GO:0090636 outer dense plaque of desmosome: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0090636 describes the outer dense plaque of the desmosome, the electron-dense cytoplasmic plaque region that contains plakoglobins, plakophilins, the N-termini of desmoplakins, and the cytoplasmic tails of desmosomal cadherins.
• The outer dense plaque physically couples desmosomal cadherins at the plasma membrane to the intermediate filament cytoskeleton, providing mechanical resilience to epithelial tissues.
• Integrative structural modeling and super-resolution imaging have revealed that the outer dense plaque is a layered, stoichiometrically organized assembly rather than an amorphous dense region.
• Proteomic dissection of desmosomes has identified both canonical plaque components and novel accessory proteins required for epidermal integrity.
• Mutations affecting desmosomal plaque proteins, including those of the outer dense plaque, cause arrhythmogenic right ventricular dysplasia and related cell adhesion cardiomyopathies.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are powerful tools for dissecting outer dense plaque protein function in epithelial and cardiac cells.
Description
The outer dense plaque of the desmosome (GO:0090636) is a specialized cytoplasmic protein assembly that forms the membrane-proximal layer of the desmosomal plaque. Desmosomes are intercellular adhesive junctions that are particularly abundant in tissues subjected to mechanical stress, such as epidermis and myocardium, and the outer dense plaque is the region where desmosomal cadherins, plakoglobins, plakophilins, and the N-terminal domains of desmoplakins converge to anchor the junction to the plasma membrane. Early electron microscopy defined desmosomes as a distinct junctional complex with a dense plaque, and subsequent molecular mapping established the layered organization of the plaque. Understanding GO:0090636 matters because the outer dense plaque is not merely a static anchor; it is a hub for protein-protein interactions that determine desmosome assembly, stability, and signaling. Integrative structural modeling has provided a molecular architecture of the outer dense plaque, revealing how plakoglobin, plakophilin, desmoplakin N-termini, and cadherin tails are arranged in a stoichiometric complex. Super-resolution and volume electron microscopy have further refined this picture by resolving the three-dimensional organization of desmosomes in cells and tissues. For researchers, GO:0090636 provides a precise annotation target for cellular-component studies of desmosome biology. Proteomic analyses have expanded the inventory of outer dense plaque-associated proteins and linked them to epidermal integrity, while genotype-phenotype studies have connected plaque protein mutations to arrhythmogenic right ventricular dysplasia. This article reviews the definition, composition, assembly, regulation, disease relevance, and experimental methods for studying the outer dense plaque of the desmosome.
outer dense plaque of desmosome At A Glance
| GO ID | GO:0090636 |
|---|---|
| GO term | outer dense plaque of desmosome |
| Ontology | cellular_component |
| Synonym | None listed in QuickGO |
| Major function | Anchors desmosomal cadherins to the plasma membrane and organizes the membrane-proximal plaque of the desmosome |
| Key components | Plakoglobins, plakophilins, N-termini of desmoplakins, cytoplasmic tails of desmosomal cadherins |
| Subcellular location | Cytoplasmic face of the desmosomal plasma membrane |
| Related structures | Inner dense plaque of desmosome, desmosomal cadherins, intermediate filaments |
| Relevance | Mechanical integrity of epithelia and myocardium; target of disease-associated mutations |
What Is GO:0090636?
According to the Gene Ontology, GO:0090636 (outer dense plaque of desmosome) is the desmosomal part containing plakoglobins, plakophilins, the N-termini of desmoplakins, as well as the cytoplasmic tails of the desmosomal cadherins, which together attach the plaque to the plasma membrane. In other words, it is the membrane-proximal dense layer of the desmosomal plaque, distinct from the inner dense plaque that is associated with intermediate filament anchorage. The term is a cellular_component annotation and has no synonyms in QuickGO.
Why Is outer dense plaque of desmosome Important in Cell Biology?
The outer dense plaque of the desmosome is important because it is the structural interface where desmosomal adhesion is converted into mechanical coupling with the intermediate filament cytoskeleton. Without a properly assembled outer dense plaque, desmosomes cannot resist mechanical stress, and tissues such as epidermis and heart become vulnerable to injury. The precise molecular architecture of this plaque, as revealed by integrative structural modeling and advanced imaging, explains how mutations in plaque proteins can disrupt adhesion and cause disease. Moreover, the outer dense plaque is a dynamic assembly whose composition is regulated during differentiation and in response to signaling, making it a relevant target for studies of tissue homeostasis and disease.
• Provides the membrane-proximal anchor for desmosomal cadherins, linking adhesion to the plaque.
• Contains plakoglobin and plakophilin family proteins that are essential for plaque assembly and stability.
• Includes the N-terminal domains of desmoplakin, which connect the outer plaque to the inner plaque and intermediate filaments.
• Its disruption impairs epidermal integrity, as shown by proteomic identification of novel desmosome components.
• Mutations in desmosomal plaque proteins cause arrhythmogenic right ventricular dysplasia and related cardiomyopathies.
• Serves as a model system for studying protein-protein interaction networks at cell junctions.
• Is a target for super-resolution and volume electron microscopy studies of junction architecture.
• Provides cellular-component annotation for interpreting gene expression and proteomic datasets in epithelial and cardiac biology.
• Offers a structural basis for understanding how point mutations affect plaque assembly and function.
• Represents a potential therapeutic target for diseases of cell adhesion.
What Happens During outer dense plaque of desmosome?
Initiation of desmosome assembly at the plasma membrane
In simple terms: Desmosome assembly begins when adhesion proteins on neighboring cells start to connect and recruit plaque proteins inside the cell.
Desmosome assembly is initiated by interactions between desmosomal cadherins on adjacent cells, which cluster at the plasma membrane and recruit cytoplasmic plaque proteins. Early electron microscopy defined desmosomes as a junctional complex with a dense plaque, providing the first morphological description of the outer dense plaque region. Molecular mapping later showed that the plaque is a layered structure with distinct protein compositions, including plakoglobin and desmoplakin at the membrane-proximal region.
Recruitment of plakoglobin and plakophilins
In simple terms: Plakoglobin and plakophilin proteins are recruited to the cadherin tails and help build the outer dense plaque.
Plakoglobin and plakophilins are core components of the outer dense plaque that bind to the cytoplasmic tails of desmosomal cadherins and to each other. Integrative structural modeling has provided a molecular architecture of the outer dense plaque, showing how these proteins are arranged in a stoichiometric complex with the N-termini of desmoplakins. Super-resolution imaging has further resolved the nanoscale organization of these proteins within the plaque.
Incorporation of desmoplakin N-termini
In simple terms: The N-terminal ends of desmoplakin molecules are inserted into the outer dense plaque, connecting it to the rest of the desmosome.
Desmoplakin is a cytolinker protein whose N-terminus is part of the outer dense plaque, while its C-terminus associates with intermediate filaments. The outer dense plaque definition explicitly includes the N-termini of desmoplakins, which together with plakoglobin and plakophilin attach the plaque to the plasma membrane. Molecular mapping studies have localized desmoplakin within the plaque and demonstrated its role in linking the plaque to the cytoskeleton.
Maturation and stabilization of the plaque
In simple terms: Once the core proteins are in place, the plaque matures and becomes a stable structure that can withstand mechanical stress.
Maturation of the outer dense plaque involves additional protein-protein interactions and post-translational regulation that stabilize the assembly. Volume electron microscopy has revealed the three-dimensional architecture of desmosomes in epithelial cells and tissue models, showing how the plaque is organized in mature junctions. Proteomic analysis of desmosomes has identified novel components required for epidermal integrity, indicating that the plaque is a dynamic and complex assembly.
Key Genes Involved in GO:0090636 outer dense plaque of desmosome
The following genes encode proteins that are core or associated components of the outer dense plaque of the desmosome, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| JUP | Encodes plakoglobin, a core outer dense plaque protein that binds cadherin tails and desmoplakin | Central to plaque assembly; mutations linked to arrhythmogenic right ventricular dysplasia |
| DSP | Encodes desmoplakin, whose N-terminus is part of the outer dense plaque and C-terminus binds intermediate filaments | Key cytolinker; mutations cause cardiac and skin disease |
| PKP1 | Encodes plakophilin-1, a plakophilin family member in the outer dense plaque | Important for epidermal integrity; studied in desmosome assembly |
| PKP2 | Encodes plakophilin-2, a core plaque protein in cardiomyocytes | Frequently mutated in arrhythmogenic right ventricular dysplasia |
| PKP3 | Encodes plakophilin-3, a plakophilin family member in epithelial desmosomes | Contributes to plaque composition and epidermal integrity |
| DSG1 | Encodes desmoglein-1, a desmosomal cadherin whose cytoplasmic tail binds outer dense plaque proteins | Target of autoimmune and genetic skin diseases |
| DSG2 | Encodes desmoglein-2, a desmosomal cadherin in myocardium and epithelia | Mutations associated with arrhythmogenic cardiomyopathy |
| DSG3 | Encodes desmoglein-3, a desmosomal cadherin in stratified epithelia | Relevant to pemphigus and epidermal adhesion |
| DSC1 | Encodes desmocollin-1, a desmosomal cadherin whose tail interacts with plaque proteins | Contributes to cadherin-plaque coupling |
| DSC2 | Encodes desmocollin-2, a desmosomal cadherin in cardiac and epithelial tissues | Mutations linked to arrhythmogenic right ventricular dysplasia |
| DSC3 | Encodes desmocollin-3, a desmosomal cadherin in stratified epithelia | Involved in epidermal desmosome assembly |
| CTNNB1 | Encodes beta-catenin, a plakoglobin-related protein that can interact with desmosomal components | Studied in junctional signaling and adhesion |
| KRT5 | Encodes keratin 5, an intermediate filament protein that indirectly associates with the inner plaque | Relevant to mechanical coupling of desmosomes |
| KRT14 | Encodes keratin 14, an intermediate filament partner of keratin 5 in basal epidermis | Used as a marker of desmosome-cytoskeleton linkage |
| DES | Encodes desmin, the intermediate filament protein in cardiac and muscle cells | Links desmosomes to the cytoskeleton in myocardium |
| PRPH | Encodes peripherin, an intermediate filament protein in peripheral neurons | Potential context for desmosome-like junctions |
| EPB41L5 | Encodes a band 4.1-like protein implicated in junctional complexes | Candidate accessory protein in desmosome proteomics |
| AHNAK | Encodes a large scaffolding protein identified in desmosome proteomics | Novel component required for epidermal integrity |
How Is outer dense plaque of desmosome Regulated?
The outer dense plaque of the desmosome is regulated at multiple levels, including protein expression, post-translational modification, and interaction with signaling pathways. Proteomic analysis of desmosomes has identified novel components and potential regulatory proteins required for epidermal integrity, suggesting that plaque composition is dynamically controlled. Integrative structural modeling indicates that the stoichiometry and binding interfaces of plakoglobin, plakophilin, and desmoplakin N-termini are critical for plaque assembly, implying that changes in protein levels or mutations can shift the assembly equilibrium. In cardiac tissue, mutations in plaque protein genes such as PKP2 and DSP are associated with arrhythmogenic right ventricular dysplasia, highlighting the importance of proper regulation for tissue function. Super-resolution imaging has shown that plaque proteins are organized in nanoscale clusters, which may be remodeled during differentiation or stress.
outer dense plaque of desmosome and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PKP2 | Arrhythmogenic right ventricular dysplasia | Knockout or point-mutation in cardiomyocytes |
| DSP | Arrhythmogenic cardiomyopathy and skin fragility | Knock-in of patient mutations in epithelial cells |
| JUP | Arrhythmogenic right ventricular dysplasia and epidermal defects | Knockout in keratinocytes or cardiac cells |
| DSG2 | Arrhythmogenic cardiomyopathy | Point-mutation knock-in in cardiac organoids |
| DSC2 | Arrhythmogenic right ventricular dysplasia | Knockout in cardiomyocytes |
Arrhythmogenic right ventricular dysplasia and desmosomal plaque mutations
Arrhythmogenic right ventricular dysplasia is a cell adhesion cardiomyopathy caused by mutations in desmosomal genes, including those encoding outer dense plaque proteins. Genotype-phenotype assessment has provided insights into disease pathogenesis, linking mutations in desmosomal components to impaired adhesion and cardiac dysfunction. The outer dense plaque is directly implicated because it contains plakoglobin, plakophilin, and desmoplakin N-termini, all of which can be affected by disease-associated mutations.
Epidermal fragility and desmosome component defects
Proteomic analysis of desmosomes has revealed novel components required for epidermal integrity, indicating that the outer dense plaque and its associated proteins are essential for skin barrier function. Defects in desmosomal cadherins or plaque proteins can lead to blistering diseases and epidermal fragility, as the plaque is necessary for mechanical coupling.
Autoimmune targeting of desmosomal cadherins
Desmosomal cadherins, whose cytoplasmic tails are part of the outer dense plaque, are targets of autoantibodies in pemphigus, leading to loss of adhesion. Molecular mapping of the desmosomal plaque has provided a framework for understanding how autoantibody binding disrupts plaque assembly and function. The outer dense plaque is the region where cadherin tails connect to plakoglobin and desmoplakin, so disruption of these interactions can compromise tissue integrity.
From outer dense plaque of desmosome-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of losing a core outer dense plaque protein? | CRISPR knockout of JUP, DSP, or PKP2 in epithelial or cardiac cells |
| How does a disease-associated point mutation affect plaque assembly? | Point-mutation knock-in of PKP2 or DSP variants |
| Can a tagged plaque protein be used to track assembly dynamics? | Knock-in of fluorescent or epitope tags at endogenous loci |
| Does overexpression of a plaque protein alter desmosome stability? | Overexpression of plakoglobin or plakophilin in cultured cells |
| Which proteins are required for epidermal integrity? | Proteomic analysis of desmosomes from knockout or knockdown cells |
| How is the plaque organized in three dimensions? | Volume electron microscopy of epithelial tissue models |
How to Study the outer dense plaque of desmosome Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Integrative structural modeling | Molecular architecture and protein interfaces | Building models of the outer dense plaque |
| Super-resolution microscopy | Nanoscale protein localization | Resolving plaque protein clusters |
| Volume electron microscopy | Three-dimensional ultrastructure | Visualizing desmosome architecture in tissues |
| Proteomics | Protein composition of isolated desmosomes | Identifying novel plaque components |
| Immunoelectron microscopy | Protein localization at ultrastructural level | Mapping plaque proteins |
| CRISPR knockout | Loss-of-function effects | Testing requirement of plaque genes |
| Knock-in tagging | Endogenous protein dynamics | Tracking plaque assembly |
| Genotype-phenotype analysis | Association of mutations with disease | Linking plaque gene variants to cardiomyopathy |
Integrative structural modeling
Integrative structural modeling combines data from multiple sources to build a molecular architecture of the outer dense plaque. This approach has been used to propose how plakoglobin, plakophilin, and desmoplakin N-termini are arranged in the plaque, providing testable hypotheses about protein interfaces.
Super-resolution and volume electron microscopy
Super-resolution imaging, such as direct stochastic optical reconstruction microscopy, has resolved the nanoscale organization of desmosomal proteins, including those in the outer dense plaque. Volume electron microscopy has revealed the three-dimensional architecture of desmosomes in epithelial cells and tissue models, offering a detailed view of plaque structure.
Proteomic analysis of desmosomes
Proteomic analysis of isolated desmosomes has identified both known and novel components, including proteins required for epidermal integrity. This method is useful for discovering accessory proteins that associate with the outer dense plaque and for assessing changes in plaque composition under different conditions.
Molecular mapping and imaging of plaque proteins
Molecular mapping using immunoelectron microscopy and related techniques has localized specific proteins within the desmosomal plaque, including the outer dense plaque region. These methods help define the spatial relationships between plakoglobin, plakophilin, desmoplakin, and cadherin tails.
How CRISPR Can Be Used to Study GO:0090636 outer dense plaque of desmosome
Knockout
CRISPR knockout of genes encoding outer dense plaque proteins, such as JUP, DSP, or PKP2, can reveal their requirement for desmosome assembly and tissue integrity. Proteomic studies of desmosomes have used knockout or knockdown approaches to identify components required for epidermal integrity. Knockout models are also useful for testing whether a candidate plaque protein is essential for cadherin-plaque coupling.
Point Mutation
Point-mutation knock-in using CRISPR can model disease-associated variants in outer dense plaque genes. For example, mutations in PKP2 and DSP identified in arrhythmogenic right ventricular dysplasia patients can be introduced into cell lines or organoids to study effects on plaque assembly and adhesion. Such models help establish causality between specific variants and plaque dysfunction.
Knock-in
Knock-in of fluorescent or epitope tags at endogenous loci allows visualization and biochemical isolation of outer dense plaque proteins. This approach has been used in super-resolution imaging studies to track plaque protein localization and dynamics. Tagged knock-in models are valuable for studying assembly and turnover of the outer dense plaque in living cells.
Overexpression
Overexpression of outer dense plaque proteins, such as plakoglobin or plakophilin, can be used to test whether increased protein levels alter desmosome stability or composition. Proteomic analysis of desmosomes has shown that changes in plaque protein levels can affect epidermal integrity. Overexpression models complement loss-of-function studies by revealing gain-of-function or dominant-negative effects.
How EDITGENE Supports outer dense plaque of desmosome Research
Researchers studying outer dense plaque of desmosome-related genes often need to determine whether a candidate gene is causally involved in plaque assembly, adhesion, or disease. CRISPR-based models provide a precise way to manipulate these genes and assess their functions in relevant cell types.
Contact EDITGENE today to design your custom CRISPR model for outer dense plaque of desmosome research.
Frequently Asked Questions About outer dense plaque of desmosome
What is the outer dense plaque of the desmosome?
The outer dense plaque of the desmosome (GO:0090636) is the desmosomal part containing plakoglobins, plakophilins, the N-termini of desmoplakins, and the cytoplasmic tails of desmosomal cadherins, which together attach the plaque to the plasma membrane.
What genes are involved in the outer dense plaque of the desmosome?
Key genes include JUP (plakoglobin), DSP (desmoplakin), PKP1, PKP2, PKP3 (plakophilins), and desmosomal cadherin genes such as DSG1, DSG2, DSG3, DSC1, DSC2, and DSC3.
What is the function of GO:0090636?
GO:0090636 describes a cellular component that anchors desmosomal cadherins to the plasma membrane and organizes the membrane-proximal plaque of the desmosome.
How is the outer dense plaque of the desmosome structured?
It is a layered protein assembly containing plakoglobin, plakophilins, desmoplakin N-termini, and cadherin tails, as revealed by integrative structural modeling and super-resolution imaging.
What diseases are associated with outer dense plaque proteins?
Mutations in desmosomal plaque genes, including PKP2, DSP, and JUP, are associated with arrhythmogenic right ventricular dysplasia and related cell adhesion cardiomyopathies.
How can I study the outer dense plaque of the desmosome?
Common methods include integrative structural modeling, super-resolution microscopy, volume electron microscopy, proteomics, and CRISPR-based gene editing.
What is the difference between the outer dense plaque and the inner dense plaque?
The outer dense plaque is membrane-proximal and contains plakoglobin, plakophilins, desmoplakin N-termini, and cadherin tails, while the inner dense plaque is associated with intermediate filament anchorage.
Which proteins bind to desmosomal cadherins in the outer dense plaque?
Plakoglobin and plakophilins bind to the cytoplasmic tails of desmosomal cadherins, and desmoplakin N-termini are also part of this complex.
Can CRISPR be used to model outer dense plaque diseases?
Yes, CRISPR knockout, point-mutation knock-in, and tagged knock-in models can be used to study the effects of plaque gene mutations on desmosome function and disease phenotypes.
What experimental models are available for outer dense plaque research?
Available models include CRISPR knockout and knock-in cell lines, overexpression models, and tissue models for volume electron microscopy and proteomics.
Conclusion
The outer dense plaque of the desmosome (GO:0090636) is a structurally and functionally critical cellular component that anchors desmosomal cadherins to the plasma membrane and organizes the membrane-proximal plaque. Advances in integrative structural modeling, super-resolution imaging, volume electron microscopy, and proteomics have provided a detailed molecular picture of this assembly and its components. Mutations in outer dense plaque proteins are linked to arrhythmogenic right ventricular dysplasia and epidermal fragility, underscoring the clinical importance of this structure. CRISPR-based approaches, including knockout, point-mutation knock-in, tagged knock-in, and overexpression, offer powerful ways to dissect the roles of individual plaque proteins and to model disease-associated variants. Researchers can leverage these tools to advance understanding of desmosome biology and to develop new insights into cell adhesion diseases.
References
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