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Morales-Romero B, Muñoz-Pujol G, Artuch R, García-Cazorla A, O'Callaghan M, Sykut-Cegielska J, Campistol J, Moreno-Lozano PJ, Oud MM, Wevers RA, Lefeber DJ, Esteve-Codina A, Yepez VA, Gagneur J, Wortmann SB, Prokisch H, Ribes A, García-Villoria J, Tort F. Genome and RNA sequencing were essential to reveal cryptic intronic variants associated to defective ATP6AP1 mRNA processing. Mol Genet Metab 2024; 142:108511. [PMID: 38878498 DOI: 10.1016/j.ymgme.2024.108511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 07/05/2024]
Abstract
The diagnosis of Mendelian disorders has notably advanced with integration of whole exome and genome sequencing (WES and WGS) in clinical practice. However, challenges in variant interpretation and uncovered variants by WES still leave a substantial percentage of patients undiagnosed. In this context, integrating RNA sequencing (RNA-seq) improves diagnostic workflows, particularly for WES inconclusive cases. Additionally, functional studies are often necessary to elucidate the impact of prioritized variants on gene expression and protein function. Our study focused on three unrelated male patients (P1-P3) with ATP6AP1-CDG (congenital disorder of glycosylation), presenting with intellectual disability and varying degrees of hepatopathy, glycosylation defects, and an initially inconclusive diagnosis through WES. Subsequent RNA-seq was pivotal in identifying the underlying genetic causes in P1 and P2, detecting ATP6AP1 underexpression and aberrant splicing. Molecular studies in fibroblasts confirmed these findings and identified the rare intronic variants c.289-233C > T and c.289-289G > A in P1 and P2, respectively. Trio-WGS also revealed the variant c.289-289G > A in P3, which was a de novo change in both patients. Functional assays expressing the mutant alleles in HAP1 cells demonstrated the pathogenic impact of these variants by reproducing the splicing alterations observed in patients. Our study underscores the role of RNA-seq and WGS in enhancing diagnostic rates for genetic diseases such as CDG, providing new insights into ATP6AP1-CDG molecular bases by identifying the first two deep intronic variants in this X-linked gene. Additionally, our study highlights the need to integrate RNA-seq and WGS, followed by functional validation, in routine diagnostics for a comprehensive evaluation of patients with an unidentified molecular etiology.
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Affiliation(s)
- Blai Morales-Romero
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Gerard Muñoz-Pujol
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Rafael Artuch
- Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, CIBERER, Esplugues de Llobregat, Barcelona, Spain.
| | - Angels García-Cazorla
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Mar O'Callaghan
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Jolanta Sykut-Cegielska
- Department of Inborn Errors of Metabolism and Pediatrics, Institute of Mother and Child, Warsaw, Poland
| | - Jaume Campistol
- Neurology Department, Hospital Sant Joan de Déu, Institut de Recerca Hospital Sant Joan de Déu, CIBERER and MetabERN, Esplugues de Llobregat, Barcelona, Spain.
| | - Pedro Juan Moreno-Lozano
- Inherited Metabolic Diseases and Muscle Disorders' Research Group, Department of Internal Medicine, Hospital Clinic de Barcelona, IDIBAPS, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.
| | - Machteld M Oud
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Ron A Wevers
- Department of Human Genetics, Translational Metabolic Laboratory (TML), Radboud University Medical Center, Nijmegen, the Netherlands; United for Metabolic Diseases, The Netherlands.
| | - Dirk J Lefeber
- Department of Human Genetics, Translational Metabolic Laboratory (TML), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Neurology, Donders Institute for Brain, Cognition, and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Anna Esteve-Codina
- Centro Nacional de Análisis Genómico (CNAG), Parc Científic de Barcelona, Barcelona, Spain.
| | - Vicente A Yepez
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; TUM School of Computation, Information and Technology, Technical University of Munich, 85748 Garching, Germany.
| | - Julien Gagneur
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; TUM School of Computation, Information and Technology, Technical University of Munich, 85748 Garching, Germany.
| | - Saskia B Wortmann
- University Children's Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria; Amalia Children's Hospital, Department of Pediatrics, Radboudumc, Nijmegen, the Netherlands.
| | - Holger Prokisch
- Institute of Human Genetics, School of Medicine, Technical University of Munich, 81675 Munich, Germany; Institute of Neurogenomics, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
| | - Antonia Ribes
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Judit García-Villoria
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
| | - Frederic Tort
- Section of Inborn Errors of Metabolism-IBC, Biochemistry and Molecular Genetics Department, Hospital Clínic de Barcelona, IDIBAPS, CIBERER, ISCIII, Barcelona, Spain.
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Cao X, Lake M, Van der Hoeven G, Claes Z, Del Pino García J, Lemaire S, Greiner EC, Karamanou S, Van Eynde A, Kettenbach AN, Natera de Benito D, Carrera García L, Hernando Davalillo C, Ortez C, Nascimento A, Urreizti R, Bollen M. SDS22 coordinates the assembly of holoenzymes from nascent protein phosphatase-1. Nat Commun 2024; 15:5359. [PMID: 38918402 PMCID: PMC11199634 DOI: 10.1038/s41467-024-49746-4] [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: 11/24/2023] [Accepted: 06/18/2024] [Indexed: 06/27/2024] Open
Abstract
SDS22 forms an inactive complex with nascent protein phosphatase PP1 and Inhibitor-3. SDS22:PP1:Inhibitor-3 is a substrate for the ATPase p97/VCP, which liberates PP1 for binding to canonical regulatory subunits. The exact role of SDS22 in PP1-holoenzyme assembly remains elusive. Here, we show that SDS22 stabilizes nascent PP1. In the absence of SDS22, PP1 is gradually lost, resulting in substrate hyperphosphorylation and a proliferation arrest. Similarly, we identify a female individual with a severe neurodevelopmental disorder bearing an unstable SDS22 mutant, associated with decreased PP1 levels. We furthermore find that SDS22 directly binds to Inhibitor-3 and that this is essential for the stable assembly of SDS22:PP1: Inhibitor-3, the recruitment of p97/VCP, and the extraction of SDS22 during holoenzyme assembly. SDS22 with a disabled Inhibitor-3 binding site co-transfers with PP1 to canonical regulatory subunits, thereby forming non-functional holoenzymes. Our data show that SDS22, through simultaneous interaction with PP1 and Inhibitor-3, integrates the major steps of PP1 holoenzyme assembly.
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Affiliation(s)
- Xinyu Cao
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Madryn Lake
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Gerd Van der Hoeven
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Zander Claes
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Javier Del Pino García
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Sarah Lemaire
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Elora C Greiner
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Dartmouth Cancer Center, Lebanon, NH, USA
| | - Spyridoula Karamanou
- Laboratory of Molecular Bacteriology, KU Leuven Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Dartmouth Cancer Center, Lebanon, NH, USA
| | | | - Laura Carrera García
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | | | - Carlos Ortez
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Andrés Nascimento
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Roser Urreizti
- Clinical Biochemistry Department, Institut de Recerca Sant Joan de Deu, Hospital Sant Joan de Deu, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000, Leuven, Belgium.
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Antolínez-Fernández Á, Esteban-Ramos P, Fernández-Moreno MÁ, Clemente P. Molecular pathways in mitochondrial disorders due to a defective mitochondrial protein synthesis. Front Cell Dev Biol 2024; 12:1410245. [PMID: 38855161 PMCID: PMC11157125 DOI: 10.3389/fcell.2024.1410245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/09/2024] [Indexed: 06/11/2024] Open
Abstract
Mitochondria play a central role in cellular metabolism producing the necessary ATP through oxidative phosphorylation. As a remnant of their prokaryotic past, mitochondria contain their own genome, which encodes 13 subunits of the oxidative phosphorylation system, as well as the tRNAs and rRNAs necessary for their translation in the organelle. Mitochondrial protein synthesis depends on the import of a vast array of nuclear-encoded proteins including the mitochondrial ribosome protein components, translation factors, aminoacyl-tRNA synthetases or assembly factors among others. Cryo-EM studies have improved our understanding of the composition of the mitochondrial ribosome and the factors required for mitochondrial protein synthesis and the advances in next-generation sequencing techniques have allowed for the identification of a growing number of genes involved in mitochondrial pathologies with a defective translation. These disorders are often multisystemic, affecting those tissues with a higher energy demand, and often present with neurodegenerative phenotypes. In this article, we review the known proteins required for mitochondrial translation, the disorders that derive from a defective mitochondrial protein synthesis and the animal models that have been established for their study.
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Affiliation(s)
- Álvaro Antolínez-Fernández
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Esteban-Ramos
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Miguel Ángel Fernández-Moreno
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paula Clemente
- Instituto de Investigaciones Biomédicas Sols-Morreale (IIBM), Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de Madrid, Madrid, Spain
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Baleva MV, Piunova U, Chicherin I, Vasilev R, Levitskii S, Kamenski P. Mitochondrial Protein SLIRP Affects Biosynthesis of Cytochrome c Oxidase Subunits in HEK293T Cells. Int J Mol Sci 2023; 25:93. [PMID: 38203264 PMCID: PMC10779364 DOI: 10.3390/ijms25010093] [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: 11/18/2023] [Revised: 12/16/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Mitochondria carry out various vital roles in eukaryotic cells, including ATP energy synthesis, the regulation of apoptosis, Fe-S cluster formation, and the metabolism of fatty acids, amino acids, and nucleotides. Throughout evolution, mitochondria lost most of their ancestor's genome but kept the replication, transcription, and translation machinery. Protein biosynthesis in mitochondria is specialized in the production of highly hydrophobic proteins encoded by mitochondria. These proteins are components of oxidative phosphorylation chain complexes. The coordination of protein synthesis must be precise to ensure the correct assembly of nuclear-encoded subunits for these complexes. However, the regulatory mechanisms of mitochondrial translation in human cells are not yet fully understood. In this study, we examined the contribution of the SLIRP protein in regulating protein biosynthesis in mitochondria. Using a click-chemistry approach, we discovered that deletion of the SLIRP gene disturbs mitochondrial translation, leading to the dysfunction of complexes I and IV, but it has no significant effect on complexes III and V. We have shown that this protein interacts only with the small subunit of the mitochondrial ribosome, which may indicate its involvement in the regulation of the mitochondrial translation initiation stage.
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Affiliation(s)
| | | | | | | | - Sergey Levitskii
- Faculty of Biology, Lomonosov Moscow State University, 1/12 Leninskie Gory, 119234 Moscow, Russia; (M.V.B.); (U.P.); (I.C.); (R.V.)
| | - Piotr Kamenski
- Faculty of Biology, Lomonosov Moscow State University, 1/12 Leninskie Gory, 119234 Moscow, Russia; (M.V.B.); (U.P.); (I.C.); (R.V.)
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Hu Y, Huang M, Wen J, Gao J, Long W, Shen Y, Zeng Q, Chen Y, Zhang T, Liao J, Liu Q, Li N, Lin S. Case report: splicing effect of a novel heterozygous variant of the NUS1 gene in a child with epilepsy. Front Genet 2023; 14:1224949. [PMID: 37470039 PMCID: PMC10352580 DOI: 10.3389/fgene.2023.1224949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023] Open
Abstract
NUS1 is responsible for encoding of the Nogo-B receptor (NgBR), which is a subunit of cis-prenyltransferase. Over 25 variants in NUS1 have been reported, and these variants have been found to be associated with various phenotypes, such as congenital disorders of glycosylation (CDG) and developmental and epileptic encephalopathy (DEE). We report on the case of a patient who presented with language and motor retardation, epilepsy, and electroencephalogram abnormalities. Upon conducting whole-exome sequencing, we discovered a novel pathogenic variant (chr6:118024873, NM_138459.5: c.791 + 6T>G) in NUS1, which was shown to cause Exon 4 to be skipped, resulting in a loss of 56 amino acids. Our findings strongly suggest that this novel variant of NUS1 is responsible for the development of neurological disorders, including epilepsy. It is believed that the truncation of Nogo-B receptor results in the loss of cis-prenyltransferase activity, which may be the underlying cause of the disease.
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Affiliation(s)
- Yan Hu
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Mingwei Huang
- Aegicare (Shenzhen) Technology Co., Ltd., Shenzhen, China
| | - Jialun Wen
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jian Gao
- Aegicare (Shenzhen) Technology Co., Ltd., Shenzhen, China
| | - Weiwei Long
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yansheng Shen
- Aegicare (Shenzhen) Technology Co., Ltd., Shenzhen, China
| | - Qi Zeng
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Yan Chen
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Tian Zhang
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Qiuli Liu
- Aegicare (Shenzhen) Technology Co., Ltd., Shenzhen, China
| | - Nannan Li
- Aegicare (Shenzhen) Technology Co., Ltd., Shenzhen, China
| | - Sufang Lin
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
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