Cadherin related family member 3 (CDHR3), also known as CDH28 or its abbreviation CDHR3, is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

that in humans is encoded by the ''CDHR3''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

. The protein is predominately expressed in

respiratory epithelium Respiratory epithelium, or airway epithelium, is a type of ciliated columnar epithelium found lining most of the respiratory tract as respiratory mucosa, where it serves to moisten and protect the airways. It is not present in the vocal cords o ...

and the first notion of its clinical implications was from the discovery that genetic variation of ''CDHR3'' is strongly associated to early severe

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, cou ...

exacerbations in children. Subsequent studies have suggested that CDHR3 is a receptor for a subtype of

rhinovirus The rhinovirus (from the grc, ῥίς, rhis "nose", , romanized: "of the nose", and the la, vīrus) is the most common viral infectious agent in humans and is the predominant cause of the common cold. Rhinovirus infection proliferates in tem ...

Function and cellular location

The exact physiological role of CDHR3 is not known, but as the CDHR3 protein is expressed in epithelial tissues and has six extracellular

cadherin Cadherins (named for "calcium-dependent adhesion") are a type of cell adhesion molecule (CAM) that is important in the formation of adherens junctions to allow cells to adhere to each other . Cadherins are a class of type-1 transmembrane proteins, ...

domains plus a short

transmembrane segment A transmembrane domain (TMD) is a membrane-spanning protein domain. TMDs generally adopt an alpha helix topological conformation, although some TMDs such as those in porins can adopt a different conformation. Because the interior of the lipid bil ...

, it is believed to be related to the function of similar cadherins which function in

cell adhesion Cell adhesion is the process by which cells interact and attach to neighbouring cells through specialised molecules of the cell surface. This process can occur either through direct contact between cell surfaces such as cell junctions or indir ...

and

cell-to-cell signaling In biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellula ...

. Two single-cell RNA expression studies furthermore found CDHR3 to be highly selectively expressed in ciliated epithelial cells, compared to other cell types in the respiratory epithelium, and thereby to be a marker for ciliated cells in respiratory airway tissue.

Clinical significance

A nonsynonymous mutation in ''CDHR3'' at rs6967330 (C529Y) was at first found to be associated with severe asthma exacerbations in early childhood, with genome-wide significance. Functional experiments further indicated that this gene polymorphism leads to increased surface

expression Expression may refer to: Linguistics * Expression (linguistics), a word, phrase, or sentence * Fixed expression, a form of words with a specific meaning * Idiom, a type of fixed expression * Metaphorical expression, a particular word, phrase, o ...

of the CDHR3 protein. A subsequent study found that CDHR3 is a probable receptor for rhinovirus type C, a common form of

. Recent studies furthermore found that ''CDHR3'' gene variation is not associated with childhood

bronchiolitis Bronchiolitis is inflammation of the small airways in the lungs. Acute bronchiolitis is due to a viral infection usually affecting children younger than two years of age. Symptoms may include fever, cough, runny nose, wheezing, and breathing ...

from

respiratory syncytial virus Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a common, contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. ...

(RSV) infection, which resemble early asthma exacerbations as a phenotype. However, childhood bronchiolitis not caused by RSV infection, of which rhinovirus is often implicated, was associated with the CDHR3 gene variation. This is line with the results from a study on

chronic rhinosinusitis Sinusitis, also known as rhinosinusitis, is inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include thick nasal mucus, a plugged nose, and facial pain. Other signs and symptoms may include fever, headac ...

, which often is associated rhinovirus infection, where ''CDHR3'' gene variation also was found to be a strong

risk factor In epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Due to a lack of harmonization across disciplines, determinant, in its more widely accepted scientific meaning, is often use ...

. Therefore, CDHR3 seems to causally linked to increased propensity for rhinovirus C infection.

Function and cellular location

Clinical significance

References

Further reading