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Trinchillo A, Valente V, Esposito M, Migliaccio M, Iovino A, Picciocchi M, Cuomo N, Caccavale C, Nocerino C, De Rosa L, Salvatore E, Pierantoni GM, Menchise V, Paladino S, Criscuolo C. Expanding SPG18 clinical spectrum: autosomal dominant mutation causes complicated hereditary spastic paraplegia in a large family. Neurol Sci 2024:10.1007/s10072-024-07500-0. [PMID: 38607533 DOI: 10.1007/s10072-024-07500-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024]
Abstract
BACKGROUND SPG18 is caused by mutations in the endoplasmic reticulum lipid raft associated 2 (ERLIN2) gene. Autosomal recessive (AR) mutations are usually associated with complicated hereditary spastic paraplegia (HSP), while autosomal dominant (AD) mutations use to cause pure SPG18. AIM To define the variegate clinical spectrum of the SPG18 and to evaluate a dominant negative effect of erlin2 (encoded by ERLIN2) on oligomerization as causing differences between AR and AD phenotypes. METHODS In a four-generation pedigree with an AD pattern, a spastic paraplegia multigene panel test was performed. Oligomerization of erlin2 was analyzed with velocity gradient assay in fibroblasts of the proband and healthy subjects. RESULTS Despite the common p.V168M mutation identified in ERLIN2, a phenoconversion to amyotrophic lateral sclerosis (ALS) was observed in the second generation, pure HSP in the third generation, and a complicated form with psychomotor delay and epilepsy in the fourth generation. Erlin2 oligomerization was found to be normal. DISCUSSION We report the first AD SPG18 family with a complicated phenotype, and we ruled out a dominant negative effect of V168M on erlin2 oligomerization. Therefore, our data do not support the hypothesis of a relationship between the mode of inheritance and the phenotype, but confirm the multifaceted nature of SPG18 on both genetic and clinical point of view. Clinicians should be aware of the importance of conducting an in-depth clinical evaluation to unmask all the possible manifestations associated to an only apparently pure SPG18 phenotype. We confirm the genotype-phenotype correlation between V168M and ALS emphasizing the value of close follow-up.
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Affiliation(s)
- Assunta Trinchillo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Valeria Valente
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | | | | | - Aniello Iovino
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Michele Picciocchi
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Nunzia Cuomo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Carmela Caccavale
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Cristofaro Nocerino
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy
| | - Laura De Rosa
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Elena Salvatore
- CDCD Neurology, "Federico II" University Hospital, Naples, Italy
| | - Giovanna Maria Pierantoni
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Valeria Menchise
- Institute of Biostructure and Bioimaging, National Research Council (CNR) and Molecular Biotechnology Center, Turin, Italy
| | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Chiara Criscuolo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, Naples, Italy.
- CDCD Neurology, "Federico II" University Hospital, Naples, Italy.
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2
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Awuah WA, Tan JK, Shkodina AD, Ferreira T, Adebusoye FT, Mazzoleni A, Wellington J, David L, Chilcott E, Huang H, Abdul-Rahman T, Shet V, Atallah O, Kalmanovich J, Jiffry R, Madhu DE, Sikora K, Kmyta O, Delva MY. Hereditary spastic paraplegia: Novel insights into the pathogenesis and management. SAGE Open Med 2023; 12:20503121231221941. [PMID: 38162912 PMCID: PMC10757446 DOI: 10.1177/20503121231221941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/28/2023] [Indexed: 01/03/2024] Open
Abstract
Hereditary spastic paraplegia is a genetically heterogeneous neurodegenerative disorder characterised primarily by muscle stiffness in the lower limbs. Neurodegenerative disorders are conditions that result from cellular and metabolic abnormalities, many of which have strong genetic ties. While ageing is a known contributor to these changes, certain neurodegenerative disorders can manifest early in life, progressively affecting a person's quality of life. Hereditary spastic paraplegia is one such condition that can appear in individuals of any age. In hereditary spastic paraplegia, a distinctive feature is the degeneration of long nerve fibres in the corticospinal tract of the lower limbs. This degeneration is linked to various cellular and metabolic processes, including mitochondrial dysfunction, remodelling of the endoplasmic reticulum membrane, autophagy, abnormal myelination processes and alterations in lipid metabolism. Additionally, hereditary spastic paraplegia affects processes like endosome membrane trafficking, oxidative stress and mitochondrial DNA polymorphisms. Disease-causing genetic loci and associated genes influence the progression and severity of hereditary spastic paraplegia, potentially affecting various cellular and metabolic functions. Although hereditary spastic paraplegia does not reduce a person's lifespan, it significantly impairs their quality of life as they age, particularly with more severe symptoms. Regrettably, there are currently no treatments available to halt or reverse the pathological progression of hereditary spastic paraplegia. This review aims to explore the metabolic mechanisms underlying the pathophysiology of hereditary spastic paraplegia, emphasising the interactions of various genes identified in recent network studies. By comprehending these associations, targeted molecular therapies that address these biochemical processes can be developed to enhance treatment strategies for hereditary spastic paraplegia and guide clinical practice effectively.
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Affiliation(s)
| | | | - Anastasiia D Shkodina
- Department of Neurological Diseases, Poltava State Medical University, Poltava, Ukraine
| | - Tomas Ferreira
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | | | - Adele Mazzoleni
- Barts and the London School of Medicine and Dentistry, London, UK
| | - Jack Wellington
- Cardiff University School of Medicine, Cardiff University, Wales, UK
| | - Lian David
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Ellie Chilcott
- Cardiff University School of Medicine, Cardiff University, Wales, UK
| | - Helen Huang
- Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | | | - Vallabh Shet
- Faculty of Medicine, Bangalore Medical College and Research Institute, Karnataka, India
| | - Oday Atallah
- Department of Neurosurgery, Hannover Medical School, Hannover, Germany
| | | | - Riaz Jiffry
- Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | | | | | | | - Mykhailo Yu Delva
- Department of Neurological Diseases, Poltava State Medical University, Poltava, Ukraine
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3
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Lipid Dyshomeostasis and Inherited Cerebellar Ataxia. Mol Neurobiol 2022; 59:3800-3828. [PMID: 35420383 PMCID: PMC9148275 DOI: 10.1007/s12035-022-02826-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/01/2022] [Indexed: 12/04/2022]
Abstract
Cerebellar ataxia is a form of ataxia that originates from dysfunction of the cerebellum, but may involve additional neurological tissues. Its clinical symptoms are mainly characterized by the absence of voluntary muscle coordination and loss of control of movement with varying manifestations due to differences in severity, in the site of cerebellar damage and in the involvement of extracerebellar tissues. Cerebellar ataxia may be sporadic, acquired, and hereditary. Hereditary ataxia accounts for the majority of cases. Hereditary ataxia has been tentatively divided into several subtypes by scientists in the field, and nearly all of them remain incurable. This is mainly because the detailed mechanisms of these cerebellar disorders are incompletely understood. To precisely diagnose and treat these diseases, studies on their molecular mechanisms have been conducted extensively in the past. Accumulating evidence has demonstrated that some common pathogenic mechanisms exist within each subtype of inherited ataxia. However, no reports have indicated whether there is a common mechanism among the different subtypes of inherited cerebellar ataxia. In this review, we summarize the available references and databases on neurological disorders characterized by cerebellar ataxia and show that a subset of genes involved in lipid homeostasis form a new group that may cause ataxic disorders through a common mechanism. This common signaling pathway can provide a valuable reference for future diagnosis and treatment of ataxic disorders.
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Wolf LM, Lambert AM, Haenlin J, Boutros M. EVI/WLS function is regulated by ubiquitination and linked to ER-associated degradation by ERLIN2. J Cell Sci 2021; 134:271857. [PMID: 34406391 PMCID: PMC8435288 DOI: 10.1242/jcs.257790] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 07/12/2021] [Indexed: 12/16/2022] Open
Abstract
WNT signalling is important for development in all metazoans and is associated with various human diseases. The ubiquitin–proteasome system (UPS) and regulatory endoplasmic reticulum-associated degradation (ERAD) have been implicated in the production of WNT proteins. Here, we investigated how the WNT secretory factor EVI (also known as WLS) is ubiquitylated, recognised by ERAD components and subsequently removed from the secretory pathway. We performed a focused immunoblot-based RNAi screen for factors that influence EVI/WLS protein stability. We identified the VCP-binding proteins FAF2 and UBXN4 as novel interaction partners of EVI/WLS and showed that ERLIN2 links EVI/WLS to the ubiquitylation machinery. Interestingly, we also found that EVI/WLS is ubiquitylated and degraded in cells irrespective of their level of WNT production. This K11, K48 and K63-linked ubiquitylation is mediated by the E2 ubiquitin-conjugating enzymes UBE2J2, UBE2K and UBE2N, but is independent of the E3 ubiquitin ligases HRD1 (also known as SYVN1) and GP78 (also known as AMFR). Taken together, our study identifies factors that link the UPS to the WNT secretory pathway and provides mechanistic details of the fate of an endogenous substrate of regulatory ERAD in mammalian cells. This article has an associated First Person interview with the first author of the paper. Summary: The WNT secretory factor EVI/WLS is ubiquitylated and linked to ER-associated degradation by multiple proteins, providing insight into the link between WNT signalling and the ubiquitin–proteasome system.
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Affiliation(s)
- Lucie M Wolf
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant & Department for Cell and Molecular Biology, Medical Faculty Mannheim, D-69120 Heidelberg, Germany
| | - Annika M Lambert
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant & Department for Cell and Molecular Biology, Medical Faculty Mannheim, D-69120 Heidelberg, Germany
| | - Julie Haenlin
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant & Department for Cell and Molecular Biology, Medical Faculty Mannheim, D-69120 Heidelberg, Germany
| | - Michael Boutros
- German Cancer Research Center (DKFZ), Division of Signalling and Functional Genomics and Heidelberg University, BioQuant & Department for Cell and Molecular Biology, Medical Faculty Mannheim, D-69120 Heidelberg, Germany
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5
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Latypova X, Creadore SG, Dahan-Oliel N, Gustafson AG, Wei-Hung Hwang S, Bedard T, Shazand K, van Bosse HJP, Giampietro PF, Dieterich K. A Genomic Approach to Delineating the Occurrence of Scoliosis in Arthrogryposis Multiplex Congenita. Genes (Basel) 2021; 12:genes12071052. [PMID: 34356068 PMCID: PMC8305424 DOI: 10.3390/genes12071052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 12/15/2022] Open
Abstract
Arthrogryposis multiplex congenita (AMC) describes a group of conditions characterized by the presence of non-progressive congenital contractures in multiple body areas. Scoliosis, defined as a coronal plane spine curvature of ≥10 degrees as measured radiographically, has been reported to occur in approximately 20% of children with AMC. To identify genes that are associated with both scoliosis as a clinical outcome and AMC, we first queried the DECIPHER database for copy number variations (CNVs). Upon query, we identified only two patients with both AMC and scoliosis (AMC-SC). The first patient contained CNVs in three genes (FBN2, MGF10, and PITX1), while the second case had a CNV in ZC4H2. Looking into small variants, using a combination of Human Phenotype Ontogeny and literature searching, 908 genes linked with scoliosis and 444 genes linked with AMC were identified. From these lists, 227 genes were associated with AMC-SC. Ingenuity Pathway Analysis (IPA) was performed on the final gene list to gain insight into the functional interactions of genes and various categories. To summarize, this group of genes encompasses a diverse group of cellular functions including transcription regulation, transmembrane receptor, growth factor, and ion channels. These results provide a focal point for further research using genomics and animal models to facilitate the identification of prognostic factors and therapeutic targets for AMC.
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Affiliation(s)
- Xenia Latypova
- Grenoble Institut Neurosciences, Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, 38000 Grenoble, France;
| | | | - Noémi Dahan-Oliel
- Shriners Hospitals for Children, Montreal, QC H4A 0A9, Canada;
- School of Physical & Occupational Therapy, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 2M1, Canada
| | | | - Steven Wei-Hung Hwang
- Shriners Hospitals for Children, Philadelphia, PA 19140, USA; (S.W.-H.H.); (H.J.P.v.B.)
| | - Tanya Bedard
- Alberta Congenital Anomalies Surveillance System, Alberta Health Services, Edmonton, AB T5J 3E4, Canada;
| | - Kamran Shazand
- Shriners Hospitals for Children Headquarters, Tampa, FL 33607, USA; (S.G.C.); (A.G.G.); (K.S.)
| | | | - Philip F. Giampietro
- Department of Pediatrics, University of Illinois-Chicago, Chicago, IL 60607, USA
- Correspondence: (P.F.G.); (K.D.)
| | - Klaus Dieterich
- Institut of Advanced Biosciences, Université Grenoble Alpes, Inserm, U1209, CHU Grenoble Alpes, 38000 Grenoble, France
- Correspondence: (P.F.G.); (K.D.)
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Steinle H, Ellwanger K, Mirza N, Briese S, Kienes I, Pfannstiel J, Kufer TA. 14-3-3 and erlin proteins differentially interact with RIPK2 complexes. J Cell Sci 2021; 134:jcs258137. [PMID: 34152391 DOI: 10.1242/jcs.258137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/19/2021] [Indexed: 01/11/2023] Open
Abstract
The receptor interacting serine/threonine kinase 2 (RIPK2) is essential for signal transduction induced by the pattern recognition receptors NOD1 and NOD2 (referred to collectively as NOD1/2). Upon NOD1/2 activation, RIPK2 forms complexes in the cytoplasm of human cells. Here, we identified the molecular composition of these complexes. Infection with Shigella flexneri to activate NOD1-RIPK2 revealed that RIPK2 formed dynamic interactions with several cellular proteins, including A20 (also known as TNFAIP3), erlin-1, erlin-2 and 14-3-3. Whereas interaction of RIPK2 with 14-3-3 proteins was strongly reduced upon infection with Shigella, erlin-1 and erlin-2 (erlin-1/2) specifically bound to RIPK2 complexes. The interaction of these proteins with RIPK2 was validated using protein binding assays and immunofluorescence staining. Beside bacterial activation of NOD1/2, depletion of the E3 ubiquitin ligase XIAP and treatment with RIPK2 inhibitors also led to the formation of RIPK2 cytosolic complexes. Although erlin-1/2 were recruited to RIPK2 complexes following XIAP inhibition, these proteins did not associate with RIPK2 structures induced by RIPK2 inhibitors. While the specific recruitment of erlin-1/2 to RIPK2 suggests a role in innate immune signaling, the biological response regulated by the erlin-1/2-RIPK2 association remains to be determined.
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Affiliation(s)
- Heidrun Steinle
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Kornelia Ellwanger
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Nora Mirza
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Selina Briese
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Ioannis Kienes
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Jens Pfannstiel
- Core Facility Hohenheim Mass Spectrometry Module, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
| | - Thomas A Kufer
- Department of Immunology, Institute of Nutritional Medicine, University of Hohenheim, 70619 Stuttgart, Germany
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7
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van de Weijer ML, Krshnan L, Liberatori S, Guerrero EN, Robson-Tull J, Hahn L, Lebbink RJ, Wiertz EJHJ, Fischer R, Ebner D, Carvalho P. Quality Control of ER Membrane Proteins by the RNF185/Membralin Ubiquitin Ligase Complex. Mol Cell 2020; 79:768-781.e7. [PMID: 32738194 PMCID: PMC7482433 DOI: 10.1016/j.molcel.2020.07.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/06/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022]
Abstract
Misfolded proteins in the endoplasmic reticulum (ER) are degraded by ER-associated degradation (ERAD). Although ERAD components involved in degradation of luminal substrates are well characterized, much less is known about quality control of membrane proteins. Here, we analyzed the degradation pathways of two short-lived ER membrane model proteins in mammalian cells. Using a CRISPR-Cas9 genome-wide library screen, we identified an ERAD branch required for quality control of a subset of membrane proteins. Using biochemical and mass spectrometry approaches, we showed that this ERAD branch is defined by an ER membrane complex consisting of the ubiquitin ligase RNF185, the ubiquitin-like domain containing proteins TMUB1/2 and TMEM259/Membralin, a poorly characterized protein. This complex cooperates with cytosolic ubiquitin ligase UBE3C and p97 ATPase in degrading their membrane substrates. Our data reveal that ERAD branches have remarkable specificity for their membrane substrates, suggesting that multiple, perhaps combinatorial, determinants are involved in substrate selection. The RNF185 ubiquitin ligase, Membralin, and TMUB1/2 assemble into an ERAD complex RNF185/Membralin complex targets membrane proteins, including CYP51A1 and TMUB2 RNF185/Membralin and TEB4 ERAD complexes recognize distinct substrate features TEB4 ERAD complex recognizes substrates through their transmembrane domain
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Affiliation(s)
- Michael L van de Weijer
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Logesvaran Krshnan
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Sabrina Liberatori
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Elena Navarro Guerrero
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Jacob Robson-Tull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Lilli Hahn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Robert Jan Lebbink
- Medical Microbiology, University Medical Center Utrecht, 3584 Utrecht, the Netherlands
| | - Emmanuel J H J Wiertz
- Medical Microbiology, University Medical Center Utrecht, 3584 Utrecht, the Netherlands
| | - Roman Fischer
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Daniel Ebner
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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Castillo J, Bogle OA, Jodar M, Torabi F, Delgado-Dueñas D, Estanyol JM, Ballescà JL, Miller D, Oliva R. Proteomic Changes in Human Sperm During Sequential in vitro Capacitation and Acrosome Reaction. Front Cell Dev Biol 2019; 7:295. [PMID: 31824947 PMCID: PMC6879431 DOI: 10.3389/fcell.2019.00295] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/06/2019] [Indexed: 12/29/2022] Open
Abstract
The male gamete is not completely mature after ejaculation and requires further events in the female genital tract to acquire fertilizing ability, including the processes of capacitation and acrosome reaction. In order to shed light on protein changes experienced by the sperm cell in preparation for fertilization, a comprehensive quantitative proteomic profiling based on isotopic peptide labeling and liquid chromatography followed by tandem mass spectrometry was performed on spermatozoa from three donors of proven fertility under three sequential conditions: purification with density gradient centrifugation, incubation with capacitation medium, and induction of acrosome reaction by exposure to the calcium ionophore A23187. After applying strict selection criteria for peptide quantification and for statistical analyses, 36 proteins with significant changes in their relative abundance within sperm protein extracts were detected. Moreover, the presence of peptide residues potentially harboring sites for post-translational modification was revealed, suggesting that protein modification may be an important mechanism in sperm maturation. In this regard, increased levels of proteins mainly involved in motility and signaling, both regulated by protein modifiers, were detected in sperm lysates following incubation with capacitation medium. In contrast, less abundant proteins in acrosome-reacted cell lysates did not contain potentially modifiable residues, suggesting the possibility that all those proteins might be relocated or released during the process. Protein-protein interaction analysis revealed a subset of proteins potentially involved in sperm maturation, including the proteins Erlin-2 (ERLIN2), Gamma-glutamyl hydrolase (GGH) and Transmembrane emp24 domain-containing protein 10 (TMED10). These results contribute to the current knowledge of the molecular basis of human fertilization. It should now be possible to further validate the potential role of the detected altered proteins as modulators of male infertility.
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Affiliation(s)
- Judit Castillo
- Molecular Biology of Reproduction and Development Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Orleigh Adeleccia Bogle
- Molecular Biology of Reproduction and Development Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Meritxell Jodar
- Molecular Biology of Reproduction and Development Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Forough Torabi
- LIGHT Laboratories, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - David Delgado-Dueñas
- Molecular Biology of Reproduction and Development Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Josep Maria Estanyol
- Proteomics Unit, Scientific and Technical Services, Universitat de Barcelona, Barcelona, Spain
| | - Josep Lluís Ballescà
- Clinic Institute of Gynaecology, Obstetrics and Neonatology, Hospital Clínic, Barcelona, Spain
| | - David Miller
- LIGHT Laboratories, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Rafael Oliva
- Molecular Biology of Reproduction and Development Research Group, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Fundació Clínic per a la Recerca Biomèdica, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, Barcelona, Spain
- Biochemistry and Molecular Genetics Service, Hospital Clínic, Barcelona, Spain
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9
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Zhu B, Jiang L, Huang T, Zhao Y, Liu T, Zhong Y, Li X, Campos A, Pomeroy K, Masliah E, Zhang D, Xu H. ER-associated degradation regulates Alzheimer's amyloid pathology and memory function by modulating γ-secretase activity. Nat Commun 2017; 8:1472. [PMID: 29133892 PMCID: PMC5684335 DOI: 10.1038/s41467-017-01799-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022] Open
Abstract
Endoplasmic-reticulum-associated degradation (ERAD) is an important protein quality control system which maintains protein homeostasis. Constituents of the ERAD complex and its role in neurodegeneration are not yet fully understood. Here, using proteomic and FRET analyses, we demonstrate that the ER protein membralin is an ERAD component, which mediates degradation of ER luminal and membrane substrates. Interestingly, we identify nicastrin, a key component of the γ-secretase complex, as a membralin binding protein and membralin-associated ERAD substrate. We demonstrate a reduction of membralin mRNA and protein levels in Alzheimer's disease (AD) brain, the latter of which inversely correlates with nicastrin abundance. Furthermore, membralin deficiency enhances γ-secretase activity and neuronal degeneration. In a mouse AD model, downregulating membralin results in β-amyloid pathology, neuronal death, and exacerbates synaptic/memory deficits. Our results identify membralin as an ERAD component and demonstrate a critical role for ERAD in AD pathogenesis.
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Affiliation(s)
- Bing Zhu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - LuLin Jiang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Timothy Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Yingjun Zhao
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Tongfei Liu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Xiaoguang Li
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Alexandre Campos
- Proteomics Facility, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Kenneth Pomeroy
- Proteomics Facility, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Dongxian Zhang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, 361005, Fujian, China.
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Printsev I, Curiel D, Carraway KL. Membrane Protein Quantity Control at the Endoplasmic Reticulum. J Membr Biol 2017; 250:379-392. [PMID: 27743014 PMCID: PMC5392169 DOI: 10.1007/s00232-016-9931-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 09/28/2016] [Indexed: 02/07/2023]
Abstract
The canonical function of the endoplasmic reticulum-associated degradation (ERAD) system is to enforce quality control among membrane-associated proteins by targeting misfolded secreted, intra-organellar, and intramembrane proteins for degradation. However, increasing evidence suggests that ERAD additionally functions in maintaining appropriate levels of a subset of membrane-associated proteins. In this 'quantity control' capacity, ERAD responds to environmental cues to regulate the proteasomal degradation of specific ERAD substrates according to cellular need. In this review, we discuss in detail seven proteins that are targeted by the ERAD quantity control system. Not surprisingly, ERAD-mediated protein degradation is a key regulatory feature of a variety of ER-resident proteins, including HMG-CoA reductase, cytochrome P450 3A4, IP3 receptor, and type II iodothyronine deiodinase. In addition, the ERAD quantity control system plays roles in maintaining the proper stoichiometry of multi-protein complexes by mediating the degradation of components that are produced in excess of the limiting subunit. Perhaps somewhat unexpectedly, recent evidence suggests that the ERAD quantity control system also contributes to the regulation of plasma membrane-localized signaling receptors, including the ErbB3 receptor tyrosine kinase and the GABA neurotransmitter receptors. For these substrates, a proportion of the newly synthesized yet properly folded receptors are diverted for degradation at the ER, and are unable to traffic to the plasma membrane. Given that receptor abundance or concentration within the plasma membrane plays key roles in determining signaling efficiency, these observations may point to a novel mechanism for modulating receptor-mediated cellular signaling.
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Affiliation(s)
- Ignat Printsev
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, UC Davis School of Medicine, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, CA, 95817, USA
| | - Daniel Curiel
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, UC Davis School of Medicine, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, CA, 95817, USA
| | - Kermit L Carraway
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, UC Davis School of Medicine, Research Building III, Room 1100B, 4645 2nd Avenue, Sacramento, CA, 95817, USA.
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11
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Regulated Erlin-dependent release of the B12 transmembrane J-protein promotes ER membrane penetration of a non-enveloped virus. PLoS Pathog 2017; 13:e1006439. [PMID: 28614383 PMCID: PMC5484543 DOI: 10.1371/journal.ppat.1006439] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/26/2017] [Accepted: 05/30/2017] [Indexed: 12/16/2022] Open
Abstract
The molecular mechanism by which non-enveloped viruses penetrate biological membranes remains enigmatic. The non-enveloped polyomavirus SV40 penetrates the endoplasmic reticulum (ER) membrane to reach the cytosol and cause infection. We previously demonstrated that SV40 creates its own membrane penetration structure by mobilizing select transmembrane proteins to distinct puncta in the ER membrane called foci that likely function as the cytosol entry sites. How these ER membrane proteins reorganize into the foci is unknown. B12 is a transmembrane J-protein that mobilizes into the foci to promote cytosol entry of SV40. Here we identify two closely related ER membrane proteins Erlin1 and Erlin2 (Erlin1/2) as B12-interaction partners. Strikingly, SV40 recruits B12 to the foci by inducing release of this J-protein from Erlin1/2. Our data thus reveal how a non-enveloped virus promotes its own membrane translocation by triggering the release and recruitment of a critical transport factor to the membrane penetration site. Polyomavirus (PyV) is a non-enveloped DNA tumor virus that causes debilitating human diseases especially in immunocompromised individuals. At the cellular level, PyVs such as the simian PyV SV40 must enter a host cell and penetrate the ER membrane to reach the cytosol in order to cause infection. Prior to ER membrane transport, SV40 reorganizes select ER membrane proteins including the J-protein B12 to potential membrane penetration sites on the ER membrane called foci where B12 facilitates virus extraction into the cytosol. How B12 reorganizes into the foci is unclear. Here we find that two closely related ER membrane proteins Erlin1 and Erlin2 (Erlin1/2) bind to B12. During infection, SV40 induces release of this J-protein from Erlin1/2 to enable B12 to reorganize into the foci. Our data reveal how a non-enveloped virus mobilizes a specific ER membrane component to a membrane penetration structure to promote its own membrane transport.
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Bagchi P, Inoue T, Tsai B. EMC1-dependent stabilization drives membrane penetration of a partially destabilized non-enveloped virus. eLife 2016; 5. [PMID: 28012275 PMCID: PMC5224922 DOI: 10.7554/elife.21470] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/23/2016] [Indexed: 11/13/2022] Open
Abstract
Destabilization of a non-enveloped virus generates a membrane transport-competent viral particle. Here we probe polyomavirus SV40 endoplasmic reticulum (ER)-to-cytosol membrane transport, a decisive infection step where destabilization initiates this non-enveloped virus for membrane penetration. We find that a member of the ER membrane protein complex (EMC) called EMC1 promotes SV40 ER membrane transport and infection. Surprisingly, EMC1 does so by using its predicted transmembrane residue D961 to bind to and stabilize the membrane-embedded partially destabilized SV40, thereby preventing premature viral disassembly. EMC1-dependent stabilization enables SV40 to engage a cytosolic extraction complex that ejects the virus into the cytosol. Thus EMC1 acts as a molecular chaperone, bracing the destabilized SV40 in a transport-competent state. Our findings reveal the novel principle that coordinated destabilization-stabilization drives membrane transport of a non-enveloped virus. DOI:http://dx.doi.org/10.7554/eLife.21470.001
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Affiliation(s)
- Parikshit Bagchi
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Takamasa Inoue
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
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13
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Wright FA, Wojcikiewicz RJH. Chapter 4 - Inositol 1,4,5-Trisphosphate Receptor Ubiquitination. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:141-59. [PMID: 27378757 DOI: 10.1016/bs.pmbts.2016.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are large (∼300kDa) proteins that associate into tetrameric ion channels in the endoplasmic reticulum (ER) membrane. Activation and opening of the channel upon binding of IP3 and Ca(2+) allows the flow of Ca(2+) ions from stores within the ER lumen to the cytosol, thereby promoting a number of Ca(2+)-dependent cellular events, such as secretion, neurotransmitter release, and cell division. Intriguingly, it appears that the same conformational change that IP3Rs undergo during activation makes them a target for degradation by the ubiquitin-proteasome pathway and that this mode of processing allows the cell to tune its internal Ca(2+) response to extracellular signals. Here, we review recent studies showing that activated IP3Rs interact with an array of proteins that mediate their degradation, that IP3Rs are modified by a complex array of ubiquitin conjugates, that this ubiquitination and degradation functions to regulate IP3-mediated Ca(2+) responses in the cell, and that mutations to different proteins involved in IP3R degradation result in a set of similar diseases.
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Affiliation(s)
- F A Wright
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, United States
| | - R J H Wojcikiewicz
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, United States.
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14
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Zhang A, Hildreth RL, Colberg-Poley AM. Human cytomegalovirus inhibits apoptosis by proteasome-mediated degradation of Bax at endoplasmic reticulum-mitochondrion contacts. J Virol 2013; 87:5657-68. [PMID: 23487455 PMCID: PMC3648137 DOI: 10.1128/jvi.00145-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/22/2013] [Indexed: 12/30/2022] Open
Abstract
Human cytomegalovirus (HCMV) encodes the UL37 exon 1 protein (pUL37x1), which is the potent viral mitochondrion-localized inhibitor of apoptosis (vMIA), to increase survival of infected cells. HCMV vMIA traffics from the endoplasmic reticulum (ER) to ER subdomains, which are physically linked to mitochondria known as mitochondrion-associated membranes (MAM), and to mitochondria. The antiapoptotic function of vMIA is thought to primarily result from its ability to inhibit Bax-mediated permeabilization of the outer mitochondrial membrane (OMM). Here, we establish that vMIA retargets Bax to the MAM as well as to the OMM from immediate early through late times of infection. However, MAM localization of Bax results in its increased ubiquitination and proteasome-mediated degradation. Surprisingly, HCMV infection does not increase OMM-associated degradation (OMMAD) of Bax, even though the ER and mitochondria are physically connected at the MAM. It was recently found that lipid rafts at the plasma membrane can connect extrinsic and intrinsic apoptotic pathways and can serve as sites of apoptosome assembly. In transfected permissive human fibroblasts, vMIA mediates, through its cholesterol affinity, association of Bax and apoptosome components with MAM lipid rafts. While Bax association with MAM lipid rafts was detected in HCMV-infected cells, association of apoptosome components was not. These results establish that Bax recruitment to the MAM and its MAM-associated degradation (MAMAD) are a newly described antiapoptotic mechanism used by HCMV infection to increase cell survival for its growth.
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Affiliation(s)
- Aiping Zhang
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA
| | - Richard L. Hildreth
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA
- Molecular Medicine Program,
| | - Anamaris M. Colberg-Poley
- Research Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA
- Molecular Medicine Program,
- Departments of Integrative Systems Biology,
- Biochemistry and Molecular Biology,
- Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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15
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Tsai YC, Leichner GS, Pearce MMP, Wilson GL, Wojcikiewicz RJH, Roitelman J, Weissman AM. Differential regulation of HMG-CoA reductase and Insig-1 by enzymes of the ubiquitin-proteasome system. Mol Biol Cell 2012; 23:4484-94. [PMID: 23087214 PMCID: PMC3510011 DOI: 10.1091/mbc.e12-08-0631] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HMGCR is subject to Insig-dependent, sterol-accelerated ERAD. gp78 was reported to target HMGCR and Insig-1 for ubiquitination and degradation. Here gp78-mediated Insig-1 degradation is confirmed, but no role for gp78 is found in regulated ERAD of HMGCR. The identity of the HMGCR E3(s) and mechanistic details of HMGCR degradation await further study. The endoplasmic reticulum (ER)–resident enzyme 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyzes the rate-limiting step in sterol production and is the therapeutic target of statins. Understanding HMG-CoA reductase regulation has tremendous implications for atherosclerosis. HMG-CoA reductase levels are regulated in response to sterols both transcriptionally, through a complex regulatory loop involving the ER Insig proteins, and posttranslationally, by Insig-dependent protein degradation by the ubiquitin-proteasome system. The ubiquitin ligase (E3) gp78 has been implicated in the sterol-regulated degradation of HMG-CoA reductase and Insig-1 through ER-associated degradation (ERAD). More recently, a second ERAD E3, TRC8, has also been reported to play a role in the sterol-accelerated degradation of HMG-CoA reductase. We interrogated this network in gp78−/− mouse embryonic fibroblasts and also assessed two fibroblast cell lines using RNA interference. Although we consistently observe involvement of gp78 in Insig-1 degradation, we find no substantive evidence to support roles for either gp78 or TRC8 in the robust sterol-accelerated degradation of HMG-CoA reductase. We discuss factors that might lead to such discrepant findings. Our results suggest a need for additional studies before definitive mechanistic conclusions are drawn that might set the stage for development of drugs to manipulate gp78 function in metabolic disorders.
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Affiliation(s)
- Yien Che Tsai
- Laboratory of Protein Dynamics and Signaling, National Cancer Institute, Frederick, MD 20712, USA
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16
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Dingli F, Parys JB, Loew D, Saule S, Mery L. Vimentin and the K-Ras-induced actin-binding protein control inositol-(1,4,5)-trisphosphate receptor redistribution during MDCK cell differentiation. J Cell Sci 2012; 125:5428-40. [PMID: 22946050 DOI: 10.1242/jcs.108738] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inositol-(1,4,5)-triphosphate receptors (InsP(3)Rs) are ligand-gated Ca(2+) channels that control Ca(2+) release from intracellular stores and play a central role in a wide range of cellular responses. In most epithelial cells, InsP(3)Rs are not uniformly distributed within the endoplasmic reticulum (ER) membrane, with the consequence that agonist stimulation results in compartmentalized Ca(2+) signals. Despite these observations, little is known about the mechanisms that regulate the intracellular localization of InsP(3)Rs. Here, we report that exogenously expressed InsP(3)R1-GFP and endogenous InsP(3)R3 interact with the K-Ras-induced actin-binding protein (KRAP) in both differentiated and undifferentiated Madin-Darby canine kidney (MDCK) cells. KRAP mediates InsP(3)R clustering in confluent MDCK cells and functions as an adapter, linking InsP(3)Rs to vimentin intermediate filaments. Upon epithelial differentiation, KRAP and vimentin are both required for InsP(3)R accumulation at the periphery of MDCK cells. Finally, KRAP associates with vimentin in chicken B lymphocytes and with keratins in a breast cancer cell line devoid of vimentin. Collectively, our data suggest that intermediate filaments in conjunction with KRAP may govern the localization of InsP(3)Rs in a large number of cell types (including epithelial cells) and in various physiological or pathological contexts.
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Affiliation(s)
- Florent Dingli
- Laboratory of Proteomic Mass Spectrometry, Institut Curie, 75248 Paris, Cedex 05, France
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17
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Hoegg MB, Robbins SM, McGhee JD. Characterization of the C. elegans erlin homologue. BMC Cell Biol 2012; 13:2. [PMID: 22269071 PMCID: PMC3292932 DOI: 10.1186/1471-2121-13-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 01/23/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Erlins are highly conserved proteins associated with lipid rafts within the endoplasmic reticulum (ER). Biochemical studies in mammalian cell lines have shown that erlins are required for ER associated protein degradation (ERAD) of activated inositol-1,4,5-trisphosphate receptors (IP3Rs), implying that erlin proteins might negatively regulate IP3R signalling. In humans, loss of erlin function appears to cause progressive intellectual disability, motor dysfunction and joint contractures. However, it is unknown if defects in IP3R ERAD are the underlying cause of this disease phenotype, whether ERAD of activated IP3Rs is the only function of erlin proteins, and what role ERAD plays in regulating IP3R-dependent processes in the context of an intact animal or embryo. In this study, we characterize the erlin homologue of the nematode Caenorhabditis elegans and examine erlin function in vivo. We specifically set out to test whether C. elegans erlin modulates IP3R-dependent processes, such as egg laying, embryonic development and defecation rates. We also explore the possibility that erlin might play a more general role in the ERAD pathway of C. elegans. RESULTS We first show that the C. elegans erlin homologue, ERL-1, is highly similar to mammalian erlins with respect to amino acid sequence, domain structure, biochemical properties and subcellular location. ERL-1 is present throughout the C. elegans embryo; in adult worms, ERL-1 appears restricted to the germline. The expression pattern of ERL-1 thus only partially overlaps with that of ITR-1, eliminating the possibility of ERL-1 being a ubiquitous and necessary regulator of ITR-1. We show that loss of ERL-1 does not affect overall phenotype, or alter brood size, embryonic development or defecation cycle length in either wild type or sensitized itr-1 mutant animals. Moreover we show that ERL-1 deficient worms respond normally to ER stress conditions, suggesting that ERL-1 is not an essential component of the general ERAD pathway. CONCLUSIONS Although loss of erlin function apparently causes a strong phenotype in humans, no such effect is seen in C. elegans. C. elegans erlin does not appear to be a ubiquitous major modulator of IP3 receptor activity nor does erlin appear to play a major role in ERAD.
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Affiliation(s)
- Maja B Hoegg
- Department of Biochemistry & Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
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18
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Pednekar D, Wang Y, Fedotova TV, Wojcikiewicz RJH. Clustered hydrophobic amino acids in amphipathic helices mediate erlin1/2 complex assembly. Biochem Biophys Res Commun 2011; 415:135-40. [PMID: 22020079 DOI: 10.1016/j.bbrc.2011.10.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 10/07/2011] [Indexed: 12/11/2022]
Abstract
Erlin1 and erlin2 are highly homologous, ∼40kDa, endoplasmic reticulum membrane proteins that assemble into a ring-shaped complex with a mass of ∼2 MDa. How this complex is formed is not understood, but appears to involve multiple interactions, including a coiled-coil region that mediates lower-order erlin assembly, and a short hydrophobic region, termed the "assembly domain", that mediates higher-order assembly into ∼2 MDa complexes. Here we have used molecular modeling, mutagenesis and cross-linking to examine the role of the assembly domain in higher-order assembly. We find (i) that the assembly domains of erlin1 and erlin2 are amphipathic helices, (ii) that erlin1 alone and erlin2 alone can assemble into ∼2 MDa complexes, (iii) that higher-order assembly is strongly inhibited by point mutations to the assembly domain, (iv) that three interacting hydrophobic residues in the assembly domain and aromaticity are essential for higher-order assembly, and (iv) that while erlins1 and 2 are equally capable of forming lower-order homo- and hetero-oligomers, hetero-oligomers are the most prevalent form when erlin1 and erlin2 are co-expressed. Overall, we conclude that the ∼2 MDa erlin1/2 complex is composed of an assemblage of lower-order hetero-oligomers, probably heterotrimers, linked together by assembly domain hydrophobic residues.
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Affiliation(s)
- Deepa Pednekar
- Department of Pharmacology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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19
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Liu Y, Ye Y. Proteostasis regulation at the endoplasmic reticulum: a new perturbation site for targeted cancer therapy. Cell Res 2011; 21:867-83. [PMID: 21537343 PMCID: PMC3203708 DOI: 10.1038/cr.2011.75] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
To deal with the constant challenge of protein misfolding in the endoplasmic reticulum (ER), eukaryotic cells have evolved an ER protein quality control (ERQC) mechanism that is integrated with an adaptive stress response. The ERQC pathway is comprised of factors residing in the ER lumen that function in the identification and retention of aberrantly folded proteins, factors in the ER membrane for retrotranslocation of misfolded polypeptides, and enzymes in the cytosol that degrade retrotranslocated proteins. The integrated stress response (termed ER stress or unfolded protein response, UPR) contains several signaling branches elicited from the ER membrane, which fine-tune the rate of protein synthesis and entry into the ER to match the ER folding capacity. The fitness of the cell, particularly those bearing a high secretory burden, is critically dependent on functional integrity of the ER, which in turn relies on these stress-attenuating mechanisms to maintain protein homeostasis, or proteostasis. Aberrant proteostasis can trigger cellular apoptosis, making these adaptive stress response systems attractive targets for perturbation in treatment of cell malignancies. Here, we review our current understanding of how the cell preserves ER proteostasis and discuss how we may harness the mechanistic information on this process to develop new cancer therapeutics.
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Affiliation(s)
- Yanfen Liu
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0540, USA
| | - Yihong Ye
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0540, USA
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20
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Lu JP, Wang Y, Sliter DA, Pearce MMP, Wojcikiewicz RJH. RNF170 protein, an endoplasmic reticulum membrane ubiquitin ligase, mediates inositol 1,4,5-trisphosphate receptor ubiquitination and degradation. J Biol Chem 2011; 286:24426-33. [PMID: 21610068 DOI: 10.1074/jbc.m111.251983] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) receptors are endoplasmic reticulum membrane calcium channels that, upon activation, are degraded via the ubiquitin-proteasome pathway. While searching for novel mediators of IP(3) receptor processing, we discovered that RNF170, an uncharacterized RING domain-containing protein, associates rapidly with activated IP(3) receptors. RNF170 is predicted to have three membrane-spanning helices, is localized to the ER membrane, and possesses ubiquitin ligase activity. Depletion of endogenous RNF170 by RNA interference inhibited stimulus-induced IP(3) receptor ubiquitination, and degradation and overexpression of a catalytically inactive RNF170 mutant suppressed stimulus-induced IP(3) receptor processing. A substantial proportion of RNF170 is constitutively associated with the erlin1/2 (SPFH1/2) complex, which has been shown previously to bind to IP(3) receptors immediately after their activation. Depletion of RNF170 did not affect the binding of the erlin1/2 complex to stimulated IP(3) receptors, whereas erlin1/2 complex depletion inhibited RNF170 binding. These results suggest a model in which the erlin1/2 complex recruits RNF170 to activated IP(3) receptors where it mediates IP(3) receptor ubiquitination. Thus, RNF170 plays an essential role in IP(3) receptor processing via the ubiquitin-proteasome pathway.
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Affiliation(s)
- Justine P Lu
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA
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21
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Jo Y, Sguigna PV, DeBose-Boyd RA. Membrane-associated ubiquitin ligase complex containing gp78 mediates sterol-accelerated degradation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. J Biol Chem 2011; 286:15022-31. [PMID: 21343306 PMCID: PMC3083207 DOI: 10.1074/jbc.m110.211326] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum (ER)-associated degradation (ERAD) pathway in the yeast Saccharomyces cerevisiae is mediated by two membrane-bound ubiquitin ligases, Doa10 and Hrd1. These enzymes are found in distinct multiprotein complexes that allow them to recognize and target a variety of substrates for proteasomal degradation. Although multiprotein complexes containing mammalian ERAD ubiquitin ligases likely exist, they have yet to be identified and characterized in detail. Here, we identify two ER membrane proteins, SPFH2 and TMUB1, as associated proteins of mammalian gp78, a membrane-bound ubiquitin ligase that bears significant sequence homology with mammalian Hrd1 and mediates sterol-accelerated ERAD of the cholesterol biosynthetic enzyme HMG-CoA reductase. Co-immunoprecipitation studies indicate that TMUB1 bridges SPFH2 to gp78 in ER membranes. The functional significance of these interactions is revealed by the observation that RNA interference (RNAi)-mediated knockdown of SPFH2 and TMUB1 blunts both the sterol-induced ubiquitination and degradation of endogenous reductase in HEK-293 cells. These studies mark the initial steps in the characterization of the mammalian gp78 ubiquitin ligase complex, the further elucidation of which may yield important insights into mechanisms underlying gp78-mediated ERAD.
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Affiliation(s)
- Youngah Jo
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046, USA
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22
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Yıldırım Y, Orhan EK, Iseri SAU, Serdaroglu-Oflazer P, Kara B, Solakoğlu S, Tolun A. A frameshift mutation of ERLIN2 in recessive intellectual disability, motor dysfunction and multiple joint contractures. Hum Mol Genet 2011; 20:1886-92. [PMID: 21330303 DOI: 10.1093/hmg/ddr070] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We present a family afflicted with a novel autosomal recessive disease characterized by progressive intellectual disability, motor dysfunction and multiple joint contractures. No pathology was found by cranial imaging, electromyography and muscle biopsy, but electron microscopy in leukocytes revealed large vacuoles containing flocculent material. We mapped the disease gene by SNP genome scan and linkage analysis to an ∼0.80 cM and 1 Mb region at 8p11.23 with a multipoint logarithm of odds (LOD) score of 12. By candidate gene approach, we identified a homozygous two-nucleotide insertion in ERLIN2, predicted to lead to the truncation of the protein by about 20%. The gene encodes endoplasmic reticulum (ER) lipid raft-associated protein 2 that mediates the ER-associated degradation of activated inositol 1,4,5-trisphosphate receptors and other substrates.
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Affiliation(s)
- Yeşerin Yıldırım
- Department of Molecular Biology and Genetics, Boğaziçi University, Istanbul 34342, Turkey
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