Juvenile Amyotrophic Lateral Sclerosis Research Articles

Serine Palmitoyltransferase (SPT)-related Neurodegenerative and Neurodevelopmental Disorders.

Motor neuron diseases and peripheral neuropathies are heterogeneous groups of neurodegenerative disorders that manifest with distinct symptoms due to progressive dysfunction or loss of specific neuronal subpopulations during different stages of development. A few monogenic, neurodegenerative diseases associated with primary metabolic disruptions of sphingolipid biosynthesis have been recently discovered. Sphingolipids are a subclass of lipids that form critical building blocks of all cellular and subcellular organelle membranes including the membrane components of the nervous system cells. They are especially abundant within the lipid portion of myelin. In this review, we will focus on our current understanding of disease phenotypes in three monogenic, neuromuscular diseases associated with pathogenic variants in components of serine palmitoyltransferase, the first step in sphingolipid biosynthesis. These include hereditary sensory and autonomic neuropathy type 1 (HSAN1), a sensory predominant peripheral neuropathy, and two neurodegenerative disorders: juvenile amyotrophic lateral sclerosis affecting the upper and lower motor neurons with sparing of sensory neurons, and a complicated form of hereditary spastic paraplegia with selective involvement of the upper motor neurons and more broad CNS neurodegeneration. We will also review our current understanding of disease pathomechanisms, therapeutic approaches, and the unanswered questions to explore in future studies.

Modeling sporadic juvenile ALS in iPSC-derived motor neurons explores the pathogenesis of FUSR503fs mutation.

Fused in sarcoma (FUS) mutations represent the most common genetic etiology of juvenile amyotrophic lateral sclerosis (JALS), for which effective treatments are lacking. In a prior report, we identified a novel FUS mutation, c.1509dupA: p. R503fs (FUSR503fs), in a sporadic JALS patient. The physicochemical properties and structure of FUSR503fs protein were analyzed by software: Multi-electrode array (MEA) assay, calcium activity imaging assay and transcriptome analysis were used to explore the pathophysiological mechanism of iPSC derived motor neurons. Structural analysis and predictions regarding physical and chemical properties of this mutation suggest that the reduction of phosphorylation and glycosylation sites, along with alterations in the amino acid sequence, may contribute to abnormal FUS accumulation within the cytoplasm and nucleus of induced pluripotent stem cell- derived motor neurons (MNs). Multi-electrode array and calcium activity imaging indicate diminished spontaneous electrical and calcium activity signals in MNs harboring the FUSR503fs mutation. Transcriptomic analysis reveals upregulation of genes associated with viral infection and downregulation of genes involved in neural function maintenance, such as the ATP6V1C2 gene. Treatment with ropinirole marginally mitigates the electrophysiological decline in FUSR503fs MNs, suggesting the utility of this cell model for mechanistic exploration and drug screening. iPSCs-derived motor neurons from JALS patients are promising tools for drug screening. The pathological changes in motor neurons of FUSR503fs may occur earlier than in other known mutation types that have been reported.

A Rare Case of Juvenile Amyotrophic Lateral Sclerosis

A Rare Case of Juvenile Amyotrophic Lateral Sclerosis

Brief Report on Juvenile Amyotrophic Lateral Sclerosis Cases in the United State National ALS Registry: 2010–2018 (P6-11.014)

Brief Report on Juvenile Amyotrophic Lateral Sclerosis Cases in the United State National ALS Registry: 2010–2018 (P6-11.014)

Clinical and Genetic Aspects of Juvenile Amyotrophic Lateral Sclerosis: A Promising Era Emerges.

Juvenile Amyotrophic Lateral Sclerosis is a genetically heterogeneous neurodegenerative disorder, which is frequently misdiagnosed due to low clinical suspicion and little knowledge about disease characteristics. More than 20 different genetic loci have been associated with both sporadic and familial juvenile Amyotrophic Lateral Sclerosis. Currently, almost 40% of cases have an identifiable monogenic basis; type 6, associated with FUS gene variants, is the most prevalent globally. Despite several upper motor neuron-dominant forms being generally associated with long-standing motor symptoms and slowly progressive course, certain subtypes with lower motor neuron-dominant features and early bulbar compromise lead to rapidly progressive motor handicap. For some monogenic forms, there is a well-established genotypic-phenotypic correlation. There are no specific biochemical and neuroimaging biomarkers for the diagnosis of juvenile Amyotrophic Lateral Sclerosis. There are several inherited neurodegenerative and neurometabolic disorders which can lead to the signs of motor neuron impairment. This review emphasizes the importance of high clinical suspicion, assessment, and proper diagnostic work-up for juvenile Amyotrophic Lateral Sclerosis.

Disruption of MAM integrity in mutant FUS oligodendroglial progenitors from hiPSCs

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disorder, characterized by selective loss of motor neurons (MNs). A number of causative genetic mutations underlie the disease, including mutations in the fused in sarcoma (FUS) gene, which can lead to both juvenile and late-onset ALS. Although ALS results from MN death, there is evidence that dysfunctional glial cells, including oligodendroglia, contribute to neurodegeneration. Here, we used human induced pluripotent stem cells (hiPSCs) with a R521H or a P525L mutation in FUS and their isogenic controls to generate oligodendrocyte progenitor cells (OPCs) by inducing SOX10 expression from a TET-On SOX10 cassette. Mutant and control iPSCs differentiated efficiently into OPCs. RNA sequencing identified a myelin sheath-related phenotype in mutant OPCs. Lipidomic studies demonstrated defects in myelin-related lipids, with a reduction of glycerophospholipids in mutant OPCs. Interestingly, FUSR521H OPCs displayed a decrease in the phosphatidylcholine/phosphatidylethanolamine ratio, known to be associated with maintaining membrane integrity. A proximity ligation assay further indicated that mitochondria-associated endoplasmic reticulum membranes (MAM) were diminished in both mutant FUS OPCs. Moreover, both mutant FUS OPCs displayed increased susceptibility to ER stress when exposed to thapsigargin, and exhibited impaired mitochondrial respiration and reduced Ca2+ signaling from ER Ca2+ stores. Taken together, these results demonstrate a pathological role of mutant FUS in OPCs, causing defects in lipid metabolism associated with MAM disruption manifested by impaired mitochondrial metabolism with increased susceptibility to ER stress and with suppressed physiological Ca2+ signaling. As such, further exploration of the role of oligodendrocyte dysfunction in the demise of MNs is crucial and will provide new insights into the complex cellular mechanisms underlying ALS.

Juvenile amyotrophic lateral sclerosis caused by a mutation in the SPTLC2 gene: case presentation

Juvenile amyotrophic lateral sclerosis (ALS) is a rare group of motor neuron diseases, with the age of onset up to 25 years. Juvenile ALS more commonly has genetic origin vs. sporadic forms of ALS that develop in adulthood. Genetic analysis of these cases with early onset makes it possible to identify the genes responsible for the disease. Here we present a case of a rare variant of juvenile ALS caused due to the SPTLC2 gene mutation.
 Cases with early disease onset are characterized by slow progression and variable phenotype, which often makes accurate diagnosis challenging. Therefore patients with combined upper and lower motor neuron disorders aged under 25 years should undergo comprehensive examination, in particular to identify gene mutations.

Recurrent de novo SPTLC2 variant causes childhood-onset amyotrophic lateral sclerosis (ALS) by excess sphingolipid synthesis

BackgroundAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the upper and lower motor neurons with varying ages of onset, progression and pathomechanisms. Monogenic childhood-onset ALS, although rare, forms an...

Association of TRMT2B gene variants with juvenile amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive degeneration of motor neurons, and it demonstrates high clinical heterogeneity and complex genetic architecture. A variation within TRMT2B (c.1356G>T; p.K452N) was identified to be associated with ALS in a family comprising two patients with juvenile ALS (JALS). Two missense variations and one splicing variation were identified in 10 patients with ALS in a cohort with 910 patients with ALS, and three more variants were identified in a public ALS database including 3317 patients with ALS. A decreased number of mitochondria, swollen mitochondria, lower expression of ND1, decreased mitochondrial complex I activities, lower mitochondrial aerobic respiration, and a high level of ROS were observed functionally in patient-originated lymphoblastoid cell lines and TRMT2B interfering HEK293 cells. Further, TRMT2B variations overexpression cells also displayed decreased ND1. In conclusion, a novel JALS-associated gene called TRMT2B was identified, thus broadening the clinical and genetic spectrum of ALS.

Multiomics Approach Reveal Novel Insights in FUS Driven Juvenile Amyotrophic Lateral Sclerosis: A Family Quartet Analysis

Background Juvenile amyotrophic lateral sclerosis (JALS) is a rare and severe form of motor neuron disease characterized by progressive loss of upper and lower motor neurons with an early onset (<25 years). Purpose Due to complex etiology and clinical heterogeneity, it is indispensable to unravel molecular mechanisms underlying JALS pathology. The study aimed to identify disease-specific signatures in a 14-years-old sporadic JALS patient. Methods Genomic, transcriptomic, and metabolomic analysis of proband and first-degree relatives (FDR). Results Exome sequencing identified a novel de novo frameshift variation (c.1465dupG: p.D490Gfs*26) in the fused in sarcoma (FUS) gene in proband. Interestingly, rare and potentially deleterious, disease-modifying variations in DDHD domain containing 1 (DDHD1) and fibrillin 2 (FBN2) were observed. Differentially expressed genes (DGEs) enriched in neuromuscular transmission and inflammatory response were identified by RNA-sequencing. In addition, alterations in purine and pyrimidine, vitamin B6, and sphingolipid metabolism reflect the involvement of inflammatory process in disease pathobiology. Conclusion Our findings suggest the involvement of multiple genetic factors coupled with hampered neuromuscular transmission and systemic inflammation in the onset and disease course of JALS.

Epidemiological and clinical profile of amyotrophic lateral sclerosis in Ethiopia: a 5-year multicenter retrospective study

Background Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that results in progressive weakness of skeletal muscles including respiratory muscles. Epidemiological and clinical aspects of ALS are derived from a few world regions with very little representation of low- and middle-income countries. We therefore set out to determine the epidemiological and clinical phenotype of individuals with ALS in Ethiopia. Methods Multicenter retrospective analysis was conducted using clinical records from ALS patients seen in Ethiopia at Tikur Anbessa Specialized Hospital and Yehuleshet specialty clinic between January 2016 and August 2021. The data collected included clinical characteristics, disease-related symptoms, a revised ALS functional rating scale, and medications. Results Patients in Ethiopia had a younger age of onset with a mean age of disease onset of 51.9 years. 2.9% of patients had juvenile ALS, and the male-to-female ratio was almost 2:1. 4.9% had a positive family history of the disease. 68% of patients had spinal region involvement at onset, while 32% had bulbar region involvement at onset. Riluzole was used by 31% of ALS patients. 20.6% of patients had some respiratory symptoms, but none received a standard respiratory function assessment. 33.3% of patients were wheelchair-bound. Conclusion In this retrospective study spanning 5 years, we examined the clinical phenotype of ALS in Ethiopian patients. Our findings suggest that most patients had clinically definite ALS with spinal region involvement. Further research, including genetic and epigenetic information, is necessary to understand the early onset of the disease in Ethiopia.

SPTLC1 p.Leu38Arg, a novel mutation associated with childhood ALS

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neuromuscular disease. Recently, several gain-of-function mutations in SPTLC1 were associated with juvenile ALS. SPTLC1 encodes for a subunit of the serine-palmitoyltransferase (SPT) - the rate-limiting enzyme in the de novo synthesis of sphingolipids (SL). SPT activity, and thus SL de novo synthesis, is tightly controlled by a homeostatic feedback mechanism mediated by ORMDL proteins. Here we report a novel SPTLC1p.L38R mutation in a young Chinese girl with a signature of juvenile ALS. The patient presented with muscular weakness and atrophy, tongue tremor and fasciculation, breathing problems and positive pyramidal signs. All SPTLC1-ALS mutations including the SPTLC1 p.L38R are located within a single membrane-spanning domain of the protein and impede the interaction with the regulatory ORMDL subunit of SPT. Pertinent to the altered homeostatic control, lipid analysis showed overall increased SL levels in the patient plasma. An increased SPT activity and SL de novo synthesis was confirmed in p.L38R expressing HEK293 cells. Particularily dihydro-sphingolipids (dhSL) were signficantly increased in patient plasma and p.L38R mutant expressing cells. Increased dhSL formation has been previously linked to neurotoxicity and may be involved in the pathomechanism of SPTLC1-ALS mutations.

Sigma-1 receptor maintains ATAD3A as a monomer to inhibit mitochondrial fragmentation at the mitochondria-associated membrane in amyotrophic lateral sclerosis

Organelle contact sites are multifunctional platforms for maintaining cellular homeostasis. Alternations of the mitochondria-associated membranes (MAM), one of the organelle contact sites where the endoplasmic reticulum (ER) is tethered to the mitochondria, have been involved in the pathogenesis of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). However, the detailed mechanisms through which MAM integrity is disrupted in ALS have not been fully elucidated. Here, we examined whether AAA ATPase domain-containing protein 3A (ATAD3A), a mitochondrial membrane AAA ATPase accumulating at the MAM, is involved in ALS. We found that sigma-1 receptor (σ1R), an ER-resident MAM protein causative for inherited juvenile ALS, required ATAD3A to maintain the MAM. In addition, σ1R retained ATAD3A as a monomer, which is associated with an inhibition of mitochondrial fragmentation. ATAD3A dimerization and mitochondrial fragmentation were significantly induced in σ1R-deficient or SOD1-linked ALS mouse spinal cords. Overall, these observations indicate that MAM induction by σ1R depends on ATAD3A and that σ1R maintains ATAD3A as a monomer to inhibit mitochondrial fragmentation. Our findings suggest that targeting σ1R–ATAD3A axis would be promising for a novel therapeutic strategy to treat mitochondrial dysfunction in neurological disorders, including ALS.

Clinical feature difference between juvenile amyotrophic lateral sclerosis with SPTLC1 and FUS mutations.

Juvenile amyotrophic lateral sclerosis (JALS) is an uncommon form of amyotrophic lateral sclerosis whose age at onset (AAO) is defined as prior to 25 years. FUS mutations are the most common cause of JALS. SPTLC1 was recently identified as a disease-causative gene for JALS, which has rarely been reported in Asian populations. Little is known regarding the difference in clinical features between JALS patients carrying FUS and SPTLC1 mutations. This study aimed to screen mutations in JALS patients and to compare the clinical features between JALS patients with FUS and SPTLC1 mutations. Sixteen JALS patients were enrolled, including three newly recruited patients between July 2015 and August 2018 from the Second Affiliated Hospital, Zhejiang University School of Medicine. Mutations were screened by whole-exome sequencing. In addition, clinical features such as AAO, onset site and disease duration were extracted and compared between JALS patients carrying FUS and SPTLC1 mutations through a literature review. A novel and de novo SPTLC1 mutation (c.58G>A, p.A20T) was identified in a sporadic patient. Among 16 JALS patients, 7/16 carried FUS mutations and 5/16 carried respective SPTLC1 , SETX , NEFH , DCTN1 , and TARDBP mutations. Compared with FUS mutation patients, those with SPTLC1 mutations had an earlier AAO (7.9 ± 4.6 years vs. 18.1 ± 3.9 years, P < 0.01), much longer disease duration (512.0 [416.7-607.3] months vs. 33.4 [21.6-45.1] months, P < 0.01), and no onset of bulbar. Our findings expand the genetic and phenotypic spectrum of JALS and help to better understand the genotype-phenotype correlation of JALS.

No Association between the SORD Gene and Amyotrophic Lateral Sclerosis in a Chinese Cohort.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. Recently a juvenile ALS patient was reported carrying the c.757delG mutation of the sorbitol dehydrogenase (SORD) gene, which was also a related mutation of Charcot-Marie-Tooth disease (CMT) and distal hereditary motor neuropathy (dHMN). ALS shares pathogenesis and overlapping genes with CMT and dHMN. We used whole-exome sequencing technology to screen the full-length SORD gene in 601 Chinese sporadic ALS patients and 174 controls without a history of neurological diseases. No SORD pathogenic variants were identified in the ALS patients. Our current results did not find an association between SORD and ALS in Chinese patients, and further studies will be required.

Juvenile amyotrophic lateral sclerosis type 4: case report and review

Juvenile amyotrophic lateral sclerosis (ALS) presents a group of few rare monogenic disorders with onset from early childhood up to 25 years and much more benign course than “classic” ALS. Autosomal dominant ALS type 4 (ALS4) related to SETX gene is one of them. In spite of characteristic combined involvement of central and peripheral motor neurons, ALS4 clinical diagnostics may be difficult, particularly in atypical and/or non‑familial cases and electroneuromyography underestimation. Massive parallel sequencing permits diagnosing majority of cases and performing genetic counselling in families.Aim of this work: to describe non‑familial ALS4 case detected by whole‑exome sequencing and present a review on poorly known disorder.A 21‑year‑old female patient in a consanguineous family was examined; methods: clinical, genealogical, electroneuromyography, peripheral nerves ultrasound; molecular: panel and whole‑exome sequencing, bioinformatical analysis.The girl is an only child and an only patient in a family of Mountain Jews – first cousins. She had spastic paraparesis since age of independent walking (1.5 y.o.) and early feet deformation, her first diagnosis was cerebral palsy. In 12 years spasticity progressed, walking was lost. After orthopedic surgery in 15 years supported walking restored, at that age leg distal amyotrophy developed with no further progressing. Due to electroneuromyography results polyneuropathy was misdiagnosed. In 21 years repeated electroneuromyography excluded polyneuropathy and detected generalized motor neuron impairment and juvenile ALS was suggested. On neurological examination pronounced spastic paraparesis together with peripheral leg paraparesis without sensory impairment were detected; her supported gait was of mixed spastic and paretic types; there were no fasciculations or fibrillations.Whole‑exome sequencing detected a novel heterozygous missense mutation c.4442A&gt;G (p.Lys1481Arg) in SETX exon 10. Sanger familial sequencing was not possible, but DNA finding matching the phenotype supported ALS4 diagnosis. Juvenile ALS4 (SETX gene) is a relatively benign autosomal dominant disease, imitating in different stages other nervous disorders of early and young age; genealogy is not always informative. Along with typical cases (like our patient) clinical variability exists. Electroneuromyography is the main instrumental tool. Methods of massive parallel sequencing are optimal in DNA testing of juvenile ALS.

Phenotype Analysis of Fused in Sarcoma Mutations in Amyotrophic Lateral Sclerosis.

Background and ObjectivesPathogenic variations in fused in sarcoma (FUS) are among the most common genetic causes of amyotrophic lateral sclerosis (ALS) worldwide. They are supposedly characterized by a homogeneous pure motor phenotype with early-onset and short disease duration. However, a few FUS-mutated cases with a very late disease onset and slow progression have been reported. To analyze genotype-phenotype correlations and identify the prognostic factors in FUS-ALS cases.MethodsWe identified and cross-sectionally analyzed 22 FUS-ALS patient histories from a single-center cohort of 2,615 genetically tested patients and reviewed 289 previously published FUS-ALS cases. Survival analysis was performed by Kaplan-Meier survival curves, followed by the log-rank test and multivariate Cox analysis.ResultsSurvival of FUS-ALS is age-dependent: In our cohort, early-onset cases had a rapid disease progression and short survival (p = 0.000003) while the outcome of FUS-mutated patients with mid-to-late onset did not differ from non–FUS-ALS patients (p = 0.437). Meta-analysis of literature data confirmed this trend (p = 0.00003). This survival pattern is not observed in other ALS-related genes in our series. We clustered FUS-ALS patients in 3 phenotypes: (1) axial ALS, with upper cervical and dropped-head onset in mid-to-late adulthood; (2) benign ALS, usually with a late-onset and slow disease progression; and (3) juvenile ALS, often with bulbar onset and preceded by learning disability or mild mental retardation. Those phenotypes arise from different mutations.DiscussionWe observed specific genotype-phenotype correlations of FUS-ALS and identified age at onset as the most critical prognostic factor. Our results demonstrated that FUS mutations underlie a specific subtype of ALS and enable a careful stratification of newly diagnosed FUS-ALS cases for clinical course and potential therapeutic windows. This will be crucial in the light of incoming gene-specific therapy.

Genotype-phenotype correlation in Tunisian patients with Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease. To date, mutations in more than 30 genes have been linked to familial ALS forms. However, no mutational screenings have been reported in African populations so far. We aimed to investigate the presence of rare genetic variants in the 4 most common ALS causative genes among a Tunisian cohort. Patients were screened for mutations in SOD1 (exons 1-5), TARDBP (exon 6), FUS (exons 5, 6, 13/14, and 15). Juvenile ALS (JALS) patients were screened also for ALS2 (exons 3, 10, 28). Analysis of C9ORF72 was conducted by fluorescent amplicon-length analysis and repeat-primed PCR. We analyzed 197 Tunisian ALS patients, including 11 familial forms (fALS) with 17 ALS cases, 167 sporadic (sALS) and 13 JALS cases. The pathogenic variant TARDBP p.G294A mutation was reported among 18 patients. Repeat expansion in C9orf72 was recorded in 9 patients. Interestingly, 2 unrelated patients carried a double mutation in both C9orf72 and TARDBP genes. Finally, the p.Asp91Val mutation in SOD1 was identified among 4 cases in homozygous state including 3 sALS and 1 familial JALS with recessive inheritance. No pathogenic variants in FUS were identified, nor ALS2 variants in JALS cases. In our Tunisian cohort the most frequently mutated gene is TARDBP (9.4%), followed by C9orf72 (3.9%) and SOD1 (2.1%). Our study broadens the mutational spectrum in patients with ALS and defines for the first time the mutational frequency of the main ALS genes in patients of African ethnicity.

A novel mutation in the ALS2 gene in an iranian kurdish family with juvenile amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a rare disorder that affects both upper and lower motor neurons. Mutations in Alsin Rho Guanine Nucleotide Exchange Factor (ALS2) correlates with three similar but distinctive syndromes, including the juvenile form of ALS. An Iranian Kurdish family was involved in this study and all members were evaluated with relevant clinical guidelines. Whole exome sequencing and sanger sequencing were applied to all family members to undermine the possible genetic factors. A substitution c. 2110 C>T (p. Arg704X) identified in the ALS2 gene. Bioinformatics analysis indicated the mutation is located in the well-conserved and functional domain of the protein. This study recognized a novel mutation in the ALS2 gene in a proband with the juvenile form of ALS. To our knowledge, this is the first identified ALS2 mutation among the Iranian population.

Proximity-based labeling reveals DNA damage–induced phosphorylation of fused in sarcoma (FUS) causes distinct changes in the FUS protein interactome

Accumulation of cytoplasmic inclusions containing fused in sarcoma (FUS), an RNA/DNA-binding protein, is a common hallmark of frontotemporal lobar degeneration and amyotrophic lateral sclerosis neuropathology. We have previously shown that DNA damage can trigger the cytoplasmic accumulation of N-terminally phosphorylated FUS. However, the functional consequences of N-terminal FUS phosphorylation are unknown. To gain insight into this question, we utilized proximity-dependent biotin labeling via ascorbate peroxidase 2 aired with mass spectrometry to investigate whether N-terminal phosphorylation alters the FUS protein–protein interaction network (interactome), and subsequently, FUS function. We report the first analysis comparing the interactomes of three FUS variants: homeostatic wildtype FUS (FUS WT), phosphomimetic FUS (FUS PM; a proxy for N-terminally phosphorylated FUS), and the toxic FUS proline 525 to leucine mutant (FUS P525L) that causes juvenile amyotrophic lateral sclerosis. We found that the phosphomimetic FUS interactome is uniquely enriched for a group of cytoplasmic proteins that mediate mRNA metabolism and translation, as well as nuclear proteins involved in the spliceosome and DNA repair functions. Furthermore, we identified and validated the RNA-induced silencing complex RNA helicase MOV10 as a novel interacting partner of FUS. Finally, we provide functional evidence that N-terminally phosphorylated FUS may disrupt homeostatic translation and steady-state levels of specific mRNA transcripts. Taken together, these results highlight phosphorylation as a unique modulator of the interactome and function of FUS.