scholarly journals Cdc48/VCP and endocytosis regulate TDP-43 and FUS toxicity and turnover

2019 ◽  
Author(s):  
Guangbo Liu ◽  
Aaron Byrd ◽  
Fen Pei ◽  
Allison Buchanan ◽  
Eman Basha ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Therapeutic Target ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Dna Binding Protein ◽  
Fused In Sarcoma ◽  
Lateral Sclerosis ◽  
Novel Therapeutic ◽  
Common Defect

AbstractAmyotrophic lateral sclerosis (ALS) is a fatal motor neuron degenerative disease. TDP-43 (TAR DNA-binding protein 43) and FUS (fused in sarcoma) are aggregation-prone RNA-binding proteins that in ALS can mis-localize to the cytoplasm of affected motor neuron cells, often forming cytoplasmic aggregates in the process. Such mis-localization and aggregation are implicated in ALS pathology, though the mechanisms of TDP-43 and FUS cytoplasmic toxicity remains unclear. Recently, we determined that the endocytic function aids turnover of TDP-43 and reduces TDP-43 toxicity. Here, we identified that Cdc48 and Ubx3, a Cdc48 co-factor implicated in endocytic function, regulates the turnover and toxicity of TDP-43 and FUS expressed in S. cerevisiae. Cdc48 physically interacts and co-localizes with TDP-43, as does VCP in ALS patient tissue. In yeast, FUS toxicity also depends strongly on endocytic function, but not autophagy under normal conditions. FUS expression also impairs endocytic function, as previously observed with TDP-43. Taken together, our data identifies a role for Cdc48/VCP and endocytosis function in regulating TDP-43 and FUS toxicity and turnover. Furthermore, endocytic dysfunction may be a common defect affecting cytoplasmic clearance of ALS aggregation-prone proteins and may represent a novel therapeutic target of promise.

scholarly journals Cdc48/VCP and Endocytosis Regulate TDP-43 and FUS Toxicity and Turnover

2019 ◽  
Vol 40 (4) ◽  
Author(s):  
Guangbo Liu ◽  
Aaron Byrd ◽  
Amanda N. Warner ◽  
Fen Pei ◽  
Eman Basha ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Motor Neuron ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Dna Binding Protein ◽  
Content Type ◽  
Fused In Sarcoma ◽  
Lateral Sclerosis ◽  
Novel Therapeutic ◽  
Common Defect

ABSTRACT Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron degenerative disease. TDP-43 (TAR DNA-binding protein 43) and FUS (fused in sarcoma) are aggregation-prone RNA-binding proteins that in ALS can mislocalize to the cytoplasm of affected motor neuron cells, often forming cytoplasmic aggregates in the process. Such mislocalization and aggregation are implicated in ALS pathology, though the mechanism(s) of TDP-43 and FUS cytoplasmic toxicity remains unclear. Recently, we determined that the endocytic function aids the turnover (i.e., protein degradation) of TDP-43 and reduces TDP-43 toxicity. Here, we identified that Cdc48 and Ubx3, a Cdc48 cofactor implicated in endocytic function, regulates the turnover and toxicity of TDP-43 and FUS expressed in Saccharomyces cerevisiae. Cdc48 physically interacts and colocalizes with TDP-43, as does VCP, in ALS patient tissue. In yeast, FUS toxicity also depends strongly on endocytic function but not on autophagy under normal conditions. FUS expression also impairs endocytic function, as previously observed with TDP-43. Taken together, our data identify a role for Cdc48/VCP and endocytic function in regulating TDP-43 and FUS toxicity and turnover. Furthermore, endocytic dysfunction may be a common defect affecting the cytoplasmic clearance of ALS aggregation-prone proteins and may represent a novel therapeutic target of promise.

scholarly journals Connecting RNA-Modifying Similarities of TDP-43, FUS, and SOD1 with MicroRNA Dysregulation Amidst A Renewed Network Perspective of Amyotrophic Lateral Sclerosis Proteinopathy

2020 ◽  
Vol 21 (10) ◽  
pp. 3464 ◽  
Author(s):  
Jade Pham ◽  
Matt Keon ◽  
Samuel Brennan ◽  
Nitin Saksena
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Rna Splicing ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Future Research ◽  
Fused In Sarcoma ◽  
Traditional Approaches ◽  
Microrna Dysregulation ◽  
Lateral Sclerosis

Beyond traditional approaches in understanding amyotrophic lateral sclerosis (ALS), multiple recent studies in RNA-binding proteins (RBPs)—including transactive response DNA-binding protein (TDP-43) and fused in sarcoma (FUS)—have instigated an interest in their function and prion-like properties. Given their prominence as hallmarks of a highly heterogeneous disease, this prompts a re-examination of the specific functional interrelationships between these proteins, especially as pathological SOD1—a non-RBP commonly associated with familial ALS (fALS)—exhibits similar properties to these RBPs including potential RNA-regulatory capabilities. Moreover, the cytoplasmic mislocalization, aggregation, and co-aggregation of TDP-43, FUS, and SOD1 can be identified as proteinopathies akin to other neurodegenerative diseases (NDs), eliciting strong ties to disrupted RNA splicing, transport, and stability. In recent years, microRNAs (miRNAs) have also been increasingly implicated in the disease, and are of greater significance as they are the master regulators of RNA metabolism in disease pathology. However, little is known about the role of these proteins and how they are regulated by miRNA, which would provide mechanistic insights into ALS pathogenesis. This review seeks to discuss current developments across TDP-43, FUS, and SOD1 to build a detailed snapshot of the network pathophysiology underlying ALS while aiming to highlight possible novel therapeutic targets to guide future research.

scholarly journals Motor neuron translatome reveals deregulation of SYNGR4 and PLEKHB1 in mutant TDP-43 amyotrophic lateral sclerosis models

2020 ◽  
Vol 29 (16) ◽  
pp. 2647-2661 ◽  
Author(s):  
Rita F Marques ◽  
Jan B Engler ◽  
Katrin Küchler ◽  
Ross A Jones ◽  
Thomas Lingner ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Amyotrophic Lateral Sclerosis ◽  
Motor Neuron ◽  
Symptom Onset ◽  
Rna Binding ◽  
Affinity Purification ◽  
Disease Onset ◽  
Motor Symptom ◽  
Pathological Feature ◽  
Lateral Sclerosis

Abstract Amyotrophic lateral sclerosis (ALS) is an incurable neurological disease with progressive loss of motor neuron (MN) function in the brain and spinal cord. Mutations in TARDBP, encoding the RNA-binding protein TDP-43, are one cause of ALS, and TDP-43 mislocalization in MNs is a key pathological feature of >95% of ALS cases. While numerous studies support altered RNA regulation by TDP-43 as a major cause of disease, specific changes within MNs that trigger disease onset remain unclear. Here, we combined translating ribosome affinity purification (TRAP) with RNA sequencing to identify molecular changes in spinal MNs of TDP-43–driven ALS at motor symptom onset. By comparing the MN translatome of hTDP-43A315T mice to littermate controls and to mice expressing wild type hTDP-43, we identified hundreds of mRNAs that were selectively up- or downregulated in MNs. We validated the deregulated candidates Tex26, Syngr4, and Plekhb1 mRNAs in an independent TRAP experiment. Moreover, by quantitative immunostaining of spinal cord MNs, we found corresponding protein level changes for SYNGR4 and PLEKHB1. We also observed these changes in spinal MNs of an independent ALS mouse model caused by a different patient mutant allele of TDP-43, suggesting that they are general features of TDP-43-driven ALS. Thus, we identified SYNGR4 and PLEKHB1 to be deregulated in MNs at motor symptom onset in TDP-43-driven ALS models. This spatial and temporal pattern suggests that these proteins could be functionally important for driving the transition to the symptomatic phase of the disease.

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 M1 and M2 Functional Imprinting of Primary Microglia: Role of P2X7 Activation and miR-125b

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Chiara Parisi ◽  
Giulia Napoli ◽  
Pablo Pelegrin ◽  
Cinzia Volonté
Keyword(s):  
Motor Neuron ◽  
Target Genes ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Short Review ◽  
Severe Form ◽  
Primary Microglia ◽  
Neuron Death ◽  
Fused In Sarcoma ◽  
Neuroprotective Actions

Amyotrophic lateral sclerosis (ALS) is a most frequently occurring and severe form of motor neuron disease, causing death within 3–5 years from diagnosis and with a worldwide incidence of about 2 per 100,000 person-years. Mutations in over twenty genes associated with familial forms of ALS have provided insights into the mechanisms leading to motor neuron death. Moreover, mutations in two RNA binding proteins, TAR DNA binding protein 43 and fused in sarcoma, have raised the intriguing possibility that perturbations of RNA metabolism, including that of the small endogenous RNA molecules that repress target genes at the posttranscriptional level, that is, microRNAs, may contribute to disease pathogenesis. At present, the mechanisms by which microglia actively participate to both toxic and neuroprotective actions in ALS constitute an important matter of research. Among the pathways involved in ALS-altered microglia responses, in previous works we have uncovered the hyperactivation of P2X7 receptor by extracellular ATP and the overexpression of miR-125b, both leading to uncontrolled toxic M1 reactions. In order to shed further light on the complexity of these processes, in this short review we will describe the M1/M2 functional imprinting of primary microglia and a role played by P2X7 and miR-125b in ALS microglia activation.

scholarly journals RNA-Binding Proteins in Amyotrophic Lateral Sclerosis and Neurodegeneration

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Scott E. Ugras ◽  
James Shorter
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Neurodegenerative Disease ◽  
Rna Processing ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Future Studies ◽  
Inclusion Formation ◽  
Als Patients ◽  
Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is an adult onset neurodegenerative disease, which is universally fatal. While the causes of this devastating disease are poorly understood, recent advances have implicated RNA-binding proteins (RBPs) that contain predicted prion domains as a major culprit. Specifically, mutations in the RBPs TDP-43 and FUS can cause ALS. Cytoplasmic mislocalization and inclusion formation are common pathological features of TDP-43 and FUS proteinopathies. Though these RBPs share striking pathological and structural similarities, considerable evidence suggests that the ALS-linked mutations in TDP-43 and FUS can cause disease by disparate mechanisms. In a recent study, Couthouis et al. screened for protein candidates that were also involved in RNA processing, contained a predicted prion domain, shared other phenotypic similarities with TDP-43 and FUS, and identified TAF15 as a putative ALS gene. Subsequent sequencing of ALS patients successfully identified ALS-linked mutations in TAF15 that were largely absent in control populations. This study underscores the important role that perturbations in RNA metabolism might play in neurodegeneration, and it raises the possibility that future studies will identify other RBPs with critical roles in neurodegenerative disease.

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 Loss of nucleoporin Nup50 is a risk factor for amyotrophic lateral sclerosis

2021 ◽  
Author(s):  
Salim Megat ◽  
Natalia Mora ◽  
Jason Sanogo ◽  
Alberto Catanese ◽  
Najwa Ouali ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Association Studies ◽  
Nuclear Pore ◽  
Genome Wide Association Studies ◽  
Gene Encoding ◽  
Pathogenic Variants ◽  
Or Gene ◽  
Lateral Sclerosis

The genetic basis of amyotrophic lateral sclerosis (ALS) is still incompletely understood. Using two independent genetic strategies, we show here that a large part of ALS heritability lies in genes expressed in inhibitory and excitatory neurons, especially at splicing sites regulated by a defined set of RNA binding proteins including TDP-43 and FUS. We conducted a transcriptome wide association study (TWAS) and identified 59 loci associated with ALS, including 14 previously identified genes, some of them not previously reaching significance in genome wide association studies. Among the 45 novel genes, several genes are involved in pathways known to be affected in ALS such as mitochondrial metabolism (including ATP5H, ATP5D, BCS1L), proteostasis (including COPS7A, G2E3, TMEM175, USP35) or gene expression and RNA metabolism (including ARID1B, ATXN3, PTBP2, TAF10). Interestingly, decreased expression of NUP50, a constrained gene encoding a nuclear pore basket protein, was associated with ALS in TWAS (Zscore = -4, FDR = 0.034). 11 potentially pathogenic variants (CADD score > 20) in 23 patients were identified in the NUP50 gene, most of them in the region of the protein mediating interaction with Importin alpha, and including 2 frameshift mutations. In cells from two patients carrying NUP50 variants, we showed decreased levels of NUP50 protein. Importantly, knocking down Nup50 led to increased neuronal death associated with p62 and nucleoporin inclusions in cultured neurons, and motor defects in Drosophila and zebrafish models. In all, our study identifies alterations in splicing in neurons as a critical pathogenic process in ALS, uncovers several new loci potentially contributing to ALS missing heritability, and provides genetic evidence linking nuclear pore defects to ALS.

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