GO:0097512 cardiac myofibril: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0097512 cardiac myofibril is a cellular component term describing the myofibril specific to cardiac muscle cells.
• Cardiac myofibrils are the contractile machines of cardiomyocytes, built from sarcomeres containing actin, myosin, titin and associated proteins.
• Assembly and maintenance of cardiac myofibrils depend on titin ligands and focal adhesion signaling.
• Mutations in sarcomeric genes such as MYH7 cause hypertrophic cardiomyopathy with hypercontractility and altered mitochondrial respiration.
• KIAA0196 is a susceptibility gene for myofibril structural disorganization during cardiac development.
• Epigenetic regulation controls cardiac myofibril gene expression during heart development.
Description
The Gene Ontology (GO) term GO:0097512 cardiac myofibril defines the myofibril that is specific to cardiac muscle cells. Myofibrils are the cylindrical, contractile organelles that fill the cytoplasm of striated muscle cells, and the cardiac variant is specialized for the rhythmic, continuous contraction required by the heart. Understanding this structure is central to cardiac biology because its assembly, maintenance and regulation determine normal heart function and are disrupted in inherited and acquired cardiomyopathies. Researchers study cardiac myofibrils to dissect sarcomere assembly, mechanotransduction and the molecular basis of heart disease. The term is used in annotation of gene products that localize to or function within the cardiac myofibril, providing a framework for interpreting genomic and proteomic data in heart development and disease.
cardiac myofibril At A Glance
| GO ID | GO:0097512 |
|---|---|
| GO term | cardiac myofibril |
| Ontology | cellular_component |
| Synonym | None |
| Major function | Contractile apparatus of cardiac muscle cells; site of sarcomere-based force generation |
| Related structures | Sarcomere, Z-disc, M-band, intercalated disc |
| Key proteins | MYH7, ACTC1, TNNT2, TNNI3, MYBPC3, TTN, and others |
| Associated processes | Cardiac myofibril assembly, maintenance, and mechanotransduction |
| Disease relevance | Hypertrophic cardiomyopathy, dilated cardiomyopathy, developmental myofibril disorganization |
What Is GO:0097512?
GO:0097512 cardiac myofibril is a cellular component term defined as a myofibril specific to cardiac muscle cells. In practice, it refers to the contractile apparatus of cardiomyocytes, composed of repeating sarcomeres that contain actin thin filaments, myosin thick filaments, titin and numerous accessory proteins. This structure enables force generation and transmission during each heartbeat and is distinct from skeletal muscle myofibrils in its isoform composition and regulatory properties.
Why Is cardiac myofibril Important in Cell Biology?
Cardiac myofibrils are the ultimate effectors of heart contraction, and their proper assembly and regulation are essential for life. Defects in myofibril components or assembly factors cause severe cardiomyopathies and developmental heart defects, making this GO term a focal point for understanding cardiac disease mechanisms and for identifying therapeutic targets.
• Mutations in sarcomeric genes such as MYH7 cause hypertrophic cardiomyopathy with hypercontractility.
• KIAA0196 is linked to myofibril structural disorganization in cardiac development.
• Focal adhesion kinase signaling regulates myofibril viscosity in cardiac myocytes.
• Titin ligands are critical for cardiac myofibril assembly and maintenance.
• Epigenetic mechanisms control cardiac myofibril gene expression during heart development.
• Myofibril ATPase activity reflects cardiac muscle performance and adaptation to exercise.
• Frank's law of the heart links myofibril function to translational physiology.
• Cardiac myofibril networks can induce shear stress, influencing surrounding cells.
• Understanding myofibril assembly informs regenerative strategies for heart repair.
• GO:0097512 enables functional annotation of cardiac-specific contractile proteins.
What Happens During cardiac myofibril?
Assembly of sarcomeres
In simple terms: Building the repeating contractile units of the heart muscle.
Cardiac myofibril assembly begins with the formation of sarcomeres, the basic contractile units. Titin and its ligands play essential roles in this process, acting as a molecular scaffold that organizes actin and myosin filaments. Studies in cardiomyocytes show that focal adhesion kinase activity influences myofibril viscosity and structural integrity during assembly. Disruption of assembly factors such as KIAA0196 leads to myofibril disorganization in cardiac development.
Maintenance and remodeling
In simple terms: Keeping the contractile machinery in good shape and adapting it to demand.
Once formed, cardiac myofibrils undergo continuous maintenance and remodeling. Titin ligands are required not only for assembly but also for long-term maintenance of myofibril structure. Epigenetic regulation of cardiac myofibril gene expression contributes to remodeling during heart development and in response to stress. Myofibril ATPase activity, a measure of contractile protein function, changes with exercise and physiological demand.
Force generation and transmission
In simple terms: How the heart muscle generates and transmits force with each beat.
Cardiac myofibrils generate force through cyclic interactions between actin and myosin, regulated by calcium and accessory proteins. The efficiency of this process is reflected in myofibril ATPase activity. Mutations such as MYH7 G256E can cause hypercontractility and elevated mitochondrial respiration, demonstrating the tight coupling between myofibril mechanics and cellular metabolism. The mechanical activity of myofibril networks can also induce shear stress on surrounding structures.
Integration with cellular signaling
In simple terms: How the myofibril communicates with the rest of the cell.
Cardiac myofibrils are not isolated structures; they are integrated with signaling pathways that sense mechanical load and metabolic state. Focal adhesion kinase modulates myofibril viscosity, linking adhesion signaling to contractile function. Frank's law of the heart describes how myofibril length and tension translate into changes in contractility, a fundamental physiological principle. These signaling interactions ensure that myofibril function adapts to the needs of the organism.
Key Genes Involved in GO:0097512 cardiac myofibril
The following genes encode proteins that localize to or are essential for the cardiac myofibril, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MYH7 | Beta-myosin heavy chain, thick filament component | Mutations cause hypertrophic cardiomyopathy; G256E mutation studied for hypercontractility |
| ACTC1 | Alpha-cardiac actin, thin filament component | Key for sarcomere assembly; mutations linked to cardiomyopathies |
| TNNT2 | Cardiac troponin T, regulates calcium-dependent contraction | Mutations associated with hypertrophic and dilated cardiomyopathy |
| TNNI3 | Cardiac troponin I, inhibitory subunit | Phosphorylation regulates contractility; disease mutations known |
| MYBPC3 | Myosin binding protein C, modulates contraction | Commonly mutated in hypertrophic cardiomyopathy |
| TTN | Titin, giant sarcomere scaffold | Central to myofibril assembly and maintenance; ligand interactions studied |
| KIAA0196 | Component of WASH complex, affects myofibril organization | Susceptibility gene for myofibril disorganization in cardiac development |
| PTK2 | Focal adhesion kinase, signaling | Inhibition increases myofibril viscosity in cardiac myocytes |
| MYL2 | Regulatory myosin light chain | Regulates myosin activity; mutations cause cardiomyopathy |
| MYL3 | Essential myosin light chain | Structural and regulatory roles in myosin |
| TPM1 | Alpha-tropomyosin, thin filament regulation | Mutations linked to hypertrophic cardiomyopathy |
| ACTN2 | Alpha-actinin-2, Z-disc component | Maintains sarcomere structure; disease associations |
| DES | Desmin, intermediate filament | Connects myofibrils to cytoskeleton; mutations cause desmin-related myopathy |
| JPH2 | Junctophilin-2, links sarcolemma and sarcoplasmic reticulum | Important for calcium handling and myofibril function |
| CACNA1C | Voltage-gated calcium channel | Provides calcium for contraction; mutations cause Timothy syndrome |
| RYR2 | Ryanodine receptor 2, calcium release channel | Essential for excitation-contraction coupling |
| NPPA | Atrial natriuretic peptide | Marker of cardiac stress; regulated by myofibril function |
How Is cardiac myofibril Regulated?
Cardiac myofibril assembly and function are regulated at multiple levels. Epigenetic mechanisms control the expression of cardiac myofibril genes during heart development. Focal adhesion kinase signaling modulates myofibril viscosity and structural dynamics. Titin and its ligands provide mechanical regulation, sensing and responding to changes in load. Additionally, physiological factors such as exercise influence myofibril ATPase activity, reflecting metabolic and contractile adaptation. These regulatory layers ensure that the cardiac myofibril can adapt to developmental and physiological demands.
cardiac myofibril and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MYH7 | Hypertrophic cardiomyopathy | Knock-in mouse or iPSC-derived cardiomyocytes with G256E mutation |
| KIAA0196 | Myofibril disorganization in cardiac development | Knockout or knockdown in zebrafish or cardiomyocytes |
| TTN | Cardiomyopathy, myofibril assembly defects | Titin ligand knockout models |
| PTK2 | Altered myofibril viscosity | FAK inhibitor treatment in cardiac myocytes |
| TNNT2 | Hypertrophic/dilated cardiomyopathy | Point mutation knock-in models |
Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in sarcomeric genes. The MYH7 G256E mutation, for example, leads to hypercontractility and elevated mitochondrial respiration, demonstrating how a single amino acid change in a myofibril protein can alter both mechanics and metabolism. Other sarcomeric genes such as MYBPC3, TNNT2, and TNNI3 are also commonly implicated in HCM.
Developmental myofibril disorganization
Disruption of cardiac myofibril assembly during development can lead to congenital heart defects. KIAA0196 has been identified as a novel susceptibility gene for myofibril structural disorganization in cardiac development, highlighting the importance of proper assembly for normal heart formation.
Cardiac dysfunction and mechanotransduction
Alterations in myofibril viscosity and mechanotransduction contribute to cardiac dysfunction. Inhibition of focal adhesion kinase increases myofibril viscosity, suggesting that adhesion signaling is critical for maintaining normal contractile properties. Furthermore, myofibril networks can induce shear stress, which may influence cardiac remodeling and disease progression.
From cardiac myofibril-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate gene affect cardiac myofibril assembly? | Knockout in iPSC-derived cardiomyocytes or zebrafish |
| Does a specific point mutation cause hypercontractility? | Point mutation knock-in in mouse or human iPSCs |
| How does a gene variant affect myofibril structure? | Knock-in of tagged protein for live imaging |
| Can overexpression of a gene rescue myofibril defects? | Overexpression in cardiomyocytes or mouse heart |
| What is the role of a gene in myofibril maintenance? | Inducible knockout in adult mouse heart |
| How does a mutation affect myofibril viscosity? | Point mutation knock-in combined with rheology |
How to Study the cardiac myofibril Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Immunofluorescence microscopy | Myofibril structure and sarcomere organization | Assessment of myofibril assembly defects |
| Electron microscopy | Ultrastructure of sarcomeres | Detailed analysis of myofibril disorganization |
| Myofibril ATPase assay | Contractile protein enzymatic activity | Evaluating functional changes in myofibrils |
| Traction force microscopy | Force generation by cardiomyocytes | Measuring contractility in disease models |
| RNA-seq | Gene expression profiles | Identifying myofibril gene expression changes |
| ChIP-seq | Epigenetic marks and transcription factor binding | Studying regulation of myofibril genes |
| Proteomics | Protein composition and modifications | Identifying novel myofibril components |
| Microrheology | Myofibril viscosity | Assessing mechanical properties |
Imaging of myofibril structure
Fluorescence and electron microscopy are used to visualize cardiac myofibril organization. Immunostaining for sarcomeric proteins such as actin, myosin, and titin reveals sarcomere periodicity and structural defects. Live-cell imaging with tagged proteins allows dynamic assessment of assembly and maintenance.
Functional assays for contractility
Myofibril ATPase activity assays measure the enzymatic rate of myosin ATP hydrolysis, reflecting contractile function. Traction force microscopy and microrheology can assess myofibril viscosity and force generation in cardiomyocytes. These assays are critical for linking genetic variants to functional outcomes.
Transcriptomic and epigenomic profiling
RNA-seq and ChIP-seq are used to study the expression and epigenetic regulation of cardiac myofibril genes during development and disease. These methods identify regulatory elements and transcription factors controlling myofibril gene programs.
Proteomics and interactomics
Mass spectrometry-based proteomics can identify components of the cardiac myofibril and their post-translational modifications. Interactomics studies reveal binding partners of sarcomeric proteins, such as titin ligands, providing insights into assembly and maintenance.
How CRISPR Can Be Used to Study GO:0097512 cardiac myofibril
Knockout
CRISPR knockout is used to eliminate candidate genes and assess their requirement for cardiac myofibril assembly and function. For example, knocking out KIAA0196 in cardiomyocytes can test its role in myofibril organization. Knockout models help distinguish essential from redundant factors.
Point Mutation
CRISPR point mutation introduces specific disease-associated variants, such as MYH7 G256E, to study their effects on myofibril contractility and metabolism. This approach provides precise genotype-phenotype links.
Knock-in
Knock-in of tagged proteins (e.g., fluorescently labeled titin) allows live imaging of myofibril dynamics. Knock-in of human disease mutations into model organisms recapitulates cardiomyopathy phenotypes.
Overexpression
CRISPR activation or transgenic overexpression can increase levels of myofibril proteins to test sufficiency in rescuing defects or inducing hypertrophy. Overexpression of titin ligands, for instance, may enhance myofibril assembly.
How EDITGENE Supports cardiac myofibril Research
Researchers studying cardiac myofibril-related genes often need to determine whether a candidate gene is causally involved in myofibril assembly, maintenance, or disease. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell and animal models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for cardiac myofibril research.
Frequently Asked Questions About cardiac myofibril
What is GO:0097512 cardiac myofibril?
GO:0097512 is a Gene Ontology cellular component term for the myofibril specific to cardiac muscle cells, the contractile apparatus of the heart.
What genes are involved in cardiac myofibril?
Key genes include MYH7, ACTC1, TNNT2, TNNI3, MYBPC3, TTN, and KIAA0196, among others.
How is cardiac myofibril assembled?
Assembly involves titin and its ligands, focal adhesion signaling, and sarcomere formation.
What diseases are linked to cardiac myofibril defects?
Hypertrophic cardiomyopathy, dilated cardiomyopathy, and developmental myofibril disorganization.
What is the role of MYH7 in cardiac myofibril?
MYH7 encodes beta-myosin heavy chain, a core component of the thick filament; mutations cause hypercontractility.
How does focal adhesion kinase affect cardiac myofibril?
Inhibition of focal adhesion kinase increases myofibril viscosity in cardiac myocytes.
What is KIAA0196 and its link to cardiac myofibril?
KIAA0196 is a susceptibility gene for myofibril structural disorganization in cardiac development.
How is cardiac myofibril gene expression regulated?
Epigenetic mechanisms regulate cardiac myofibril gene expression during heart development.
What methods are used to study cardiac myofibril?
Imaging, ATPase assays, RNA-seq, ChIP-seq, proteomics, and microrheology.
Can CRISPR be used to model cardiac myofibril diseases?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used.
Conclusion
GO:0097512 cardiac myofibril represents the specialized contractile machinery of cardiac muscle cells, essential for heart function. Its assembly and regulation involve a complex interplay of sarcomeric proteins, signaling pathways, and epigenetic control. Disruption of these processes leads to severe cardiac diseases, making the cardiac myofibril a critical focus for basic and translational research. Advanced CRISPR models and multi-omics approaches continue to unravel its biology, offering hope for new therapeutic strategies.
References
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- 2. Taneja N et al.. 2020. Inhibition of focal adhesion kinase increases myofibril viscosity in cardiac myocytes.. Cytoskeleton (Hoboken) 77(9):342-350 PMID: 32885903
- 3. Lee S et al.. 2024. Incomplete-penetrant hypertrophic cardiomyopathy MYH7 G256E mutation causes hypercontractility and elevated mitochondrial respiration.. Proc Natl Acad Sci U S A 121(19):e2318413121 PMID: 38683993
- 4. McElhinny AS et al.. 2000. Probing the functional roles of titin ligands in cardiac myofibril assembly and maintenance.. Adv Exp Med Biol 481:67-86; discussion 86-8 PMID: 10987067
- 5. Bu H et al.. 2020. Identification of KIAA0196 as a novel susceptibility gene for myofibril structural disorganization in cardiac development.. Int J Cardiol 314:81-88 PMID: 32417190
- 6. Zhao W et al.. 2015. Epigenetic regulation of cardiac myofibril gene expression during heart development.. Cardiovasc Toxicol 15(3):203-9 PMID: 25296860
- 7. Belcastro AN et al.. 1984. Myofibril ATPase activity of cardiac and skeletal muscle of exhaustively exercised rats.. Int J Biochem 16(3):297-303 PMID: 6230276
- 8. de Tombe PP et al.. 2018. Frank's law of the heart: Found in translation.. J Mol Cell Cardiol 121:33-35 PMID: 29908919
