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Srivastava D, Yadav RP, Inamdar SM, Huang Z, Sokolov M, Boyd K, Artemyev NO. Transducin Partners Outside the Phototransduction Pathway. Front Cell Neurosci 2020; 14:589494. [PMID: 33173469 PMCID: PMC7591391 DOI: 10.3389/fncel.2020.589494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/10/2020] [Indexed: 11/13/2022] Open
Abstract
Transducin mediates signal transduction in a classical G protein-coupled receptor (GPCR) phototransduction cascade. Interactions of transducin with the receptor and the effector molecules had been extensively investigated and are currently defined at the atomic level. However, partners and functions of rod transducin α (Gαt 1) and βγ (Gβ1γ1) outside the visual pathway are not well-understood. In particular, light-induced redistribution of rod transducin from the outer segment to the inner segment and synaptic terminal (IS/ST) allows Gαt1 and/or Gβ1γ1 to modulate synaptic transmission from rods to rod bipolar cells (RBCs). Protein-protein interactions underlying this modulation are largely unknown. We discuss known interactors of transducin in the rod IS/ST compartment and potential pathways leading to the synaptic effects of light-dispersed Gαt1 and Gβ1γ1. Furthermore, we show that a prominent non-GPCR guanine nucleotide exchange factor (GEF) and a chaperone of Gα subunits, resistance to inhibitors of cholinesterase 8A (Ric-8A) protein, is expressed throughout the retina including photoreceptor cells. Recent structures of Ric-8A alone and in complexes with Gα subunits have illuminated the structural underpinnings of the Ric-8A activities. We generated a mouse model with conditional knockout of Ric-8A in rods in order to begin defining the functional roles of the protein in rod photoreceptors and the retina. Our analysis suggests that Ric-8A is not an obligate chaperone of Gαt1. Further research is needed to investigate probable roles of Ric-8A as a GEF, trafficking chaperone, or a mediator of the synaptic effects of Gαt1.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Ravi P Yadav
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Shivangi M Inamdar
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Zhen Huang
- Department of Neurology and Neuroscience, University of Wisconsin-Madison, Madison, WI, United States
| | - Maxim Sokolov
- Department of Ophthalmology, Biochemistry and Neuroscience, West Virginia University, Morgantown, WV, United States
| | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA, United States.,Department of Ophthalmology and Visual Sciences, Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA, United States
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Trosclair K, Dhaibar HA, Gautier NM, Mishra V, Glasscock E. Neuron-specific Kv1.1 deficiency is sufficient to cause epilepsy, premature death, and cardiorespiratory dysregulation. Neurobiol Dis 2020; 137:104759. [PMID: 31978607 DOI: 10.1016/j.nbd.2020.104759] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/03/2020] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of epilepsy-related mortality, but the precise cellular substrates involved remain elusive. Epilepsy-associated ion channel genes with co-expression in brain and heart have been proposed as SUDEP candidate genes since they provide a singular unifying link between seizures and lethal cardiac arrhythmias. Here, we generated a conditional knockout (cKO) mouse with neuron-specific deletion of Kcna1, a SUDEP-associated gene with brain-heart co-expression, to test whether seizure-evoked cardiac arrhythmias and SUDEP require the absence of Kv1.1 in both brain and heart or whether ablation in neurons is sufficient. To obtain cKO mice, we developed a floxed Kcna1 mouse which we crossed to mice with the Synapsin1-Cre transgene, which selectively deletes Kcna1 in most neurons. Molecular analyses confirmed neuron-specific Kcna1 deletion in cKO mice and corresponding loss of Kv1.1 except in cerebellum where Synapsin1-Cre is not highly expressed. Survival studies and electroencephalography, electrocardiography, and plethysmography recordings showed that cKO mice exhibit premature death, epilepsy, and cardiorespiratory dysregulation but to a lesser degree than global knockouts. Heart rate variability (HRV) was increased in cKO mice with peaks during daytime suggesting disturbed diurnal HRV patterns as a SUDEP biomarker. Residual Kv1.1 expression in cKO cerebellum suggests it may play an unexpected role in regulating ictal cardiorespiratory dysfunction and SUDEP risk. This work demonstrates the principle that channelopathies with brain-heart expression patterns can increase death risk by brain-driven mechanisms alone without a functionally compromised heart, reinforcing seizure control as a primary clinical strategy for SUDEP prevention.
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Affiliation(s)
- Krystle Trosclair
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Hemangini A Dhaibar
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Nicole M Gautier
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Vikas Mishra
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America.
| | - Edward Glasscock
- Department of Cellular Biology and Anatomy, Louisiana State University Health Sciences Center Shreveport, LA 71103, United States of America; Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States of America.
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Gennaro VJ, Wedegaertner H, McMahon SB. Interaction between the BAG1S isoform and HSP70 mediates the stability of anti-apoptotic proteins and the survival of osteosarcoma cells expressing oncogenic MYC. BMC Cancer 2019; 19:258. [PMID: 30902071 PMCID: PMC6429775 DOI: 10.1186/s12885-019-5454-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 03/12/2019] [Indexed: 02/07/2023] Open
Abstract
Background The oncoprotein MYC has the dual capacity to drive cell cycle progression or induce apoptosis, depending on the cellular context. BAG1 was previously identified as a transcriptional target of MYC that functions as a critical determinant of this cell fate decision. The BAG1 protein is expressed as multiple isoforms, each having an array of distinct biochemical functions; however, the specific effector function of BAG1 that directs MYC-dependent cell survival has not been defined. Methods In our studies the human osteosarcoma line U2OS expressing a conditional MYC-ER allele was used to induce oncogenic levels of MYC. We interrogated MYC-driven survival processes by modifying BAG1 protein expression. The function of the separate BAG1 isoforms was investigated by depleting cells of endogenous BAG1 and reintroducing the distinct isoforms. Flow cytometry and immunoblot assays were performed to analyze the effect of specific BAG1 isoforms on MYC-dependent apoptosis. These experiments were repeated to determine the role of the HSP70 chaperone complex in BAG1 survival processes. Finally, a proteomic approach was used to identify a set of specific pro-survival proteins controlled by the HSP70/BAG1 complex. Results Loss of BAG1 resulted in robust MYC-induced apoptosis. Expression of the larger isoforms of BAG1, BAG1L and BAG1M, were insufficient to rescue survival in cells with oncogenic levels of MYC. Alternatively, reintroduction of BAG1S significantly reduced the level of apoptosis. Manipulation of the BAG1S interaction with HSP70 revealed that BAG1S provides its pro-survival function by serving as a cofactor for the HSP70 chaperone complex. Via a proteomic approach we identified and classified a set of pro-survival proteins controlled by this HSP70/BAG1 chaperone complex that contribute to the BAG1 anti-apoptotic phenotype. Conclusions The small isoform of BAG1, BAG1S, in cooperation with the HSP70 chaperone complex, selectively mediates cell survival in MYC overexpressing tumor cells. We identified a set of specific pro-survival clients controlled by the HSP70/BAG1S chaperone complex. These clients define new nodes that could be therapeutically targeted to disrupt the survival of tumor cells driven by MYC activation. With MYC overexpression occurring in most human cancers, this introduces new strategies for cancer treatment. Electronic supplementary material The online version of this article (10.1186/s12885-019-5454-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Victoria J Gennaro
- Department of Biochemistry and Molecular Biology Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Helen Wedegaertner
- Department of Biochemistry and Molecular Biology Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA
| | - Steven B McMahon
- Department of Biochemistry and Molecular Biology Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
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Kask K, Tikker L, Ruisu K, Lulla S, Oja EM, Meier R, Raid R, Velling T, Tõnissoo T, Pooga M. Targeted deletion of RIC8A in mouse neural precursor cells interferes with the development of the brain, eyes, and muscles. Dev Neurobiol 2018; 78:374-390. [PMID: 29380551 DOI: 10.1002/dneu.22578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 11/11/2022]
Abstract
Autosomal recessive disorders such as Fukuyama congenital muscular dystrophy, Walker-Warburg syndrome, and the muscle-eye-brain disease are characterized by defects in the development of patient's brain, eyes, and skeletal muscles. These syndromes are accompanied by brain malformations like type II lissencephaly in the cerebral cortex with characteristic overmigrations of neurons through the breaches of the pial basement membrane. The signaling pathways activated by laminin receptors, dystroglycan and integrins, control the integrity of the basement membrane, and their malfunctioning may underlie the pathologies found in the rise of defects reminiscent of these syndromes. Similar defects in corticogenesis and neuromuscular disorders were found in mice when RIC8A was specifically removed from neural precursor cells. RIC8A regulates a subset of G-protein α subunits and in several model organisms, it has been reported to participate in the control of cell division, signaling, and migration. Here, we studied the role of RIC8A in the development of the brain, muscles, and eyes of the neural precursor-specific conditional Ric8a knockout mice. The absence of RIC8A severely affected the attachment and positioning of radial glial processes, Cajal-Retzius' cells, and the arachnoid trabeculae, and these mice displayed additional defects in the lens, skeletal muscles, and heart development. All the discovered defects might be linked to aberrancies in cell adhesion and migration, suggesting that RIC8A has a crucial role in the regulation of cell-extracellular matrix interactions and that its removal leads to the phenotype characteristic to type II lissencephaly-associated diseases. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 374-390, 2018.
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Affiliation(s)
- Keiu Kask
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Laura Tikker
- Department of Biosciences, University of Helsinki, P.O. Box 56, Viikinkaari 9, FIN-00014, Helsinki, Finland
| | - Katrin Ruisu
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Sirje Lulla
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Eva-Maria Oja
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Riho Meier
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Raivo Raid
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Teet Velling
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Tambet Tõnissoo
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Margus Pooga
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia.,Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
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Ruisu K, Meier R, Kask K, Tõnissoo T, Velling T, Pooga M. RIC8A is essential for the organisation of actin cytoskeleton and cell-matrix interaction. Exp Cell Res 2017; 357:181-191. [PMID: 28526238 DOI: 10.1016/j.yexcr.2017.05.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/09/2017] [Accepted: 05/14/2017] [Indexed: 01/07/2023]
Abstract
RIC8A functions as a chaperone and guanine nucleotide exchange factor for a subset of G protein α subunits. Multiple G protein subunits mediate various signalling events that regulate cell adhesion and migration and the involvement of RIC8A in some of these processes has been demonstrated. We have previously shown that the deficiency of RIC8A causes a failure in mouse gastrulation and neurogenesis - major events in embryogenesis that rely on proper association of cells with the extracellular matrix (ECM) and involve active cell migration. To elaborate on these findings, we used Ric8a-/- mouse embryonic stem cells and Ric8a-deficient mouse embryonic fibroblasts, and found that RIC8A plays an important role in the organisation and remodelling of actin cytoskeleton and cell-ECM association. Ric8a-deficient cells were able to attach to different ECM components, but were unable to spread correctly, and did not form stress fibres or focal adhesion complexes. We also found that the presence of RIC8A is necessary for the activation of β1 integrins and integrin-mediated cell migration.
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Affiliation(s)
- Katrin Ruisu
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia.
| | - Riho Meier
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia; Competence Centre on Health Technologies, Tiigi 61b, 50410 Tartu, Estonia
| | - Keiu Kask
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia
| | - Tambet Tõnissoo
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia; Competence Centre on Health Technologies, Tiigi 61b, 50410 Tartu, Estonia
| | - Teet Velling
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia; Competence Centre on Health Technologies, Tiigi 61b, 50410 Tartu, Estonia
| | - Margus Pooga
- Department of Developmental Biology, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St., Tartu 51010, Estonia; Competence Centre on Health Technologies, Tiigi 61b, 50410 Tartu, Estonia
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Boularan C, Hwang IY, Kamenyeva O, Park C, Harrison K, Huang Z, Kehrl JH. B Lymphocyte-Specific Loss of Ric-8A Results in a Gα Protein Deficit and Severe Humoral Immunodeficiency. THE JOURNAL OF IMMUNOLOGY 2015; 195:2090-102. [PMID: 26232433 DOI: 10.4049/jimmunol.1500523] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/06/2015] [Indexed: 01/05/2023]
Abstract
Resistance to inhibitors of cholinesterase 8A (Ric-8A) is a highly evolutionarily conserved cytosolic protein initially identified in Caenorhabditis elegans, where it was assigned a regulatory role in asymmetric cell divisions. It functions as a guanine nucleotide exchange factor for Gαi, Gαq, and Gα12/13 and as a molecular chaperone required for the initial association of nascent Gα subunits with cellular membranes in embryonic stem cell lines. To test its role in hematopoiesis and B lymphocytes specifically, we generated ric8 (fl/fl) vav1-cre and ric8 (fl/fl) mb1-cre mice. The major hematopoietic cell lineages developed in the ric8 (fl/fl) vav1-cre mice, notwithstanding severe reduction in Gαi2/3, Gαq, and Gα13 proteins. B lymphocyte-specific loss of Ric-8A did not compromise bone marrow B lymphopoiesis, but splenic marginal zone B cell development failed, and B cells underpopulated lymphoid organs. The ric8 (fl/fl) mb1-cre B cells exhibited poor responses to chemokines, abnormal trafficking, improper in situ positioning, and loss of polarity components during B cell differentiation. The ric8 (fl/fl) mb1-cre mice had a severely disrupted lymphoid architecture and poor primary and secondary Ab responses. In B lymphocytes, Ric-8A is essential for normal Gα protein levels and is required for B cell differentiation, trafficking, and Ab responses.
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Affiliation(s)
- Cedric Boularan
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Il-Young Hwang
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Olena Kamenyeva
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Chung Park
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Kathleen Harrison
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Zhen Huang
- Department of Neurology, University of Wisconsin-Madison, Madison, WI 53706; and Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - John H Kehrl
- B-Cell Molecular Immunology Section, Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892;
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Kask K, Ruisu K, Tikker L, Karis K, Saare M, Meier R, Karis A, Tõnissoo T, Pooga M. Deletion of RIC8A in neural precursor cells leads to altered neurogenesis and neonatal lethality of mouse. Dev Neurobiol 2015; 75:984-1002. [DOI: 10.1002/dneu.22264] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 12/10/2014] [Accepted: 12/29/2014] [Indexed: 12/14/2022]
Affiliation(s)
- Keiu Kask
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Katrin Ruisu
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Laura Tikker
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Kirstin Karis
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Merly Saare
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Riho Meier
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Alar Karis
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Tambet Tõnissoo
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
| | - Margus Pooga
- Department of Developmental Biology; Institute of Molecular and Cell Biology, University of Tartu; 23 Riia St., Tartu 51010 Estonia
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Blasche S, Arens S, Ceol A, Siszler G, Schmidt MA, Häuser R, Schwarz F, Wuchty S, Aloy P, Uetz P, Stradal T, Koegl M. The EHEC-host interactome reveals novel targets for the translocated intimin receptor. Sci Rep 2014; 4:7531. [PMID: 25519916 PMCID: PMC4269881 DOI: 10.1038/srep07531] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 11/21/2014] [Indexed: 12/20/2022] Open
Abstract
Enterohemorrhagic E. coli (EHEC) manipulate their human host through at least 39 effector proteins which hijack host processes through direct protein-protein interactions (PPIs). To identify their protein targets in the host cells, we performed yeast two-hybrid screens, allowing us to find 48 high-confidence protein-protein interactions between 15 EHEC effectors and 47 human host proteins. In comparison to other bacteria and viruses we found that EHEC effectors bind more frequently to hub proteins as well as to proteins that participate in a higher number of protein complexes. The data set includes six new interactions that involve the translocated intimin receptor (TIR), namely HPCAL1, HPCAL4, NCALD, ARRB1, PDE6D, and STK16. We compared these TIR interactions in EHEC and enteropathogenic E. coli (EPEC) and found that five interactions were conserved. Notably, the conserved interactions included those of serine/threonine kinase 16 (STK16), hippocalcin-like 1 (HPCAL1) as well as neurocalcin-delta (NCALD). These proteins co-localize with the infection sites of EPEC. Furthermore, our results suggest putative functions of poorly characterized effectors (EspJ, EspY1). In particular, we observed that EspJ is connected to the microtubule system while EspY1 appears to be involved in apoptosis/cell cycle regulation.
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Affiliation(s)
- Sonja Blasche
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Stefan Arens
- Institute of Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster
| | - Arnaud Ceol
- 1] Joint IRB-BSC Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain [2] Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia (IIT), Via Adamello 16, 20139 Milan - Italy
| | - Gabriella Siszler
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - M Alexander Schmidt
- Institute of Infectiology, ZMBE, University of Münster, Von-Esmarch-Str. 56, D-48149 Münster
| | - Roman Häuser
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Frank Schwarz
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Stefan Wuchty
- 1] Dept. of Computer Science, Univ. of Miami, 1365 Memorial Drive, Coral Gables, FL 33146, USA [2] Center for Computational Science, Univ. of Miami, 1365 Memorial Drive, Coral Gables, FL 33146, USA
| | - Patrick Aloy
- 1] Joint IRB-BSC Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain [2] Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Peter Uetz
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Theresia Stradal
- 1] Institute of Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster [2] Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig
| | - Manfred Koegl
- Genomics and Proteomics Core Facilities, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
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Tse MK, Morris CJ, Zhang M, Wong YH. Activator of G protein signaling 3 forms a complex with resistance to inhibitors of cholinesterase-8A without promoting nucleotide exchange on Gα(i3). Mol Cell Biochem 2014; 401:27-38. [PMID: 25480567 DOI: 10.1007/s11010-014-2289-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 11/26/2014] [Indexed: 01/04/2023]
Abstract
Activator of G protein signaling 3 (AGS3) is a guanine nucleotide dissociation inhibitor (GDI) which stabilizes the Gα(i/o) subunits as an AGS3/Gα(i/o)-GDP complex. It has recently been demonstrated in reconstitution experiments that the AGS3/Gα(i/o)-GDP complex may act as a substrate of resistance to inhibitors of cholinesterase 8A (Ric-8A), a guanine exchange factor (GEF) for heterotrimeric Gα proteins. Since the ability of Ric-8A to activate Gα(i/o) subunits that are bound to AGS3 in a cellular environment has not been confirmed, we thus examined the effect of Ric-8A on cAMP accumulation in HEK293 cells expressing different forms of AGS3 and Gα(i3). Co-immunoprecipitation assays indicate that full-length AGS3 and its N- and C-terminal truncated mutants can interact with Ric-8A in HEK293 cells. Yeast two-hybrid assay further confirmed that Ric-8A can directly bind to AGS3S, a short form of AGS3 which is endogenously expressed in heart. However, Ric-8A failed to facilitate Gα(i)-induced suppression of adenylyl cyclase, suggesting that it may not serve as a GEF for AGS3/Gα(i/o)-GDP complex in a cellular environment.
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Affiliation(s)
- Man K Tse
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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