FERM domain
Encyclopedia
In molecular biology, the FERM domain (F for 4.1 protein, E for ezrin, R for radixin
Radixin
Radixin is a protein that in humans is encoded by the RDX gene.Radixin is a cytoskeletal protein that may be important in linking actin to the plasma membrane. It is highly similar in sequence to both ezrin and moesin. The radixin gene has been localized by fluorescence in situ hybridization to...

 and M for moesin
Moesin
Moesin is a protein that in humans is encoded by the MSN gene.Moesin is a member of the ERM protein family which includes ezrin and radixin. ERM proteins appear to function as cross-linkers between plasma membranes and actin-based cytoskeletons...

) is a widespread protein
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...

 module involved in localising protein
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...

s to the plasma membrane. FERM domains
Protein domain
A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...

 are found in a number of cytoskeletal-associated proteins that associate with various proteins at the interface between the plasma membrane and the cytoskeleton
Cytoskeleton
The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

. The FERM domain is located at the N terminus in the majority of proteins in which it is found.

FERM domain containing proteins include:
  • Band 4.1
    Band 4.1
    Protein 4.1, also known as Beatty's Protein, is a protein associated with the cytoskeleton that in humans is encoded by the EPB41 gene.Protein 4.1 is a major structural element of the erythrocyte membrane skeleton. It plays a key role in regulating membrane physical properties of mechanical...

    , which links the spectrin
    Spectrin
    Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane of many cell types in pentagonal or hexagonal arrangements, forming a scaffolding and playing an important role in maintenance of plasma membrane integrity and cytoskeletal structure...

    -actin
    Actin
    Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...

     cytoskeleton
    Cytoskeleton
    The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

     of erythrocytes to the plasma membrane.

  • Ezrin, a component of the undercoat of the microvilli plasma membrane.

  • Moesin, which is probably involved in binding major cytoskeletal structure
    Cytoskeleton
    The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...

    s to the plasma membrane.

  • Radixin, which is involved in the binding of the barbed end of actin filaments to the plasma membrane in the undercoat of the cell-to-cell adherens junction.
    Adherens junction
    Adherens junctions are protein complexes that occur at cell–cell junctions in epithelial tissues, usually more basal than tight junctions...


  • Talin
    Talin
    Talin is a town in the Aragatsotn province of Armenia. It has a population of 5,371. The seventh century Talin Cathedral is located in the town.- History :...

    , a cytoskeletal protein concentrated in regions of cell-substratum contact and, in lymphocytes, of cell-cell contacts.

  • Filopodin, a slime mould
    Slime mould
    Slime mold or mould is a broad term describing protists that use spores to reproduce. Slime molds were formerly classified as fungi, but are no longer considered part of this kingdom....

     protein that binds actin
    Actin
    Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...

     and which is involved in the control of cell motility and chemotaxis
    Chemotaxis
    Chemotaxis is the phenomenon in which somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment. This is important for bacteria to find food by swimming towards the highest concentration of food molecules,...

    .

  • Merlin
    Merlin (protein)
    Merlin is a cytoskeletal protein. In humans, it is a tumor suppressor protein involved in Neurofibromatosis type II. Sequence data reveal its similarity to the ERM protein family....

     (or schwannomin).

  • Protein NBL4.

  • Unconventional myosin
    Myosin
    Myosins comprise a family of ATP-dependent motor proteins and are best known for their role in muscle contraction and their involvement in a wide range of other eukaryotic motility processes. They are responsible for actin-based motility. The term was originally used to describe a group of similar...

    s X, VIIa and XV, which are mutated
    Mutation
    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...

     in congenital deafness.

  • Focal-adhesion kinases (FAKs), cytoplasm
    Cytoplasm
    The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

    ic protein tyrosine kinases involved in signalling through integrins.

  • Janus tyrosine kinases (JAKs), cytoplasmic tyrosine
    Tyrosine
    Tyrosine or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group...

     kinase
    Kinase
    In chemistry and biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates, a process referred to as phosphorylation. Kinases are part of the larger family of phosphotransferases...

    s that are non-covalently associated with the cytoplasmic tails of receptor
    Receptor (biochemistry)
    In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

    s for cytokine
    Cytokine
    Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...

    s or polypeptidic hormones.

  • Non-receptor tyrosine-protein kinase TYK2.

  • Protein-tyrosine phosphatases
    Protein tyrosine phosphatase
    Protein tyrosine phosphatases are a group of enzymes that remove phosphate groups from phosphorylated tyrosine residues on proteins. Protein tyrosine phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular...

     PTPN3
    PTPN3
    Tyrosine-protein phosphatase non-receptor type 3 is an enzyme that in humans is encoded by the PTPN3 gene.-Further reading:...

     and PTPN4
    PTPN4
    Tyrosine-protein phosphatase non-receptor type 4 is an enzyme that in humans is encoded by the PTPN4 gene.-Further reading:...

    , enzymes that appear to act at junctions between the membrane and the cytoskeleton.

  • Protein-tyrosine phosphatases PTPN14
    PTPN14
    Tyrosine-protein phosphatase non-receptor type 14 is an enzyme that in humans is encoded by the PTPN14 gene.-Interactions:PTPN14 has been shown to interact with Beta-catenin.-Further reading:...

     and PTP-D1, PTP-RL10 and PTP2E.

  • Caenorhabditis elegans
    Caenorhabditis elegans
    Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...

    protein phosphatase ptp-1.


Ezrin, moesin, and radixin are highly related proteins (ERM protein family), but the other proteins in which the FERM domain is found do not share any region of similarity outside of this domain. ERM proteins are made of three domains, the FERM domain, a central helical domain and a C-terminal tail domain, which binds F-actin. The amino-acid sequence
Sequence (biology)
A sequence in biology is the one-dimensional ordering of monomers, covalently linked within in a biopolymer; it is also referred to as the primary structure of the biological macromolecule.-See also:* Protein sequence* DNA sequence...

 of the FERM domain is highly conserved among ERM proteins and is responsible for membrane
Cell membrane
The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...

 association by direct binding to the cytoplasmic domain or tail of integral membrane protein
Integral membrane protein
An integral membrane protein is a protein molecule that is permanently attached to the biological membrane. Proteins that cross the membrane are surrounded by "annular" lipids, which are defined as lipids that are in direct contact with a membrane protein...

s. ERM proteins are regulated by an intramolecular association of the FERM and C-terminal tail domains that masks their binding site
Binding site
In biochemistry, a binding site is a region on a protein, DNA, or RNA to which specific other molecules and ions—in this context collectively called ligands—form a chemical bond...

s for other molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s. For cytoskeleton-membrane cross-linking, the dormant molecules becomes activated and the FERM domain attaches to the membrane by binding specific membrane proteins, while the last 34 residue
Residue
Residue may refer to:* Residue , material remaining after a distillation or an evaporation, or portion of a larger molecule** In particular, in biology, often refers specifically to an amino acid...

s of the tail bind actin filaments. Aside from binding to membranes, the activated FERM domain of ERM proteins can also bind the guanine
Guanine
Guanine is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine . In DNA, guanine is paired with cytosine. With the formula C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine-imidazole ring system with...

 nucleotide
Nucleotide
Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling , and are incorporated into important cofactors of enzymatic reactions...

 dissociation inhibitor of Rho GTPase
GTPase
GTPases are a large family of hydrolase enzymes that can bind and hydrolyze guanosine triphosphate . The GTP binding and hydrolysis takes place in the highly conserved G domain common to all GTPases.-Functions:...

 (RhoDGI), which suggests that in addition to functioning as a cross-linker, ERM proteins may influence Rho signalling pathways. The crystal structure
Crystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...

 of the FERM domain reveals that it is composed of three structural
Secondary structure
In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

 modules (F1, F2, and F3) that together form a compact clover-shaped structure
Secondary structure
In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

. The N-terminal module is ubiquitin
Ubiquitin
Ubiquitin is a small regulatory protein that has been found in almost all tissues of eukaryotic organisms. Among other functions, it directs protein recycling.Ubiquitin can be attached to proteins and label them for destruction...

-like. The C-terminal module is a PH-like domain.

The FERM domain has also been called the amino-terminal domain, the 30kDa domain, 4.1N30, the membrane-cytoskeletal-linking domain, the ERM-like domain, the ezrin-like domain of the band 4.1 superfamily, the conserved
Conserved sequence
In biology, conserved sequences are similar or identical sequences that occur within nucleic acid sequences , protein sequences, protein structures or polymeric carbohydrates across species or within different molecules produced by the same organism...

N-terminal region, and the membrane attachment domain.
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