Biology subjects

Jutzi, D.

Publications and source records attributed to Jutzi, D..

4 recordsLinked to original sources

bioRxiv2026

Breaking β-sheets in FUS prion-like domain preserves phase separation and function but prevents aggregation and toxicity

The RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation associated with RNA processing. However, the prion-like low complexity (LC) domain of FUS forms solid-like aggregates in neurodegenerative diseases. Whether the formation of {beta}-sheet structure associated with pathology is also physiologically/functionally relevant is debated. Similarly, if mislocalization alone or concomitant aggregation is responsible for FUS gain-of-function toxicity remains to be probed. Here, we introduce {beta}-sheet breaking proline residues into FUS LC with the goal of preventing cross-{beta}-driven aggregation without disrupting essential functions and phase separation. {beta}-sheet-deficient FUS variants maintain native-like global motions, disorder, and phase separation, but no longer show a liquid-to-solid transition (LST). Biochemical partitioning, cellular localization, and auto- and cross-regulatory functions of FUS all remain essentially unchanged. Conversely, FUS-induced neurodegeneration in several Drosophila models is drastically reduced. These findings suggest a strategy for mitigating disease-related toxicity through backbone structure modulation to prevent prion-like domain protein aggregation. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/706410v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@d15f63org.highwire.dtl.DTLVardef@1cd6221org.highwire.dtl.DTLVardef@e58126org.highwire.dtl.DTLVardef@181ec67_HPS_FORMAT_FIGEXP M_FIG C_FIG SUMMARYThe RNA-binding protein Fused in Sarcoma (FUS) undergoes phase separation as part of its physiological function but can aberrantly aggregate into solid-like assemblies in amyotrophic lateral sclerosis and frontotemporal dementia. To dissect the role of {beta}-sheets in both function and pathological transition, we engineered {beta}-sheet-preventing FUS variants via targeted proline residue insertions in the prion-like disordered region. These variants retained native structure, motions, and phase behavior yet showed dramatically reduced aggregation, both as an isolated prion-like domain and in full-length FUS. Crucially, these variants maintained a panel of FUS cellular functions that depend on FUS condensation but prevented FUS toxicity in fly models of neurodegeneration. Our findings implicate {beta}-sheets as key drivers of FUS condensate maturation and neuronal toxicity, highlighting {beta}-sheet modulation as a therapeutic strategy against FUS-related neurodegeneration. HIGHLIGHTSO_LITargeted proline additions disrupt {beta}-sheet formation in FUS without altering native conformations, dynamics, or phase separation behavior C_LIO_LI{beta}-sheet-deficient FUS variants prevent aggregation and liquid-to-solid transitions while retaining key biological functions C_LIO_LIIn vivo models reveal attenuated toxicity of {beta}-sheet-deficient FUS in Drosophila C_LIO_LI{beta}-sheets are identified as central drivers of condensate maturation and neuronal death, offering a therapeutic entry point for modulating prion-like domain pathology C_LI

biochemistry↗

bioRxiv2026

The Structured RNA-binding Domains and Condensation Capacity of FUS Shape its RNA-binding Landscape and Function.

RNA-binding proteins (RBPs) are key regulators of gene expression and often contain intrinsically disordered regions that drive biomolecular condensation. Yet, how condensation affects RBP specificity and function remains poorly defined. Here, we use strategically designed point mutations to selectively impair canonical RNA-binding and condensation of the amyotrophic lateral sclerosis (ALS)-linked RBP Fused in Sarcoma (FUS). Using automated high-content imaging, we show that both properties shape nuclear ribonucleoprotein condensates and govern distinct aspects of FUS function in the DNA damage response. Transcriptome-wide mapping of FUS-RNA interactions reveals that the canonical RNA-binding domains recognise G-rich and C-rich motifs, whereas condensation selectively enhances binding to G-rich and structured sequences, often acting in concert with canonical RNA-binding to control transcriptional programs and splicing decisions. These findings provide a mechanistic framework for how FUS integrates condensation with sequence-specific RNA recognition to orchestrate nuclear organisation, genome stability and RNA metabolism. Furthermore, our rigorously validated mutants offer a platform for future mechanistic dissection of ALS pathogenesis and the development of targeted therapeutic strategies. HighlightsO_LIFUS condensation and RNA-binding can be functionally uncoupled with targeted point mutations C_LIO_LICondensation drives FUS recruitment and assembly of nuclear RNP condensates C_LIO_LIFUS condensation and RNA-binding play distinct roles in the DNA damage response C_LIO_LIThe structured RNA-binding domains confer specificity to G-rich and C-rich motifs C_LIO_LICondensation enhances FUS binding to G-rich, structured RNA elements C_LIO_LIFUS condensation and canonical RNA-binding synergistically regulate gene expression C_LI

molecular biology↗

bioRxiv2022

The cancer-associated RBM39 bridges the pre-mRNA, U1 and U2 snRNPs to regulate alternative splicing

Pharmacologic depletion of RNA-binding motif 39 (RBM39) using aryl sulfonamides represents a promising anti-cancer therapy. However, its efficiency correlates with the expression level of DCAF15 which acts at the interface between RBM39, the drug and the E3-ubiquitin ligase. Consequently, the identification of alternative approaches to deplete RBM39 independently of DCAF15 is required. Here, we combined transcriptomic analysis, functional assays, and structural biology to elucidate the molecular mechanisms governing RBM39 homeostasis. Our data revealed that RBM39 autoregulates the splicing of its own pre-mRNA by triggering the inclusion of a poison exon. During this process, RBM39 selects the 3-splice site of the toxic exon, helps the recruitment of U1 snRNP on its weak 5-splice site and bridges the 3-splice site recognition machinery. The elucidation of the molecular mechanisms controlling RBM39 homeostasis provides unprecedented insights into alternative 3-splice site selection and a solid frame to design alternative anti-cancer therapies.

molecular biology↗

bioRxiv2019

The phase separation-dependent FUS interactome reveals nuclear and cytoplasmic function of liquid-liquid phase separation

Liquid-liquid phase separation (LLPS) of proteins and RNAs has emerged as the driving force underlying the formation of membrane-less organelles. Such biomolecular condensates have various biological functions and have been linked to disease. One of the best studied proteins undergoing LLPS is Fused in Sarcoma (FUS), a predominantly nuclear RNA-binding protein. Mutations in FUS have been causally linked to Amyotrophic Lateral Sclerosis (ALS), an adult-onset motor neuron disease, and LLPS followed by aggregation of cytoplasmic FUS has been proposed to be a crucial disease mechanism. In spite of this, it is currently unclear how LLPS impacts the behaviour of FUS in cells, e.g. its interactome. In order to study the consequences of LLPS on FUS and its interaction partners, we developed a method that allows for the purification of phase separated FUS-containing droplets from cell lysates. We observe substantial alterations in the interactome of FUS, depending on its biophysical state. While non-phase separated FUS interacts mainly with its well-known interaction partners involved in pre-mRNA processing, phase-separated FUS predominantly binds to proteins involved in chromatin remodelling and DNA damage repair. Interestingly, factors with function in mitochondria are strongly enriched with phase-separated FUS, providing a potential explanation for early changes in mitochondrial gene expression observed in mouse models of ALS-FUS. In summary, we present a methodology that allows to investigate the interactome of phase-separating proteins and provide evidence that LLPS strongly shapes the FUS interactome with important implications for function and disease.

molecular biology↗