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The official name of this gene is “parkinson protein 2, E3 ubiquitin protein ligase (parkin).”
PARK2 is the gene's official symbol. The PARK2 gene is also known by other names, listed below.
The PARK2 gene, one of the largest human genes, provides instructions for making a protein called parkin. Parkin plays a role in the cell machinery that breaks down (degrades) unneeded proteins by tagging damaged and excess proteins with molecules called ubiquitin. Ubiquitin serves as a signal to move unneeded proteins into specialized cell structures known as proteasomes, where the proteins are degraded. The ubiquitin-proteasome system acts as the cell's quality control system by disposing of damaged, misshapen, and excess proteins. This system also regulates the availability of proteins that are involved in several critical cell activities, such as the timing of cell division and growth. Because of its activity in the ubiquitin-proteasome system, parkin belongs to a group of proteins called E3 ubiquitin ligases.
Parkin appears to be involved in the maintenance of mitochondria, the energy-producing centers in cells. However, little is known about its role in mitochondrial function. Research suggests that parkin may help trigger the destruction of mitochondria that are not working properly.
Studies of the structure and activity of parkin have led researchers to propose several additional activities for this protein. Parkin may act as a tumor suppressor protein, which means it prevents cells from growing and dividing too rapidly or in an uncontrolled way. Parkin may also regulate the supply and release of sacs called synaptic vesicles from nerve cells. Synaptic vesicles contain chemical messengers that transmit signals from one nerve cell to another.
The PARK2 gene belongs to a family of genes called PARK (Parkinson disease).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
Researchers have identified more than 200 PARK2 gene mutations that cause Parkinson disease, a condition characterized by progressive problems with movement and balance. Mutations in this gene are associated with the juvenile form of Parkinson disease, which appears before age 20, and some cases of the more common, late-onset form that begins after age 50.
Some PARK2 gene mutations lead to an abnormally small parkin protein that is nonfunctional and is rapidly broken down (degraded) within cells. Other mutations insert, delete, or change DNA building blocks (nucleotides) in the PARK2 gene, leading to a defective version of the parkin protein or preventing the production of this protein. The PARK2 gene mutations associated with Parkinson disease usually lead to a loss of parkin activity.
It is unclear how PARK2 gene mutations cause Parkinson disease. The loss of parkin activity probably disturbs the ubiquitin-proteasome system, which allows unneeded proteins to accumulate. A buildup of these proteins could disrupt normal cell activities such as the supply and release of synaptic vesicles, particularly those that contain a chemical messenger called dopamine. As parkin is normally abundant in the brain, its loss could lead to the impairment or death of nerve cells, including those that produce dopamine. Loss of dopamine-producing nerve cells is a characteristic feature of Parkinson disease.
Mutations in the PARK2 gene may also disrupt the regulation of mitochondria. Researchers speculate that mitochondrial dysfunction in dopamine-producing nerve cells may play an important role in causing the signs and symptoms of Parkinson disease.
The PARK2 gene spans part of a region on chromosome 6 known as FRA6E. This region is known as a fragile area because it is unstable and prone to breakage and rearrangement. Changes involving the FRA6E region have been reported in several forms of human cancer, including glioblastoma (a form of brain cancer), colorectal cancer, lung cancer, and ovarian cancer. In some of these cancerous tumors, segments of the FRA6E region, including part or all of the PARK2 gene, are abnormally deleted or duplicated. These genetic changes are described as somatic because they occur only in tumor cells and are not inherited. As a result of these alterations, parkin activity is reduced or absent in these cells. Because parkin is thought to act as a tumor suppressor, a shortage of this protein's function could allow cells to grow and divide in an uncontrolled manner, leading to tumor formation.
Studies suggest that common variations (polymorphisms) in the PARK2 gene (and a neighboring gene called PACRG) can increase the risk of contracting Hansen disease, also known as leprosy. This disease affects the nerves and skin and is caused by the bacterium Mycobacterium leprae. It remains unclear how PARK2 polymorphisms increase susceptibility to Hansen disease. Researchers believe that the ubiquitin-proteasome system may play a role in controlling infection. Polymorphisms in the PARK2 gene may subtly alter parkin's function, making the ubiquitin-proteasome system less efficient.
Cytogenetic Location: 6q25.2-q27
Molecular Location on chromosome 6: base pairs 161,768,589 to 163,148,833
The PARK2 gene is located on the long (q) arm of chromosome 6 between positions 25.2 and 27.
More precisely, the PARK2 gene is located from base pair 161,768,589 to base pair 163,148,833 on chromosome 6.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about PARK2 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
autosomal ; autosomal recessive ; cancer ; cell ; cell division ; chromosome ; colorectal ; DNA ; dopamine ; gene ; glioblastoma ; infection ; juvenile ; ligase ; mitochondria ; mycobacterium ; nerve cell ; ovarian ; proteasome ; protein ; rearrangement ; recessive ; susceptibility ; synaptic vesicles ; tumor ; ubiquitin
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.