Search Results (152)

The cytoskeleton fulfills many essential roles that are necessary for cell function. Perhaps the most important of these roles is the formation of the mitotic spindle. The mitotic spindle is a complex and dynamic structure made up mainly of microtubules and numerous microtubule-associated proteins (MAPs), but the mechanisms behind its creation and regulation are not fully characterized. Recent research has focused on the link between liquid–liquid phase separation (LLPS) of MAPs and these microtubule organizations. Here, we focus on the protein regulator of cytokinesis 1 (PRC1), a spindle midzone-associated anti-parallel microtubule crosslinker. PRC1 is known to undergo LLPS to form condensed droplets without the need for additional crowders. Using confocal fluorescence microscopy and different constructs of PRC1, we investigate the ability of PRC1’s structural domains to form droplets and hierarchically organize microtubule tactoids. We find that the removal of PRC1’s unstructured C-terminal tail does not inhibit its ability to form droplets or microtubule tactoids in vitro. Removing part of PRC1’s N-terminal rod domain inhibits but does not completely suppress droplet formation. Full article

Liquid–liquid phase separation (LLPS) underlies the formation of membraneless cellular compartments, yet experimental strategies that directly connect quantitative LLPS behavior with residue-level structural information remain limited. Here, we present an integrated protocol that combines quantitative LLPS assays with nuclear magnetic resonance (NMR) spectroscopy and structure-guided mutagenesis to regulate protein phase separation. Using the VAPB MSP domain as a representative example, this workflow links residue-specific structural features to macroscopic LLPS behavior and enables suppression or enhancement of phase separation through targeted amino acid substitutions. This protocol provides a generalizable framework for systematic, residue-level regulation of protein LLPS. Full article

DEAD-box (DDX) RNA helicases are essential regulators of RNA metabolism and gene expression. Among them, DDX10 remains poorly characterized despite growing evidence supporting its involvement in human diseases. This review provides a comprehensive analysis of DDX10, from its structural and functional features to its emerging roles in solid tumors and hematologic malignancies. We discuss how DDX10, through its conserved domains, contributes to pre-rRNA processing, ribosome biogenesis, and cell proliferation, and explore potential links between DDX10 and processes such as liquid–liquid phase separation (LLPS) and epigenetic regulation, which may underlie its roles in cancer cell plasticity and stress response. We argue that the dysregulation of these fundamental cellular processes positions DDX10 as a focal point where aberrant RNA metabolism and altered molecular condensates converge to disrupt transcriptional homeostasis and drive oncogenic transformation. Aberrant DDX10 expression is a recurrent feature across multiple cancers, where it promotes tumor progression, therapy resistance, and poor prognosis. Moreover, DDX10 participates in oncogenic fusion events, most notably the NUP98::DDX10 fusion identified in a subset of acute myeloid leukemias, which drives leukemogenesis by disrupting transcriptional regulation and cellular differentiation. Given its tumor-associated expression and diverse biological functions, DDX10 is increasingly recognized as a potential diagnostic biomarker and a promising target for therapeutic strategies. By consolidating current knowledge under this unifying framework, this review highlights the multifaceted roles of DDX10 in cancer biology, advocating further research into its molecular functions and translational potential. Full article

Thrombosis is a cardiovascular disease characterized by the pathological formation of a fibrin clot in blood vessels. Currently available fibrinolytic enzymes have some limitations, including severe side effects, high cost, short half-life, and low fibrin specificity. Proteins from microalgae and cyanobacteria have various biological effects and are emerging as promising sources for fibrinolytic enzymes. In this study, bioinformatics tools were used to evaluate the intrinsic disorder predisposition of microalgal fibrinolytic proteins, their capability to undergo liquid–liquid phase separation (LLPS), and the presence of disorder-based functional regions, and short linear motifs (SLiMs). Analysis revealed that these proteins are predominantly hydrophilic and exhibit acidic (pI 3.96–6.49) or basic (pI 8.05–11.0) isoelectric points. Most of them are expected to be moderately (61.4%) or highly disordered proteins (6.8%) and associated with LLPS, with nine proteins being predicted to behave as droplet drivers (i.e., being capable of spontaneous LLPS), and twenty-five proteins being expected to be droplet clients. These observations suggest that LLPS may be related to the regulation of the functionality of microalgal fibrinolytic proteins. The majority of these proteins belong to the blood coagulation inhibitor (disintegrin) 1 hit superfamily, which can inhibit fibrinogen binding to integrin receptors, preventing platelet aggregation. Furthermore, the SLiM-centered analysis indicated that the main motifs found in these proteins are MOD_GlcNHglycan and CLV_PCSK_SKI1_1, which can also play different roles in thrombolytic activity. Finally, Fisher and conservation analysis indicated that CLV_NRD_NRD_1, CLV_PCSK_FUR_1, CLV_PCSK_PC7_1, and MOD_Cter_Amidation motifs are enriched in intrinsically disordered regions (IDRs) of these proteins, showing significant conservation and suggesting compatibility with proteolytic activation and post-translational processing. These data provide important information regarding microalgal proteins with potential thrombolytic effects, which can be realized through protein–protein interactions mediated by SLiMs present in intrinsically disordered regions (IDRs). Additional analyses should be conducted to confirm these observations using experimental in vitro and in vivo approaches. Full article

The recognition of liquid–liquid phase separation (LLPS) as a widespread organizing principle has revolutionized our view of cellular biochemistry. By forming biomolecular condensates, cells spatially orchestrate reactions without membranes. However, the dysregulation of this precise physical organization is emerging as a driver of diverse pathologies, collectively termed “Condensatopathies.” Unlike traditional proteinopathies defined by static aggregates, these disorders span a dynamic spectrum of material state dysfunctions, from the failure to assemble essential compartments to the formation of aberrant, toxic phases. While research has largely focused on neurodegeneration and cancer, the impact of condensate dysfunction likely extends across broad physiological landscapes. A central unresolved challenge lies in deciphering the “molecular grammar” that governs the transition from functional fluids to pathological solids and, critically, visualizing these transitions in situ. This “material science” perspective presents a profound conundrum for drug discovery: how to target the collective physical state of a protein ensemble rather than a fixed active site. This review navigates the evolving therapeutic horizon, examining the limitations of current pharmacological approaches in addressing the complex “condensatome.” Moving beyond inhibition, we propose that the future of intervention lies in “reverse-engineering” the biophysical codes of phase separation. We discuss how deciphering these principles enables the creation of programmable molecular tools—such as synthetic peptides and state-specific degraders—designed to precisely modulate or dismantle pathological condensates, paving the way for a new era of precision medicine governed by soft matter physics. Full article

Catalytic coacervates, or droplet reactors, represent a forefront research area in chemistry and materials science. Despite advancements in this field, challenges persist in achieving liquid–liquid phase separation (LLPS) droplet compartmentalization and site-specific reactant recruitment/localization for reaction catalysis, similar to those within biological systems. Herein, we describe the catalytic coacervates for aqueous photo-RAFT in dilution, focusing on the site-specific recruitment/localization of ionized monomer with the aid of macromolecular crowding and confinement. Cooperative hydrogen-bonded interpolymer complexation (IPC) of imidazolium-copolymers initiates the ion-cluster formation. Further hierarchical inter-cluster complexation (ICC) leads to the LLPS droplet compartmentalization into charged dense-phase and neutral dilute-phase compartments. Site-specific recruitment and localization of the oppositely charged monomer into dense-phase compartments are achieved by salt-bridging molecular recognition. “Substantial DMA-dilution” (that is, macromolecular crowding) results in sustainable dense-phase catalytic sites within dilute-phase crowding surroundings, enabling reaction catalysis in dilution (<2% w/w monomer) to 97% conversion in 12 min. These findings underscore the key roles of macromolecular crowding and confinement in the tailorable LLPS droplet compartmentalization and also the site-specific reactant recruitment/localization essential for enzyme reaction catalysis, and provide practical guidelines for creating catalytic coacervates towards lifelike reaction functions. Full article

Protein droplets exhibit complex self-assembly and deposition behaviors driven by evaporation, which has attracted increasing attention in recent years. Under evaporation, limited volume and locally concentrated protein solutions can undergo liquid–liquid phase separation (LLPS) and liquid–liquid crystalline phase separation (LLCPS), inducing the formation of concentrated droplets and anisotropic structures. The combined effects of interfacial tension and internal flow field induce a variety of deposition patterns on the substrate, providing great significance for the development of functional biomaterials. This paper reviews the physical processes experienced by protein/fibril droplets during evaporation, focusing on the formation mechanism of evaporation and their phase separation behaviors. At the same time, the review systematically summarized the key factors affecting the deposition patterns, and a variety of methods were introduced to pattern deposition, such as external electric field and micro-structured substrates. Furthermore, the potential applications of proteins/fibrils droplet deposition were discussed in multiple fields. This review aims to provide systematic theoretical support and experimental reference for understanding and controlling the deposition behavior of proteins/fibrils droplets, and to promote their further application in functional materials and biomedical engineering. Full article

Best known as an organizer of the mitotic spindle, the protein product of the human assembly factor for spindle microtubules (ASPM) gene has recently been shown to function in the interphase nucleus during multiple DNA-associated processes, including BRCA1-mediated DNA DSB repair, ATR-CHK1 activation during replication stress, and transcription regulation alongside the transcription factor FOXM1. In this review, we provide an overview of these DNA-related roles of ASPM. Additionally, we suggest the facilitation of liquid–liquid phase separation (LLPS) as a potential unifying mechanism underlying ASPM function. We also consider the implications of LLPS and ASPM dysfunction in disease, and highlight the impact of cellular context including cell cycle phase-dependent post-translational protein modifications and ion concentrations. An increased understanding of LLPS in ASPM function relevant to genome stability may enable future drug discovery for diseases such as cancer. Full article

Metabolic immune evasion is a major factor limiting the long-term efficacy of intravesical Bacillus Calmette–Guérin (BCG) therapy in non-muscle-invasive bladder cancer (NMIBC). TIA1 is a stress granule RNA-binding protein with liquid–liquid phase separation (LLPS) capacity. Its role in tumor metabolism and immunotherapy response has been unclear. Here, we demonstrated that high TIA1 expression was independently associated with favorable survival across multiple cohorts. Full-length TIA1 formed cytoplasmic condensates, repressed LDHA/PKM2/HK2, reduced lactate, and lowered extracellular acidification. A condensate-defective ΔLCD (deletion of the low-complexity domain) mutant was inactive. TIA1 showed physical association with these glycolytic mRNAs in human cells, consistent with mRNA-linked control. Condensate-competent TIA1 promoted CD8⁺ T-cell proliferation, increased CD69 and Granzyme-B, and reduced PD-1 in co-culture. TIMER (Tumor Immune Estimation Resource) and spatial-omics supported co-localization with tumoral CD8A. BCG induced this metabolic–immune signature in cell lines, murine models, and patient explants, but the effects were abolished by TIA1 knock-down. Conversely, TIA1 over-expression alone limited tumor growth and recapitulated BCG-mediated glycolytic restraint and T-cell activation. Together, these results support an LLPS-linked, mRNA-associated regulation of tumor glycolysis. BCG-driven glycolytic suppression and CD8⁺ T cell activation track with the condensate-forming capacity of TIA1. TIA1 emerges as a prognostic biomarker and a potential therapeutic axis to improve intravesical immunotherapy in NMIBC. Full article

The COVID-19 pandemic caused by the SARS-CoV-2 virus has exposed the urgency of research on rapid and efficient virus detection and strategies to inhibit its replication. Previous studies have mostly focused on traditional immunoassay or optical methods, but they have limitations in terms of sensitivity, timeliness, and in-depth analysis of molecular interaction mechanisms. Solid-state nanopore single-molecule detection methods, which can monitor molecular conditions in real time at the single-molecule level, bring new opportunities to solve this problem. The nucleocapsid protein (N protein) of SARS-CoV-2 was systematically investigated under different conditions, such as external drive voltage, pH, nanopore size, and N protein concentration. The translocation of the N protein through the nanopore was then analyzed. Subsequently, we analyzed the translocation characteristics of the N protein, RNA, and N protein–RNA complexes. With the aid of EMSA experiments, we conclusively confirmed that RNA binds to the N protein. Building on this finding, we further explored small molecules that could affect the nanopore translocation of N protein–RNA complexes, such as gallocatechin gallate (GCG), epigallocatechin gallate (EGCG), and the influenza A viral inhibitor Nucleozin. The results show that GCG can disrupt the liquid-phase condensation of the N protein–RNA complex and inhibit the replication of the N protein. Meanwhile, the structural isomer EGCG of GCG and the small molecule Nucleozin can also block RNA-triggered N protein liquid–liquid phase separation (LLPS). Our results confirmed that GCG, EGCG, and Nucleozin exhibit antagonistic effects on the N protein, with differences in their effective concentrations and the potency of their antagonism. Herein, using solid-state nanopore single-molecule detection technology, we developed an experimental method that can effectively detect RNA-induced changes in N protein properties and the regulatory effects of small molecules on the LLPS of N protein–RNA complexes. These findings not only provide highly valuable insights for in-depth research on the molecular interactions involved in viral replication, but also open up promising new avenues for future responses to similar viral outbreaks, the development of a rapid and effective detection method based on solid-state nanopores and single-molecule detection, and antiviral therapies targeting N protein–RNA interactions. Full article

Low-complexity domains (LCDs) are protein regions characterized by a simple amino acid composition and low sequence complexity, as they are typically composed of repeats or a limited set of a few amino acids. Historically dismissed as “garbage sequences”, these regions are now acknowledged as critical functional elements. This review systematically explores the structural characteristics, biological functions, pathological roles, and research methodologies associated with LCDs. Structurally, LCDs are marked by intrinsic disorder and conformational dynamics, with their amino acid composition (e.g., G/Y-rich, Q-rich, S/R-rich, P-rich) dictating structural tendencies (e.g., β-sheet formation, phase separation ability). Functionally, LCDs mediate protein–protein interactions, drive liquid–liquid phase separation (LLPS) to form biomolecular condensates, and play roles in signal transduction, transcriptional regulation, cytoskeletal organization, and nuclear pore transportation. Pathologically, LCD dysfunction—such as aberrant phase separation or aggregation—is implicated in neurodegenerative diseases (e.g., ALS, AD), cancer (e.g., Ewing sarcoma), and prion diseases. We also summarize the methodological advances in LCD research, including biochemical (CD, NMR), structural (cryo-EM, HDX-MS), cellular (fluorescence microscopy), and computational (MD simulations, AI prediction) approaches. Finally, we highlight current challenges (e.g., structural heterogeneity, causal ambiguity of phase separation) and future directions (e.g., single-molecule techniques, AI-driven LCD design, targeted therapies). This review provides a comprehensive perspective on LCDs, illuminating their pivotal roles in cellular physiology and disease, and offering insights for future research and therapeutic development. Full article

Alzheimer’s disease is driven by multiple molecular drivers, including the pathological behavior of two intrinsically disordered proteins, amyloid-β (Aβ) and tau, whose aggregation is regulated by sequence-encoded ensembles and liquid–liquid phase separation (LLPS). This review integrates recent advances in biophysics, structural biology, and computational modeling to provide a multiscale perspective on how sequence determinants, post-translational modifications, and protein dynamics regulate the conformational landscapes of Aβ and tau. We discuss sequence-to-ensemble principles, from charge patterning and aromatic binders to familial mutations that reprogram structural ensembles and modulate LLPS. Structural studies, including NMR, SAXS, cryo-EM, and cryo-electron tomography, trace transitions from disordered monomers to fibrils and tissue-level structures. We highlight experimental challenges in LLPS assays, emerging standards for reproducibility, e.g., LLPSDB, PhaSePro, and FUS benchmarks, and computational strategies to refine and condensate modeling. Finally, we explore the therapeutic implications, including condensate-aware medicinal chemistry, ensemble-driven docking, and novel insights from clinical trials of anti-Aβ antibodies. Together, these perspectives underscore a paradigm shift toward environment- and ensemble-aware therapeutic design for Alzheimer’s and related protein condensation disorders. Full article

The picornavirus 3CD protein is a precursor to the 3C main protease and the 3D RNA-dependent RNA polymerase. In addition to its functions in proteolytic processing of the virus polyprotein and cleavage of key host factors, the 3C domain interacts with cis-acting replication elements (CREs) within the viral genome to regulate replication and translation events. We investigated the molecular determinants of RNA binding to 3C using a wide range of biophysical and computational methods. These studies showed that 3C binds to a broad spectrum of RNA oligonucleotides, displaying minimal sequence and structure dependence, at least for these shorter RNAs. However, they also uncovered a novel aspect of these interactions, that is, 3C-RNA binding can induce liquid–liquid phase separation (LLPS), with 3CD–RNA interactions likewise leading to LLPS. This may be a general phenomenon for other 3C and 3C-like proteases and polyproteins incorporating 3C domains. These findings have potential implications in understanding virally induced apoptosis and the control of stress granules, which involve LLPS and include other proteins with known interactions with 3C/3CD. Full article

The localization and remodeling of mRNPs is inextricably linked to translational control. In recent years there has been great progress in the field of mRNA translational control due to the characterization of the proteins and small RNAs that compose mRNPs. But our initial assumptions about the physical nature and participation of germ cell granules/condensates in mRNA regulation may have been misguided. These “granules” were found to be non-membrane-bound liquid–liquid phase-separated (LLPS) condensates that form around proteins with intrinsically disordered regions (IDRs) and RNA. Their macrostructures are dynamic as germ cells differentiate into gametes and subsequently join to form embryos. In addition, they segregate translation-repressing RNA-binding proteins (RBPs), selected eIF4 initiation factors, Vasa/GLH-1 and other helicases, several Argonautes and their associated small RNAs, and frequently components of P bodies and stress granules (SGs). Condensate movement, separation, fusion, and dissolution were long conjectured to mediate the translational control of mRNAs residing in contained mRNPs. New high-resolution microscopy and tagging techniques identified order in their organization, showing the segregation of similar mRNAs and the stratification of proteins into distinct mRNPs. Functional transitions from repression to activation seem to corelate with the overt granule dynamics. Yet increasing evidence suggests that the resident mRNPs, and not the macroscopic condensates, exert the bulk of the regulation. Full article

Transcription is a core hallmark of cancer, wherein many different proteins assemble at specific sites in the nucleus and act in concert to transcribe functionally relevant genes. Central to this process are transcription factors that bind to their cognate DNA motifs on enhancers and super-enhancers to recruit cofactors, coactivators, and epigenetic modifiers, thereby inducing or repressing gene expression. Super-enhancers drive oncogenic transcription, to which cancer cells become highly addicted and confer tumor dependencies on super-enhancer-driven transcription machinery. Transcriptional condensates (TCs) are nuclear membrane-less assemblies of DNA-binding transcription factors, transcription co-activators, and the transcriptional machinery (such as RNA polymerases, non-coding RNAs) formed through liquid–liquid phase separation (LLPS). The function of transcriptionally active oncogenic proteins and their interplay with nucleic acids are carried out within these biomolecular condensates, allowing them to spatiotemporally regulate oncogene expression and lead to the induction and maintenance of cancer. With this growing understanding, specific inhibitors and strategies targeting TC assembly and activation should be considered promising therapeutic opportunities for treating various tumors, including hematological malignancies. Full article