and ArfGAP1 as Candidate Genetic Modifiers of the Eye Pigmentation Phenotype of Adaptor Protein-3 (AP-3) Mutants in Drosophila melanogaster. PLoS One 2015; 10:e0143026. [PMID: 26565960 PMCID: PMC4643998 DOI: 10.1371/journal.pone.0143026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/29/2015] [Indexed: 11/19/2022] Open
Abstract
The Adaptor Protein (AP)-3 complex is an evolutionary conserved, molecular sorting device that mediates the intracellular trafficking of proteins to lysosomes and related organelles. Genetic defects in AP-3 subunits lead to impaired biogenesis of lysosome-related organelles (LROs) such as mammalian melanosomes and insect eye pigment granules. In this work, we have performed a forward screening for genetic modifiers of AP-3 function in the fruit fly, Drosophila melanogaster. Specifically, we have tested collections of large multi-gene deletions–which together covered most of the autosomal chromosomes–to identify chromosomal regions that, when deleted in single copy, enhanced or ameliorated the eye pigmentation phenotype of two independent AP-3 subunit mutants. Fine-mapping led us to define two non-overlapping, relatively small critical regions within fly chromosome 3. The first critical region included the Atg2 gene, which encodes a conserved protein involved in autophagy. Loss of one functional copy of Atg2 ameliorated the pigmentation defects of mutants in AP-3 subunits as well as in two other genes previously implicated in LRO biogenesis, namely Blos1 and lightoid, and even increased the eye pigment content of wild-type flies. The second critical region included the ArfGAP1 gene, which encodes a conserved GTPase-activating protein with specificity towards GTPases of the Arf family. Loss of a single functional copy of the ArfGAP1 gene ameliorated the pigmentation phenotype of AP-3 mutants but did not to modify the eye pigmentation of wild-type flies or mutants in Blos1 or lightoid. Strikingly, loss of the second functional copy of the gene did not modify the phenotype of AP-3 mutants any further but elicited early lethality in males and abnormal eye morphology when combined with mutations in Blos1 and lightoid, respectively. These results provide genetic evidence for new functional links connecting the machinery for biogenesis of LROs with molecules implicated in autophagy and small GTPase regulation.
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Affiliation(s)
- Imilce A. Rodriguez-Fernandez
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Esteban C. Dell’Angelica
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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12
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Chittaranjan S, Xu J, Kuzyk M, Dullat HK, Wilton J, DeVorkin L, Lebovitz C, Morin GB, Marra MA, Gorski SM. The Drosophila TIPE family member Sigmar interacts with the Ste20-like kinase Misshapen and modulates JNK signaling, cytoskeletal remodeling and autophagy. Biol Open 2015; 4:672-84. [PMID: 25836674 PMCID: PMC4434819 DOI: 10.1242/bio.20148417] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
TNFAIP8 and other mammalian TIPE family proteins have attracted increased interest due to their associations with disease-related processes including oncogenic transformation, metastasis, and inflammation. The molecular and cellular functions of TIPE family proteins are still not well understood. Here we report the molecular and genetic characterization of the Drosophila TNFAIP8 homolog, CG4091/sigmar. Previous gene expression studies revealed dynamic expression of sigmar in larval salivary glands prior to histolysis. Here we demonstrate that in sigmar loss-of-function mutants, the salivary glands are morphologically abnormal with defects in the tubulin network and decreased autophagic flux. Sigmar localizes subcellularly to microtubule-containing projections in Drosophila S2 cells, and co-immunoprecipitates with the Ste20-like kinase Misshapen, a regulator of the JNK pathway. Further, the Drosophila TNF ligand Eiger can induce sigmar expression, and sigmar loss-of-function leads to altered localization of pDJNK in salivary glands. Together, these findings link Sigmar to the JNK pathway, cytoskeletal remodeling and autophagy activity during salivary gland development, and provide new insights into TIPE family member function.
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Affiliation(s)
- Suganthi Chittaranjan
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Jing Xu
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Michael Kuzyk
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Harpreet K Dullat
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada
| | - James Wilton
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Lindsay DeVorkin
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Chandra Lebovitz
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Gregg B Morin
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada Department of Medical Genetics, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Marco A Marra
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Sharon M Gorski
- The Genome Sciences Centre, BC Cancer Agency, 675 West 10 Avenue, Vancouver, BC V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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13
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Lee SA, Kim SM, Suh BK, Sun HY, Park YU, Hong JH, Park C, Nguyen MD, Nagata KI, Yoo JY, Park SK. Disrupted-in-schizophrenia 1 (DISC1) regulates dysbindin function by enhancing its stability. J Biol Chem 2015; 290:7087-96. [PMID: 25635053 DOI: 10.1074/jbc.m114.614750] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Dysbindin and DISC1 are schizophrenia susceptibility factors playing roles in neuronal development. Here we show that the physical interaction between dysbindin and DISC1 is critical for the stability of dysbindin and for the process of neurite outgrowth. We found that DISC1 forms a complex with dysbindin and increases its stability in association with a reduction in ubiquitylation. Furthermore, knockdown of DISC1 or expression of a deletion mutant, DISC1 lacking amino acid residues 403-504 of DISC1 (DISC1(Δ403-504)), effectively decreased levels of endogenous dysbindin. Finally, the neurite outgrowth defect induced by knockdown of DISC1 was partially reversed by coexpression of dysbindin. Taken together, these results indicate that dysbindin and DISC1 form a physiologically functional complex that is essential for normal neurite outgrowth.
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Affiliation(s)
- Seol-Ae Lee
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Seong-Mo Kim
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Bo Kyoung Suh
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Hwa-Young Sun
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Young-Un Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Ji-Ho Hong
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Cana Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Minh Dang Nguyen
- the Hotchkiss Brain Institute, Departments of Clinical Neurosciences, Cell Biology and Anatomy, and Biochemistry and Molecular Biology, University of Calgary, Calgary T2N 4N1, Canada, and
| | - Koh-Ichi Nagata
- the Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Joo-Yeon Yoo
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Sang Ki Park
- From the Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea,
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14
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DeVorkin L, Go NE, Hou YCC, Moradian A, Morin GB, Gorski SM. The Drosophila effector caspase Dcp-1 regulates mitochondrial dynamics and autophagic flux via SesB. ACTA ACUST UNITED AC 2014; 205:477-92. [PMID: 24862573 PMCID: PMC4033768 DOI: 10.1083/jcb.201303144] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Increasing evidence reveals that a subset of proteins participates in both the autophagy and apoptosis pathways, and this intersection is important in normal physiological contexts and in pathological settings. In this paper, we show that the Drosophila effector caspase, Drosophila caspase 1 (Dcp-1), localizes within mitochondria and regulates mitochondrial morphology and autophagic flux. Loss of Dcp-1 led to mitochondrial elongation, increased levels of the mitochondrial adenine nucleotide translocase stress-sensitive B (SesB), increased adenosine triphosphate (ATP), and a reduction in autophagic flux. Moreover, we find that SesB suppresses autophagic flux during midoogenesis, identifying a novel negative regulator of autophagy. Reduced SesB activity or depletion of ATP by oligomycin A could rescue the autophagic defect in Dcp-1 loss-of-function flies, demonstrating that Dcp-1 promotes autophagy by negatively regulating SesB and ATP levels. Furthermore, we find that pro-Dcp-1 interacts with SesB in a nonproteolytic manner to regulate its stability. These data reveal a new mitochondrial-associated molecular link between nonapoptotic caspase function and autophagy regulation in vivo.
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Affiliation(s)
- Lindsay DeVorkin
- The Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Nancy Erro Go
- The Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Ying-Chen Claire Hou
- The Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Annie Moradian
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 1L3, Canada
| | - Gregg B Morin
- The Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V5Z 1L3, Canada
| | - Sharon M Gorski
- The Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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15
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Han MHJ, Hu Z, Chen CY, Chen Y, Gucek M, Li Z, Markey SP. Dysbindin-associated proteome in the p2 synaptosome fraction of mouse brain. J Proteome Res 2014; 13:4567-80. [PMID: 25198678 PMCID: PMC4227559 DOI: 10.1021/pr500656z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
The
gene DTNBP1 encodes the protein dysbindin and is among the
most promising and highly investigated schizophrenia-risk genes. Accumulating
evidence suggests that dysbindin plays an important role in the regulation
of neuroplasticity. Dysbindin was reported to be a stable component
of BLOC-1 complex in the cytosol. However, little is known about the
endogenous dysbindin-containing complex in the brain synaptosome.
In this study, we investigated the associated proteome of dysbindin
in the P2 synaptosome fraction of mouse brain. Our data suggest that
dysbindin has three isoforms associating with different complexes
in the P2 fraction of mouse brain. To facilitate immunopurification,
BAC transgenic mice expressing a tagged dysbindin were generated,
and 47 putative dysbindin-associated proteins, including all components
of BLOC-1, were identified by mass spectrometry in the dysbindin-containing
complex purified from P2. The interactions of several selected candidates,
including WDR11, FAM91A1, snapin, muted, pallidin, and two proteasome
subunits, PSMD9 and PSMA4, were verified by coimmunoprecipitation.
The specific proteasomal activity is significantly reduced in the
P2 fraction of the brains of the dysbindin-null mutant (sandy) mice.
Our data suggest that dysbindin is functionally interrelated to the
ubiquitin-proteasome system and offer a molecular repertoire for future
study of dysbindin functional networks in brain.
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Affiliation(s)
- Meng-Hsuan J Han
- National Institute of Mental Health , Bethesda, Maryland 20892, United States
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16
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Cochet-Bissuel M, Lory P, Monteil A. The sodium leak channel, NALCN, in health and disease. Front Cell Neurosci 2014; 8:132. [PMID: 24904279 PMCID: PMC4033012 DOI: 10.3389/fncel.2014.00132] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/28/2014] [Indexed: 12/12/2022] Open
Abstract
Ion channels are crucial components of cellular excitability and are involved in many neurological diseases. This review focuses on the sodium leak, G protein-coupled receptors (GPCRs)-activated NALCN channel that is predominantly expressed in neurons where it regulates the resting membrane potential and neuronal excitability. NALCN is part of a complex that includes not only GPCRs, but also UNC-79, UNC-80, NLF-1 and src family of Tyrosine kinases (SFKs). There is growing evidence that the NALCN channelosome critically regulates its ion conduction. Both in mammals and invertebrates, animal models revealed an involvement in many processes such as locomotor behaviors, sensitivity to volatile anesthetics, and respiratory rhythms. There is also evidence that alteration in this NALCN channelosome can cause a wide variety of diseases. Indeed, mutations in the NALCN gene were identified in Infantile Neuroaxonal Dystrophy (INAD) patients, as well as in patients with an Autosomal Recessive Syndrome with severe hypotonia, speech impairment, and cognitive delay. Deletions in NALCN gene were also reported in diseases such as 13q syndrome. In addition, genes encoding NALCN, NLF- 1, UNC-79, and UNC-80 proteins may be susceptibility loci for several diseases including bipolar disorder, schizophrenia, Alzheimer's disease, autism, epilepsy, alcoholism, cardiac diseases and cancer. Although the physiological role of the NALCN channelosome is poorly understood, its involvement in human diseases should foster interest for drug development in the near future. Toward this goal, we review here the current knowledge on the NALCN channelosome in physiology and diseases.
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Affiliation(s)
- Maud Cochet-Bissuel
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, Universités Montpellier 1&2 Montpellier, France ; INSERM, U 661 Montpellier, France ; LabEx 'Ion Channel Science and Therapeutics' Montpellier, France
| | - Philippe Lory
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, Universités Montpellier 1&2 Montpellier, France ; INSERM, U 661 Montpellier, France ; LabEx 'Ion Channel Science and Therapeutics' Montpellier, France
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, CNRS UMR 5203, Universités Montpellier 1&2 Montpellier, France ; INSERM, U 661 Montpellier, France ; LabEx 'Ion Channel Science and Therapeutics' Montpellier, France
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17
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Orozco IJ, Koppensteiner P, Ninan I, Arancio O. The schizophrenia susceptibility gene DTNBP1 modulates AMPAR synaptic transmission and plasticity in the hippocampus of juvenile DBA/2J mice. Mol Cell Neurosci 2013; 58:76-84. [PMID: 24321452 DOI: 10.1016/j.mcn.2013.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 10/31/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022] Open
Abstract
The dystrobrevin binding protein (DTNBP) 1 gene has emerged over the last decade as a potential susceptibility locus for schizophrenia. While no causative mutations have been found, reduced expression of the encoded protein, dysbindin, was reported in patients. Dysbindin likely plays a role in the neuronal trafficking of proteins including receptors. One important pathway suspected to be affected in schizophrenia is the fast excitatory glutamatergic transmission mediated by AMPA receptors. Here, we investigated excitatory synaptic transmission and plasticity in hippocampal neurons from dysbindin-deficient sandy mice bred on the DBA/2J strain. In cultured neurons an enhancement of AMPAR responses was observed. The enhancement of AMPAR-mediated transmission was confirmed in hippocampal CA3-CA1 synapses, and was not associated with changes in the expression of GluA1-4 subunits or an increase in GluR2-lacking receptor complexes. Lastly, an enhancement in LTP was also found in these mice. These data provide compelling evidence that dysbindin, a widely suspected susceptibility protein in schizophrenia, is important for AMPAR-mediated synaptic transmission and plasticity in the developing hippocampus.
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Affiliation(s)
- Ian J Orozco
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
| | - Peter Koppensteiner
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Ipe Ninan
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
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18
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The 3' overhangs at Tetrahymena thermophila telomeres are packaged by four proteins, Pot1a, Tpt1, Pat1, and Pat2. EUKARYOTIC CELL 2013; 13:240-5. [PMID: 24297442 DOI: 10.1128/ec.00275-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Although studies with the ciliate Tetrahymena thermophila have played a central role in advancing our understanding of telomere biology and telomerase mechanisms and composition, the full complement of Tetrahymena telomere proteins has not yet been identified. Previously, we demonstrated that in Tetrahymena, the telomeric 3' overhang is protected by a three-protein complex composed of Pot1a, Tpt1, and Pat1. Here we show that Tpt1 and Pat1 associate with a fourth protein, Pat2 (Pot1 associated Tetrahymena 2). Mass spectrometry of proteins copurifying with Pat1 or Tpt1 identified peptides from Pat2, Pot1a, Tpt1, and Pat1. The lack of other proteins copurifying with Pat1 or Tpt1 implies that the overhang is protected by a four-protein Pot1a-Tpt1-Pat1-Pat2 complex. We verified that Pat2 localizes to telomeres, but we were unable to detect direct binding to telomeric DNA. Cells depleted of Pat2 continue to divide, but the telomeres exhibit gradual shortening. The lack of growth arrest indicates that, in contrast to Pot1a and Tpt1, Pat2 is not required for the sequestration of the telomere from the DNA repair machinery. Instead, Pat2 is needed to regulate telomere length, most likely by acting in conjunction with Pat1 to allow telomerase access to the telomere.
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19
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Seshadri S, Zeledon M, Sawa A. Synapse-specific contributions in the cortical pathology of schizophrenia. Neurobiol Dis 2013; 53:26-35. [PMID: 23336981 DOI: 10.1016/j.nbd.2013.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/06/2013] [Accepted: 01/10/2013] [Indexed: 12/22/2022] Open
Abstract
Schizophrenia (SZ) is often described as a disease of neuronal connectivity. Cognitive processes such as working memory, which are particularly dependent on the proper functioning of complex cortical circuitry, are disturbed in the disease. Reciprocal connections between pyramidal neurons and interneurons, as well as dopaminergic innervations, form the basis for higher cognition in the cortex. Nonetheless, only a few review articles are available which address how each synapse operates, and is possibly disturbed in SZ, at least in part by the mechanisms involving genetic susceptibility factors for SZ. In this review, we provide an overview of cortical glutamatergic, GABAergic, and dopaminergic circuitry, review SZ-associated deficits at each of these synapses, and discuss how genetic factors for SZ may contribute to SZ-related phenotype deficits in a synapse-specific manner. Pinpointing the spatially and temporally distinct sites of action of putative SZ susceptibility factors may help us better understand the pathological mechanisms of SZ, especially those associated with synaptic functioning and neuronal connectivity.
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Affiliation(s)
- Saurav Seshadri
- Department of Psychiatry, Johns Hopkins University, Baltimore, MD 21287, USA
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20
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van Wietmarschen N, Moradian A, Morin GB, Lansdorp PM, Uringa EJ. The mammalian proteins MMS19, MIP18, and ANT2 are involved in cytoplasmic iron-sulfur cluster protein assembly. J Biol Chem 2012; 287:43351-8. [PMID: 23150669 DOI: 10.1074/jbc.m112.431270] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Iron-sulfur (Fe-S) clusters are essential cofactors of proteins with a wide range of biological functions. A dedicated cytosolic Fe-S cluster assembly (CIA) system is required to assemble Fe-S clusters into cytosolic and nuclear proteins. Here, we show that the mammalian nucleotide excision repair protein homolog MMS19 can simultaneously bind probable cytosolic iron-sulfur protein assembly protein CIAO1 and Fe-S proteins, confirming that MMS19 is a central protein of the CIA machinery that brings Fe-S cluster donor proteins and the receiving apoproteins into proximity. In addition, we show that mitotic spindle-associated MMXD complex subunit MIP18 also interacts with both CIAO1 and Fe-S proteins. Specifically, it binds the Fe-S cluster coordinating regions in Fe-S proteins. Furthermore, we show that ADP/ATP translocase 2 (ANT2) interacts with Fe-S apoproteins and MMS19 in the CIA complex but not with the individual proteins. Together, these results elucidate the composition and interactions within the late CIA complex.
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Affiliation(s)
- Niek van Wietmarschen
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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21
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Quantitative proteomic and genetic analyses of the schizophrenia susceptibility factor dysbindin identify novel roles of the biogenesis of lysosome-related organelles complex 1. J Neurosci 2012; 32:3697-711. [PMID: 22423091 DOI: 10.1523/jneurosci.5640-11.2012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Biogenesis of Lysosome-Related Organelles Complex 1 (BLOC-1) is a protein complex containing the schizophrenia susceptibility factor dysbindin, which is encoded by the gene DTNBP1. However, mechanisms engaged by dysbindin defining schizophrenia susceptibility pathways have not been quantitatively elucidated. Here, we discovered prevalent and novel cellular roles of the BLOC-1 complex in neuronal cells by performing large-scale Stable Isotopic Labeling of Cells in Culture (SILAC) quantitative proteomics combined with genetic analyses in dysbindin-null mice (Mus musculus) and the genome of schizophrenia patients. We identified 24 proteins that associate with the BLOC-1 complex, many of which were altered in content/distribution in cells or tissues deficient in BLOC-1. New findings include BLOC-1 interactions with the COG complex, a Golgi apparatus tether, and antioxidant enzymes peroxiredoxins 1-2. Importantly, loci encoding eight of the 24 proteins are affected by genomic copy number variation in schizophrenia patients. Thus, our quantitative proteomic studies expand the functional repertoire of the BLOC-1 complex and provide insight into putative molecular pathways of schizophrenia susceptibility.
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22
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Schmitt A, Leonardi-Essmann F, Durrenberger PF, Wichert SP, Spanagel R, Arzberger T, Kretzschmar H, Zink M, Herrera-Marschitz M, Reynolds R, Rossner MJ, Falkai P, Gebicke-Haerter PJ. Structural synaptic elements are differentially regulated in superior temporal cortex of schizophrenia patients. Eur Arch Psychiatry Clin Neurosci 2012; 262:565-77. [PMID: 22441714 PMCID: PMC3464383 DOI: 10.1007/s00406-012-0306-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/01/2012] [Indexed: 11/26/2022]
Abstract
Inaccurate wiring and synaptic pathology appear to be major hallmarks of schizophrenia. A variety of gene products involved in synaptic neurotransmission and receptor signaling are differentially expressed in brains of schizophrenia patients. However, synaptic pathology may also develop by improper expression of intra- and extra-cellular structural elements weakening synaptic stability. Therefore, we have investigated transcription of these elements in the left superior temporal gyrus of 10 schizophrenia patients and 10 healthy controls by genome-wide microarrays (Illumina). Fourteen up-regulated and 22 downregulated genes encoding structural elements were chosen from the lists of differentially regulated genes for further qRT-PCR analysis. Almost all genes confirmed by this method were downregulated. Their gene products belonged to vesicle-associated proteins, that is, synaptotagmin 6 and syntaxin 12, to cytoskeletal proteins, like myosin 6, pleckstrin, or to proteins of the extracellular matrix, such as collagens, or laminin C3. Our results underline the pivotal roles of structural genes that control formation and stabilization of pre- and post-synaptic elements or influence axon guidance in schizophrenia. The glial origin of collagen or laminin highlights the close interrelationship between neurons and glial cells in establishment and maintenance of synaptic strength and plasticity. It is hypothesized that abnormal expression of these and related genes has a major impact on the pathophysiology of schizophrenia.
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Affiliation(s)
- Andrea Schmitt
- Department of Psychiatry and Psychotherapy, University of Göttingen, Germany.
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23
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Linger BR, Morin GB, Price CM. The Pot1a-associated proteins Tpt1 and Pat1 coordinate telomere protection and length regulation in Tetrahymena. Mol Biol Cell 2011; 22:4161-70. [PMID: 21900503 PMCID: PMC3204076 DOI: 10.1091/mbc.e11-06-0551] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We have identified two new Pot1a-associated telomere proteins, Pat1 and Tpt1, from Tetrahymena. Tpt1 is required to prevent telomere elongation and appears to be the Tetrahymena equivalent of vertebrate TPP1. Pat1 depletion causes gradual telomere shortening, indicating that it is needed for telomerase to gain access to the DNA terminus. We have identified two new telomere proteins, Tpt1 and Pat1, from the ciliate Tetrahymena thermophila. Although Tetrahymena telomerase is well characterized, only one telomere protein had previously been identified. This was the G-overhang binding-protein Pot1a. Tpt1 and Pat1 were isolated as Pot1a binding partners and shown to localize to telomeres. As Tpt1 and Pat1 were both found to be essential, conditional cell lines were generated to explore their function. Tpt1 depletion caused a rapid growth arrest and telomere elongation in the absence of cell division. The phenotype was similar to that seen after Pot1a depletion suggesting that Tpt1 and Pot1a function together to regulate telomere length and prevent telomere deprotection. In contrast, Pat1 depletion had a modest effect on cell growth but caused progressive telomere shortening similar to that observed upon TERT depletion. Thus Pat1 appears to be needed for telomerase to maintain the chromosome terminus. Analysis of Pot1a-Tpt1-Pat1 complex formation using purified proteins indicated that Tpt1 interacts directly with Pot1a while Pat1 interacts with Tpt1. Our results indicate that Tpt1 is the Tetrahymena equivalent of mammalian TPP1, Schizosaccharomyces pombe Tpz1, and Oxytricha nova TEBPβ.
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Affiliation(s)
- Benjamin R Linger
- Department of Cancer and Cell Biology, University of Cincinnati, Cincinnati, OH 45267, USA
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24
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Mullin AP, Gokhale A, Larimore J, Faundez V. Cell biology of the BLOC-1 complex subunit dysbindin, a schizophrenia susceptibility gene. Mol Neurobiol 2011; 44:53-64. [PMID: 21520000 PMCID: PMC3321231 DOI: 10.1007/s12035-011-8183-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 04/12/2011] [Indexed: 11/28/2022]
Abstract
There is growing interest in the biology of dysbindin and its genetic locus (DTNBP1) due to genetic variants associated with an increased risk of schizophrenia. Reduced levels of dysbindin mRNA and protein in the hippocampal formation of schizophrenia patients further support involvement of this locus in disease risk. Here, we discuss phylogenetically conserved dysbindin molecular interactions that define its contribution to the assembly of the biogenesis of lysosome-related organelles complex-1 (BLOC-1). We explore fundamental cellular processes where dysbindin and the dysbindin-containing BLOC-1 complex are implicated. We propose that cellular, tissue, and system neurological phenotypes from dysbindin deficiencies in model genetic organisms, and likely individuals affected with schizophrenia, emerge from abnormalities in few core cellular mechanisms controlled by BLOC-1-dysbindin-containing complex rather than from defects in dysbindin itself.
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Affiliation(s)
- Ariana P Mullin
- Graduate Program in Neuroscience, Emory University, Atlanta, GA, USA
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25
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Ghiani CA, Dell'Angelica EC. Dysbindin-containing complexes and their proposed functions in brain: from zero to (too) many in a decade. ASN Neuro 2011; 3:e00058. [PMID: 21504412 PMCID: PMC3155195 DOI: 10.1042/an20110010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/18/2011] [Accepted: 04/20/2011] [Indexed: 02/07/2023] Open
Abstract
Dysbindin (also known as dysbindin-1 or dystrobrevin-binding protein 1) was identified 10 years ago as a ubiquitously expressed protein of unknown function. In the following years, the protein and its encoding gene, DTNBP1, have become the focus of intensive research owing to genetic and histopathological evidence suggesting a potential role in the pathogenesis of schizophrenia. In this review, we discuss published results demonstrating that dysbindin function is required for normal physiology of the mammalian central nervous system. In tissues other than brain and in non-neuronal cell types, the protein has been characterized as a stable component of a multi-subunit complex, named BLOC-1 (biogenesis of lysosome-related organelles complex-1), which has been implicated in intracellular protein trafficking and the biogenesis of specialized organelles of the endosomal-lysosomal system. In the brain, however, dysbindin has been proposed to associate into multiple complexes with alternative binding partners, and to play a surprisingly wide variety of functions including transcriptional regulation, neurite and dendritic spine formation, synaptic vesicle biogenesis and exocytosis, and trafficking of glutamate and dopamine receptors. This puzzling array of molecular and functional properties ascribed to the dysbindin protein from brain underscores the need of further research aimed at ascertaining its biological significance in health and disease.
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Key Words
- biogenesis of lysosome-related organelles complex-1 (bloc-1)
- dtnbp1
- dysbindin
- dystrobrevin-binding protein
- schizophrenia
- ap-3, adaptor protein-3
- bloc, biogenesis of lysosome-related organelles complex
- coip, co-immunoprecipitation
- hek-293 cells, human embryonic kidney cells
- hps, hermansky–pudlak syndrome
- jnk, c-jun n-terminal kinase
- ms/ms, tandem mass spectrometry
- rnai, rna interference
- shrna, short-hairpin rna
- sirna, small-interfering rna
- wash, wiskott–aldrich syndrome protein and scar homologue
- vamp-7, vesicle-associated membrane protein 7
- wave, wasp (wiskott–aldrich syndrome protein) verprolin homologous
- y2h, yeast two-hybrid
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Affiliation(s)
- Cristina A Ghiani
- *Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
- †Department of Psychiatry, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
| | - Esteban C Dell'Angelica
- *Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
- ‡Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, U.S.A
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Johnstone M, Thomson PA, Hall J, McIntosh AM, Lawrie SM, Porteous DJ. DISC1 in schizophrenia: genetic mouse models and human genomic imaging. Schizophr Bull 2011; 37:14-20. [PMID: 21149852 PMCID: PMC3004186 DOI: 10.1093/schbul/sbq135] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Schizophrenia and related disorders have a major genetic component. Several large-scale studies have uncovered a number of possible candidate genes, but these have yet to be consistently replicated and their underlying biological function remains elusive. One exception is 'Disrupted in schizophrenia 1' (DISC1), a gene locus originally identified in a large Scottish family, showing a heavy burden of major mental illnesses associated with a balanced t(1;11)(q42.1;q14.3) chromosome translocation. Substantial genetic and biological research on DISC1 has been reported in the intervening 10 years: DISC1 is now recognized as a genetic risk factor for a spectrum of psychiatric disorders and DISC1 impacts on many aspects of central nervous system (CNS) function, including neurodevelopment, neurosignaling, and synaptic functioning. Evidence has emerged from genetic studies showing a relationship between DISC1 and quantitative traits, including working memory, cognitive aging, gray matter volume in the prefrontal cortex, and abnormalities in hippocampal structures and function. DISC1 interacts with numerous proteins also involved in neuronal migration, neurite outgrowth, cytoskeletal modulation, and signal transduction, some of which have been reported as independent genetic susceptibility factors for psychiatric morbidity. Here, we focus on the growing literature relating genetic variation in the DISC1 pathway to functional and structural studies of the brain in humans and in the mouse.
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Affiliation(s)
- Mandy Johnstone
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Pippa A. Thomson
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Jeremy Hall
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Andrew M. McIntosh
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Stephen M. Lawrie
- Department of Psychiatry, The Royal Edinburgh Hospital, Morningside Terrace, Edinburgh EH10 5HF, UK
| | - David J. Porteous
- Medical Genetics Section, Institute of Genetics and Molecular Medicine, University of Edinburgh Molecular Medicine Centre, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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Hoyle DJ, Rodriguez-Fernandez IA, Dell'angelica EC. Functional interactions between OCA2 and the protein complexes BLOC-1, BLOC-2, and AP-3 inferred from epistatic analyses of mouse coat pigmentation. Pigment Cell Melanoma Res 2010; 24:275-81. [PMID: 21392365 DOI: 10.1111/j.1755-148x.2010.00815.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The biogenesis of melanosomes is a multistage process that requires the function of cell-type-specific and ubiquitously expressed proteins. OCA2, the product of the gene defective in oculocutaneous albinism type 2, is a melanosomal membrane protein with restricted expression pattern and a potential role in the trafficking of other proteins to melanosomes. The ubiquitous protein complexes AP-3, BLOC-1, and BLOC-2, which contain as subunits the products of genes defective in various types of Hermansky-Pudlak syndrome, have been likewise implicated in trafficking to melanosomes. We have tested for genetic interactions between mutant alleles causing deficiency in OCA2 (pink-eyed dilution unstable), AP-3 (pearl), BLOC-1 (pallid), and BLOC-2 (cocoa) in C57BL/6J mice. The pallid allele was epistatic to pink-eyed dilution, and the latter behaved as a semi-dominant phenotypic enhancer of cocoa and, to a lesser extent, of pearl. These observations suggest functional links between OCA2 and these three protein complexes involved in melanosome biogenesis.
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Affiliation(s)
- Diego J Hoyle
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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