GO:0014723 regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril: Calcium Sensitivity Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0014723 describes how skeletal muscle contraction is tuned by changing the calcium ion binding affinity of the myofibril, rather than by changing calcium release itself.
• The term is a biological_process that sits at the intersection of excitation-contraction coupling, thin-filament cooperativity, and sarcomere mechanics.
• Redox state is a major modulator of myofibrillar calcium sensitivity; low peroxide concentrations can alter contractile responses in skeletal muscle.
• Cysteine modifications, including disulfide bond formation, can change myofilament calcium sensitivity and contractile function.
• Sarcomere length and thin-filament cooperative activation are coordinated regulators of calcium-dependent force production.
• Histidine-containing dipeptides such as carnosine and beta-alanine influence skeletal muscle physiology and are relevant to calcium sensitivity and fatigue.
Description
GO:0014723, regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril, is a biological_process that explains how muscle force can be adjusted without necessarily changing the amount of calcium released from the sarcoplasmic reticulum. Instead, the sensitivity of the myofibril to calcium is altered, so that the same calcium concentration produces more or less force. This term is important because it captures a fundamental tuning mechanism in skeletal muscle physiology and is directly relevant to fatigue, redox biology, and contractile regulation. Researchers studying muscle mechanics, excitation-contraction coupling, and sarcomeric proteins need this ontology term to annotate experiments that measure calcium sensitivity rather than calcium transients. The term also provides a framework for understanding how post-translational modifications and small molecules can modulate contractile performance.
regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril At A Glance
| GO ID | GO:0014723 |
|---|---|
| GO term | regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril |
| Ontology | biological_process |
| Synonym | regulation of calcium ion sensitivity of myofibril involved in skeletal muscle contraction |
| Major function | Modulates skeletal muscle contraction by changing calcium ion binding affinity of the myofibril |
| Related process | Excitation-contraction coupling and thin-filament cooperative activation |
| Key modulators | Redox state, cysteine modifications, sarcomere length, and small molecules such as carnosine |
| Experimental readout | Calcium sensitivity of skinned fibers or myofibrillar preparations |
What Is GO:0014723?
In simple terms, GO:0014723 is the process that changes how strongly the myofibril binds calcium, thereby changing how much force the muscle produces for a given calcium signal. The QuickGO definition states that it is any process that modulates the frequency, rate or extent of skeletal muscle contraction by changing calcium ion binding affinity of the myofibril. This is distinct from processes that change calcium release or reuptake; here the modulation occurs at the level of the myofilament itself.
Why Is regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril Important in Cell Biology?
This process is important because it allows skeletal muscle to fine-tune force output under conditions where calcium release is unchanged, which is critical for fatigue resistance, metabolic stress, and redox balance. Dysregulation of myofibrillar calcium sensitivity has been linked to contractile dysfunction, and understanding it can inform therapeutic strategies for muscle weakness and related disorders.
• It enables force modulation independent of calcium release, a key mechanism in skeletal muscle plasticity.
• Redox modulation of myofibrillar calcium sensitivity is a likely target for peroxide-mediated contractile changes.
• Cysteine disulfide formation can enhance contractile function by altering myofilament calcium sensitivity.
• Sarcomere length-dependent calcium activation coordinates thin-filament cooperativity and passive force.
• Histidine-containing dipeptides such as carnosine and beta-alanine affect exercising skeletal muscle and may influence calcium sensitivity.
• The process is relevant to understanding fatigue, recovery, and adaptation to exercise.
• It provides a mechanistic basis for interpreting skinned fiber experiments and calcium sensitivity curves.
• It helps distinguish calcium sensitivity changes from calcium handling changes in disease models.
• It is a target for pharmacological and nutritional interventions in muscle performance.
• It supports annotation of muscle physiology datasets in functional genomics.
What Happens During regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril?
Calcium binding to troponin and thin-filament activation
In simple terms: Calcium binds to troponin on the thin filament, which moves tropomyosin and allows myosin to interact with actin.
The primary event in this process is the binding of calcium to troponin C, which triggers a conformational change that relieves tropomyosin inhibition and permits cross-bridge cycling. The sensitivity of this step can be modulated, meaning that the same calcium concentration can produce different levels of thin-filament activation depending on the state of the myofilament.
Thin-filament cooperative activation
In simple terms: Once one myosin head binds, it makes it easier for neighboring heads to bind, creating a cooperative response.
Thin-filament cooperative activation is a key determinant of the steepness of the calcium-force relationship. Sarcomere length-dependent calcium activation involves coordinated regulation of thin-filament cooperativity and passive force, which together shape the calcium sensitivity of the myofibril.
Redox modulation of myofibrillar calcium sensitivity
In simple terms: Oxidizing or reducing conditions can change how sensitive the myofibril is to calcium.
Low peroxide concentrations can alter the contractile response of skeletal muscle, and myofibrillar calcium sensitivity is a likely target for this redox modulation. This means that reactive oxygen species can directly tune the calcium sensitivity of the contractile apparatus, independent of changes in calcium release.
Cysteine modifications and disulfide bond formation
In simple terms: Chemical changes to cysteine residues can alter how the myofilament responds to calcium.
Nitroxyl-mediated disulfide bond formation between myofilament cysteines can enhance contractile function, demonstrating that specific cysteine modifications can modulate calcium sensitivity. Such modifications represent a molecular mechanism by which the myofibril's calcium responsiveness can be adjusted.
Sarcomere length and passive force
In simple terms: The length of the sarcomere changes how sensitive the muscle is to calcium.
Sarcomere length-dependent calcium activation in skinned rabbit psoas muscle fibers involves coordinated regulation of thin-filament cooperative activation and passive force. This length-dependent modulation is a classic example of how calcium sensitivity can be tuned by mechanical context.
Key Genes Involved in GO:0014723 regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril
The following genes and proteins are central to the regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril, based on the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TNNC1 | Troponin C, calcium-binding subunit of the thin filament | Directly mediates calcium binding and sensitivity |
| TNNI1 | Troponin I, inhibitory subunit | Regulates thin-filament activation and cooperativity |
| TNNT1 | Troponin T, tropomyosin-binding subunit | Links troponin to tropomyosin and affects calcium sensitivity |
| TPM1 | Tropomyosin, thin-filament regulatory protein | Controls actin-myosin interaction and cooperative activation |
| ACTA1 | Alpha-actin, main thin-filament component | Provides the track for myosin and is central to force generation |
| MYH1 | Myosin heavy chain, fast-twitch fiber type | Motor protein whose interaction with actin is calcium-sensitive |
| MYH2 | Myosin heavy chain, fast-twitch fiber type | Contributes to contractile properties and calcium sensitivity |
| MYH7 | Myosin heavy chain, slow-twitch fiber type | Affects calcium sensitivity and fatigue resistance |
| CKM | Creatine kinase, muscle type | Supports energy metabolism during contraction |
| CARN | Carnosine synthase, histidine dipeptide synthesis | Produces carnosine, which influences muscle physiology |
| SLC15A3 | Beta-alanine transporter | Affects carnosine content and muscle buffering |
| N/A | Cysteine residues in myofilament proteins | Targets for redox modification and disulfide formation |
| N/A | Reactive oxygen species (e.g., peroxide) | Modulate myofibrillar calcium sensitivity |
| N/A | Nitroxyl (HNO) | Induces disulfide bonds and enhances contractile function |
| N/A | Sarcomere length | Mechanical modulator of calcium sensitivity |
| N/A | Passive force | Contributes to length-dependent activation |
| N/A | Thin-filament cooperativity | Determines the steepness of calcium-force relationship |
How Is regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril Regulated?
The process is regulated by redox state, as low peroxide concentrations can modulate myofibrillar calcium sensitivity. Cysteine modifications, including disulfide bond formation, can enhance contractile function by altering calcium sensitivity. Sarcomere length and passive force also regulate calcium sensitivity through thin-filament cooperative activation. Additionally, histidine-containing dipeptides such as carnosine and beta-alanine may influence muscle physiology and calcium sensitivity during exercise.
regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TNNC1 | Calcium sensitivity and contractile dysfunction | Point mutation knock-in in skeletal muscle cells |
| TNNI1 | Thin-filament regulation and myopathy | Knockout or point mutation in mouse muscle |
| TPM1 | Tropomyosin-related contractile defects | Knock-in of disease-associated variants |
| ACTA1 | Actin myopathy and contractile weakness | Overexpression or knockout in muscle cell lines |
| MYH7 | Slow-twitch fiber contractile properties | Knock-in of fiber-type specific mutations |
Redox imbalance and muscle dysfunction
Altered redox state can change myofibrillar calcium sensitivity, potentially contributing to contractile dysfunction in conditions associated with oxidative stress. Understanding this link may help explain fatigue and weakness in metabolic and inflammatory myopathies.
Cysteine modification and contractile regulation
Disulfide bond formation between myofilament cysteines can enhance contractile function, suggesting that dysregulated cysteine modifications may contribute to abnormal calcium sensitivity in muscle disease.
Sarcomere length-dependent dysfunction
Length-dependent calcium activation is a fundamental property of muscle, and its disruption could contribute to impaired force production in conditions such as heart failure and skeletal muscle myopathies.
From regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate gene affect calcium sensitivity? | Knockout cell model (e.g., C2C12 myotubes) |
| Does a specific point mutation alter calcium sensitivity? | Point mutation knock-in in skeletal muscle cells |
| Does a disease-associated variant change contractile function? | Knock-in mouse model or human iPSC-derived myotubes |
| Where is a protein localized in the sarcomere? | Tagged knock-in with fluorescent tag |
| Does overexpression of a gene enhance calcium sensitivity? | Overexpression cell model |
| Which genes regulate calcium sensitivity in a genome-wide screen? | CRISPR library screening in muscle cells |
How to Study the regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Skinned fiber calcium sensitivity assay | Force-calcium relationship | Studying length-dependent activation |
| Redox treatment (e.g., peroxide) | Effect of redox state on calcium sensitivity | Testing redox modulation |
| Disulfide bond detection | Cysteine modification status | Linking modifications to function |
| Carnosine/beta-alanine assay | Histidine dipeptide levels | Exercise physiology studies |
| CRISPR knockout | Gene function loss | Identifying regulators of calcium sensitivity |
| CRISPR knock-in | Specific mutation effects | Modeling disease variants |
| Overexpression | Gain-of-function effects | Testing enhancers of calcium sensitivity |
| CRISPR library screening | Genome-wide regulators | Discovering new modulators |
Skinned fiber calcium sensitivity assays
Skinned fiber preparations allow direct measurement of force at controlled calcium concentrations, revealing changes in myofibrillar calcium sensitivity. This method is classic for studying length-dependent activation and cooperative effects.
Redox modulation experiments
Treating muscle fibers with low peroxide concentrations can reveal redox-sensitive changes in calcium sensitivity. Such experiments help identify whether a given intervention acts via redox modulation.
Cysteine modification analysis
Detecting disulfide bond formation between myofilament cysteines can link specific modifications to changes in contractile function. Mass spectrometry and biochemical assays are useful for this purpose.
Histidine dipeptide measurement
Measuring carnosine and beta-alanine levels in muscle can provide insight into their role in exercise physiology and calcium sensitivity. This is often done with biochemical assays or metabolomics.
How CRISPR Can Be Used to Study GO:0014723 regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril
Knockout
CRISPR knockout of candidate genes in skeletal muscle cells can reveal whether they are required for normal calcium sensitivity. This approach is useful for validating genes identified in screens.
Point Mutation
Introducing point mutations in genes such as TNNC1 or TNNI1 can model disease-associated variants and test their effects on calcium sensitivity. This helps establish causality.
Knock-in
Knock-in of tagged or disease variants allows precise tracking of protein localization and function in the sarcomere. This is valuable for understanding structure-function relationships.
Overexpression
Overexpression of genes like CARN or SLC15A3 can test whether increasing their levels enhances calcium sensitivity or muscle performance. This can identify therapeutic targets.
How EDITGENE Supports regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril Research
Researchers studying regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril-related genes often need to determine whether a candidate gene is causally involved in calcium sensitivity or is merely correlated with it. This requires precise genetic models that can isolate the contribution of a single gene or mutation.
Contact EDITGENE today to design your custom CRISPR model for regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril research.
Frequently Asked Questions About regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril
What is GO:0014723?
GO:0014723 is the biological process of regulating skeletal muscle contraction by modulating the calcium ion sensitivity of the myofibril.
What genes are involved in regulation of skeletal muscle contraction by modulation of calcium ion sensitivity of myofibril?
Key genes include TNNC1, TNNI1, TNNT1, TPM1, ACTA1, and MYH isoforms, which together control thin-filament activation and calcium sensitivity.
How does calcium sensitivity affect muscle contraction?
It changes how much force is produced for a given calcium concentration, allowing fine-tuning of contraction.
What is the role of redox in myofibrillar calcium sensitivity?
Redox state, such as low peroxide concentrations, can modulate myofibrillar calcium sensitivity and alter contractile responses.
Can cysteine modifications change calcium sensitivity?
Yes, disulfide bond formation between myofilament cysteines can enhance contractile function by altering calcium sensitivity.
What is sarcomere length-dependent calcium activation?
It is the phenomenon where calcium sensitivity changes with sarcomere length, involving thin-filament cooperativity and passive force.
How do carnosine and beta-alanine relate to muscle contraction?
They are histidine-containing dipeptides that influence exercising skeletal muscle physiology and may affect calcium sensitivity.
What experimental methods study myofibrillar calcium sensitivity?
Skinned fiber assays, redox treatments, disulfide detection, and histidine dipeptide measurements are commonly used.
What diseases are linked to altered calcium sensitivity?
Redox imbalance and cysteine modifications can contribute to muscle dysfunction and contractile abnormalities.
How can CRISPR help study GO:0014723?
CRISPR knockout, knock-in, point mutation, and overexpression models can test the causal role of specific genes in calcium sensitivity.
Conclusion
GO:0014723 captures a vital layer of skeletal muscle regulation: the modulation of calcium sensitivity at the myofibril. This process integrates redox signals, cysteine modifications, sarcomere mechanics, and small molecules to fine-tune contraction. Understanding it is essential for muscle physiology and for developing interventions against contractile dysfunction.
References
- 1. Andrade FH et al.. 2001. Contractile response of skeletal muscle to low peroxide concentrations: myofibrillar calcium sensitivity as a likely target for redox-modulation.. FASEB J 15(2):309-11 PMID: 11156946
- 2. Matthews JJ et al.. 2019. The Physiological Roles of Carnosine and β-Alanine in Exercising Human Skeletal Muscle.. Med Sci Sports Exerc 51(10):2098-2108 PMID: 31083045
- 3. Gao WD et al.. 2012. Nitroxyl-mediated disulfide bond formation between cardiac myofilament cysteines enhances contractile function.. Circ Res 111(8):1002-11 PMID: 22851540
- 4. Fukuda N et al.. 2011. Sarcomere length-dependent Ca2+ activation in skinned rabbit psoas muscle fibers: coordinated regulation of thin filament cooperative activation and passive force.. J Physiol Sci 61(6):515-23 PMID: 21901640
