Protein 4.1, (Erythrocyte membrane protein band 4.1), is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
associated with the
cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...
that in humans is encoded by the ''EPB41''
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 ...
. Protein 4.1 is a major structural element of the
erythrocyte
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood ce ...
membrane
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...
skeleton. It plays a key role in regulating membrane physical properties of mechanical stability and deformability by stabilizing
spectrin
Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma mem ...
-
actin
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...
interaction. Protein 4.1 (80 kD) interacts with spectrin and short
actin filaments
Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other p ...
to form the erythrocyte membrane skeleton. Mutations of spectrin and protein 4.1 are associated with
elliptocytosis
Hereditary elliptocytosis, also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the person's red blood cells are elliptical rather than the typical biconcave disc shape. Such morphologically distinctiv ...
or
spherocytosis
Spherocytosis is the presence of spherocytes in the blood, i.e. erythrocytes (red blood cells) that are sphere-shaped rather than bi-concave disk shaped as normal. Spherocytes are found in all hemolytic anemias to some degree. Hereditary spheroc ...
and
anemia
Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
of varying severity.
Clinical significance
Elliptocytosis is a hematologic disorder characterized by elliptically shaped erythrocytes and a variable degree of hemolytic anemia. Inherited as an autosomal dominant, elliptocytosis results from mutation in any one of several genes encoding proteins of the red cell membrane skeleton. The form discussed here is the one found in the 1950s to be linked to Rh blood group and more recently shown to be caused by a defect in protein 4.1. 'Rh-unlinked' forms of elliptocytosis are caused by mutation in the alpha-
spectrin
Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma mem ...
gene (MIM 182860), the beta-
spectrin
Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane in eukaryotic cells. Spectrin forms pentagonal or hexagonal arrangements, forming a scaffold and playing an important role in maintenance of plasma mem ...
gene (MIM 182870), or the
band 3
Band 3 anion transport protein, also known as anion exchanger 1 (AE1) or band 3 or solute carrier family 4 member 1 (SLC4A1), is a protein that is encoded by the gene in humans.
Band 3 anion transport protein is a phylogenetically-preserved ...
gene (MIM 109270)
upplied by OMIM
Interactions
Protein 4.1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization advocating for the legal and human rights of children with intersex traits. The organization was founded in 2006 and fo ...
with:
*
CENPJ
Centromere protein J is a protein that in humans is encoded by the ''CENPJ'' gene. It is also known as centrosomal P4.1-associated protein (CPAP). During cell division, this protein plays a structural role in the maintenance of centrosome integrit ...
,
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EIF3G
Eukaryotic translation initiation factor 3 subunit G (eIF3g) is a protein that in humans is encoded by the ''EIF3G'' gene.
Interactions
EIF3G has been shown to interact with Band 4.1, EIF3C and EIF3A
Eukaryotic translation initiation fac ...
*
NUMA1
Nuclear mitotic apparatus protein 1 is a protein that in humans is encoded by the ''NUMA1'' 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 ...
,
and
*
TJP2.
See also
*
Elliptocytosis
Hereditary elliptocytosis, also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the person's red blood cells are elliptical rather than the typical biconcave disc shape. Such morphologically distinctiv ...
References
Further reading
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External links
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{{gene-1-stub