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Cochlear implantation in a 16-month-old with Chudley-McCullough Syndrome. Am J Otolaryngol 2022; 43:103487. [PMID: 35569212 DOI: 10.1016/j.amjoto.2022.103487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 05/01/2022] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The purpose of this report is to describe a case of bilateral cochlear implantation (CI) in a pediatric patient with Chudley-McCullough Syndrome (CMS). By reviewing the literature, we hope to describe common clinical presentations to aid in early diagnosis and management of pediatric patients with CMS. METHODS Case report with literature review. RESULTS We present a case of a 16-month-old female with CMS who presented to clinic after a failed newborn hearing screen and was found to have bilateral sensorineural hearing loss. After a failed trial of hearing amplification, the patient underwent successful bilateral CI. The patient had no surgical complications, and her follow up visit showed satisfactory speech and language development. CONCLUSION This case validates that cochlear implantation in pediatric patients who present with CMS is both safe and efficacious. It also demonstrates the importance of early detection and treatment of sensorineural hearing loss in CMS to prevent speech and language delay.
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Shi Y, Lin L, Wang C, Zhu J. Promotion of row 1-specific tip complex condensates by Gpsm2-Gαi provides insights into row identity of the tallest stereocilia. SCIENCE ADVANCES 2022; 8:eabn4556. [PMID: 35687681 PMCID: PMC9187228 DOI: 10.1126/sciadv.abn4556] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 04/26/2022] [Indexed: 06/12/2023]
Abstract
The mechanosensory stereocilia in hair cells are organized into rows of graded height, a property crucial for auditory perception. Gpsm2-Gαi-Whirlin-Myo15-Eps8 complex at tips of the tallest stereocilia is proposed to define hair bundle row identity, although the underlying mechanism remains elusive. Here, we find that Gpsm2 could undergo phase separation. Moreover, row 1-specific Gpsm2-Gαi complex significantly promotes the formation of the five-component tip complex density (5xTCD) condensates. The 5xTCD condensates display much stronger actin-bundling ability than those without Gpsm2-Gαi, which may provide critical insights into how Gpsm2-Gαi specifies the tallest stereocilia. A deafness-associated mutation of Gpsm2 leads to impaired formation of the 5xTCD condensates and consequently reduced actin bundling, providing possible clues for etiology of hearing loss in patients with Chudley-McCullough syndrome.
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Affiliation(s)
- Yingdong Shi
- Department of Neurology, the First Affiliated Hospital of USTC, Ministry of Education Key Laboratory for Cellular Dynamics, Biomedical Sciences and Health Laboratory of Anhui Province, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Lin Lin
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chao Wang
- Department of Neurology, the First Affiliated Hospital of USTC, Ministry of Education Key Laboratory for Cellular Dynamics, Biomedical Sciences and Health Laboratory of Anhui Province, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Jinwei Zhu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
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Blauen A, Stutterd CA, Stouffs K, Dumitriu D, Deggouj N, Lockhart PJ, Leventer RJ, Nassogne MC, Jansen AC. Chudley-McCullough Syndrome: A Recognizable Clinical Entity Characterized by Deafness and Typical Brain Malformations. J Child Neurol 2021; 36:152-158. [PMID: 33016209 DOI: 10.1177/0883073820960314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chudley-McCullough syndrome, a rare autosomal recessive disorder due to pathogenic variants in the GPSM2 (G-protein signaling modulator 2) gene, is characterized by early-onset sensorineural deafness and a typical combination of brain malformations, including ventriculomegaly, (partial) agenesis of the corpus callosum, cerebellar dysplasia, arachnoid cysts, frontal subcortical heterotopia, and midline polymicrogyria. When hearing loss is managed early, most patients have minor or no impairment of motor and cognitive development, despite the presence of brain malformations. We report 2 cases of Chudley-McCullough syndrome, one presenting with congenital deafness and normal development except for speech delay and one presenting prenatally with ventriculomegaly and an atypical postnatal course characterized by epileptic spasms, deafness, and moderate intellectual disability. These highlight the challenges faced by clinicians when predicting prognosis based on pre- or postnatal imaging of brain malformations. We have also reviewed the phenotype and genotype of previous published cases to better understand Chudley-McCullough syndrome.
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Affiliation(s)
- Aglaë Blauen
- Pediatric Neurology Unit, 70492Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Chloe A Stutterd
- Department of Neurology, 6453Royal Children's Hospital, Melbourne, Australia.,34361Murdoch Children's Research Institute, Melbourne, Australia.,Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Katrien Stouffs
- Center for Medical Genetics, UZ Brussel, Brussels, Belgium.,Neurogenetics Research Group, Reproduction-Genetics & Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium
| | - Dana Dumitriu
- Pediatric Radiology Unit, 70492Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Naima Deggouj
- Department of Oto-Rhino-Laryngology, Cliniques Universitaires Saint-Luc, 83415Université Catholique de Louvain, Brussels, Belgium
| | - Paul J Lockhart
- 34361Murdoch Children's Research Institute, Melbourne, Australia.,Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Richard J Leventer
- Department of Neurology, 6453Royal Children's Hospital, Melbourne, Australia.,34361Murdoch Children's Research Institute, Melbourne, Australia.,Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Marie-Cécile Nassogne
- Pediatric Neurology Unit, 70492Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Anna C Jansen
- Neurogenetics Research Group, Reproduction-Genetics & Regenerative Medicine Research Cluster, Vrije Universiteit Brussel, Brussels, Belgium.,Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Brussels, Belgium
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4
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Abstract
Chudley-McCullough syndrome (CMS), an autosomal recessive condition first reported by Chudley et al., in 1997, comprises profound sensorineural hearing loss and specific brain abnormalities. The hearing loss may be congenital or early onset. Brain abnormalities are striking, but despite these brain malformations, individuals with CMS do not present significant neurodevelopmental abnormalities. Recently, the cause of CMS has been shown to be the inactivating mutations in G protein signaling modulator 2. We aimed to present a 36-year-old male who has the characteristic clinical and neuroimaging findings of CMS.
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Affiliation(s)
- Meltem Özdemir
- Department of Radiology, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
| | - Alper Dilli
- Department of Radiology, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey
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5
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Defective Gpsm2/Gα i3 signalling disrupts stereocilia development and growth cone actin dynamics in Chudley-McCullough syndrome. Nat Commun 2017; 8:14907. [PMID: 28387217 PMCID: PMC5385604 DOI: 10.1038/ncomms14907] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 02/13/2017] [Indexed: 01/14/2023] Open
Abstract
Mutations in GPSM2 cause Chudley-McCullough syndrome (CMCS), an autosomal recessive neurological disorder characterized by early-onset sensorineural deafness and brain anomalies. Here, we show that mutation of the mouse orthologue of GPSM2 affects actin-rich stereocilia elongation in auditory and vestibular hair cells, causing deafness and balance defects. The G-protein subunit Gαi3, a well-documented partner of Gpsm2, participates in the elongation process, and its absence also causes hearing deficits. We show that Gpsm2 defines an ∼200 nm nanodomain at the tips of stereocilia and this localization requires the presence of Gαi3, myosin 15 and whirlin. Using single-molecule tracking, we report that loss of Gpsm2 leads to decreased outgrowth and a disruption of actin dynamics in neuronal growth cones. Our results elucidate the aetiology of CMCS and highlight a new molecular role for Gpsm2/Gαi3 in the regulation of actin dynamics in epithelial and neuronal tissues. Mutations in GPSM2 cause a rare disease characterized by deafness and brain abnormalities. Here the authors show that Gpsm2 forms a molecular complex with a heterotrimeric G-protein subunit, whirlin and a myosin motor to regulate actin dynamics in neurons and auditory hair cell stereocilia.
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6
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Tadenev ALD, Tarchini B. The Spindle Orientation Machinery Beyond Mitosis: When Cell Specialization Demands Polarization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:209-225. [DOI: 10.1007/978-3-319-57127-0_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Tarchini B, Tadenev ALD, Devanney N, Cayouette M. A link between planar polarity and staircase-like bundle architecture in hair cells. Development 2016; 143:3926-3932. [PMID: 27660326 DOI: 10.1242/dev.139089] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/14/2016] [Indexed: 01/14/2023]
Abstract
Sensory perception in the inner ear relies on the hair bundle, the highly polarized brush of movement detectors that crowns hair cells. We previously showed that, in the mouse cochlea, the edge of the forming bundle is defined by the 'bare zone', a microvilli-free sub-region of apical membrane specified by the Insc-LGN-Gαi protein complex. We now report that LGN and Gαi also occupy the very tip of stereocilia that directly abut the bare zone. We demonstrate that LGN and Gαi are both essential for promoting the elongation and differential identity of stereocilia across rows. Interestingly, we also reveal that total LGN-Gαi protein amounts are actively balanced between the bare zone and stereocilia tips, suggesting that early planar asymmetry of protein enrichment at the bare zone confers adjacent stereocilia their tallest identity. We propose that LGN and Gαi participate in a long-inferred signal that originates outside the bundle to model its staircase-like architecture, a property that is essential for direction sensitivity to mechanical deflection and hearing.
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Affiliation(s)
- Basile Tarchini
- The Jackson Laboratory, Bar Harbor, ME 04609, USA .,Department of Medicine, Tufts University, Boston, MA 02111, USA.,Graduate School of Biomedical Science and Engineering (GSBSE), University of Maine, Orono, ME 04469, USA.,Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada H2W 1R7
| | | | | | - Michel Cayouette
- Cellular Neurobiology Research Unit, Institut de recherches cliniques de Montréal (IRCM), Montreal, Quebec, Canada H2W 1R7 .,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada H3T 1J4.,Department of Anatomy and Cell Biology, and Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada H3A 0G4
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8
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Hamzeh AR, Nair P, Mohamed M, Saif F, Tawfiq N, Al-Ali MT, Bastaki F. A novel nonsense GPSM2 mutation in a Yemeni family underlying Chudley-McCullough syndrome. Eur J Med Genet 2016; 59:337-41. [DOI: 10.1016/j.ejmg.2016.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/08/2016] [Accepted: 05/09/2016] [Indexed: 11/25/2022]
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Bhonker Y, Abu-Rayyan A, Ushakov K, Amir-Zilberstein L, Shivatzki S, Yizhar-Barnea O, Elkan-Miller T, Tayeb-Fligelman E, Kim SM, Landau M, Kanaan M, Chen P, Matsuzaki F, Sprinzak D, Avraham KB. The GPSM2/LGN GoLoco motifs are essential for hearing. Mamm Genome 2015; 27:29-46. [PMID: 26662512 DOI: 10.1007/s00335-015-9614-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/17/2015] [Indexed: 11/24/2022]
Abstract
The planar cell polarity (PCP) pathway is responsible for polarizing and orienting cochlear hair cells during development through movement of a primary cilium, the kinocilium. GPSM2/LGN, a mitotic spindle-orienting protein associated with deafness in humans, is a PCP effector involved in kinocilium migration. Here, we link human and mouse truncating mutations in the GPSM2/LGN gene, both leading to hearing loss. The human variant, p.(Trp326*), was identified by targeted genomic enrichment of genes associated with deafness, followed by massively parallel sequencing. Lgn (ΔC) mice, with a targeted deletion truncating the C-terminal GoLoco motifs, are profoundly deaf and show misorientation of the hair bundle and severe malformations in stereocilia shape that deteriorates over time. Full-length protein levels are greatly reduced in mutant mice, with upregulated mRNA levels. The truncated Lgn (ΔC) allele is translated in vitro, suggesting that mutant mice may have partially functioning Lgn. Gαi and aPKC, known to function in the same pathway as Lgn, are dependent on Lgn for proper localization. The polarization of core PCP proteins is not affected in Lgn mutants; however, Lgn and Gαi are misoriented in a PCP mutant, supporting the role of Lgn as a PCP effector. The kinocilium, previously shown to be dependent on Lgn for robust localization, is essential for proper localization of Lgn, as well as Gαi and aPKC, suggesting that cilium function plays a role in positioning of apical proteins. Taken together, our data provide a mechanism for the loss of hearing found in human patients with GPSM2/LGN variants.
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Affiliation(s)
- Yoni Bhonker
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Amal Abu-Rayyan
- Department of Biological Sciences, Bethlehem University, Bethlehem, Palestine
| | - Kathy Ushakov
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Liat Amir-Zilberstein
- Department of Biochemistry and Molecular Biology, Weiss Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Shaked Shivatzki
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Ofer Yizhar-Barnea
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Tal Elkan-Miller
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Einav Tayeb-Fligelman
- Department of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Sun Myoung Kim
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Moien Kanaan
- Department of Biological Sciences, Bethlehem University, Bethlehem, Palestine
| | - Ping Chen
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA
| | - Fumio Matsuzaki
- Laboratory of Cell Asymmetry, Center for Developmental Biology, Riken, Kobe, 650-0047, Japan
| | - David Sprinzak
- Department of Biochemistry and Molecular Biology, Weiss Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel.
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10
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Najmabadi H, Kahrizi K. Genetics of non-syndromic hearing loss in the Middle East. Int J Pediatr Otorhinolaryngol 2014; 78:2026-36. [PMID: 25281338 DOI: 10.1016/j.ijporl.2014.08.036] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 08/24/2014] [Accepted: 08/25/2014] [Indexed: 12/23/2022]
Abstract
Hearing impairment is the most common sensory disorder, present 1 in every 500 newborns. About 80% of genetic HL is classified as non-syndromic deafness. To date, over 115 non-syndromic loci have been identified of which fifty associated with autosomal recessive non-syndromic hearing loss (ARNSHL). In this review article, we represent the 40 genes function and contribution to genetic deafness in different Middle Eastern populations as well as gene frequencies and mutation spectrum. The wide variety of mutations have so far detected in 19 countries reflects the heterogeneity of the genes involved in HL in this region. The deafness genes can cause dysfunction of cochlear homeostasis, cellular organization, neuronal transmission, cell growth, differentiation, and survival, some coding for tectorial membrane-associated proteins, and the remaining with unknown functions. Non-syndromic deafness is highly heterogeneous and mutations in the GJB2 are responsible for almost 30-50% in northwest to as low as 0-5% in south and southeast of the Middle East, it remain as major gene in ARNSHL in Middle East. The other genes contributing to AR/ADNSHL in some countries have been determined while for many other countries in the Middle East have not been studied or little study has been done. With the advancement of next generation sequencing one could expect in next coming year many of the remaining genes to be determine and to understand their function in the inner ear.
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Affiliation(s)
- Hossein Najmabadi
- Genetics Research Centre (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
| | - Kimia Kahrizi
- Genetics Research Centre (GRC), University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
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12
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A molecular blueprint at the apical surface establishes planar asymmetry in cochlear hair cells. Dev Cell 2013; 27:88-102. [PMID: 24135232 DOI: 10.1016/j.devcel.2013.09.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 08/29/2013] [Accepted: 09/13/2013] [Indexed: 11/22/2022]
Abstract
Sound perception relies on the planar polarization of the mechanosensory hair cell apex, which develops a V-shaped stereocilia bundle pointing toward an eccentric kinocilium. It remains unknown how intrinsically asymmetric bundles arise and are concomitantly oriented in the tissue. We report here that mInsc, LGN, and Gαi proteins, which classically regulate mitotic spindle orientation, are polarized in a lateral microvilli-free region, or "bare zone," at the apical hair cell surface. By creating and extending the bare zone, these proteins trigger a relocalization of the eccentric kinocilium midway toward the cell center. aPKC is restrained medially by mInsc/LGN/Gαi, resulting in compartmentalization of the apical surface that imparts the V-shaped distribution of stereocilia and brings the asymmetric bundle in register with the relocalized kinocilium. Gαi is additionally required for lateral orientation of cochlear hair cells, providing a possible mechanism to couple the emergence of asymmetric stereocilia bundles with planar cell polarity.
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13
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Blumer JB, Lanier SM. Activators of G protein signaling exhibit broad functionality and define a distinct core signaling triad. Mol Pharmacol 2013; 85:388-96. [PMID: 24302560 DOI: 10.1124/mol.113.090068] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Activators of G protein signaling (AGS), initially discovered in the search for receptor-independent activators of G protein signaling, define a broad panel of biologic regulators that influence signal transfer from receptor to G-protein, guanine nucleotide binding and hydrolysis, G protein subunit interactions, and/or serve as alternative binding partners for Gα and Gβγ independently of the classic heterotrimeric Gαβγ. AGS proteins generally fall into three groups based upon their interaction with and regulation of G protein subunits: group I, guanine nucleotide exchange factors (GEF); group II, guanine nucleotide dissociation inhibitors; and group III, entities that bind to Gβγ. Group I AGS proteins can engage all subclasses of G proteins, whereas group II AGS proteins primarily engage the Gi/Go/transducin family of G proteins. A fourth group of AGS proteins with selectivity for Gα16 may be defined by the Mitf-Tfe family of transcription factors. Groups I-III may act in concert, generating a core signaling triad analogous to the core triad for heterotrimeric G proteins (GEF + G proteins + effector). These two core triads may function independently of each other or actually cross-integrate for additional signal processing. AGS proteins have broad functional roles, and their discovery has advanced new concepts in signal processing, cell and tissue biology, receptor pharmacology, and system adaptation, providing unexpected platforms for therapeutic and diagnostic development.
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Affiliation(s)
- Joe B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina
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Chen CP, Chen M, Su YN, Huang JP, Chern SR, Wu PS, Su JW, Chang SP, Chen YT, Lee CC, Chen LF, Pan CW, Wang W. Mosaic small supernumerary marker chromosome 1 at amniocentesis: prenatal diagnosis, molecular genetic analysis and literature review. Gene 2013; 529:169-75. [PMID: 23933412 DOI: 10.1016/j.gene.2013.07.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/01/2013] [Accepted: 07/10/2013] [Indexed: 11/28/2022]
Abstract
We present prenatal diagnosis and molecular cytogenetic analysis of mosaic small supernumerary marker chromosome 1 [sSMC(1)]. We review the literature of sSMC(1) at amniocentesis and chromosome 1p21.1-p12 duplication syndrome. We discuss the genotype-phenotype correlation of the involved genes of ALX3, RBM15, NTNG1, SLC25A24, GPSM2, TBX15 and NOTCH2 in this case.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
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Sipe CW, Liu L, Lee J, Grimsley-Myers C, Lu X. Lis1 mediates planar polarity of auditory hair cells through regulation of microtubule organization. Development 2013; 140:1785-95. [PMID: 23533177 DOI: 10.1242/dev.089763] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The V-shaped hair bundles atop auditory hair cells and their uniform orientation are manifestations of epithelial planar cell polarity (PCP) required for proper perception of sound. PCP is regulated at the tissue level by a conserved core Wnt/PCP pathway. However, the hair cell-intrinsic polarity machinery is poorly understood. Recent findings implicate hair cell microtubules in planar polarization of hair cells. To elucidate the microtubule-mediated polarity pathway, we analyzed Lis1 function in the auditory sensory epithelium in the mouse. We show that conditional deletion of Lis1 in developing hair cells causes defects in cytoplasmic dynein and microtubule organization, resulting in planar polarity defects without overt effects on the core PCP pathway. Lis1 ablation during embryonic development results in defects in hair bundle morphology and orientation, cellular organization and junctional nectin localization. We present evidence that Lis1 regulates localized Rac-PAK signaling in embryonic hair cells, probably through microtubule-associated Tiam1, a guanine nucleotide exchange factor for Rac. Lis1 ablation in postnatal hair cells significantly disrupts centrosome anchoring and the normal V-shape of hair bundles, accompanied by defects in the pericentriolar matrix and microtubule organization. Lis1 is also required for proper positioning of the Golgi complex and mitochondria as well as for hair cell survival. Together, our results demonstrate that Lis1 mediates the planar polarity of hair cells through regulation of microtubule organization downstream of the tissue polarity pathway.
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Affiliation(s)
- Conor W Sipe
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA 22908, USA
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16
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Almomani R, Sun Y, Aten E, Hilhorst-Hofstee Y, Peeters-Scholte CM, van Haeringen A, Hendriks YM, den Dunnen JT, Breuning MH, Kriek M, Santen GW. GPSM2and Chudley-McCullough Syndrome: A Dutch Founder Variant Brought to North America. Am J Med Genet A 2013; 161A:973-6. [PMID: 23494849 DOI: 10.1002/ajmg.a.35808] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 11/18/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Rowida Almomani
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Yu Sun
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Emmelien Aten
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Yvonne Hilhorst-Hofstee
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | | | - Arie van Haeringen
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Yvonne M.C. Hendriks
- Department of Clinical Genetics; VU University Medical Center; Amsterdam; The Netherlands
| | | | - Martijn H. Breuning
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Marjolein Kriek
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
| | - Gijs W.E. Santen
- Center for Human and Clinical Genetics; Leiden University Medical Center; Leiden; The Netherlands
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17
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Diaz-Horta O, Sirmaci A, Doherty D, Nance W, Arnos K, Pandya A, Tekin M. GPSM2 mutations in Chudley-McCullough syndrome. Am J Med Genet A 2012; 158A:2972-3. [PMID: 22987632 DOI: 10.1002/ajmg.a.35636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/24/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Oscar Diaz-Horta
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA
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18
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Doherty D, Chudley A, Coghlan G, Ishak G, Innes A, Lemire E, Rogers R, Mhanni A, Phelps I, Jones S, Zhan S, Fejes A, Shahin H, Kanaan M, Akay H, Tekin M, Triggs-Raine B, Zelinski T, Zelinski T. GPSM2 mutations cause the brain malformations and hearing loss in Chudley-McCullough syndrome. Am J Hum Genet 2012; 90:1088-93. [PMID: 22578326 DOI: 10.1016/j.ajhg.2012.04.008] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 11/27/2022] Open
Abstract
Autosomal-recessive inheritance, severe to profound sensorineural hearing loss, and partial agenesis of the corpus callosum are hallmarks of the clinically well-established Chudley-McCullough syndrome (CMS). Although not always reported in the literature, frontal polymicrogyria and gray matter heterotopia are uniformly present, whereas cerebellar dysplasia, ventriculomegaly, and arachnoid cysts are nearly invariant. Despite these striking brain malformations, individuals with CMS generally do not present with significant neurodevelopmental abnormalities, except for hearing loss. Homozygosity mapping and whole-exome sequencing of DNA from affected individuals in eight families (including the family in the first report of CMS) revealed four molecular variations (two single-base deletions, a nonsense mutation, and a canonical splice-site mutation) in the G protein-signaling modulator 2 gene, GPSM2, that underlie CMS. Mutations in GPSM2 have been previously identified in people with profound congenital nonsyndromic hearing loss (NSHL). Subsequent brain imaging of these individuals revealed frontal polymicrogyria, abnormal corpus callosum, and gray matter heterotopia, consistent with a CMS diagnosis, but no ventriculomegaly. The gene product, GPSM2, is required for orienting the mitotic spindle during cell division in multiple tissues, suggesting that the sensorineural hearing loss and characteristic brain malformations of CMS are due to defects in asymmetric cell divisions during development.
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Blumer JB, Oner SS, Lanier SM. Group II activators of G-protein signalling and proteins containing a G-protein regulatory motif. Acta Physiol (Oxf) 2012; 204:202-18. [PMID: 21615707 DOI: 10.1111/j.1748-1716.2011.02327.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Beyond the core triad of receptor, Gαβγ and effector, there are multiple accessory proteins that provide alternative modes of signal input and regulatory adaptability to G-protein signalling systems. Such accessory proteins may segregate a signalling complex to microdomains of the cell, regulate the basal activity, efficiency and specificity of signal propagation and/or serve as alternative binding partners for Gα or Gβγ independent of the classical heterotrimeric Gαβγ complex. The latter concept led to the postulate that Gα and Gβγ regulate intracellular events distinct from their role as transducers for cell surface seven-transmembrane span receptors. One general class of such accessory proteins is defined by AGS proteins or activators of G-protein signalling that refer to mammalian cDNAs identified in a specific yeast-based functional screen. The discovery of AGS proteins and related entities revealed a number of unexpected mechanisms for regulation of G-protein signalling systems and expanded functional roles for this important signalling system.
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Affiliation(s)
- J B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, 29425, USA
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