GO:0051371 muscle alpha-actinin binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0051371 muscle alpha-actinin binding describes the molecular function of selectively binding to muscle isoforms of alpha-actinin (ACTN2 and ACTN3), which are localized to the Z-disc of skeletal and cardiac muscle.
• Muscle alpha-actinin is an actin cross-linking protein that anchors the sarcomeric actin thin filaments at the Z-disc and interacts with multiple structural and signaling proteins.
• Key binding partners include myozenin (MYOZ1/2), synaptopodin 2-like (SYNPO2L), and parvins, which together contribute to Z-disc assembly, actin bundle formation, and mechanosignaling.
• The ACTN3 R577X polymorphism (rs1815739) is associated with elite athletic performance, illustrating the physiological importance of muscle alpha-actinin interactions.
• Muscle alpha-actinin binding is studied using knockout, knock-in, and tagged knock-in cell and animal models, combined with imaging, proteomics, and functional assays.
• Dysregulation of muscle alpha-actinin and its binding partners has been linked to skeletal muscle and cardiac disorders, making this GO term relevant to inherited myopathies and cardiomyopathies.
Description
Muscle alpha-actinin binding (GO:0051371) is a molecular function defined as the selective interaction with muscle-specific isoforms of alpha-actinin, primarily ACTN2 and ACTN3, which are localized to the Z-disc of skeletal and cardiac muscle. Alpha-actinin is a member of the spectrin superfamily and functions as an actin cross-linking protein that anchors the barbed ends of actin thin filaments at the Z-disc, thereby maintaining sarcomeric architecture and transmitting contractile forces. The muscle isoforms are distinguished from non-muscle alpha-actinin (ACTN1 and ACTN4) by their tissue distribution and dynamic behavior at the Z-line. This binding function is critical for the assembly and stability of the sarcomere, and for integrating mechanical and signaling cues at the Z-disc. Researchers study muscle alpha-actinin binding to understand how Z-disc proteins cooperate to build and maintain muscle cytoarchitecture, and how mutations or polymorphisms in binding partners contribute to muscle disease and performance phenotypes. The interaction between muscle alpha-actinin and proteins such as myozenin, synaptopodin 2-like, and parvins has been characterized biochemically and structurally, revealing multiple binding interfaces and regulatory mechanisms. Because the Z-disc is a hub for mechanotransduction and signaling, muscle alpha-actinin binding is also relevant to cardiac and skeletal muscle adaptation and disease. This article provides a research-grade overview of GO:0051371, covering its definition, biological context, key genes, regulatory features, disease associations, and experimental methods, with a focus on CRISPR-based models for functional dissection.
muscle alpha-actinin binding At A Glance
| GO ID | GO:0051371 |
|---|---|
| GO term | muscle alpha-actinin binding |
| Ontology | molecular_function |
| Synonym | alpha-actinin 2 binding, alpha-actinin 3 binding |
| Definition | Binding to muscle isoforms of actinin. Muscle alpha-actinin isoforms are found in skeletal and cardiac muscle and are localized to the Z-disc. |
| Major function | Anchoring and cross-linking actin filaments at the Z-disc; scaffolding for signaling and structural proteins |
| Localization | Z-disc of skeletal and cardiac muscle |
| Representative binders | MYOZ1, MYOZ2, SYNPO2L, PARVB, PARVG, SMITIN |
| Related disease | Inherited myopathies, cardiomyopathies, athletic performance variation |
What Is GO:0051371?
GO:0051371 muscle alpha-actinin binding is the molecular function of binding to muscle isoforms of actinin. Muscle alpha-actinin isoforms are found in skeletal and cardiac muscle and are localized to the Z-disc. This function is distinct from binding to non-muscle alpha-actinin isoforms, and it is mediated by specific protein domains that recognize the muscle alpha-actinin rod or head regions.
Why Is muscle alpha-actinin binding Important in Cell Biology?
Muscle alpha-actinin binding is essential for the structural integrity and function of the sarcomere, as it links actin thin filaments to the Z-disc and serves as a platform for multiple proteins that regulate muscle contraction, signaling, and adaptation. Disruption of these interactions can lead to sarcomeric instability, muscle weakness, and cardiomyopathy, and natural variation in binding partners such as ACTN3 has been linked to athletic performance. Understanding this molecular function therefore has implications for muscle physiology, inherited muscle disease, and the development of therapeutic strategies targeting the Z-disc.
• Maintains sarcomeric architecture by anchoring actin filaments at the Z-disc.
• Provides a scaffold for signaling proteins that regulate muscle growth and adaptation.
• Mutations in binding partners are associated with skeletal muscle and cardiac disorders.
• ACTN3 R577X polymorphism influences sprint/power athletic performance.
• Muscle alpha-actinin dynamics differ from non-muscle isoforms, affecting Z-line remodeling.
• Binding to synaptopodin 2-like promotes actin bundle formation in cardiomyocytes.
• Parvins link alpha-actinin to integrin-mediated adhesion and signaling.
• Myozenin anchors calcineurin and other signaling molecules at the Z-disc.
• Smooth muscle alpha-actinin interacts with smitin, contributing to cytoskeletal organization.
• Aortic single-nuclear RNA sequencing has implicated alpha-actinin interactions in aneurysm biology.
Molecular Mechanism of muscle alpha-actinin binding
Domain architecture of muscle alpha-actinin
In simple terms: Muscle alpha-actinin has a structure that allows it to grab actin and hold onto other proteins.
Muscle alpha-actinin isoforms (ACTN2 and ACTN3) contain an N-terminal actin-binding domain, a central rod domain composed of spectrin repeats, and a C-terminal calmodulin-like domain with EF-hand motifs. The rod domain mediates antiparallel dimerization, which is required for actin cross-linking, while the EF-hand region undergoes calcium-dependent conformational changes that regulate binding to some partners. The muscle isoforms differ from non-muscle isoforms in their expression pattern and dynamic behavior at the Z-line.
Binding to myozenin and Z-disc anchoring
In simple terms: Myozenin acts like a clamp that connects alpha-actinin to other Z-disc proteins.
Myozenin (MYOZ1 and MYOZ2) binds directly to the rod domain of alpha-actinin and to gamma-filamin, forming a ternary complex that anchors the Z-disc to the sarcolemma and cytoskeleton. This interaction is critical for Z-disc assembly and for the recruitment of signaling molecules such as calcineurin, which regulates muscle gene expression. Mutations in MYOZ2 have been linked to hypertrophic cardiomyopathy, underscoring the importance of this binding interface.
Interaction with synaptopodin 2-like in cardiomyocytes
In simple terms: Synaptopodin 2-like helps alpha-actinin organize actin into bundles in heart muscle cells.
Synaptopodin 2-like (SYNPO2L) directly binds to alpha-actinin and promotes actin bundle formation in cardiomyocytes. This interaction is mediated by specific regions of SYNPO2L that are required for its localization to the Z-disc and for its ability to stabilize actin filaments. Knockdown of SYNPO2L disrupts sarcomeric actin organization, highlighting its role in cardiac muscle structure.
Parvins as linkers to integrin signaling
In simple terms: Parvins connect alpha-actinin to the cell membrane and outside signals.
The parvins (PARVA, PARVB, PARVG) are actin-binding proteins that interact with alpha-actinin and integrin-linked kinase, linking the Z-disc to integrin-mediated adhesion and signaling. This interaction is important for mechanotransduction and for the regulation of cell survival and migration in muscle and other tissues. Parvin mutations have been associated with muscular dystrophy and cardiomyopathy, further emphasizing the functional significance of alpha-actinin binding.
Regulation by calcium and phosphorylation
In simple terms: Calcium and chemical modifications can change how tightly alpha-actinin binds its partners.
Calcium binding to the EF-hand motifs of alpha-actinin can modulate its interaction with actin and other proteins, although the exact effects vary by isoform and binding partner. Phosphorylation of alpha-actinin and its partners has been reported to regulate Z-disc dynamics and binding affinity, but the specific kinases and sites remain incompletely characterized. The differential dynamics of muscle versus non-muscle alpha-actinin at the Z-line suggest that isoform-specific regulatory mechanisms exist.
Smitin and smooth muscle alpha-actinin
In simple terms: In smooth muscle, alpha-actinin binds smitin to help organize the cytoskeleton.
Smooth muscle alpha-actinin interacts with smitin, a protein that shares homology with myozenin, to organize the cytoskeleton in smooth muscle cells. This interaction is distinct from the skeletal and cardiac muscle Z-disc complexes but highlights the conserved role of alpha-actinin as a cytoskeletal organizer. The binding of smitin to alpha-actinin is mediated by a conserved region that is also found in myozenin family proteins.
Key Genes Involved in GO:0051371 muscle alpha-actinin binding
The following genes encode proteins that bind to muscle alpha-actinin or are directly involved in its function and regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACTN2 | Muscle alpha-actinin isoform in cardiac and skeletal muscle | Core component of Z-disc; mutations cause cardiomyopathy |
| ACTN3 | Muscle alpha-actinin isoform in fast-twitch skeletal muscle | R577X polymorphism associated with athletic performance |
| MYOZ1 | Myozenin 1, binds alpha-actinin and gamma-filamin | Z-disc assembly and signaling in skeletal muscle |
| MYOZ2 | Myozenin 2, binds alpha-actinin and gamma-filamin | Mutations linked to hypertrophic cardiomyopathy |
| SYNPO2L | Synaptopodin 2-like, binds alpha-actinin | Promotes actin bundle formation in cardiomyocytes |
| PARVA | Parvin alpha, binds alpha-actinin | Links Z-disc to integrin signaling; muscular dystrophy |
| PARVB | Parvin beta, binds alpha-actinin | Cell adhesion and cytoskeletal regulation |
| PARVG | Parvin gamma, binds alpha-actinin | Expressed in hematopoietic cells; adhesion |
| SMITIN | Smooth muscle alpha-actinin binding protein | Cytoskeletal organization in smooth muscle |
| ACTN1 | Non-muscle alpha-actinin isoform | Comparison with muscle isoforms; dynamics |
| ACTN4 | Non-muscle alpha-actinin isoform | Comparison with muscle isoforms; disease |
| ILK | Integrin-linked kinase, interacts with parvins | Signaling at Z-disc and focal adhesions |
| FLNC | Filamin C, binds myozenin and alpha-actinin | Z-disc stability; myofibrillar myopathy |
| TTN | Titin, interacts with alpha-actinin at Z-disc | Sarcomere assembly and signaling |
| MYPN | Myopalladin, binds alpha-actinin | Z-disc and I-band signaling |
| ANKRD1 | Ankyrin repeat domain 1, binds alpha-actinin | Cardiac stress response and signaling |
| CSRP3 | Muscle LIM protein, interacts with alpha-actinin | Cardiomyopathy and Z-disc signaling |
How Is muscle alpha-actinin binding Regulated?
The binding of muscle alpha-actinin to its partners is regulated at multiple levels. Calcium binding to the EF-hand motifs of alpha-actinin can modulate its conformation and affinity for actin and other proteins. Phosphorylation of alpha-actinin and its binding partners may alter Z-disc dynamics, although specific regulatory pathways are still being defined. The differential dynamics of muscle versus non-muscle alpha-actinin at the Z-line suggest that isoform-specific regulatory mechanisms exist. Additionally, the expression of muscle alpha-actinin isoforms is developmentally regulated and responsive to muscle activity and stress.
muscle alpha-actinin binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACTN3 | Athletic performance variation | ACTN3 R577X knock-in mouse or human myoblast knockout |
| MYOZ2 | Hypertrophic cardiomyopathy | MYOZ2 knockout or point-mutation knock-in in cardiomyocytes |
| SYNPO2L | Cardiac actin bundle formation | SYNPO2L knockout in iPSC-derived cardiomyocytes |
| PARVB | Muscular dystrophy and adhesion defects | PARVB knockout in skeletal muscle cells |
| FLNC | Myofibrillar myopathy | FLNC knockout or tagged knock-in in muscle cells |
Inherited myopathies and cardiomyopathies
Mutations in genes encoding muscle alpha-actinin binding partners, such as MYOZ2 and FLNC, have been linked to hypertrophic cardiomyopathy and myofibrillar myopathy. Disruption of the Z-disc complex can lead to sarcomeric instability, impaired force transmission, and muscle weakness. These findings highlight the clinical importance of muscle alpha-actinin binding for muscle integrity.
Athletic performance and ACTN3 polymorphism
The ACTN3 R577X polymorphism (rs1815739) results in the absence of alpha-actinin-3 in fast-twitch muscle fibers and is associated with elite sprint/power athletic performance. This common variant illustrates how natural variation in a muscle alpha-actinin isoform can influence human physical performance. Studies of ACTN3 and its binding partners continue to shed light on muscle fiber type specialization.
Aortic aneurysm and vascular biology
Single-nuclear RNA sequencing of human aortic aneurysms has identified cellular diversity and prioritized genes involved in cytoskeletal and contractile functions, including alpha-actinin interactions. Although the role of muscle alpha-actinin in vascular smooth muscle is less characterized, these findings suggest potential contributions to vascular remodeling. Further research is needed to clarify the relevance of GO:0051371 in aortic disease.
From muscle alpha-actinin binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ACTN3 affect Z-disc structure? | ACTN3 knockout mouse or human myoblast knockout |
| How does the ACTN3 R577X variant alter binding? | Point-mutation knock-in of R577X in muscle cells |
| Where does SYNPO2L localize in cardiomyocytes? | Tagged knock-in of SYNPO2L with fluorescent tag |
| Can MYOZ2 mutations cause cardiomyopathy? | MYOZ2 point-mutation knock-in mouse |
| What proteins interact with muscle alpha-actinin? | Overexpression of tagged ACTN2 followed by proteomics |
| Does PARVB loss disrupt integrin signaling? | PARVB knockout in skeletal muscle cells |
How to Study the muscle alpha-actinin binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence microscopy | Localization and dynamics of tagged proteins | Z-disc assembly in live muscle cells |
| Co-immunoprecipitation | Protein-protein interactions | Identifying alpha-actinin binding partners |
| Mass spectrometry | Proteomic composition of complexes | Discovering novel Z-disc interactors |
| Actin co-sedimentation | Actin binding and cross-linking | Functional testing of alpha-actinin variants |
| CRISPR knockout | Loss-of-function phenotypes | Determining gene requirement for Z-disc integrity |
| CRISPR knock-in | Tagged or mutant protein expression | Tracking localization and dynamics |
| RNA-seq | Transcriptional changes | Assessing downstream effects of alpha-actinin loss |
Imaging of Z-disc dynamics
Fluorescence microscopy of tagged alpha-actinin and its binding partners allows visualization of Z-disc assembly and dynamics in live muscle cells. Photoactivatable or photoconvertible tags can be used to track protein turnover at the Z-line. This approach has revealed differential dynamics of muscle versus non-muscle alpha-actinin isoforms.
Proteomic identification of binding partners
Affinity purification coupled with mass spectrometry can identify proteins that bind to muscle alpha-actinin in muscle lysates. This method has been used to discover interactions with synaptopodin 2-like and other Z-disc proteins. Quantitative proteomics can also assess how mutations affect the interactome.
Functional assays for actin bundling
In vitro actin co-sedimentation and bundling assays can measure the ability of alpha-actinin and its partners to cross-link actin filaments. These assays are useful for testing the impact of disease-associated mutations on binding and bundling activity. They can be combined with knockout or knock-in cell models to validate findings.
CRISPR screening for modifiers
Genome-wide CRISPR knockout or activation screens can identify genes that modulate muscle alpha-actinin binding or Z-disc integrity. Such screens may uncover novel regulators of the Z-disc and potential therapeutic targets. Bioinformatics analysis of screening data can prioritize candidate genes for follow-up.
How CRISPR Can Be Used to Study GO:0051371 muscle alpha-actinin binding
Knockout
CRISPR knockout of ACTN2, ACTN3, or their binding partners in muscle cell lines or primary myoblasts can reveal their requirement for Z-disc assembly and muscle function. Knockout models are valuable for assessing loss-of-function phenotypes and for identifying compensatory mechanisms. For example, ACTN3 knockout mice show altered muscle metabolism and fiber type composition.
Point Mutation
CRISPR point mutation can introduce disease-associated variants, such as ACTN3 R577X or MYOZ2 mutations, into muscle cells to study their effects on binding and sarcomere structure. These models allow precise dissection of how single amino acid changes alter protein interactions. Point-mutation knock-in is particularly useful for studying common polymorphisms.
Knock-in
CRISPR knock-in of fluorescent or epitope tags into endogenous ACTN2, ACTN3, or SYNPO2L loci enables real-time imaging and biochemical isolation of native protein complexes. Tagged knock-in models preserve endogenous regulation and are ideal for studying dynamics and interactions. This approach has been used to track alpha-actinin dynamics at the Z-line.
Overexpression
CRISPR activation or cDNA overexpression can be used to increase levels of muscle alpha-actinin or its binding partners to study gain-of-function effects and to identify saturating interactions. Overexpression of tagged proteins followed by proteomics can reveal new binding partners. This approach complements knockout studies by providing a different direction of perturbation.
How EDITGENE Supports muscle alpha-actinin binding Research
Researchers studying muscle alpha-actinin binding-related genes often need to determine whether a candidate gene is causally involved in Z-disc assembly, sarcomere function, or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell and animal models, enabling functional validation of genes and variants associated with GO:0051371.
Contact EDITGENE today to design your custom CRISPR model for muscle alpha-actinin binding research.
Related Products
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| PDLIM5 Knockout HEK293 Cell Line | EDJ-KQ2340 | Human | 10611 | Details Get a Quote |
| PALLD Knockout HEK293 Cell Line | EDJ-KQ2360 | Human | 23022 | Details Get a Quote |
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| NRAP Knockout HEK293 Cell Line | EDJ-KQ5361 | Human | 4892 | Details Get a Quote |
| PDLIM4 Knockout HEK293 Cell Line | EDJ-KQ6291 | Human | 8572 | Details Get a Quote |
| PKD2L1 Knockout HEK293 Cell Line | EDJ-KQ6437 | Human | 9033 | Details Get a Quote |
| PDLIM1 Knockout HEK293 Cell Line | EDJ-KQ6467 | Human | 9124 | Details Get a Quote |
| PDLIM7 Knockout HEK293 Cell Line | EDJ-KQ6531 | Human | 9260 | Details Get a Quote |
| PDLIM3 Knockout HEK293 Cell Line | EDJ-KQ8750 | Human | 27295 | Details Get a Quote |
| PRICKLE4 Knockout HEK293 Cell Line | EDJ-KQ9111 | Human | 29964 | Details Get a Quote |
| MYPN Knockout HEK293 Cell Line | EDJ-KQ10154 | Human | 84665 | Details Get a Quote |
| PDLIM2 Knockout HEK293 Cell Line | EDJ-KQ14715 | Human | 64236 | Details Get a Quote |
| SYNPO2 Knockout HEK293 Cell Line | EDJ-KQ15583 | Human | 171024 | Details Get a Quote |
| PDLIM3 Knockout HCT 116 Cell Line | EDJ-KQ34997 | Human | 27295 | Details Get a Quote |
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Frequently Asked Questions About muscle alpha-actinin binding
What is GO:0051371 muscle alpha-actinin binding?
GO:0051371 is a molecular function term describing the binding to muscle isoforms of alpha-actinin, which are found in skeletal and cardiac muscle and localized to the Z-disc.
What genes are involved in muscle alpha-actinin binding?
Key genes include ACTN2 and ACTN3 (encoding muscle alpha-actinin isoforms), MYOZ1, MYOZ2, SYNPO2L, PARVA, PARVB, PARVG, and SMITIN.
What is the role of ACTN3 in muscle?
ACTN3 encodes alpha-actinin-3, a fast-twitch muscle isoform; the R577X polymorphism is associated with elite athletic performance.
How does muscle alpha-actinin bind to actin?
Muscle alpha-actinin binds actin through its N-terminal actin-binding domain and cross-links filaments via antiparallel dimerization mediated by its rod domain.
What diseases are linked to muscle alpha-actinin binding?
Mutations in binding partners such as MYOZ2 and FLNC are linked to hypertrophic cardiomyopathy and myofibrillar myopathy.
What is the difference between muscle and non-muscle alpha-actinin?
Muscle isoforms (ACTN2, ACTN3) are localized to the Z-disc and show different dynamics compared to non-muscle isoforms (ACTN1, ACTN4).
How can I study muscle alpha-actinin binding in the lab?
Common methods include fluorescence imaging of tagged proteins, co-immunoprecipitation, mass spectrometry, actin co-sedimentation, and CRISPR knockout or knock-in models.
What is the ACTN3 R577X polymorphism?
It is a common nonsense variant (rs1815739) that results in the absence of alpha-actinin-3 in fast-twitch muscle fibers and is associated with sprint/power performance.
What proteins interact with muscle alpha-actinin at the Z-disc?
Myozenin, synaptopodin 2-like, parvins, filamin C, myopalladin, and ankyrin repeat domain 1 are among the key interactors.
Can CRISPR be used to model muscle alpha-actinin binding disorders?
Yes, CRISPR knockout, point mutation, and knock-in models in muscle cells can recapitulate disease-associated variants and study their effects on Z-disc function.
Conclusion
GO:0051371 muscle alpha-actinin binding is a central molecular function for sarcomere assembly and muscle physiology, involving a network of structural and signaling proteins at the Z-disc. Understanding its mechanisms, regulation, and disease relevance requires integrated approaches including CRISPR-based models, imaging, and proteomics. EDITGENE provides end-to-end services to support research on this important interaction.
References
- 1. Yang N et al.. 2003. ACTN3 genotype is associated with human elite athletic performance.. Am J Hum Genet 73(3):627-31 PMID: 12879365
- 2. Yamada H et al.. 2024. Direct Binding of Synaptopodin 2-Like Protein to Alpha-Actinin Contributes to Actin Bundle Formation in Cardiomyocytes.. Cells 13(16) PMID: 39195263
- 3. Sjöblom B et al.. 2008. Alpha-actinin structure and regulation.. Cell Mol Life Sci 65(17):2688-701 PMID: 18488141
- 4. Sepulveda JL et al.. 2006. The parvins.. Cell Mol Life Sci 63(1):25-35 PMID: 16314921
- 5. Chi RJ et al.. 2005. Smooth muscle alpha-actinin interaction with smitin.. Int J Biochem Cell Biol 37(7):1470-82 PMID: 15833278
- 6. Hsu CP et al.. 2018. Sarcomeric and nonmuscle α-actinin isoforms exhibit differential dynamics at skeletal muscle Z-lines.. Cytoskeleton (Hoboken) 75(5):213-228 PMID: 29518289
- 7. Takada F et al.. 2001. Myozenin: an alpha-actinin- and gamma-filamin-binding protein of skeletal muscle Z lines.. Proc Natl Acad Sci U S A 98(4):1595-600 PMID: 11171996
- 8. Chou EL et al.. 2022. Aortic Cellular Diversity and Quantitative Genome-Wide Association Study Trait Prioritization Through Single-Nuclear RNA Sequencing of the Aneurysmal Human Aorta.. Arterioscler Thromb Vasc Biol 42(11):1355-1374 PMID: 36172868
