ATP7A
Encyclopedia
Copper-transporting ATPase 1 also known as copper pump 1 or Menkes disease-associated protein is a protein
that in humans is encoded by the ATP7A gene
.
between positions 13.2 and 13.3, from base pair
76,972,353 to base pair 77,112,036.
levels in the body. This protein is found in most tissues, but it is absent from the liver
. In the small intestine, the ATP7A protein helps control the absorption of copper from food. In other organs and tissues, the ATP7A protein has a dual role and shuttles between two locations within the cell. The protein normally resides in a cell structure called the Golgi apparatus
, which modifies and transports newly produced enzymes and other proteins. Here, the ATP7A protein supplies copper to certain enzymes that are critical for the structure and function of bone, skin, hair, blood vessels, and the nervous system. If copper levels in the cell environment are elevated, however, the ATP7A protein moves to the cell membrane and eliminates excess copper from the cell.
with ATOX1
and GLRX
.
s in the ATP7A gene. Researchers have identified more than 100 ATP7A mutations that cause Menkes syndrome and occipital horn syndrome
, the milder form of Menkes syndrome. Many of these mutations delete part of the gene and are predicted to produce a shortened ATP7A protein that is unable to transport copper. Other mutations insert additional DNA building blocks (base pairs) or use the wrong building blocks, which leads to ATP7A proteins that do not function properly.
The altered proteins that result from ATP7A mutations impair the absorption of copper from food, fail to supply copper to certain enzymes, or get stuck in the cell membrane, unable to shuttle back and forth from the Golgi. As a result of the disrupted activity of the ATP7A protein, copper is poorly distributed to cells in the body. Copper accumulates in some tissues, such as the small intestine and kidneys, while the brain and other tissues have unusually low levels. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes that are necessary for the structure and function of bone, skin, hair, blood vessels, and the nervous system.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that in humans is encoded by the ATP7A gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Gene
The ATP7A gene is located on the long (q) arm of the X chromosomeX chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
between positions 13.2 and 13.3, from base pair
Base pair
In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...
76,972,353 to base pair 77,112,036.
Function
ATP7A is important for regulating copperCopper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
levels in the body. This protein is found in most tissues, but it is absent from the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
. In the small intestine, the ATP7A protein helps control the absorption of copper from food. In other organs and tissues, the ATP7A protein has a dual role and shuttles between two locations within the cell. The protein normally resides in a cell structure called the Golgi apparatus
Golgi apparatus
The Golgi apparatus is an organelle found in most eukaryotic cells. It was identified in 1898 by the Italian physician Camillo Golgi, after whom the Golgi apparatus is named....
, which modifies and transports newly produced enzymes and other proteins. Here, the ATP7A protein supplies copper to certain enzymes that are critical for the structure and function of bone, skin, hair, blood vessels, and the nervous system. If copper levels in the cell environment are elevated, however, the ATP7A protein moves to the cell membrane and eliminates excess copper from the cell.
Interactions
ATP7A has been shown to interactProtein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...
with ATOX1
ATOX1
Copper transport protein ATOX1 is a protein that in humans is encoded by the ATOX1 gene.-Interactions:ATOX1 has been shown to interact with Wilson disease protein and ATP7A.-Further reading:...
and GLRX
GLRX
Glutaredoxin-1 is a protein that in humans is encoded by the GLRX gene.-Interactions:GLRX has been shown to interact with Wilson disease protein and ATP7A.-Further reading:...
.
Clinical significance
Menkes syndrome is caused by mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s in the ATP7A gene. Researchers have identified more than 100 ATP7A mutations that cause Menkes syndrome and occipital horn syndrome
Occipital horn syndrome
Occipital horn syndrome , formerly considered a variant of Ehlers-Danlos syndrome, is an X-linked recessive connective tissue disorder. It is caused by a deficiency in the transport of the essential mineral copper, associated with mutations in the ATP7A gene...
, the milder form of Menkes syndrome. Many of these mutations delete part of the gene and are predicted to produce a shortened ATP7A protein that is unable to transport copper. Other mutations insert additional DNA building blocks (base pairs) or use the wrong building blocks, which leads to ATP7A proteins that do not function properly.
The altered proteins that result from ATP7A mutations impair the absorption of copper from food, fail to supply copper to certain enzymes, or get stuck in the cell membrane, unable to shuttle back and forth from the Golgi. As a result of the disrupted activity of the ATP7A protein, copper is poorly distributed to cells in the body. Copper accumulates in some tissues, such as the small intestine and kidneys, while the brain and other tissues have unusually low levels. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes that are necessary for the structure and function of bone, skin, hair, blood vessels, and the nervous system.