Desmosome
Desmosome | |
---|---|
Details | |
Identifiers | |
Latin | Desmosoma Macula adhaerens |
MeSH | D003896 |
TH | H1.00.01.1.02015 |
FMA | 67412 |
Anatomical terminology |
A desmosome (
Structure
Desmosomes are composed of desmosome-intermediate filament complexes (DIFC), which is a network of cadherin proteins, linker proteins and intermediate filaments.[4] The DIFCs can be broken into three regions: the extracellular core region, or desmoglea, the outer dense plaque, or ODP, and the inner dense plaque, or IDP.[3]
The extracellular core region, approximately 34 nm in length, contains desmoglein and desmocollin, which are in the cadherin family of cell adhesion proteins. Both have five extracellular domains, and have calcium-binding motifs. Extracellular calcium helps form the cadherin adhesion by allowing the cadherin extracellular domain on desmoglein and desmocollin to become rigid.[5] They bind to each other via heterophilic interactions in the extracellular space near their N-termini, in contrast with the homophilic binding characteristic of other cadherins.[6] Desmoglein and desmocollin have a single pass transmembrane region plus an intracellular anchor to secure its position in the cell membrane. Desmogleins and the desmocollin isoform "Dsc-a" contain an intracellular cadherin domain, which binds to plakoglobin.[3]
The outer dense plaque, which is about 15–20 nm in length, contains the intracellular ends of desmocollin and desmoglein, the N-terminus side of
The inner dense plaque, also about 15–20 nm in length, contains the C-terminus end of desmoplakin and their attachment to keratin intermediate filaments. Desmoplakin is the most abundant part of the desmosome,[7] as it operates as the mediator between the cadherin proteins in the plasma membrane and the keratin filaments. Desmoplakin has two isoforms that differ in the length of their middle rod domain. All desmoplakins have an N-terminal head, a C-tail consisting of three plakin repeats, and a glycine-serine-arginine rich domain (GSR) at the C-end.[citation needed]
Clinical significance
Arrhythmogenic cardiomyopathy
Mutations within the desmosome are the main cause of arrhythmogenic cardiomyopathy (ACM), a life-threatening disease caused by mutations usually in desmoglein 2, but sometimes in desmocollin 2. It often afflicts individuals between 20 and 50 years, and has been publicly known as a cause of death in young athletes, although the majority of sudden deaths do not occur in close connection to physical activity. The current incidence within the population is accepted as 1/10,000; however, it is thought that 1/200 may have a mutation that may predispose to ACM.[8] Symptoms of ACM include fainting, shortness of breath, and heart palpitations and the condition is treated by implanting a small defibrillator device.
Blisters
Blistering diseases such as
Similar symptoms occur with
Epidermolysis bullosa simplex is an epidermal blistering disease caused by mutations in genes coding for keratin 5 and 14, which attach to desmoplakin. This disease manifests as rupture of the basal epidermis when stress is applied. Ectodermal dysplasia or skin fragility syndrome is caused by plakophillin 1 mutations. This is manifested by detachment of intermediate filaments and desmoplakin from the desmosome.[4]
History
The desmosome was first discovered by
See also
- Arrhythmogenic right ventricular cardiomyopathy
- Epidermolysis bullosa
- Hemidesmosome
References
- ^ "Desmosome". Lexico UK English Dictionary. Oxford University Press. Archived from the original on 2020-01-27.
- ^ "Desmosome". Merriam-Webster.com Dictionary. Retrieved 2016-01-21.
- ^ PMID 20066089.
- ^ PMID 17854763.
- PMID 17539752.
- PMID 27298358.
- PMID 6341602.
- PMID 21397041.
External links
- MedEd at Loyola Histo/practical/epithelium/hp1-13.html
- Histology image: 20502loa – Histology Learning System at Boston University – "Ultrastructure of the Cell: microvillous border, Junctional Complex of absorptive epithelium"
- Histology image: 20604loa – Histology Learning System at Boston University – "Ultrastructure of the Cell: microvillous border and Junctional Complex, desmosomes and zonula adhaerens"
- Histology image: 22502loa – Histology Learning System at Boston University – "Ultrastructure of the Cell: cardiac muscle, intercalated disk"