1
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Höppner S, Schröder B, Fluhrer R. Structure and function of SPP/SPPL proteases: insights from biochemical evidence and predictive modeling. FEBS J 2023; 290:5456-5474. [PMID: 37786993 DOI: 10.1111/febs.16968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 09/13/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
More than 20 years ago, signal peptide peptidase (SPP) and its homologues, the signal peptide peptidase-like (SPPL) proteases have been identified based on their sequence similarity to presenilins, a related family of intramembrane aspartyl proteases. Other than those for the presenilins, no high-resolution structures for the SPP/SPPL proteases are available. Despite this limitation, over the years bioinformatical and biochemical data have accumulated, which altogether have provided a picture of the overall structure and topology of these proteases, their localization in the cell, the process of substrate recognition, their cleavage mechanism, and their function. Recently, the artificial intelligence-based structure prediction tool AlphaFold has added high-confidence models of the expected fold of SPP/SPPL proteases. In this review, we summarize known structural aspects of the SPP/SPPL family as well as their substrates. Of particular interest are the emerging substrate recognition and catalytic mechanisms that might lead to the prediction and identification of more potential substrates and deeper insight into physiological and pathophysiological roles of proteolysis.
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Affiliation(s)
- Sabine Höppner
- Biochemistry and Molecular Biology, Faculty of Medicine, Institute of Theoretical Medicine, University of Augsburg, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Technische Universität Dresden, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Faculty of Medicine, Institute of Theoretical Medicine, University of Augsburg, Germany
- Center for Interdisciplinary Health Research, University of Augsburg, Germany
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2
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Yamamura Y, Fukami M, Matsuyama M, Sawada H. A novel variant of IGSF1 in siblings with congenital central hypothyroidism whose diagnosis was prompted by school health checkups. Clin Pediatr Endocrinol 2023; 33:17-22. [PMID: 38299175 PMCID: PMC10825655 DOI: 10.1297/cpe.2023-0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/03/2023] [Indexed: 02/02/2024] Open
Abstract
Following the partial revision of the enforcement regulations of the School Health and Safety Act, school health checkups incorporated growth evaluation of schoolchildren in April 2016 using growth charts. We report cases of congenital central hypothyroidism (C-CH) in siblings with a novel nonsense variant in the immunoglobulin superfamily member 1 gene (IGSF1); their diagnoses were prompted by school health checkups. School checkups revealed that the older brother was overweight and had a reduced growth rate at the age of 11 yr, whereas the younger brother was overweight and had short stature at the age of 8 yr. They were diagnosed with C-CH because of normal thyroid-stimulating hormone (TSH) levels despite a low free thyroxine level and low TSH response in the thyrotropin-releasing hormone stress test. Only the older brother had prolactin deficiency and testicular growth without elevated testosterone levels. The siblings harbored a novel nonsense variant in exon 16 of IGSF1 (NM_001555.5: c.3056G>A: p.Trp1019Ter) and were diagnosed with IGSF1 deficiency. In Japan, C-CH may be overlooked because TSH-based newborn screening alone is usually performed for patients with congenital hypothyroidism. The implementation of growth monitoring using growth charts in school health checkups may prompt new C-CH diagnoses.
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Affiliation(s)
- Yoshiko Yamamura
- Department of Pediatrics, Miyazaki Prefectural Miyazaki Hospital, Miyazaki, Japan
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Misayo Matsuyama
- Division of Pediatrics, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Hirotake Sawada
- Department of Fundamental Nursing, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
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3
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Brûlé E, Silander TL, Wang Y, Zhou X, Bak B, Groeneweg S, Bernard DJ. IGSF1 Deficiency Leads to Reduced TSH Production Independent of Alterations in Thyroid Hormone Action in Male Mice. Endocrinology 2022; 163:6609251. [PMID: 35708735 PMCID: PMC9258739 DOI: 10.1210/endocr/bqac092] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Indexed: 11/19/2022]
Abstract
Loss of function mutations in IGSF1/Igsf1 cause central hypothyroidism. Igsf1 knockout mice have reduced pituitary thyrotropin-releasing hormone receptor, Trhr, expression, perhaps contributing to the phenotype. Because thyroid hormones negatively regulate Trhr, we hypothesized that IGSF1 might affect thyroid hormone availability in pituitary thyrotropes. Consistent with this idea, IGSF1 coimmunoprecipitated with the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) in transfected cells. This association was impaired with IGSF1 bearing patient-derived mutations. Wild-type IGSF1 did not, however, alter MCT8-mediated thyroid hormone import into heterologous cells. IGSF1 and MCT8 are both expressed in the apical membrane of the choroid plexus. However, MCT8 protein levels and localization in the choroid plexus were unaltered in Igsf1 knockout mice, ruling out a necessary chaperone function for IGSF1. MCT8 expression was low in the pituitary and was similarly unaffected in Igsf1 knockouts. We next assessed whether IGSF1 affects thyroid hormone transport or action, by MCT8 or otherwise, in vivo. To this end, we treated hypothyroid wild-type and Igsf1 knockout mice with exogenous thyroid hormones. T4 and T3 inhibited TSH release and regulated pituitary and forebrain gene expression similarly in both genotypes. Interestingly, pituitary TSH beta subunit (Tshb) expression was consistently reduced in Igsf1 knockouts relative to wild-type regardless of experimental condition, whereas Trhr was more variably affected. Although IGSF1 and MCT8 can interact in heterologous cells, the physiological relevance of their association is not clear. Nevertheless, the results suggest that IGSF1 loss can impair TSH production independently of alterations in TRHR levels or thyroid hormone action.
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Affiliation(s)
- Emilie Brûlé
- Department of Anatomy and Cell Biology, McGill University, Montreal H3G 1Y6, Canada
| | - Tanya L Silander
- Integrated Program in Neuroscience, McGill University, Montreal H3G 1Y6, Canada
| | - Ying Wang
- Department of Pharmacology and Therapeutics, McGill University, Montreal H3G 1Y6, Canada
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montreal H3G 1Y6, Canada
| | - Beata Bak
- Department of Pharmacology and Therapeutics, McGill University, Montreal H3G 1Y6, Canada
| | - Stefan Groeneweg
- Department of Internal Medicine, Erasmus Medical Center, Academic Center for Thyroid Diseases, Rotterdam, The Netherlands
| | - Daniel J Bernard
- Correspondence: Daniel J. Bernard, PhD, Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building, 3655 Prom. Sir William Osler, Room 1320, Montreal, Quebec H3G 1Y6, Canada.
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4
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Smith CL, Harrison PM, Bernard DJ. The extant immunoglobulin superfamily, member 1 gene results from an ancestral gene duplication in eutherian mammals. PLoS One 2022; 17:e0267744. [PMID: 35653309 PMCID: PMC9162367 DOI: 10.1371/journal.pone.0267744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Immunoglobulin superfamily, member 1 (IGSF1) is a transmembrane glycoprotein with high expression in the mammalian pituitary gland. Mutations in the IGSF1 gene cause congenital central hypothyroidism in humans. The IGSF1 protein is co-translationally cleaved into N- and C-terminal domains (NTD and CTD), the latter of which is trafficked to the plasma membrane and appears to be the functional portion of the molecule. Though the IGSF1-NTD is retained in the endoplasmic reticulum and has no apparent function, it has a high degree of sequence identity with the IGSF1-CTD and is conserved across mammalian species. Based upon phylogenetic analyses, we propose that the ancestral IGSF1 gene encoded the IGSF1-CTD, which was duplicated and integrated immediately upstream of itself, yielding a larger protein encompassing the IGSF1-NTD and IGSF1-CTD. The selective pressures favoring the initial gene duplication and subsequent retention of a conserved IGSF1-NTD are unresolved.
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Affiliation(s)
- Courtney L. Smith
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Paul M. Harrison
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Daniel J. Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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5
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Türkkahraman D, Karataş Torun N, Randa NC. A Case of Congenital Central Hypothyroidism Caused by a Novel Variant (Gln1255Ter) in IGSF1 Gene. J Clin Res Pediatr Endocrinol 2021; 13:353-357. [PMID: 32772515 PMCID: PMC8388056 DOI: 10.4274/jcrpe.galenos.2020.2020.0149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Loss-of-function mutations in the immunoglobulin superfamily, member 1 (IGSF1) gene cause X-linked central hypothyroidism, and therefore its mutation affects mainly males. Central hypothyroidism in males is the hallmark of the disorder, however some patients additionally present with hypoprolactinemia, transient and partial growth hormone deficiency, early/normal timing of testicular enlargement but delayed testosterone rise in puberty, and adult macro-orchidism. Here, we report a boy with congenital central hypothyroidism caused by a novel variant in the IGSF1 gene. In our patient, early testicular enlargement but delayed testosterone rise with central hypothyroidism and hypoprolactinemia were the most important clues for diagnosis. In genetic analysis, we identified a novel, hemizygous nonsense c.3763 C>T (G1n1255Ter) variant in IGSF1 gene. To our knowledge, this is the first reported case of IGSF1 deficiency from Turkey.
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Affiliation(s)
- Doğa Türkkahraman
- University of Health Sciences Turkey, Antalya Training and Research Hospital, Clinic of Pediatric Endocrinology, Antalya, Turkey,* Address for Correspondence: University of Health Sciences Turkey, Antalya Training and Research Hospital, Clinic of Pediatric Endocrinology, Antalya, Turkey Phone: +90 505 250 13 96 E-mail:
| | - Nimet Karataş Torun
- University of Healty Sciences Turkey, Antalya Training and Research Hospital, Clinic of Pediatrics, Antalya, Turkey
| | - Nadide Cemre Randa
- University of Healty Sciences Turkey, Antalya Training and Research Hospital, Clinic of Medical Genetics, Antalya, Turkey
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6
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Brûlé E, Heinen CA, Smith CL, Schang G, Li Y, Zhou X, Wang Y, Joustra SD, Wit JM, Fliers E, Repping S, van Trotsenburg ASP, Bernard DJ. IGSF1 Does Not Regulate Spermatogenesis or Modify FSH Synthesis in Response to Inhibins or Activins. J Endocr Soc 2021; 5:bvab023. [PMID: 33796801 PMCID: PMC7986638 DOI: 10.1210/jendso/bvab023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Indexed: 12/03/2022] Open
Abstract
Loss-of-function mutations in the X-linked immunoglobulin superfamily, member 1 (IGSF1) gene result in central hypothyroidism, often associated with macroorchidism. Testicular enlargement in these patients might be caused by increases in follicle-stimulating hormone (FSH) levels, as IGSF1 has been proposed to function as an inhibin B receptor or as an inhibitor of activin type I receptor (ALK4) activity in pituitary gonadotrope cells. If true, loss of IGSF1 should lead to reduced inhibin B action or disinhibition of activin signaling, thereby increasing FSH synthesis. Here, we show that FSH levels and sperm counts are normal in male Igsf1 knockout mice, although testis size is mildly increased. Sperm parameters are also normal in men with IGSF1 deficiency, although their FSH levels may trend higher and their testes are enlarged. Inhibin B retains the ability to suppress FSH synthesis in pituitaries of Igsf1-knockout mice and IGSF1 does not interact with ALK4 or alter activin A/ALK4 stimulation of FSHβ (Fshb/FSHB) subunit transcription or expression. In light of these results, it is unlikely that macroorchidism in IGSF1 deficiency derives from alterations in spermatogenesis or inhibin/activin regulation of FSH.
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Affiliation(s)
- Emilie Brûlé
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Charlotte A Heinen
- Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatric Endocrinology, 1105 Amsterdam, the Netherlands.,Amsterdam University Medical Centers, University of Amsterdam, Department of Endocrinology & Metabolism, Meibergdreef 9, 1105 Amsterdam, the Netherlands
| | - Courtney L Smith
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Gauthier Schang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Yining Li
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Ying Wang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Sjoerd D Joustra
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, 2300 Leiden, the Netherlands.,Department of Pediatrics, Leiden University Medical Center, 2300 Leiden, the Netherlands
| | - Jan M Wit
- Department of Pediatrics, Leiden University Medical Center, 2300 Leiden, the Netherlands
| | - Eric Fliers
- Amsterdam University Medical Centers, University of Amsterdam, Department of Endocrinology & Metabolism, Meibergdreef 9, 1105 Amsterdam, the Netherlands
| | - Sjoerd Repping
- Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 Amsterdam, the Netherlands
| | - A S Paul van Trotsenburg
- Emma Children's Hospital, Amsterdam University Medical Centers, University of Amsterdam, Department of Pediatric Endocrinology, 1105 Amsterdam, the Netherlands
| | - Daniel J Bernard
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
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7
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Signal Peptide Peptidase-Type Proteases: Versatile Regulators with Functions Ranging from Limited Proteolysis to Protein Degradation. J Mol Biol 2020; 432:5063-5078. [DOI: 10.1016/j.jmb.2020.05.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/02/2020] [Accepted: 05/19/2020] [Indexed: 12/15/2022]
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8
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Joustra SD, Roelfsema F, van Trotsenburg ASP, Schneider HJ, Kosilek RP, Kroon HM, Logan JG, Butterfield NC, Zhou X, Toufaily C, Bak B, Turgeon MO, Brûlé E, Steyn FJ, Gurnell M, Koulouri O, Le Tissier P, Fontanaud P, Duncan Bassett JH, Williams GR, Oostdijk W, Wit JM, Pereira AM, Biermasz NR, Bernard DJ, Schoenmakers N. IGSF1 Deficiency Results in Human and Murine Somatotrope Neurosecretory Hyperfunction. J Clin Endocrinol Metab 2020; 105:5606971. [PMID: 31650157 PMCID: PMC7108761 DOI: 10.1210/clinem/dgz093] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 10/03/2019] [Indexed: 12/11/2022]
Abstract
CONTEXT The X-linked immunoglobulin superfamily, member 1 (IGSF1), gene is highly expressed in the hypothalamus and in pituitary cells of the POU1F1 lineage. Human loss-of-function mutations in IGSF1 cause central hypothyroidism, hypoprolactinemia, and macroorchidism. Additionally, most affected adults exhibit higher than average IGF-1 levels and anecdotal reports describe acromegaloid features in older subjects. However, somatotrope function has not yet been formally evaluated in this condition. OBJECTIVE We aimed to evaluate the role of IGSF1 in human and murine somatotrope function. PATIENTS, DESIGN, AND SETTING We evaluated 21 adult males harboring hemizygous IGSF1 loss-of-function mutations for features of GH excess, in an academic clinical setting. MAIN OUTCOME MEASURES We compared biochemical and tissue markers of GH excess in patients and controls, including 24-hour GH profile studies in 7 patients. Parallel studies were undertaken in male Igsf1-deficient mice and wild-type littermates. RESULTS IGSF1-deficient adult male patients demonstrated acromegaloid facial features with increased head circumference as well as increased finger soft-tissue thickness. Median serum IGF-1 concentrations were elevated, and 24-hour GH profile studies confirmed 2- to 3-fold increased median basal, pulsatile, and total GH secretion. Male Igsf1-deficient mice also demonstrated features of GH excess with increased lean mass, organ size, and skeletal dimensions and elevated mean circulating IGF-1 and pituitary GH levels. CONCLUSIONS We demonstrate somatotrope neurosecretory hyperfunction in IGSF1-deficient humans and mice. These observations define a hitherto uncharacterized role for IGSF1 in somatotropes and indicate that patients with IGSF1 mutations should be evaluated for long-term consequences of increased GH exposure.
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Affiliation(s)
- Sjoerd D Joustra
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, Netherlands
- Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
- Correspondence and Reprint Requests: Nadia Schoenmakers, University of Cambridge Metabolic Research Laboratories, Level 4, Wellcome Trust-MRC Institute of Metabolic Science, Box 289, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 0QQ UK. E-mail:
| | - Ferdinand Roelfsema
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, Netherlands
| | - A S Paul van Trotsenburg
- Emma Children’s Hospital, Amsterdam UMC, University of Amsterdam, Pediatric Endocrinology, Amsterdam, Netherlands
| | - Harald J Schneider
- Department of Endocrinology, Ludwig-Maximilians University, Munich, Germany
| | - Robert P Kosilek
- Department of Endocrinology, Ludwig-Maximilians University, Munich, Germany
| | - Herman M Kroon
- Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - John G Logan
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, London, UK
| | - Natalie C Butterfield
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, London, UK
| | - Xiang Zhou
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Chirine Toufaily
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Beata Bak
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Marc-Olivier Turgeon
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Emilie Brûlé
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Frederik J Steyn
- The University of Queensland Centre for Clinical Research, Brisbane, Australia
| | - Mark Gurnell
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ UK
| | - Olympia Koulouri
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ UK
| | - Paul Le Tissier
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
| | - Pierre Fontanaud
- CNRS, Institut de Génomique Fonctionnelle, INSERM, and Université de Montpellier, Montpellier, France
| | - J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, London, UK
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, London, UK
| | - Wilma Oostdijk
- Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Jan M Wit
- Department of Pediatrics, Leiden University Medical Center, Leiden, Netherlands
| | - Alberto M Pereira
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, Netherlands
| | - Nienke R Biermasz
- Department of Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, Netherlands
| | - Daniel J Bernard
- Departments of Anatomy and Cell Biology & Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Nadia Schoenmakers
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ UK
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Guselnikov SV, Taranin AV. Unraveling the LRC Evolution in Mammals: IGSF1 and A1BG Provide the Keys. Genome Biol Evol 2019; 11:1586-1601. [PMID: 31106814 PMCID: PMC6557307 DOI: 10.1093/gbe/evz102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2019] [Indexed: 12/30/2022] Open
Abstract
Receptors of the leukocyte receptor cluster (LRC) play a range of important functions in the human immune system. However, the evolution of the LRC remains poorly understood, even in m\ammals not to mention nonmammalian vertebrates. We conducted a comprehensive bioinformatics analysis of the LRC-related genes in the publicly available genomes of six species that represent eutherian, marsupial, and monotreme lineages of mammals. As a result, the LRCs of African elephant and armadillo were characterized, two new genes, IGSF1 and A1BG, were attributed to the LRC of eutherian mammals, the LRC gene content was substantially extended in the short-tailed opossum and Tasmanian devil and, finally, four LRC genes were identified in the platypus genome. These findings have for the first time provided a solid basis for inference of the LRC phylogeny across mammals. Our analysis suggests that the mammalian LRC family likely derived from two ancestral genes, which evolved in a lineage-specific manner by expansion/contraction, extensive exon shuffling, and sequence divergence. The striking structural and functional diversity of eutherian LRC molecules appears largely lineage specific. The only family member retained in all the three mammalian lineages is a collagen-binding receptor OSCAR. Strong sequence conservation of a transmembrane domain known to associate with FcRγ suggests an adaptive role of this domain subtype in the LRC evolution.
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Affiliation(s)
- Sergey V Guselnikov
- Laboratory of Immunogenetics, Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Russia
| | - Alexander V Taranin
- Laboratory of Immunogenetics, Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Russia
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10
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Roche EF, McGowan A, Koulouri O, Turgeon M, Nicholas AK, Heffernan E, El‐Khairi R, Abid N, Lyons G, Halsall D, Bonomi M, Persani L, Dattani MT, Gurnell M, Bernard DJ, Schoenmakers N. A novel IGSF1 mutation in a large Irish kindred highlights the need for familial screening in the IGSF1 deficiency syndrome. Clin Endocrinol (Oxf) 2018; 89:813-823. [PMID: 30086211 PMCID: PMC6282842 DOI: 10.1111/cen.13827] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Loss-of-function mutations in IGSF1 result in X-linked central congenital hypothyroidism (CeCH), occurring in isolation or associated with additional pituitary hormone deficits. Intrafamilial penetrance is highly variable and a minority of heterozygous females are also affected. We identified and characterized a novel IGSF1 mutation and investigated its associated phenotypes in a large Irish kindred. DESIGN, PATIENTS AND MEASUREMENTS A novel hemizygous IGSF1 mutation was identified by direct sequencing in two brothers with CeCH, and its functional consequences were characterized in vitro. Genotype-phenotype correlations were investigated in the wider kindred. RESULTS The mutant IGSF1 protein (c.2318T > C, p.L773P) exhibited decreased plasma membrane expression in vitro due to impaired trafficking from the endoplasmic reticulum. Ten hemizygous males and 11 heterozygous females exhibited characteristic endocrine deficits. Ireland operates a TSH-based CH screening programme, which does not detect CeCH; therefore, genetic ascertainment preceded biochemical diagnosis of moderate CH in five of seven boys as well as their 75-year-old grandfather. Clinical features potentially attributable to hypothyroidism were variable; normal free T3 (FT3) and low/low normal reverse T3 (rT3) concentrations suggested that preferential deiodination of FT4 to FT3 may help maintain tissue euthyroidism in some individuals. However, neonatal jaundice, delayed speech or growth, and obesity were observed in seven subjects in whom diagnosis was delayed. CONCLUSIONS As observed with other IGSF1 mutations, p.L773P results in variably penetrant IGSF1 deficiency syndrome. Our observations emphasize the need for multi-generation genetic ascertainment in affected families, especially where TSH-based CH screening programmes may fail to detect CeCH at birth.
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Affiliation(s)
- Edna F. Roche
- Department of Paediatric Growth, Diabetes and EndocrinologyNational Children's HospitalTallaght University HospitalDublinIreland
- Trinity College DublinThe University of DublinDublinIreland
| | - Anne McGowan
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
| | - Olympia Koulouri
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
| | - Marc‐Olivier Turgeon
- Department of Pharmacology and TherapeuticsMcGill UniversityMontréalQuébecCanada
| | - Adeline K. Nicholas
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
| | - Emmeline Heffernan
- Department of Paediatric Endocrinology & DiabetesRoyal Belfast Hospital for Sick ChildrenBelfastUK
| | - Ranna El‐Khairi
- Wellcome Trust‐Medical Research Council Stem Cell InstituteAnne McLaren Laboratory, Department of SurgeryUniversity of CambridgeCambridgeUK
- Wellcome Trust Sanger InstituteCambridgeUK
| | - Noina Abid
- Department of Paediatric Endocrinology & DiabetesRoyal Belfast Hospital for Sick ChildrenBelfastUK
| | - Greta Lyons
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
| | - David Halsall
- Department of Clinical BiochemistryCambridge University Hospitals NHS Foundation TrustCambridgeUK
| | - Marco Bonomi
- Department of Clinical Sciences and Community HealthUniversity of MilanMilanItaly
- Division of Endocrinology and MetabolismIRCCS Istituto Auxologico ItalianoMilanItaly
| | - Luca Persani
- Department of Clinical Sciences and Community HealthUniversity of MilanMilanItaly
- Division of Endocrinology and MetabolismIRCCS Istituto Auxologico ItalianoMilanItaly
| | - Mehul T. Dattani
- Section of Genetics and Epigenetics in Health and DiseaseGenetics and Genomic Medicine ProgrammeUniversity College London Great Ormond Street Institute of Child HealthLondonUK
| | - Mark Gurnell
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
| | - Daniel J. Bernard
- Department of Pharmacology and TherapeuticsMcGill UniversityMontréalQuébecCanada
| | - Nadia Schoenmakers
- Wellcome Trust‐Medical Research Council Institute of Metabolic ScienceAddenbrooke's Hospital and National Institute for Health Research Cambridge Biomedical Research CentreAddenbrooke's HospitalUniversity of Cambridge Metabolic Research LaboratoriesCambridgeUK
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11
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The amyloid precursor protein binds to β-catenin and modulates its cellular distribution. Neurosci Lett 2018; 685:190-195. [DOI: 10.1016/j.neulet.2018.08.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/20/2018] [Accepted: 08/29/2018] [Indexed: 11/18/2022]
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12
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Bernard DJ, Brûlé E, Smith CL, Joustra SD, Wit JM. From Consternation to Revelation: Discovery of a Role for IGSF1 in Pituitary Control of Thyroid Function. J Endocr Soc 2018; 2:220-231. [PMID: 29594256 PMCID: PMC5841168 DOI: 10.1210/js.2017-00478] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/01/2018] [Indexed: 01/30/2023] Open
Abstract
Immunoglobulin superfamily, member 1 (IGSF1) is a transmembrane glycoprotein highly expressed in the mammalian pituitary gland. Shortly after its discovery in 1998, the protein was proposed to function as a coreceptor for inhibins (and was even temporarily renamed inhibin binding protein). However, subsequent investigations, both in vitro and in vivo, failed to support a role for IGSF1 in inhibin action. Research on IGSF1 nearly ground to a halt until 2011, when next-generation sequencing identified mutations in the X-linked IGSF1 gene in boys and men with congenital central hypothyroidism. IGSF1 was localized to thyrotrope cells, implicating the protein in pituitary control of the thyroid. Investigations in two Igsf1 knockout mouse models converged to show that IGSF1 deficiency leads to reduced expression of the receptor for thyrotropin-releasing hormone (TRH) and impaired TRH stimulation of thyrotropin secretion, providing a candidate mechanism for the central hypothyroidism observed in patients. Nevertheless, the normal functions of IGSF1 in thyrotropes and other cells remain unresolved. Moreover, IGSF1 mutations are also commonly associated with other clinical phenotypes, including prolactin and growth hormone dysregulation, and macroorchidism. How the loss of IGSF1 produces these characteristics is unknown. Although early studies of IGSF1 ran into roadblocks and blind alleys, armed with the results of detailed clinical investigations, powerful mouse models, and new reagents, the field is now poised to discover IGSF1’s function in endocrine tissues, including the pituitary and testes.
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Affiliation(s)
- Daniel J Bernard
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada.,Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Emilie Brûlé
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec H3A 0C7, Canada
| | - Courtney L Smith
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Sjoerd D Joustra
- Department of Pediatrics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Jan M Wit
- Department of Pediatrics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
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Mentrup T, Fluhrer R, Schröder B. Latest emerging functions of SPP/SPPL intramembrane proteases. Eur J Cell Biol 2017; 96:372-382. [DOI: 10.1016/j.ejcb.2017.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022] Open
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14
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Wang Y, Brûlé E, Silander T, Bak B, Joustra SD, Bernard DJ. The short mRNA isoform of the immunoglobulin superfamily, member 1 gene encodes an intracellular glycoprotein. PLoS One 2017; 12:e0180731. [PMID: 28686733 PMCID: PMC5501590 DOI: 10.1371/journal.pone.0180731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/20/2017] [Indexed: 11/18/2022] Open
Abstract
Mutations in the immunoglobulin superfamily, member 1 gene (IGSF1/Igsf1) cause an X-linked form of central hypothyroidism. The canonical form of IGSF1 is a transmembrane glycoprotein with 12 immunoglobulin (Ig) loops. The protein is co-translationally cleaved into two sub-domains. The carboxyl-terminal domain (CTD), which contains the last 7 Ig loops, is trafficked to the plasma membrane. Most pathogenic mutations in IGSF1 map to the portion of the gene encoding the CTD. IGSF1/Igsf1 encodes a variety of transcripts. A little studied, but abundant splice variant encodes a truncated form of the protein, predicted to contain the first 2 Ig loops of the full-length IGSF1. The protein (hereafter referred to as IGSF1 isoform 2 or IGSF1-2) is likely retained in most individuals with IGSF1 mutations. Here, we characterized basic biochemical properties of the protein as a foray into understanding its potential function. IGSF1-2, like the IGSF1-CTD, is a glycoprotein. In both mouse and rat, the protein is N-glycosylated at a single asparagine residue in the first Ig loop. Contrary to earlier predictions, neither the murine nor rat IGSF1-2 is secreted from heterologous or homologous cells. In addition, neither protein associates with the plasma membrane. Rather, IGSF1-2 appears to be retained in the endoplasmic reticulum. Whether the protein plays intracellular functions or is trafficked through the secretory pathway under certain physiologic or pathophysiologic conditions has yet to be determined.
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Affiliation(s)
- Ying Wang
- Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Emilie Brûlé
- Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Tanya Silander
- Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Beata Bak
- Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Sjoerd D. Joustra
- Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniel J. Bernard
- Centre for Research in Reproduction and Development, Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Turgeon MO, Silander TL, Doycheva D, Liao XH, Rigden M, Ongaro L, Zhou X, Joustra SD, Wit JM, Wade MG, Heuer H, Refetoff S, Bernard DJ. TRH Action Is Impaired in Pituitaries of Male IGSF1-Deficient Mice. Endocrinology 2017; 158:815-830. [PMID: 28324000 PMCID: PMC5460797 DOI: 10.1210/en.2016-1788] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/06/2017] [Indexed: 11/19/2022]
Abstract
Loss-of-function mutations in the X-linked immunoglobulin superfamily, member 1 (IGSF1) gene cause central hypothyroidism. IGSF1 is a transmembrane glycoprotein of unknown function expressed in thyrotropin (TSH)-producing thyrotrope cells of the anterior pituitary gland. The protein is cotranslationally cleaved, with only its C-terminal domain (CTD) being trafficked to the plasma membrane. Most intragenic IGSF1 mutations in humans map to the CTD. In this study, we used CRISPR-Cas9 to introduce a loss-of-function mutation into the IGSF1-CTD in mice. The modified allele encodes a truncated protein that fails to traffic to the plasma membrane. Under standard laboratory conditions, Igsf1-deficient males exhibit normal serum TSH levels as well as normal numbers of TSH-expressing thyrotropes. However, pituitary expression of the TSH subunit genes and TSH protein content are reduced, as is expression of the receptor for thyrotropin-releasing hormone (TRH). When challenged with exogenous TRH, Igsf1-deficient males release TSH, but to a significantly lesser extent than do their wild-type littermates. The mice show similarly attenuated TSH secretion when rendered profoundly hypothyroid with a low iodine diet supplemented with propylthiouracil. Collectively, these results indicate that impairments in pituitary TRH receptor expression and/or downstream signaling underlie central hypothyroidism in IGSF1 deficiency syndrome.
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Affiliation(s)
- Marc-Olivier Turgeon
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6 Canada
| | - Tanya L. Silander
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6 Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3A 2B4 Canada
| | - Denica Doycheva
- 4Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
- Leibniz Institute on Aging–Fritz Lipmann Institute, 07745 Jena, Germany
| | | | - Marc Rigden
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Luisina Ongaro
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6 Canada
| | - Xiang Zhou
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6 Canada
| | - Sjoerd D. Joustra
- Department of Pediatrics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Jan M. Wit
- Department of Pediatrics, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Mike G. Wade
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario K1A 0K9, Canada
| | - Heike Heuer
- 4Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Samuel Refetoff
- Department of Medicine and
- Department of Pediatrics and Committee on Genetics, University of Chicago, Chicago, Illinois 60637
| | - Daniel J. Bernard
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6 Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3A 2B4 Canada
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16
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Tenenbaum-Rakover Y, Turgeon MO, London S, Hermanns P, Pohlenz J, Bernard DJ, Bercovich D. Familial Central Hypothyroidism Caused by a Novel IGSF1 Gene Mutation. Thyroid 2016; 26:1693-1700. [PMID: 27310681 DOI: 10.1089/thy.2015.0672] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Congenital hypothyroidism of central origin (CH-C) is a rare disease in which thyroid hormone deficiency is caused by insufficient thyrotropin stimulation of a normal thyroid gland. A recently described syndrome of isolated CH-C and macroorchidism was attributed to loss-of-function mutations of the immunoglobulin superfamily, member 1 gene (IGSF1). PATIENTS AND METHODS CH-C was diagnosed in three siblings. The TRH, TRHR, and TSHB genes were sequenced followed by whole-exome sequencing in the proband. A mutation identified in IGSF1 was analyzed by direct PCR sequencing in family members. The effects of the mutation were assessed by in vitro studies in HEK293 cells. RESULTS The index case was negative for mutations in TRH, TRHR, and TSHB. Whole-exome sequencing revealed a novel insertion mutation in IGSF1, c.2284_2285insA, p.R762QfsX7, which was confirmed by direct PCR sequencing and was identified in six additional family members. The mutation introduces a frame-shift and premature stop codon in the seventh Ig loop, thereby truncating IGSF1. In vitro studies revealed that the mutated IGSF1-R762QfsX7 migrates as a doublet at ∼28 kDa, which is far smaller than the wild type protein (130-140 kDa). Both bands were endonuclease H sensitive, indicating immature glycosylation and failure of the protein to traffic out of the endoplasmic reticulum to the plasma membrane. Further phenotypic findings in the family included macroorchidism and infertility in the uncle and mild neurological phenotypes in the affected males, such as hypotonia, delayed psychomotor development, clumsy behavior, and attention deficit disorder. CONCLUSIONS We identified a novel insertion mutation in the IGSF1 gene and further delineated the phenotype of the IGSF1-deficiency syndrome. Our findings indicate a possible association between an IGSF1 mutation and neurological phenotypes.
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Affiliation(s)
- Yardena Tenenbaum-Rakover
- 1 Pediatric Endocrine Unit, Ha'Emek Medical Center , Afula, Israel
- 2 Rappaport Faculty of Medicine, Technion Israel Institute of Technology , Haifa, Israel
| | - Marc-Olivier Turgeon
- 3 Department of Pharmacology and Therapeutics, McGill University , Montreal, Canada
| | - Shira London
- 1 Pediatric Endocrine Unit, Ha'Emek Medical Center , Afula, Israel
| | - Pia Hermanns
- 4 Department of Pediatrics, Johannes Gutenberg University Medical School , Mainz, Germany
| | - Joachim Pohlenz
- 4 Department of Pediatrics, Johannes Gutenberg University Medical School , Mainz, Germany
| | - Daniel J Bernard
- 3 Department of Pharmacology and Therapeutics, McGill University , Montreal, Canada
| | - Dani Bercovich
- 5 Faculty of Medical Science, Tel Hai Academic College Upper Galilee , Israel
- 6 GGA - Galil Genetic Analysis Laboratory , Kazerin, Israel
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17
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Fang Q, George AS, Brinkmeier ML, Mortensen AH, Gergics P, Cheung LYM, Daly AZ, Ajmal A, Pérez Millán MI, Ozel AB, Kitzman JO, Mills RE, Li JZ, Camper SA. Genetics of Combined Pituitary Hormone Deficiency: Roadmap into the Genome Era. Endocr Rev 2016; 37:636-675. [PMID: 27828722 PMCID: PMC5155665 DOI: 10.1210/er.2016-1101] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/31/2016] [Indexed: 02/08/2023]
Abstract
The genetic basis for combined pituitary hormone deficiency (CPHD) is complex, involving 30 genes in a variety of syndromic and nonsyndromic presentations. Molecular diagnosis of this disorder is valuable for predicting disease progression, avoiding unnecessary surgery, and family planning. We expect that the application of high throughput sequencing will uncover additional contributing genes and eventually become a valuable tool for molecular diagnosis. For example, in the last 3 years, six new genes have been implicated in CPHD using whole-exome sequencing. In this review, we present a historical perspective on gene discovery for CPHD and predict approaches that may facilitate future gene identification projects conducted by clinicians and basic scientists. Guidelines for systematic reporting of genetic variants and assigning causality are emerging. We apply these guidelines retrospectively to reports of the genetic basis of CPHD and summarize modes of inheritance and penetrance for each of the known genes. In recent years, there have been great improvements in databases of genetic information for diverse populations. Some issues remain that make molecular diagnosis challenging in some cases. These include the inherent genetic complexity of this disorder, technical challenges like uneven coverage, differing results from variant calling and interpretation pipelines, the number of tolerated genetic alterations, and imperfect methods for predicting pathogenicity. We discuss approaches for future research in the genetics of CPHD.
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Affiliation(s)
- Qing Fang
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Akima S George
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Michelle L Brinkmeier
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda H Mortensen
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Peter Gergics
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Leonard Y M Cheung
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Alexandre Z Daly
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Adnan Ajmal
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - María Ines Pérez Millán
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - A Bilge Ozel
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jacob O Kitzman
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Ryan E Mills
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Jun Z Li
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
| | - Sally A Camper
- Department of Human Genetics (Q.F., A.S.G., M.L.B., A.H.M., P.G., L.Y.M.C., A.Z.D., M.I.P.M., A.B.O., J.O.K., R.E.M., J.Z.L., S.A.C.), Graduate Program in Bioinformatics (A.S.G.), Endocrine Division, Department of Internal Medicine (A.A.), and Department of Computational Medicine and Bioinformatics (J.O.K., R.E.M., J.Z.L.), University of Michigan, Ann Arbor, Michigan 48109
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18
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Nishigaki S, Hamazaki T, Fujita K, Morikawa S, Tajima T, Shintaku H. A Japanese Family with Central Hypothyroidism Caused by a Novel IGSF1 Mutation. Thyroid 2016; 26:1701-1705. [PMID: 27762734 DOI: 10.1089/thy.2016.0005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Hemizygous mutations in the immunoglobulin superfamily member 1 (IGSF1) gene have been demonstrated to cause congenital central hypothyroidism in males. This study reports a family with a novel mutation in the IGSF1 gene located on the long arm of the X chromosome. PATIENT FINDINGS A two-month-old boy was diagnosed with central hypothyroidism because of prolonged jaundice. A thyrotropin-releasing hormone (TRH) stimulation test indicated dysfunction in both the hypothalamus and the pituitary gland, and prompted the IGSF1 gene to be analyzed. The patient had a novel nonsense variant, c.2713C>T (p.Q905X), in exon 14 of the IGSF1 gene. Studies of the family revealed that the patient's sister and mother were heterozygous carriers of the IGSF1 mutation. The patient's maternal uncle carried the same mutation as the proband but had no overt symptoms. The mother and uncle started levothyroxine supplementation because of subclinical hypothyroidism. SUMMARY A novel mutation (c.2713C>T, p.Q905X) of the IGSF1 gene was identified that causes congenital central hypothyroidism in a Japanese family. The findings further expand the clinical heterogeneity of this entity.
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Affiliation(s)
- Satsuki Nishigaki
- 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan
| | - Takashi Hamazaki
- 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan
| | - Keinosuke Fujita
- 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan
| | - Shuntaro Morikawa
- 2 Department of Pediatrics, Hokkaido University School of Medicine , Sapporo, Japan
| | - Toshihiro Tajima
- 2 Department of Pediatrics, Hokkaido University School of Medicine , Sapporo, Japan
- 3 Department of Pediatrics, Jichi Children's Medical Center Tochigi , Shimotsuke, Japan
| | - Haruo Shintaku
- 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan
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19
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Hughes JN, Aubert M, Heatlie J, Gardner A, Gecz J, Morgan T, Belsky J, Thomas PQ. Identification of an IGSF1-specific deletion in a five-generation pedigree with X-linked Central Hypothyroidism without macroorchidism. Clin Endocrinol (Oxf) 2016; 85:609-15. [PMID: 27146357 DOI: 10.1111/cen.13094] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 05/01/2016] [Accepted: 05/03/2016] [Indexed: 11/28/2022]
Abstract
OBJECTIVES IGSF1 deficiency syndrome (IDS) is a recently described X-linked congenital central hypothyroidism disorder characterized by loss-of-function mutations in the immunoglobulin superfamily member 1 (IGSF1) gene. The phenotypic spectrum and intrafamilial variability associated with IDS remain unclear due to a paucity of large, well-characterized pedigrees. Here, we present phenotypic analysis and molecular characterization of a five-generation pedigree with IGSF1 deficiency containing 10 affected males. PATIENTS AND METHODS Pituitary function was assessed in all available family members (n = 8 affected males and n = 5 carrier females). Molecular characterization of the family was performed by Sanger sequencing of PCR products amplified from the IGSF1 locus and by array comparative genomic hybridization. RESULTS A 42-kb IGSF1 deletion spanning the entire coding sequence was identified in all affected males. TSH deficiency, although subclinical in one case, was identified in all affected males (n = 8). PRL and GH deficiency were also present in 5 of 6 and 4 of 8 affected males, respectively. In contrast to previous reports, macroorchidism was not detected in any of the four affected males who were examined for this feature. Only 1 of 5 carrier females had pituitary dysfunction (TSH and GH deficiency). CONCLUSION Individuals with identical IGSF1 deletions can exhibit variable pituitary hormone deficiencies, of which overt TSH deficiency is the most consistent feature. We also show that macroorchidism is not obligatory in males with IDS. Mutations of IGSF1 should therefore be considered in males with isolated hypopituitarism that includes TSH deficiency.
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Affiliation(s)
- James N Hughes
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia
| | - Matthew Aubert
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Jessica Heatlie
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Alison Gardner
- School of Pediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia
| | - Jozef Gecz
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia
- School of Pediatrics and Reproductive Health, The University of Adelaide, Adelaide, SA, Australia
| | - Thomas Morgan
- Novartis Institutes of Biomedical Research, Biomarkers Division, Cambridge, MA, USA
| | - Joseph Belsky
- Department of Medicine (Endocrinology), Yale University School of Medicine, New Haven, CT, USA
- Department of Medicine, Danbury Hospital, Danbury, CT, USA
| | - Paul Q Thomas
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
- Robinson Research Institute, University of Adelaide, Adelaide, SA, Australia.
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Characterization of a Non-Canonical Signal Peptidase Cleavage Site in a Replication Protein from Tomato Ringspot Virus. PLoS One 2016; 11:e0162223. [PMID: 27589230 PMCID: PMC5010249 DOI: 10.1371/journal.pone.0162223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/18/2016] [Indexed: 11/19/2022] Open
Abstract
The NTB-VPg polyprotein from tomato ringspot virus is an integral membrane replication protein associated with endoplasmic reticulum membranes. A signal peptidase (SPase) cleavage was previously detected in the C-terminal region of NTB-VPg downstream of a 14 amino acid (aa)-long hydrophobic region (termed TM2). However, the exact location of the cleavage site was not determined. Using in vitro translation assays, we show that the SPase cleavage site is conserved in the NTB-VPg protein from various ToRSV isolates, although the rate of cleavage varies from one isolate to another. Systematic site-directed mutagenesis of the NTB-VPg SPase cleavage sites of two ToRSV isolates allowed the identification of sequences that affect cleavage efficiency. We also present evidence that SPase cleavage in the ToRSV-Rasp2 isolate occurs within a GAAGG sequence likely after the AAG (GAAG/G). Mutation of a downstream MAAV sequence to AAAV resulted in SPase cleavage at both the natural GAAG/G and the mutated AAA/V sequences. Given that there is a distance of seven aa between the two cleavage sites, this indicates that there is flexibility in the positioning of the cleavage sites relative to the inner surface of the membrane and the SPase active site. SPase cleavage sites are typically located 3–7 aa downstream of the hydrophobic region. However, the NTB-VPg GAAG/G cleavage site is located 17 aa downstream of the TM2 hydrophobic region, highlighting unusual features of the NTB-VPg SPase cleavage site. A putative 11 aa-long amphipathic helix was identified immediately downstream of the TM2 region and five aa upstream of the GAAG/G cleavage site. Based on these results, we present an updated topology model in which the hydrophobic and amphipathic domains form a long tilted helix or a bent helix in the membrane lipid bilayer, with the downstream cleavage site(s) oriented parallel to the membrane inner surface.
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Asakura Y, Abe K, Muroya K, Hanakawa J, Oto Y, Narumi S, Hasegawa T, Adachi M. Combined Growth Hormone and Thyroid-Stimulating Hormone Deficiency in a Japanese Patient with a Novel Frameshift Mutation in IGSF1. Horm Res Paediatr 2016; 84:349-54. [PMID: 26302767 DOI: 10.1159/000438672] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/10/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Recent reports have indicated that loss-of-function mutations in the immunoglobulin superfamily member 1 gene (IGSF1, OMIM 300888) cause congenital central hypothyroidism with macroorchidism. METHODS We conducted a next-generation sequencing-based comprehensive mutation screening for pituitary hormone deficiencies to elucidate molecular mechanisms other than anatomical abnormalities of the pituitary that might be responsible for multiple anterior hormone deficiency in a male patient who originally visited our institute complaining of short stature. He was born large for gestational age (4,370 g, +3.0 SD) after an obstructed labour. Endocrinological evaluation revealed growth hormone and thyroid-stimulating hormone deficiency. Magnetic resonance imaging showed a discontinuity of the pituitary stalk with an ectopic posterior lobe and a hypoplastic anterior lobe, likely explaining multiple anterior pituitary hormone deficiency. RESULT We identified a novel hemizygous IGSF1 mutation (c.1137_1138delCA, p.Asn380Glnfs*6) in the patient. In reviewing the literature, we noticed that all reported Japanese male IGSF1 mutation carriers were born larger than mean standards for gestational age (mean birth weight SD score of +2.0, 95% confidence interval 1.0-3.0). CONCLUSION This case suggests that more attention should be paid to intrauterine growth and birth history when patients are suspected of having an IGSF1 mutation.
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Affiliation(s)
- Yumi Asakura
- Department of Endocrinology and Metabolism, Kanagawa Children's Medical Center, Yokohama, Japan
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22
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Schoenmakers N, Alatzoglou KS, Chatterjee VK, Dattani MT. Recent advances in central congenital hypothyroidism. J Endocrinol 2015; 227:R51-71. [PMID: 26416826 PMCID: PMC4629398 DOI: 10.1530/joe-15-0341] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 09/17/2015] [Accepted: 09/28/2015] [Indexed: 01/23/2023]
Abstract
Central congenital hypothyroidism (CCH) may occur in isolation, or more frequently in combination with additional pituitary hormone deficits with or without associated extrapituitary abnormalities. Although uncommon, it may be more prevalent than previously thought, affecting up to 1:16 000 neonates in the Netherlands. Since TSH is not elevated, CCH will evade diagnosis in primary, TSH-based, CH screening programs and delayed detection may result in neurodevelopmental delay due to untreated neonatal hypothyroidism. Alternatively, coexisting growth hormones or ACTH deficiency may pose additional risks, such as life threatening hypoglycaemia. Genetic ascertainment is possible in a minority of cases and reveals mutations in genes controlling the TSH biosynthetic pathway (TSHB, TRHR, IGSF1) in isolated TSH deficiency, or early (HESX1, LHX3, LHX4, SOX3, OTX2) or late (PROP1, POU1F1) pituitary transcription factors in combined hormone deficits. Since TSH cannot be used as an indicator of euthyroidism, adequacy of treatment can be difficult to monitor due to a paucity of alternative biomarkers. This review will summarize the normal physiology of pituitary development and the hypothalamic-pituitary-thyroid axis, then describe known genetic causes of isolated central hypothyroidism and combined pituitary hormone deficits associated with TSH deficiency. Difficulties in diagnosis and management of these conditions will then be discussed.
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Affiliation(s)
- Nadia Schoenmakers
- University of Cambridge Metabolic Research LaboratoriesWellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, Level 4, PO Box 289, Hills Road, Cambridge CB2 0QQ, UKDevelopmental Endocrinology Research GroupSection of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, UCL Institute of Child Health, London, UK
| | - Kyriaki S Alatzoglou
- University of Cambridge Metabolic Research LaboratoriesWellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, Level 4, PO Box 289, Hills Road, Cambridge CB2 0QQ, UKDevelopmental Endocrinology Research GroupSection of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, UCL Institute of Child Health, London, UK
| | - V Krishna Chatterjee
- University of Cambridge Metabolic Research LaboratoriesWellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, Level 4, PO Box 289, Hills Road, Cambridge CB2 0QQ, UKDevelopmental Endocrinology Research GroupSection of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, UCL Institute of Child Health, London, UK
| | - Mehul T Dattani
- University of Cambridge Metabolic Research LaboratoriesWellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, Level 4, PO Box 289, Hills Road, Cambridge CB2 0QQ, UKDevelopmental Endocrinology Research GroupSection of Genetics and Epigenetics in Health and Disease, Genetics and Genomic Medicine Programme, UCL Institute of Child Health, London, UK
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23
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Joustra SD, Meijer OC, Heinen CA, Mol IM, Laghmani EH, Sengers RMA, Carreno G, van Trotsenburg ASP, Biermasz NR, Bernard DJ, Wit JM, Oostdijk W, van Pelt AMM, Hamer G, Wagenaar GTM. Spatial and temporal expression of immunoglobulin superfamily member 1 in the rat. J Endocrinol 2015; 226:181-91. [PMID: 26163525 DOI: 10.1530/joe-15-0204] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/10/2015] [Indexed: 11/08/2022]
Abstract
Loss-of-function mutations in the immunoglobulin superfamily member 1 (IGSF1) gene cause an X-linked syndrome of central hypothyroidism, macroorchidism, variable prolactin and GH deficiency, delayed pubertal testosterone rise, and obesity. To understand the pathophysiology of this syndrome, knowledge on IGSF1's place in normal development is imperative. Therefore, we investigated spatial and temporal protein and mRNA expression of IGSF1 in rats using immunohistochemistry, real-time quantitative PCR (qPCR), and in situ hybridization. We observed high levels of IGSF1 expression in the brain, specifically the embryonic and adult choroid plexus and hypothalamus (principally in glial cells), and in the pituitary gland (PIT1-lineage of GH, TSH, and PRL-producing cells). IGSF1 is also expressed in the embryonic and adult zona glomerulosa of the adrenal gland, islets of Langerhans of the pancreas, and costameres of the heart and skeletal muscle. IGSF1 is highly expressed in fetal liver, but is absent shortly after birth. In the adult testis, IGSF1 is present in Sertoli cells (epithelial stages XIII-VI), and elongating spermatids (stages X-XII). Specificity of protein expression was corroborated with Igsf1 mRNA expression in all tissues. The expression patterns of IGSF1 in the pituitary gland and testis are consistent with the pituitary hormone deficiencies and macroorchidism observed in patients with IGSF1 deficiency. The expression in the brain, adrenal gland, pancreas, liver, and muscle suggest IGSF1's function in endocrine physiology might be more extensive than previously considered.
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Affiliation(s)
- Sjoerd D Joustra
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Onno C Meijer
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Charlotte A Heinen
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Isabel M Mol
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - El Houari Laghmani
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Rozemarijn M A Sengers
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Gabriela Carreno
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - A S Paul van Trotsenburg
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Nienke R Biermasz
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Daniel J Bernard
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Jan M Wit
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Wilma Oostdijk
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Ans M M van Pelt
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Geert Hamer
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - Gerry T M Wagenaar
- Department of PediatricsLeiden University Medical Center, Leiden, The NetherlandsDepartment of MedicineDivision of Endocrinology, Leiden University Medical Center, Leiden, The NetherlandsDepartment of Pediatric EndocrinologyEmma Children's Hospital, Academic Medical Center, Amsterdam, The NetherlandsEndocrinology and MetabolismAcademic Medical Center, The NetherlandsDevelopmental Biology and Cancer ProgrammeInstitute of Child Health, London, UKDepartment of Pharmacology and TherapeuticsMcGill University, Montreal, Quebec, CanadaCenter for Reproductive MedicineWomen's and Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
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24
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Ran Y, Ladd GZ, Ceballos-Diaz C, Jung JI, Greenbaum D, Felsenstein KM, Golde TE. Differential Inhibition of Signal Peptide Peptidase Family Members by Established γ-Secretase Inhibitors. PLoS One 2015; 10:e0128619. [PMID: 26046535 PMCID: PMC4457840 DOI: 10.1371/journal.pone.0128619] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/29/2015] [Indexed: 11/19/2022] Open
Abstract
The signal peptide peptidases (SPPs) are biomedically important proteases implicated as therapeutic targets for hepatitis C (human SPP, (hSPP)), plasmodium (Plasmodium SPP (pSPP)), and B-cell immunomodulation and neoplasia (signal peptide peptidase like 2a, (SPPL2a)). To date, no drug-like, selective inhibitors have been reported. We use a recombinant substrate based on the amino-terminus of BRI2 fused to amyloid β 1-25 (Aβ1-25) (FBA) to develop facile, cost-effective SPP/SPPL protease assays. Co-transfection of expression plasmids expressing the FBA substrate with SPP/SPPLs were conducted to evaluate cleavage, which was monitored by ELISA, Western Blot and immunoprecipitation/MALDI-TOF Mass spectrometry (IP/MS). No cleavage is detected in the absence of SPP/SPPL overexpression. Multiple γ-secretase inhibitors (GSIs) and (Z-LL)2 ketone differentially inhibited SPP/SPPL activity; for example, IC50 of LY-411,575 varied from 51±79 nM (on SPPL2a) to 5499±122 nM (on SPPL2b), while Compound E showed inhibition only on hSPP with IC50 of 1465±93 nM. Data generated were predictive of effects observed for endogenous SPPL2a cleavage of CD74 in a murine B-Cell line. Thus, it is possible to differentially inhibit SPP family members. These SPP/SPPL cleavage assays will expedite the search for selective inhibitors. The data also reinforce similarities between SPP family member cleavage and cleavage catalyzed by γ-secretase.
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Affiliation(s)
- Yong Ran
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
- * E-mail: (YR); (TG)
| | - Gabriela Z. Ladd
- College of Pharmacy, University of Florida, Gainesville, Florida, United States of America
| | - Carolina Ceballos-Diaz
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Joo In Jung
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Doron Greenbaum
- Pennsylvania Drug Discovery Institute, Philadelphia, Pennsylvania, United States of America
| | - Kevin M. Felsenstein
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
| | - Todd E. Golde
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine University of Florida, Gainesville, Florida, United States of America
- * E-mail: (YR); (TG)
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25
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Tajima T, Nakamura A, Morikawa S, Ishizu K. Neonatal screening and a new cause of congenital central hypothyroidism. Ann Pediatr Endocrinol Metab 2014; 19:117-21. [PMID: 25346914 PMCID: PMC4208260 DOI: 10.6065/apem.2014.19.3.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 08/14/2014] [Indexed: 11/20/2022] Open
Abstract
Congenital central hypothyroidism (C-CH) is a rare disease in which thyroid hormone deficiency is caused by insufficient thyrotropin (TSH) stimulation of a normally-located thyroid gland. Most patients with C-CH have low free thyroxine levels and inappropriately low or normal TSH levels, although a few have slightly elevated TSH levels. Autosomal recessive TSH deficiency and thyrotropin-releasing hormone receptor-inactivating mutations are known to be genetic causes of C-CH presenting in the absence of other syndromes. Recently, deficiency of the immunoglobulin superfamily member 1 (IGSF1) has also been demonstrated to cause C-CH. IGSF1 is a plasma membrane glycoprotein highly expressed in the pituitary. Its physiological role in humans remains unknown. IGSF1 deficiency causes TSH deficiency, leading to hypothyroidism. In addition, approximately 60% of patients also suffer a prolactin deficiency. Moreover, macroorchidism and delayed puberty are characteristic features. Thus, although the precise pathophysiology of IGSF1 deficiency is not established, IGSF1 is considered to be a new factor controlling growth and puberty in children.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan
| | - Akie Nakamura
- Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan
| | - Shuntaro Morikawa
- Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan
| | - Katsura Ishizu
- Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan
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26
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Voss M, Schröder B, Fluhrer R. Mechanism, specificity, and physiology of signal peptide peptidase (SPP) and SPP-like proteases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2828-39. [PMID: 24099004 DOI: 10.1016/j.bbamem.2013.03.033] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/25/2013] [Accepted: 03/29/2013] [Indexed: 01/09/2023]
Abstract
Signal peptide peptidase (SPP) and the homologous SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 belong to the family of GxGD intramembrane proteases. SPP/SPPLs selectively cleave transmembrane domains in type II orientation and do not require additional co-factors for proteolytic activity. Orthologues of SPP and SPPLs have been identified in other vertebrates, plants, and eukaryotes. In line with their diverse subcellular localisations ranging from the ER (SPP, SPPL2c), the Golgi (SPPL3), the plasma membrane (SPPL2b) to lysosomes/late endosomes (SPPL2a), the different members of the SPP/SPPL family seem to exhibit distinct functions. Here, we review the substrates of these proteases identified to date as well as the current state of knowledge about the physiological implications of these proteolytic events as deduced from in vivo studies. Furthermore, the present knowledge on the structure of intramembrane proteases of the SPP/SPPL family, their cleavage mechanism and their substrate requirements are summarised. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Matthias Voss
- Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Schillerstr. 44, 80336 Munich, Germany
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27
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Joustra SD, van Trotsenburg ASP, Sun Y, Losekoot M, Bernard DJ, Biermasz NR, Oostdijk W, Wit JM. IGSF1 deficiency syndrome: A newly uncovered endocrinopathy. ACTA ACUST UNITED AC 2013; 1:e24883. [PMID: 25002994 PMCID: PMC3915563 DOI: 10.4161/rdis.24883] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 04/15/2013] [Accepted: 04/30/2013] [Indexed: 01/29/2023]
Abstract
A recently uncovered X-linked syndrome, caused by loss-of-function of IGSF1, is characterized by congenital central hypothyroidism and macroorchidism, variable prolactin deficiency, occasional growth hormone deficiency, delayed pubertal testosterone secretion and obesity. We propose to call this endocrinopathy “IGSF1 deficiency syndrome.” Based on an estimated incidence of isolated congenital central hypothyroidism of 1:65,000, we predict that the incidence of IGSF1 deficiency related hypothyroidism is approximately 1:100,000. IGSF1 encodes a plasma membrane immunoglobulin superfamily glycoprotein that is highly expressed in pituitary and testis, but is of unknown function. The variable profile of pituitary dysfunction suggests that IGSF1 may play a role in pituitary paracrine regulation. The clinical significance of the syndrome, particularly the clinical consequences of untreated hypothyroidism, justifies screening family members of patients with IGSF1 mutations for carriership and to study potential carriers of IGSF1 mutations, including patients with idiopathic central hypothyroidism, combined GH and TSH deficiency, macroorchidism or delayed puberty.
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Affiliation(s)
- Sjoerd D Joustra
- Department of Pediatrics; Leiden University Medical Center; Leiden, The Netherlands ; Department of Endocrinology and Metabolic Disorders; Leiden University Medical Center; Leiden, The Netherlands
| | - A S Paul van Trotsenburg
- Department of Pediatric Endocrinology; Emma Children's Hospital; Academic Medical Center; University of Amsterdam; Amsterdam, The Netherlands
| | - Yu Sun
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden, The Netherlands
| | - Monique Losekoot
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden, The Netherlands
| | - Daniel J Bernard
- Department of Pharmacology and Therapeutics; McGill University; Montreal, QC Canada
| | - Nienke R Biermasz
- Department of Endocrinology and Metabolic Disorders; Leiden University Medical Center; Leiden, The Netherlands
| | - Wilma Oostdijk
- Department of Pediatrics; Leiden University Medical Center; Leiden, The Netherlands
| | - Jan M Wit
- Department of Pediatrics; Leiden University Medical Center; Leiden, The Netherlands
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28
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Tajima T, Nakamura A, Ishizu K. A novel mutation of IGSF1 in a Japanese patient of congenital central hypothyroidism without macroorchidism. Endocr J 2013; 60:245-9. [PMID: 23363888 DOI: 10.1507/endocrj.ej13-0009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Congenital central hypothyroidism (C-CH) is a rare disease known to be caused by mutations of the genes encoding TSH β or the TRH receptor gene, although the cause of the disease in a number of patients has not yet been clarified. Recently, mutations and deletions of the immunoglobulin superfamily member 1 (IGSF1) gene have been reported to be the cause of C-CH. Here we report a Japanese male patient with C-CH due to a novel IGSF1 mutation. He was detected by neonatal mass screening of simultaneous TSH and free T4 measurements and levothyroxine was initiated. At 6 years of age he underwent ¹²³I scintigraphy after levothyroxine treatment had been discontinued for one month and his thyroid and pituitary function were evaluated. Since TSH and PRL responses after TRH stimulation were low, his diagnosis of C-CH was confirmed. During follow up, whereas onset of his puberty was delayed, his secondary sex characterization completed at 17 years old. In this patient we analyzed IGSF1 and TRHR. As results, we identified a novel insertion mutation in IGSF1 (c.3528-3529insC), resulting in a premature stop codon (p.Pro1082Trpfs39X). In conclusion, we identified a novel mutation of IGSF1 in a Japanese male patient with C-CH.
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Affiliation(s)
- Toshihiro Tajima
- Department of Pediatrics, Hokkaido University School of Medicine, Sapporo 060-8635, Japan.
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Sun Y, Bak B, Schoenmakers N, van Trotsenburg ASP, Oostdijk W, Voshol P, Cambridge E, White JK, le Tissier P, Gharavy SNM, Martinez-Barbera JP, Stokvis-Brantsma WH, Vulsma T, Kempers MJ, Persani L, Campi I, Bonomi M, Beck-Peccoz P, Zhu H, Davis TME, Hokken-Koelega ACS, Del Blanco DG, Rangasami JJ, Ruivenkamp CAL, Laros JFJ, Kriek M, Kant SG, Bosch CAJ, Biermasz NR, Appelman-Dijkstra NM, Corssmit EP, Hovens GCJ, Pereira AM, den Dunnen JT, Wade MG, Breuning MH, Hennekam RC, Chatterjee K, Dattani MT, Wit JM, Bernard DJ. Loss-of-function mutations in IGSF1 cause an X-linked syndrome of central hypothyroidism and testicular enlargement. Nat Genet 2012; 44:1375-81. [PMID: 23143598 PMCID: PMC3511587 DOI: 10.1038/ng.2453] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/03/2012] [Indexed: 11/09/2022]
Abstract
Congenital central hypothyroidism occurs either in isolation or in conjunction with other pituitary hormone deficits. Using exome and candidate gene sequencing, we identified 8 distinct mutations and 2 deletions in IGSF1 in males from 11 unrelated families with central hypothyroidism, testicular enlargement and variably low prolactin concentrations. IGSF1 is a membrane glycoprotein that is highly expressed in the anterior pituitary gland, and the identified mutations impair its trafficking to the cell surface in heterologous cells. Igsf1-deficient male mice show diminished pituitary and serum thyroid-stimulating hormone (TSH) concentrations, reduced pituitary thyrotropin-releasing hormone (TRH) receptor expression, decreased triiodothyronine concentrations and increased body mass. Collectively, our observations delineate a new X-linked disorder in which loss-of-function mutations in IGSF1 cause central hypothyroidism, likely secondary to an associated impairment in pituitary TRH signaling.
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Affiliation(s)
- Yu Sun
- Center for Human and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Tamura T, Kuroda M, Oikawa T, Kyozuka J, Terauchi K, Ishimaru Y, Abe K, Asakura T. Signal peptide peptidases are expressed in the shoot apex of rice, localized to the endoplasmic reticulum. PLANT CELL REPORTS 2009; 28:1615-1621. [PMID: 19688213 DOI: 10.1007/s00299-009-0760-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 07/15/2009] [Accepted: 07/29/2009] [Indexed: 05/28/2023]
Abstract
Signal peptide peptidase (SPP) is a multi-transmembrane aspartic proteinase involved in regulated intramembrane proteolysis, which is implicated in fundamental life processes such as immunological response, cell signaling, tissue differentiation, and embryogenesis. In this study, we identified two rice SPPs: OsSPP1 and OsSPP2. Green fluorescent protein-fused OsSPP1 and OsSPP2 were localized to the ER in cultured plant cells. In situ hybridization showed that OsSPPs were strongly expressed in vegetative shoot apex, young panicle, developing panicle, and the early developing florets. Undifferentiated cells, which have the potential to differentiate into all of the aerial parts of the plant are presented in the shoot apex. OsSPPs are located in both the undifferentiated cells, and the early differentiated cells at the shoot apex. These results suggest that rice SPPs have an important function in differentiation and development at the shoot apex. The expression of the shoot apex and ER localization is equal to dicot Arabidopsis thaliana, and will have common crucial roles in plant.
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Affiliation(s)
- Tomoko Tamura
- Department of Applied Biological Chemistry, The University of Tokyo, Japan
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Golde TE, Wolfe MS, Greenbaum DC. Signal peptide peptidases: a family of intramembrane-cleaving proteases that cleave type 2 transmembrane proteins. Semin Cell Dev Biol 2009; 20:225-30. [PMID: 19429495 DOI: 10.1016/j.semcdb.2009.02.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 02/05/2009] [Accepted: 02/05/2009] [Indexed: 01/09/2023]
Abstract
Five genes encode the five human signal peptide peptidases (SPPs), which are intramembrane-cleaving aspartyl proteases (aspartyl I-CLiPs). SPPs have been conserved through evolution with family members found in higher eukaryotes, fungi, protozoa, arachea, and plants. SPPs are related to the presenilin family of aspartyl I-CLiPs but differ in several key aspects. Presenilins (PSENs) and SPPs both cleave the transmembrane region of membrane proteins; however, PSENs cleave type 1 membrane proteins whereas SPPs cleave type 2 membrane proteins. Though the overall homology between SPPs and PSENs is minimal, they are multipass membrane proteins that contain two conserved active site motifs YD and GxGD in adjacent membrane-spanning domains and a conserved PAL motif of unknown function near their COOH-termini. They differ in that the active site YD and GxGD containing transmembrane domains of SPPs are inverted relative to PSENs, thus, orienting the active site in a consistent topology relative to the substrate. At least two of the human SPPs (SPP and SPPL3) appear to function without additional cofactors, but PSENs function as a protease, called gamma-secretase, only when complexed with Nicastrin, APH-1 and Pen-2. The biological roles of SPP are largely unknown, and only a few endogenous substrates for SPPs have been identified. Nevertheless there is emerging evidence that SPP family members are highly druggable and may regulate both essential physiologic and pathophysiologic processes. Further study of the SPP family is needed in order to understand their biological roles and their potential as therapeutic targets.
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Affiliation(s)
- Todd E Golde
- Department of Neuroscience, Mayo Clinic, College of Medicine, 4500 San Pablo Road, Jacksonville, FL 32224, United States.
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