Desmocollins are a subfamily of desmosomal

cadherin Cadherins (named for "calcium-dependent adhesion") are cell adhesion molecules important in forming adherens junctions that let cells adhere to each other. Cadherins are a class of type-1 transmembrane proteins, and they depend on calcium (Ca2+) ...

s, the transmembrane constituents of

desmosome A desmosome (; "binding body"), also known as a macula adherens (plural: maculae adherentes) (Latin for ''adhering spot''), is a cell structure specialized for cell-to-cell adhesion. A type of junctional complex, they are localized spot-like ad ...

s. They are co-expressed with

desmoglein The desmogleins are a family of desmosomal cadherins consisting of proteins DSG1, DSG2, DSG3, and DSG4. They play a role in the formation of desmosomes that join cells to one another. Pathology Desmogleins are targeted in the autoimmune disease ...

s to link adjacent cells by extracellular adhesion. There are seven desmosomal cadherins in humans, three desmocollins and four desmogleins. Desmosomal cadherins allow desmosomes to contribute to the integrity of tissue structure in multicellular living organisms.

Structure

Three

isoforms A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...

of desmocollin proteins have been identified. * Desmocollin-1, coded by the DSC1 gene * Desmocollin-2, coded by the

DSC2 Desmocollin-2 is a protein that in humans is encoded by the ''DSC2'' gene. Desmocollin-2 is a cadherin-type protein that functions to link adjacent cells together in specialized regions known as desmosomes. Desmocollin-2 is widely expressed, and ...

gene * Desmocollin-3, coded by the DSC3 gene Each desmocollin

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

encodes a pair of proteins: a longer 'a' form and a shorter 'b' form. The 'a' and 'b' forms differ in the length of their

C-terminus The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein Proteins are large biomolecules and macromolecules that comp ...

tails. The protein pair is generated by

alternative splicing Alternative splicing, alternative RNA splicing, or differential splicing, is an alternative RNA splicing, splicing process during gene expression that allows a single gene to produce different splice variants. For example, some exons of a gene ma ...

. Desmocollin has four cadherin-like

extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

domains, an extracellular anchor domain, and an

intracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

anchor domain. Additionally, the 'a' form has an intracellular cadherin-like sequence domain, which provides

binding site In biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may includ ...

s for other desmosomal proteins such as

plakoglobin Plakoglobin, also known as junction plakoglobin or gamma-catenin, is a protein that in humans is encoded by the ''JUP'' gene. Plakoglobin is a member of the catenin protein family and homologous to β-catenin. Plakoglobin is a cytoplasmic compon ...

Expression

The desmosomal cadherins are expressed in tissue-specific patterns. Desmocollin-2 and desmoglein-2 are found in all desmosome-containing tissues such as colon and cardiac muscle tissues, while other desmosomal cadherins are restricted to stratified epithelial tissues. All seven desmosomal cadherins are expressed in

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...

, but in a differentiation-specific manner. The '2' and '3' isoforms of desmocollin and desmoglein are expressed in the lower epidermal layers, and the '1' proteins and desmoglein-4 are expressed in the upper epidermal layers. Different isoforms are located in the same individual cells, and single desmosomes contain more than one isoform of both desmocollin and desmoglein. It is unclear why there are multiple desmosomal cadherin isoforms. It is thought that they may have different adhesive properties that are required at different levels in stratified epithelia or that they have specific functions in epithelial differentiation.

Disorders

Desmosomes are involved in cell-cell adhesion, and are particularly important for the integrity of heart and skin tissue. Because of this, desmocollin gene mutations can affect the adhesion of cells that undergo mechanical stress, notably

cardiomyocytes Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of ...

and

keratinocyte Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the basal layer (''stratum basale'') of the skin are sometimes referre ...

s. Genetic disorders associated with desmocollin gene mutations include

Carvajal syndrome Carvajal (also spelled Carbajal) is a Spanish surname and place name. Notable people with the surname include: * Ailem Carvajal Gómez (born 1972), Cuban composer and pianist * Alfonso Carvajal (writer) (born 1958), Colombian writer and editor * ...

, striate

palmoplantar keratoderma Palmoplantar keratodermas are a heterogeneous group of skin disorders characterized by abnormal thickening (scleroderma) of the stratum corneum of the palms and soles. Autosomal recessive, dominant, X-linked, and acquired forms have all been de ...

, Naxos disease, and

arrhythmogenic right ventricular cardiomyopathy Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease. ACM is caused by genetic defects of parts of the cardiac muscle known as desmosomes, areas on the surface of muscle cells which link them together. The desmosomes are composed o ...

. There is also evidence that

autoimmunity In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an " autoimmune disease ...

against desmosomal cadherins contributes to cardiac

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

associated with arrhythmogenic right ventricular cardiomyopathy, and that anti-desmosomal cadherin

antibodies An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as bacteria and viruses, including those that caus ...

may represent new therapeutic targets.

References

{{Authority control Proteins

Structure

Expression

Disorders

See also

References