scholarly journals Perturbations in Traffic: Aberrant Nucleocytoplasmic Transport at the Heart of Neurodegeneration

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 232 ◽  
Author(s):  
Birthe Fahrenkrog ◽  
Amnon Harel
Keyword(s):  
Neurodegenerative Diseases ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Accumulation ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Loss Of Function ◽  
Fused In Sarcoma

Neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Huntington’s disease (HD), are characterized by intracellular aggregation of proteins. In the case of ALS and FTD, these protein aggregates are found in the cytoplasm of affected neurons and contain certain RNA-binding proteins (RBPs), namely the TAR DNA-binding protein of 43 kDa (TDP-43) and the fused in sarcoma (FUS) gene product. TDP-43 and FUS are nuclear proteins and their displacement to the cytoplasm is thought to be adverse in at least two ways: loss-of-function in the nucleus and gain-of-toxicity in the cytoplasm. In the case of HD, expansion of a polyglutamine (polyQ) stretch within the N-terminal domain of the Huntingtin (HTT) protein leads to nuclear accumulation of polyQ HTT (or mHTT) and a toxic gain-of-function phenotype resulting in neurodegeneration. Numerous studies in recent years have provided evidence that defects in nucleocytoplasmic transport critically contribute to the pathology of these neurodegenerative diseases. A new mechanistic view is emerging, implicating three types of perturbations in normal cellular pathways that rely on nucleocytoplasmic transport: displacement of nuclear transport receptors and nucleoporins from nuclear pore complexes (NPCs), mislocalization and aggregation of RNA-binding proteins, and weakening of the chaperone activity of nuclear import receptors.

RNA-Binding Proteins and Translation in Neurodegenerative Disease

2020 ◽  
Author(s):  
Kent E. Duncan
Keyword(s):  
Neurodegenerative Diseases ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Fragile X ◽  
Potential Contribution ◽  
Fused In Sarcoma ◽  
Specific Mrnas ◽  
Ataxia Syndrome ◽  
Research Frontiers

Both RNA-binding proteins (RBPs) and translation are increasingly implicated in several neurodegenerative diseases, but their specific roles in promoting disease are not yet fully defined. This chapter critically evaluates the evidence that altered translation of specific mRNAs mediated by RNA-binding proteins plays an important role in driving specific neurodegenerative diseases. First, diseases are discussed where a causal role for RNA-binding proteins in disease appears solid, but whether this involves altered translation is less clear. The main foci here are TAR DNA-binding protein (TDP-43) and fused in sarcoma (FUS) in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Subsequently, diseases are presented where altered translation is believed to contribute, but involvement of RNA-binding proteins is less clear. These include Huntington’s and other repeat expansion disorders such as fragile X tremor/ataxia syndrome (FXTAS), where repeat-induced non-AUG-initiated (RAN) translation is a focus. The potential contribution of both canonical and non-canonical RBPs to altered translation in Parkinson’s disease is discussed. The chapter closes by proposing key research frontiers for the field to explore and outlining methodological advances that could help to address them.

scholarly journals Multiple roles of heterogeneous nuclear ribonucleoprotein K during skeletal muscle cell differentiation

2021 ◽  
Author(s):  
Keisuke Hitachi ◽  
Yuri Kiyofuji ◽  
Masashi Nakatani ◽  
Kunihiro Tsuchida
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Myogenic Differentiation ◽  
Cell Physiology ◽  
Transcriptional Level ◽  
Loss Of Function ◽  
Independent Manner ◽  
Multiple Functions

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of hnRNPK for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level via binding to Myoparr. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays multiple lncRNA-dependent and -independent roles in the inhibition of myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.

scholarly journals RNA-binding proteins with prion-like domains in health and disease

2017 ◽  
Vol 474 (8) ◽  
pp. 1417-1438 ◽  
Author(s):  
Alice Ford Harrison ◽  
James Shorter
Keyword(s):  
Phase Transitions ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Low Complexity ◽  
Fused In Sarcoma ◽  
Heterogeneous Nuclear Ribonucleoproteins ◽  
Health And Disease ◽  
Lateral Sclerosis

Approximately 70 human RNA-binding proteins (RBPs) contain a prion-like domain (PrLD). PrLDs are low-complexity domains that possess a similar amino acid composition to prion domains in yeast, which enable several proteins, including Sup35 and Rnq1, to form infectious conformers, termed prions. In humans, PrLDs contribute to RBP function and enable RBPs to undergo liquid–liquid phase transitions that underlie the biogenesis of various membraneless organelles. However, this activity appears to render RBPs prone to misfolding and aggregation connected to neurodegenerative disease. Indeed, numerous RBPs with PrLDs, including TDP-43 (transactivation response element DNA-binding protein 43), FUS (fused in sarcoma), TAF15 (TATA-binding protein-associated factor 15), EWSR1 (Ewing sarcoma breakpoint region 1), and heterogeneous nuclear ribonucleoproteins A1 and A2 (hnRNPA1 and hnRNPA2), have now been connected via pathology and genetics to the etiology of several neurodegenerative diseases, including amyotrophic lateral sclerosis, frontotemporal dementia, and multisystem proteinopathy. Here, we review the physiological and pathological roles of the most prominent RBPs with PrLDs. We also highlight the potential of protein disaggregases, including Hsp104, as a therapeutic strategy to combat the aberrant phase transitions of RBPs with PrLDs that likely underpin neurodegeneration.

scholarly journals SPLICING ABNORMALITIES IN MYOTONIC DYSTROPHIES

2014 ◽  
pp. 9-23
Author(s):  
Denis Furling
Keyword(s):  
Clinical Features ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cardiac Conduction ◽  
Nuclear Accumulation ◽  
Common Mechanism ◽  
Inherited Disease ◽  
Loss Of Function ◽  
Coding Region ◽  
Membrane Structures

Myotonic dystrophy of type 1 (DM1) is one of the most common muscular dystrophy in adults characterized by progressive muscle wasting and weakness, myotonia, cardiac conduction defects, alteration in cognitive functions as well as several other multisystemic symptoms. DM1 is an autosomal dominant inherited disease caused by an unstable CTG expansion ranging from ~50 to more than 1,000 repeats in the 3’ non-coding region of the DMPK gene. Expression of DMPK RNAs with expanded CUG repeats supports a toxic RNA gain-of-function as a pathologic mechanism for DM1. A similar or common mechanism may also be involved in DM type 2 that is caused by CCTG expansion in the first intron of the CNP (ZNF9) gene and shares similar clinical features with DM1 disease. In both myotonic dystrophies, nuclear accumulation of pathogenic CUG/CCUGexp-RNAs alters the activities of the RNA binding proteins such as MBNL1 and CUG-BP1 that leads to alternative splicing mis-regulation of a numerous of transcripts in DM tissues and ultimately, to clinical features of the disease. An overview of the DM splicing mis-regulation will be presented, with focus on mis- regulation of the BIN1 mRNA. In muscle, BIN1 plays an important role in tubular invaginations of the plasma membrane and is required for biogenesis of T-tubules, which are specialized membrane structures essential for excitation-contraction coupling. BIN1 splicing mis-regulation in DM patients due to MBNL1 loss-of-function results in the expression of an inactive form of BIN1 deprived of phosphoinositide-binding and membrane-tubulating activities. Reproducing similar BIN1 mis-splicing defect in the muscles of wild type mice is sufficient to promote T-tubule alterations and muscle strength decrease, suggesting that alteration of BIN1 splicing may contributes to muscle weakness, a prominent feature in DM.

Subcellular localization and RNP formation of IGF2BPs (IGF2 mRNA-binding proteins) is modulated by distinct RNA-binding domains

2013 ◽  
Vol 394 (8) ◽  
pp. 1077-1090 ◽  
Author(s):  
Kristin Wächter ◽  
Marcel Köhn ◽  
Nadine Stöhr ◽  
Stefan Hüttelmaier
Keyword(s):  
Subcellular Localization ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Nuclear Accumulation ◽  
Structural Constraints ◽  
Cellular Functions ◽  
Dependent Protein ◽  
Mrna Binding

Abstract The IGF2 mRNA-binding protein family (IGF2BPs) directs the cytoplasmic fate of various target mRNAs and controls essential cellular functions. The three IGF2BP paralogues expressed in mammals comprise two RNA-recognition motifs (RRM) as well as four KH domains. How these domains direct IGF2BP paralogue-dependent protein function remains largely elusive. In this study, we analyze the role of KH domains in IGF2BPs by the mutational GXXG-GEEG conversion of single KH domain loops in the context of full-length polypeptides. These analyses reveal that all four KH domains of IGF2BP1 and IGF2BP2 are essentially involved in RNA-binding in vitro and the cellular association with RNA-binding proteins (RBPs). Moreover the KH domains prevent the nuclear accumulation of these two paralogues and facilitate their recruitment to stress granules. The role of KH domains appears less pronounced in IGF2BP3, because GxxG-GEEG conversion in all four KH domains only modestly affects RNA-binding, subcellular localization and RNA-dependent protein association of this paralogue. These findings indicate paralogue-dependent RNA-binding properties of IGF2BPs which likely direct distinct cellular functions. Our findings suggest that IGF2BPs contact target RNAs via all four KH domains. This implies significant structural constraints, which presumably allow the formation of exceedingly stable protein-RNA complexes.

scholarly journals FUS/TLS undergoes calcium-mediated nuclear egress during excitotoxic stress and is required for Gria2 mRNA processing

2018 ◽  
Author(s):  
Maeve Tischbein ◽  
Desiree M. Baron ◽  
Yen-Chen Lin ◽  
Katherine V. Gall ◽  
John E. Landers ◽  
...  
Keyword(s):  
Neurodegenerative Disease ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Physiological Stress ◽  
Nucleocytoplasmic Transport ◽  
Cellular Stress Response ◽  
Calcium Dependent ◽  
Fused In Sarcoma ◽  
Nuclear Egress ◽  
Lateral Sclerosis

AbstractExcitotoxic levels of glutamate represent a physiological stress that is strongly linked to amyotrophic lateral sclerosis (ALS) and other neurological disorders. Emerging evidence indicates a role for neurodegenerative disease linked RNA-binding proteins (RBPs) in the cellular stress response. However, the relationships between excitotoxicity, RBP function and pathology have not been explored. Here, we found that excitotoxicity induced the translocation of select ALS-linked RBPs from the nucleus to the cytoplasm within neurons. RBPs affected by excitotoxicity include TAR DNA-binding protein 43 (TDP-43) and, most robustly, fused in sarcoma/translocated in liposarcoma (FUS/TLS). FUS translocation occurs through a calcium-dependent mechanism and coincides with striking alterations in nucleocytoplasmic transport. Further, glutamate-induced upregulation of Gria2 in neurons was dependent on FUS expression, consistent with a functional role for FUS under excitotoxic stress. These findings reveal a link between prominent factors in neurodegenerative disease, namely excitotoxicity, disease-associated RBPs and nucleocytoplasmic transport.

scholarly journals Interplay of RNA-Binding Proteins and microRNAs in Neurodegenerative Diseases

2021 ◽  
Vol 22 (10) ◽  
pp. 5292
Author(s):  
Chisato Kinoshita ◽  
Noriko Kubota ◽  
Koji Aoyama
Keyword(s):  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Critical Role ◽  
Mirna Biogenesis ◽  
Brain Functions ◽  
Number Of Patients ◽  
Protein Misfolding And Aggregation

The number of patients with neurodegenerative diseases (NDs) is increasing, along with the growing number of older adults. This escalation threatens to create a medical and social crisis. NDs include a large spectrum of heterogeneous and multifactorial pathologies, such as amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and multiple system atrophy, and the formation of inclusion bodies resulting from protein misfolding and aggregation is a hallmark of these disorders. The proteinaceous components of the pathological inclusions include several RNA-binding proteins (RBPs), which play important roles in splicing, stability, transcription and translation. In addition, RBPs were shown to play a critical role in regulating miRNA biogenesis and metabolism. The dysfunction of both RBPs and miRNAs is often observed in several NDs. Thus, the data about the interplay among RBPs and miRNAs and their cooperation in brain functions would be important to know for better understanding NDs and the development of effective therapeutics. In this review, we focused on the connection between miRNAs, RBPs and neurodegenerative diseases.

scholarly journals FUS ALS-causative mutations impact FUS autoregulation and the processing of RNA-binding proteins through intron retention

2019 ◽  
Author(s):  
Jack Humphrey ◽  
Nicol Birsa ◽  
Carmelo Milioto ◽  
David Robaldo ◽  
Andrea B Eberle ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intron Retention ◽  
Loss Of Function ◽  
Sequencing Data ◽  
Induced Changes ◽  
The Impact ◽  
Progressive Weakness

AbstractMutations in the RNA-binding protein FUS cause amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease in which the loss of motor neurons induces progressive weakness and death from respiratory failure, typically only 3-5 years after onset. FUS plays a role in numerous aspects of RNA metabolism, including mRNA splicing. However, the impact of ALS-causative mutations on splicing has not been fully characterised, as most disease models have been based on FUS overexpression, which in itself alters its RNA processing functions. To overcome this, we and others have recently created knock-in models, and have generated high depth RNA-sequencing data on FUS mutants in parallel to FUS knockout. We combined three independent datasets with a joint modelling approach, allowing us to compare the mutation-induced changes to genuine loss of function. We find that FUS ALS-mutations induce a widespread loss of function on expression and splicing, with a preferential effect on RNA binding proteins. Mutant FUS induces intron retention changes through RNA binding, and we identify an intron retention event in FUS itself that is associated with its autoregulation. Altered FUS regulation has been linked to disease, and intriguingly, we find FUS autoregulation to be altered not only by FUS mutations, but also in other genetic forms of ALS, including those caused by TDP-43, VCP and SOD1 mutations, supporting the concept that multiple ALS genes interact in a regulatory network.

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