GO:0140694 membraneless organelle assembly: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140694 membraneless organelle assembly describes the aggregation, arrangement and bonding of components into non-membrane-bounded organelles.
• Membraneless organelles are biomolecular condensates formed by phase separation and multivalent interactions among proteins and RNAs.
• Architectural RNAs can act as blueprints that template the assembly of functional membraneless organelles.
• Dysregulation of membraneless organelle assembly is linked to cancer, neurodegeneration, and ageing.
• Kinase signaling, especially RAS-MAPK, can nucleate cytoplasmic protein granules that amplify signaling.
• CRISPR-based knockout, knock-in, and overexpression models enable causal testing of condensate components.
Description
Membraneless organelles are micron-scale compartments that concentrate specific proteins and nucleic acids without a surrounding lipid bilayer. The process by which these compartments form, termed membraneless organelle assembly (GO:0140694), encompasses the aggregation, arrangement, and bonding of components into a non-membrane-bounded organelle. This Gene Ontology term captures a fundamental cellular strategy for organizing biochemistry in space and time, and it is increasingly recognized as a central node in gene regulation, stress responses, and disease. Researchers study GO:0140694 because condensates such as nucleoli, stress granules, P-bodies, and nuclear speckles control RNA processing, translation, and signaling. Architectural RNAs provide scaffolds that seed assembly, ensuring that condensates contain the correct molecular partners. Moreover, condensate assembly can be tuned by post-translational modifications and small molecules, making it a tractable target for therapeutic intervention. Understanding the assembly rules of membraneless organelles therefore bridges cell biology, biophysics, and precision medicine.
membraneless organelle assembly At A Glance
| GO ID | GO:0140694 |
|---|---|
| GO term | membraneless organelle assembly |
| Ontology | biological_process |
| Synonym | non-membrane-bounded organelle assembly; non-membrane-bounded organelle formation; non-membrane-enclosed organelle assembly; non-membrane-enclosed organelle formation |
| Major function | Aggregation, arrangement and bonding of components to form a non-membrane-bounded organelle |
| Related cellular structures | Stress granules, P-bodies, nucleoli, nuclear speckles, cytoplasmic granules |
| Key driving forces | Multivalent protein-protein and protein-RNA interactions, phase separation |
| Representative regulators | Architectural RNAs, kinases, post-translational modifications |
| Disease relevance | Cancer, neurodegeneration, ageing, liver fibrosis |
What Is GO:0140694?
GO:0140694 membraneless organelle assembly is defined as the aggregation, arrangement and bonding together of a set of components to form a non-membrane-bounded organelle. In practice, this includes the nucleation, growth, and maturation of biomolecular condensates that lack a lipid bilayer, such as stress granules, P-bodies, nucleoli, and nuclear speckles. The term is synonymous with non-membrane-bounded organelle assembly, non-membrane-bounded organelle formation, non-membrane-enclosed organelle assembly, and non-membrane-enclosed organelle formation.
Why Is membraneless organelle assembly Important in Cell Biology?
Membraneless organelle assembly is important because it provides a general mechanism for concentrating biomolecules, accelerating biochemical reactions, and buffering cellular stress. Condensates formed through this process participate in gene regulation, RNA metabolism, and signal transduction, and their material properties can determine whether a cell survives or commits to death. Because condensate assembly is reversible and tunable, it represents a promising target for drug discovery across oncology, neurology, and metabolic disease.
• Membraneless organelles concentrate enzymes and substrates to enhance reaction rates and specificity.
• They serve as signaling hubs that amplify kinase cascades such as RAS-MAPK.
• Architectural RNAs template the assembly of functional condensates and ensure compositional fidelity.
• Condensate assembly is a first-line response to cellular stress, including heat shock and oxidative stress.
• Dysregulated assembly contributes to protein aggregation diseases and neurodegeneration.
• Membraneless organelles regulate gene expression at transcriptional and post-transcriptional levels.
• Lipid-induced granules in hepatocytes can alleviate liver fibrosis, highlighting metabolic roles.
• Condensate modulators are emerging as a novel drug class for cancer and other diseases.
• Micropeptide killswitches allow precise probing of condensate microenvironments.
• CRISPR screens can identify genes required for condensate assembly and maintenance.
What Happens During membraneless organelle assembly?
Nucleation and seeding
In simple terms: The first step is like forming a tiny seed that other molecules can stick to.
Assembly begins with nucleation, where a small number of multivalent proteins and RNAs come together to form a seed. Architectural RNAs can act as scaffolds that recruit specific proteins and lower the energetic barrier to nucleation. This seeding step determines the composition and identity of the resulting condensate.
Growth and fusion
In simple terms: Once a seed exists, more molecules join and small droplets merge into larger ones.
Following nucleation, condensates grow by recruiting additional components through weak, multivalent interactions. Small droplets can fuse with each other, a process driven by surface tension and liquid-like properties. Growth can be regulated by post-translational modifications that alter valency or solubility.
Maturation and material state
In simple terms: Over time, the droplet can become more solid or gel-like, changing its function.
Membraneless organelles can mature from liquid-like to gel-like or solid-like states, which affects their function and reversibility. Maturation is influenced by the concentration of components, time, and disease-associated mutations. The material state of a condensate can determine whether it remains dynamic or becomes pathological.
Disassembly and clearance
In simple terms: When the cell no longer needs the organelle, it can dissolve or be cleared away.
Disassembly occurs when interactions are weakened, for example by phosphorylation or changes in RNA availability. Clearance mechanisms include chaperone-mediated disaggregation and autophagy. Failure to disassemble can lead to persistent aggregates associated with disease.
Key Genes Involved in GO:0140694 membraneless organelle assembly
The following genes and proteins are representative components or regulators of membraneless organelle assembly, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| G3BP1 | Core stress granule nucleator | Knockout reduces stress granule assembly |
| TIA1 | Stress granule component | Mutations linked to neurodegeneration |
| FUS | RNA-binding protein in condensates | ALS-associated mutations alter phase behavior |
| EWSR1 | Condensate-forming transcription factor | Fusion proteins in Ewing sarcoma |
| NPM1 | Nucleolar and cytoplasmic granule component | Leukemia-associated mutations |
| RAS | Signaling protein that forms cytoplasmic granules | Kinase-mediated granule assembly |
| mTOR | Regulator of condensate assembly via phosphorylation | Controls stress granule dynamics |
| DDX3X | RNA helicase in stress granules | Mutations affect condensate properties |
| ATXN2 | RNA-binding protein in stress granules | PolyQ expansion alters assembly |
| TDP-43 | RNA-binding protein forming pathological aggregates | ALS and FTD models |
| HNRNPA1 | Stress granule component | Mutations cause proteinopathy |
| NEAT1 | Architectural RNA for paraspeckles | Required for paraspeckle assembly |
| MALAT1 | Architectural RNA for nuclear speckles | Regulates speckle organization |
| SGK1 | Kinase that modulates condensate formation | Potential drug target |
| UBQLN2 | Shuttles proteins to condensates | Mutations in ALS |
| VCP | ATPase involved in clearance | Mutations cause multisystem proteinopathy |
| SQSTM1 | Autophagy receptor for condensate clearance | Links condensates to degradation |
How Is membraneless organelle assembly Regulated?
Membraneless organelle assembly is regulated by post-translational modifications, particularly phosphorylation, which can alter the valency and solubility of condensate components. Kinase signaling, such as the RAS-MAPK pathway, can nucleate cytoplasmic granules that amplify signaling. Architectural RNAs provide a regulatory scaffold that determines which proteins are recruited. Additionally, cellular stress and changes in ATP levels can shift the equilibrium between assembly and disassembly.
membraneless organelle assembly and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FUS | ALS | Knock-in of ALS-associated mutations in iPSCs |
| TDP-43 | ALS/FTD | Overexpression of mutant TDP-43 in neurons |
| RAS | Cancer | Knockout of RAS granule components in cancer cell lines |
| ATXN2 | Spinocerebellar ataxia | Point mutation knock-in in mice |
| NPM1 | Leukemia | Knock-in of NPM1 mutations in hematopoietic cells |
Cancer
Membraneless organelles can concentrate oncogenic signaling molecules, and their assembly is often dysregulated in cancer. For example, RAS signaling via cytoplasmic granules promotes tumorigenesis, and condensate modulators are being explored as anticancer drugs.
Neurodegeneration
Aberrant assembly and maturation of stress granules into solid aggregates are linked to amyotrophic lateral sclerosis, frontotemporal dementia, and Alzheimer's disease. Mutations in FUS, TDP-43, and ATXN2 alter condensate dynamics and contribute to neuronal toxicity.
Metabolic and liver disease
Lipid-induced granules in hepatocytes can alleviate liver fibrosis, indicating that membraneless organelle assembly participates in metabolic stress responses. This suggests that modulating condensate formation may have therapeutic potential in liver disease.
From membraneless organelle assembly-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X nucleate stress granules? | Knockout cell line followed by stress induction |
| Does mutation Y alter condensate material properties? | Point mutation knock-in via CRISPR |
| Does tagging gene Z affect condensate localization? | Tagged knock-in with fluorescent protein |
| Does overexpression of gene W drive assembly? | Doxycycline-inducible overexpression |
| Which genes are required for condensate assembly? | Genome-wide CRISPR knockout library screening |
| What is the RNA composition of condensates? | RNA-seq after condensate purification |
How to Study the membraneless organelle assembly Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Condensate number, size, dynamics | Live-cell imaging of stress granules |
| FRAP | Molecular exchange rate | Assessing liquid-like vs solid-like state |
| Mass spectrometry | Protein composition | Identifying condensate proteome |
| RNA-seq | RNA composition | Discovering architectural RNAs |
| CRISPR knockout screen | Gene requirement for assembly | Identifying novel regulators |
| Proximity labeling | Interactome | Mapping condensate protein networks |
| Micropeptide killswitch | Condensate microenvironment | Probing pH or redox state |
Fluorescence microscopy and live imaging
Fluorescence microscopy of tagged proteins allows real-time visualization of condensate assembly and dynamics. Live imaging can track fusion, fission, and disassembly events.
Proteomics and interactomics
Mass spectrometry of purified condensates identifies their protein composition and post-translational modifications. Proximity labeling can map the interactome of condensate components.
RNA sequencing and architectural RNA analysis
RNA-seq of condensate fractions reveals enriched architectural RNAs that template assembly. Knockdown of candidate architectural RNAs can test their requirement for assembly.
CRISPR screening
Genome-wide CRISPR knockout screens can identify genes essential for membraneless organelle assembly under specific conditions. These screens link genotype to condensate phenotypes.
How CRISPR Can Be Used to Study GO:0140694 membraneless organelle assembly
Knockout
CRISPR knockout of candidate genes can test whether they are required for membraneless organelle assembly. For example, knocking out G3BP1 reduces stress granule formation.
Point Mutation
Point mutation knock-in can model disease-associated mutations that alter condensate properties. This approach is useful for studying ALS-linked mutations in FUS or TDP-43.
Knock-in
Tagged knock-in of fluorescent proteins allows visualization of endogenous condensate components. This avoids artifacts from overexpression and preserves native regulation.
Overexpression
Overexpression of condensate components can drive assembly and reveal sufficiency. Inducible systems allow temporal control of assembly.
How EDITGENE Supports membraneless organelle assembly Research
Researchers studying membraneless organelle assembly-related genes often need to determine whether a candidate gene is causally involved in condensate formation, maintenance, or disassembly. EDITGENE provides a comprehensive suite of CRISPR services to enable such causal experiments.
Contact EDITGENE today to design your custom CRISPR model for membraneless organelle assembly research.
Frequently Asked Questions About membraneless organelle assembly
What is GO:0140694 membraneless organelle assembly?
GO:0140694 is a Gene Ontology biological process term defined as the aggregation, arrangement and bonding together of a set of components to form a non-membrane-bounded organelle.
What are membraneless organelles?
Membraneless organelles are biomolecular condensates that concentrate proteins and RNAs without a lipid bilayer, such as stress granules and nucleoli.
What genes are involved in membraneless organelle assembly?
Key genes include G3BP1, TIA1, FUS, EWSR1, NPM1, RAS, and architectural RNAs like NEAT1 and MALAT1.
How is membraneless organelle assembly regulated?
It is regulated by post-translational modifications, kinase signaling, and architectural RNAs.
What diseases are linked to membraneless organelle assembly?
Cancer, neurodegeneration (ALS, FTD), and liver fibrosis are linked to dysregulated condensate assembly.
What methods study membraneless organelle assembly?
Fluorescence microscopy, FRAP, mass spectrometry, RNA-seq, and CRISPR screens are commonly used.
Can CRISPR be used to study membraneless organelles?
Yes, CRISPR knockout, knock-in, and overexpression models enable causal testing of condensate components.
What is the role of RNA in membraneless organelle assembly?
Architectural RNAs act as scaffolds that template the assembly of functional condensates.
How do stress granules form?
Stress granules form by phase separation of RNA-binding proteins and RNAs upon stress, a process regulated by phosphorylation.
What is the difference between membraneless and membrane-bound organelles?
Membraneless organelles lack a lipid bilayer and form via phase separation, while membrane-bound organelles are enclosed by membranes.
Conclusion
Membraneless organelle assembly (GO:0140694) is a fundamental biological process that organizes cellular biochemistry through phase separation and multivalent interactions. Its dysregulation is implicated in cancer, neurodegeneration, and metabolic disease, making it a compelling target for research and therapeutic development. CRISPR-based models and advanced imaging and omics methods are essential tools for dissecting the molecular rules of assembly.
References
- 1. Banani SF et al.. 2017. Biomolecular condensates: organizers of cellular biochemistry.. Nat Rev Mol Cell Biol 18(5):285-298 PMID: 28225081
- 2. Hirose T et al.. 2025. Architectural RNAs: blueprints for functional membraneless organelle assembly.. Trends Genet 41(10):919-933 PMID: 40514312
- 3. Alberti S et al.. 2021. Biomolecular condensates at the nexus of cellular stress, protein aggregation disease and ageing.. Nat Rev Mol Cell Biol 22(3):196-213 PMID: 33510441
- 4. Li Y et al.. 2026. Lipid-induced granules in hepatocytes alleviate liver fibrosis.. Cell Metab 38(4):746-762.e10 PMID: 41519131
- 5. Hirose T et al.. 2023. A guide to membraneless organelles and their various roles in gene regulation.. Nat Rev Mol Cell Biol 24(4):288-304 PMID: 36424481
- 6. Tulpule A et al.. 2021. Kinase-mediated RAS signaling via membraneless cytoplasmic protein granules.. Cell 184(10):2649-2664.e18 PMID: 33848463
- 7. Mitrea DM et al.. 2022. Modulating biomolecular condensates: a novel approach to drug discovery.. Nat Rev Drug Discov 21(11):841-862 PMID: 35974095
- 8. Zhang Y et al.. 2025. Probing condensate microenvironments with a micropeptide killswitch.. Nature 643(8073):1107-1116 PMID: 40468084
