GO:0043519 regulation of myosin II filament organization: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0043519 describes any process that modulates the frequency, rate or extent of the assembly, arrangement, or disassembly of bipolar filaments composed of myosin II molecules.
• Myosin II filament organization is driven by the dynamic equilibrium between folded, assembly-incompetent myosin II and extended, filament-competent conformations regulated by phosphorylation of the regulatory light chain and heavy chain.
• Non-muscle myosin II (NMII) isoforms NMIIA, NMIIB, and NMIIC are the principal effectors of this process in cell motility, cytokinesis, and tissue morphogenesis.
• Dysregulation of myosin II filament organization contributes to cancer invasion, metastasis, and neuromuscular disorders.
• Reconstituted actomyosin systems and model organisms have been instrumental in defining the self-organization principles of myosin II filaments.
• CRISPR-based knockout, point-mutation, and knock-in models enable causal interrogation of myosin II regulatory genes in health and disease.
Description
Regulation of myosin II filament organization (GO:0043519) is a biological process that controls the assembly, spatial arrangement, and disassembly of bipolar filaments formed by myosin II molecules. Myosin II is a mechanochemical motor protein whose filamentous form generates contractile forces essential for cytokinesis, cell migration, and tissue morphogenesis. The transition between monomeric (folded) and filamentous (extended) myosin II is tightly regulated, and this regulation determines where and when contractile forces are produced in cells. Understanding GO:0043519 is therefore central to cell biology, developmental biology, and disease research. In non-muscle cells, myosin II filament dynamics shape force generation and are modulated by phosphorylation events and conformational changes in the myosin head and tail domains. In muscle, myosin II is a core component of the sarcomeric contractile apparatus, and its assembly is coordinated with thin filament regulation. Genetic analyses in model organisms have revealed conserved mechanisms of myosin II assembly and organization. Moreover, reconstituted actomyosin bundles have demonstrated that myosin II can self-organize into contractile networks, providing mechanistic insight into filament organization. This article synthesizes authoritative QuickGO annotation and verified PubMed literature to provide a research-grade overview of GO:0043519, its key genes, disease relevance, and experimental methods.
regulation of myosin II filament organization At A Glance
| GO ID | GO:0043519 |
|---|---|
| GO term | regulation of myosin II filament organization |
| Ontology | biological_process |
| Synonym | regulation of myosin II filament assembly or disassembly; regulation of myosin II filament organisation |
| Definition | Any process that modulates the frequency, rate or extent of the assembly, arrangement of constituent parts, or disassembly of a bipolar filament composed of myosin II molecules. |
| Major function | Controls the dynamic assembly and disassembly of myosin II bipolar filaments, thereby regulating contractile force generation in non-muscle and muscle cells. |
| Key effectors | Non-muscle myosin II isoforms (NMIIA, NMIIB, NMIIC), regulatory light chain (MRLC), myosin heavy chain kinases. |
| Related processes | Cytokinesis, cell migration, mechanotransduction, sarcomere organization. |
What Is GO:0043519?
According to the Gene Ontology, GO:0043519 (regulation of myosin II filament organization) encompasses any process that modulates the frequency, rate, or extent of the assembly, arrangement of constituent parts, or disassembly of a bipolar filament composed of myosin II molecules. In other words, it covers the regulatory inputs that determine whether myosin II molecules polymerize into bipolar filaments, how those filaments are spatially organized, and when they are disassembled.
Why Is regulation of myosin II filament organization Important in Cell Biology?
GO:0043519 is important because myosin II filament organization is a fundamental determinant of cell shape, motility, and force generation, and its dysregulation is linked to cancer progression, metastasis, and neuromuscular disorders. Understanding the regulatory mechanisms of myosin II filament assembly provides insight into basic cell biology and identifies potential therapeutic targets.
• Controls cytokinesis and cell division by organizing the contractile ring.
• Regulates cell migration and invasion, with implications for cancer metastasis.
• Maintains tissue architecture through mechanosensing and cytoskeletal memory.
• Dysregulation contributes to neuromuscular disorders and satellite cell dysfunction.
• Provides a model for self-organization of contractile actomyosin networks.
• Involved in sarcomere assembly and muscle contraction.
• Serves as a target for CRISPR-based functional studies of myosin II regulators.
• Relevant to understanding force generation in non-muscle cells.
• Conserved mechanisms across model organisms inform human disease research.
• Potential therapeutic target in cancer and muscle disorders.
What Happens During regulation of myosin II filament organization?
Conformational switching of myosin II
In simple terms: Myosin II can fold into a compact shape that cannot form filaments, or unfold into a shape that can.
Myosin II exists in an equilibrium between a folded, assembly-incompetent monomer and an extended, filament-competent conformation. This conformational switch is regulated by phosphorylation of the regulatory light chain and the heavy chain, and by intramolecular interactions between the head and tail domains. The balance between these states determines the availability of myosin II for filament assembly.
Nucleation and elongation of bipolar filaments
In simple terms: Myosin II molecules stick together to form small rods that grow into bipolar filaments.
Once in the extended conformation, myosin II molecules associate via their tail domains to form bipolar filaments. Reconstituted actomyosin systems have shown that myosin II can self-organize into contractile bundles, indicating that filament nucleation and elongation are intrinsic properties modulated by regulatory inputs. The assembly process is dynamic and reversible, allowing rapid remodeling of the cytoskeleton.
Phosphorylation-dependent regulation
In simple terms: Adding phosphate groups to myosin II controls whether it can form filaments.
Phosphorylation of the myosin II regulatory light chain (MRLC) by kinases such as Rho-associated kinase (ROCK) promotes filament assembly and contractility. Conversely, phosphorylation of the heavy chain in the tail domain can inhibit filament formation by stabilizing the folded state. These phosphorylation events are tightly regulated in space and time to control local contractile activity.
Disassembly and turnover
In simple terms: Filaments can be taken apart to allow the cell to change shape or move.
Myosin II filaments undergo continuous turnover, with disassembly regulated by phosphatases and other factors. This turnover is essential for dynamic processes such as cytokinesis and cell migration, where rapid reorganization of the actomyosin cytoskeleton is required. Genetic studies in model organisms have identified conserved regulators of myosin II disassembly.
Integration with actin cytoskeleton
In simple terms: Myosin II filaments work together with actin fibers to generate force.
Myosin II filament organization is intimately linked to the actin cytoskeleton, as myosin II motors pull on actin filaments to generate contractile forces. The spatial arrangement of myosin II filaments relative to actin bundles determines the direction and magnitude of force. Regulatory pathways that control actin dynamics also influence myosin II filament organization.
Key Genes Involved in GO:0043519 regulation of myosin II filament organization
The following genes and proteins are key regulators or components of myosin II filament organization, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MYH9 | Encodes non-muscle myosin IIA heavy chain; forms bipolar filaments in non-muscle cells | Mutations cause MYH9-related disorders; studied in cell motility and cancer |
| MYH10 | Encodes non-muscle myosin IIB heavy chain; involved in cytokinesis and neuronal development | Knockout models show defects in heart and brain development |
| MYH11 | Encodes smooth muscle myosin heavy chain; forms filaments in smooth muscle | Associated with aortic aneurysms and gut motility disorders |
| MYH7 | Encodes cardiac muscle myosin heavy chain; sarcomeric filament assembly | Mutations cause hypertrophic cardiomyopathy |
| MYL9 | Encodes regulatory light chain of myosin II; regulates filament assembly via phosphorylation | Phosphorylation status controls contractility |
| MYL12B | Encodes regulatory light chain; modulates myosin II activity | Involved in cytokinesis and cell shape |
| ROCK1 | Kinase that phosphorylates MRLC to promote filament assembly | Target for cancer and cardiovascular research |
| ROCK2 | Kinase that phosphorylates MRLC; regulates contractility | Involved in cell migration and metastasis |
| MYLK | Myosin light chain kinase; phosphorylates MRLC | Regulates smooth muscle contraction |
| PPP1R12A | Myosin phosphatase target subunit; dephosphorylates MRLC to promote disassembly | Regulates filament turnover |
| CDC42 | Rho GTPase; regulates actin and myosin II organization | Involved in cell polarity and migration |
| RHOA | Rho GTPase; activates ROCK to promote myosin II filament assembly | Key regulator of contractility |
| ACTN1 | Actinin; crosslinks actin and interacts with myosin II | Structural component of contractile bundles |
| FLNA | Filamin; actin-crosslinking protein that modulates myosin II organization | Mutations cause developmental disorders |
| MYO18A | Unconventional myosin XVIII; may regulate myosin II filament organization | Studied in developmental processes |
| MYO18B | Unconventional myosin XVIIIB; involved in muscle and non-muscle functions | Potential role in filament organization |
| TTN | Titin; sarcomeric protein that interacts with myosin II | Mutations cause cardiomyopathies |
| MYBPC3 | Myosin binding protein C; regulates myosin II filament assembly in muscle | Mutations cause hypertrophic cardiomyopathy |
How Is regulation of myosin II filament organization Regulated?
Regulation of myosin II filament organization is controlled by phosphorylation events, small GTPases, and mechanical signals. RhoA activates ROCK, which phosphorylates the myosin regulatory light chain to promote filament assembly and contractility. Conversely, myosin phosphatase (PPP1R12A) dephosphorylates MRLC, favoring disassembly. Mechanical cues from the extracellular matrix can also modulate myosin II organization through mechanosensing pathways. In muscle, myosin II filament assembly is coordinated with thin filament regulation and sarcomere assembly.
regulation of myosin II filament organization and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MYH9 | MYH9-related disorders (thrombocytopenia, hearing loss) | Knockout mouse, patient-derived iPSCs |
| MYH7 | Hypertrophic cardiomyopathy | Knock-in mouse, hiPSC-derived cardiomyocytes |
| MYBPC3 | Hypertrophic cardiomyopathy | Knockout mouse, hiPSC-derived cardiomyocytes |
| ROCK1 | Cancer metastasis | Xenograft models, CRISPR knockout cell lines |
| MYH10 | Neurological and cardiac defects | Knockout mouse, zebrafish |
Cancer invasion and metastasis
Matrix mechano-sensing at the invasive front induces a cytoskeletal and transcriptional memory that supports metastasis, involving myosin II filament organization. Dysregulated myosin II activity promotes cancer cell migration and invasion.
Neuromuscular disorders
Muscle satellite cell dysfunction in neuromuscular disorders involves perturbations in myosin II filament organization and contractile machinery. Mutations in myosin heavy chain genes cause various myopathies.
Cardiomyopathies
Mutations in MYH7 and MYBPC3, which encode sarcomeric proteins, disrupt myosin II filament assembly and cause hypertrophic cardiomyopathy.
From regulation of myosin II filament organization-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MYH9 affect myosin II filament assembly? | MYH9 knockout cell line (e.g., HeLa, MEF) |
| How does a disease mutation in MYH7 alter filament organization? | MYH7 point-mutation knock-in hiPSCs |
| Can a tagged myosin II be used to visualize filament dynamics? | GFP-tagged MYH9 knock-in cell line |
| Does overexpression of ROCK1 increase filament assembly? | ROCK1 overexpression stable cell line |
| What genes regulate myosin II filament disassembly? | CRISPR library screening in model organisms |
| How does matrix stiffness affect myosin II organization? | 3D culture models with tunable stiffness |
How to Study the regulation of myosin II filament organization Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Live-cell fluorescence microscopy | Filament assembly/disassembly dynamics | Visualizing myosin II organization in real time |
| Phospho-specific Western blot | Phosphorylation levels of MRLC and MHC | Assessing regulatory states |
| In vitro reconstitution | Self-organization of actomyosin bundles | Mechanistic studies of filament assembly |
| CRISPR knockout screening | Gene requirement for filament organization | Identifying novel regulators |
| FRAP (fluorescence recovery after photobleaching) | Filament turnover rates | Quantifying dynamic exchange |
| Traction force microscopy | Contractile forces generated by myosin II | Linking organization to force |
| Proximity ligation assay | Interactions between myosin II and regulators | Detecting molecular associations |
| RNA-seq | Transcriptional changes in myosin II regulators | Profiling gene expression |
Live-cell imaging of myosin II filaments
Fluorescently tagged myosin II (e.g., GFP-MYH9) allows real-time visualization of filament assembly and disassembly dynamics in living cells.
Phosphorylation analysis
Western blotting with phospho-specific antibodies against MRLC and myosin heavy chain can quantify the phosphorylation states that regulate filament organization.
Reconstituted actomyosin systems
In vitro reconstitution of actin and myosin II allows controlled study of self-organization and force generation.
CRISPR-based genetic screens
Genome-wide CRISPR knockout screens can identify genes that regulate myosin II filament organization in various cell types.
How CRISPR Can Be Used to Study GO:0043519 regulation of myosin II filament organization
Knockout
CRISPR knockout of myosin II heavy chain genes (e.g., MYH9, MYH10) or regulatory kinases (e.g., ROCK1) can abolish filament assembly and reveal essential functions in cytokinesis and migration.
Point Mutation
Introducing disease-associated point mutations (e.g., in MYH7 or MYH9) via CRISPR base editing or HDR allows study of how specific residues affect filament organization and contractility.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) into endogenous myosin II genes enables visualization of filament dynamics at physiological expression levels.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression of myosin II regulators (e.g., ROCK1) can drive excessive filament assembly and contractility, modeling gain-of-function states.
How EDITGENE Supports regulation of myosin II filament organization Research
Researchers studying regulation of myosin II filament organization-related genes often need to determine whether a candidate gene is causally involved in filament assembly, disassembly, or contractile function. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for regulation of myosin II filament organization research.
Frequently Asked Questions About regulation of myosin II filament organization
What is GO:0043519?
GO:0043519 is the Gene Ontology term for regulation of myosin II filament organization, defined as any process that modulates the frequency, rate or extent of the assembly, arrangement, or disassembly of bipolar filaments composed of myosin II molecules.
What genes are involved in regulation of myosin II filament organization?
Key genes include MYH9, MYH10, MYH11, MYH7, MYL9, ROCK1, ROCK2, and PPP1R12A, among others.
How is myosin II filament organization regulated?
It is regulated by phosphorylation of the regulatory light chain and heavy chain, small GTPases such as RhoA, and mechanical signals.
What diseases are associated with myosin II filament organization?
Diseases include cancer metastasis, neuromuscular disorders, and cardiomyopathies.
What methods are used to study myosin II filament organization?
Methods include live-cell imaging, phospho-specific Western blotting, in vitro reconstitution, and CRISPR screens.
What is the role of non-muscle myosin II in cell migration?
Non-muscle myosin II generates contractile forces that drive cell migration and invasion, and its filament organization is dynamically regulated.
How does phosphorylation affect myosin II filaments?
Phosphorylation of the regulatory light chain promotes filament assembly, while heavy chain phosphorylation can inhibit it.
Can CRISPR be used to study myosin II filament organization?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect gene function in this process.
What is the role of ROCK in myosin II filament organization?
ROCK phosphorylates the myosin regulatory light chain to promote filament assembly and contractility.
Why is myosin II filament organization important in cancer?
Dysregulated myosin II filament organization promotes cancer cell invasion and metastasis, and is linked to mechanosensing at the invasive front.
Conclusion
Regulation of myosin II filament organization (GO:0043519) is a critical biological process that controls contractile force generation in cells. Its dysregulation is implicated in cancer, neuromuscular disorders, and cardiomyopathies. CRISPR-based models and advanced imaging techniques continue to unravel the molecular mechanisms, offering potential therapeutic targets. EDITGENE provides comprehensive services to accelerate research in this field.
References
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- 2. Ganassi M et al.. 2022. Involvement of muscle satellite cell dysfunction in neuromuscular disorders: Expanding the portfolio of satellite cell-opathies.. Eur J Transl Myol 32(1) PMID: 35302338
- 3. Maiques O et al.. 2025. Matrix mechano-sensing at the invasive front induces a cytoskeletal and transcriptional memory supporting metastasis.. Nat Commun 16(1):1394 PMID: 39952917
- 4. Morano I. 2024. The Contractile Machines of the Heart.. Adv Exp Med Biol 1441:417-433 PMID: 38884723
- 5. Pérez-Díaz R et al.. 2026. A song of heads and tails: myosin II conformational regulation and filament dynamics shape force generation in non-muscle cells.. Biophys Rev 18(1):201-220 PMID: 41909621
- 6. Landsverk ML et al.. 2005. Genetic analysis of myosin II assembly and organization in model organisms.. Cell Mol Life Sci 62(19-20):2270-82 PMID: 16142426
- 7. Szikora S et al.. 2022. The Mechanisms of Thin Filament Assembly and Length Regulation in Muscles.. Int J Mol Sci 23(10) PMID: 35628117
- 8. Stachowiak MR et al.. 2012. Self-organization of myosin II in reconstituted actomyosin bundles.. Biophys J 103(6):1265-74 PMID: 22995499
