Fibroblast growth factor receptor
Encyclopedia
The fibroblast growth factor receptors are, as their name implies, receptors
that bind to members of the fibroblast growth factor
family of proteins. Some of these receptors are involved in pathological conditions. For example, a point mutation in FGFR3
can lead to achondroplasia
.
receptors consist of an extracellular ligand
domain composed of three immunoglobulin-like domains, a single transmembrane helix
domain, and an intracellular
domain with tyrosine kinase
activity.
These receptors bind fibroblast growth factor
s, members of the largest family of growth factor ligands, comprising 22 members.
The natural alternate splicing of four fibroblast growth factor receptor (FGFR) genes results in the production of over 48 different isoforms of FGFR.
These isoforms vary in their ligand-binding properties and kinase domains, however all share the common extracellular region composed of three immunoglobulin(Ig)-like domains (D1-D3), and thus belong to the immunoglobulin superfamily
.
The three immunoglobin(Ig)-like domains - D1, D2, and D3 - present a stretch of acid
ic amino acid
s ("the acidic box") between D1 and D2. This "acidic box" can participate in the regulation of FGF binding to the FGFR. Immunoglobulin-like domains D2 and D3 are sufficient for FGF binding. Each receptor can be activated by several FGFs. In many cases, the FGFs themselves can also activate more than one receptor (i.e., FGF-1, which binds all seven principal FGFRs). FGF-7, however, can only activate FGFR2b.
A gene for a fifth FGFR protein, FGFR5, has also been identified. In contrast to FGFRs 1-4, it lacks a cytoplasmic tyrosine kinase domain and one isoform, FGFR5γ, and only contains the extracellular domains D1 and D2.
The FGFRs are known to dimer
ize as heterodimer
s and homodimers.
s and all of them belong to the tyrosine kinase
superfamily (FGFR1 to FGFR4). (see also Fibroblast growth factor receptor 1
) (= CD331) (see also Fibroblast growth factor receptor 2
) (= CD332) (see also Fibroblast growth factor receptor 3) (= CD333) (see also Fibroblast growth factor receptor 4
) (= CD334)
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...
that bind to members of the fibroblast growth factor
Fibroblast growth factor
Fibroblast growth factors, or FGFs, are a family of growth factors involved in angiogenesis, wound healing, and embryonic development. The FGFs are heparin-binding proteins and interactions with cell-surface associated heparan sulfate proteoglycans have been shown to be essential for FGF signal...
family of proteins. Some of these receptors are involved in pathological conditions. For example, a point mutation in FGFR3
FGFR3
Fibroblast growth factor receptor 3 is a protein that in humans is encoded by the FGFR3 gene. FGFR3 has also been designated as CD333 .-Structure and function:-Disease linkage:...
can lead to achondroplasia
Achondroplasia
Achondroplasia dwarfism occurs as a sporadic mutation in approximately 85% of cases or may be inherited in an autosomal dominant genetic disorder that is a common cause of dwarfism...
.
Structure
The fibroblast growth factorFibroblast growth factor
Fibroblast growth factors, or FGFs, are a family of growth factors involved in angiogenesis, wound healing, and embryonic development. The FGFs are heparin-binding proteins and interactions with cell-surface associated heparan sulfate proteoglycans have been shown to be essential for FGF signal...
receptors consist of an extracellular ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
domain composed of three immunoglobulin-like domains, a single transmembrane helix
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
domain, and an intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
domain with tyrosine kinase
Tyrosine kinase
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....
activity.
These receptors bind fibroblast growth factor
Fibroblast growth factor
Fibroblast growth factors, or FGFs, are a family of growth factors involved in angiogenesis, wound healing, and embryonic development. The FGFs are heparin-binding proteins and interactions with cell-surface associated heparan sulfate proteoglycans have been shown to be essential for FGF signal...
s, members of the largest family of growth factor ligands, comprising 22 members.
The natural alternate splicing of four fibroblast growth factor receptor (FGFR) genes results in the production of over 48 different isoforms of FGFR.
These isoforms vary in their ligand-binding properties and kinase domains, however all share the common extracellular region composed of three immunoglobulin(Ig)-like domains (D1-D3), and thus belong to the immunoglobulin superfamily
Immunoglobulin superfamily
The immunoglobulin superfamily is a large group of cell surface and soluble proteins that are involved in the recognition, binding, or adhesion processes of cells. Molecules are categorized as members of this superfamily based on shared structural features with immunoglobulins ; they all possess a...
.
The three immunoglobin(Ig)-like domains - D1, D2, and D3 - present a stretch of acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
ic amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s ("the acidic box") between D1 and D2. This "acidic box" can participate in the regulation of FGF binding to the FGFR. Immunoglobulin-like domains D2 and D3 are sufficient for FGF binding. Each receptor can be activated by several FGFs. In many cases, the FGFs themselves can also activate more than one receptor (i.e., FGF-1, which binds all seven principal FGFRs). FGF-7, however, can only activate FGFR2b.
A gene for a fifth FGFR protein, FGFR5, has also been identified. In contrast to FGFRs 1-4, it lacks a cytoplasmic tyrosine kinase domain and one isoform, FGFR5γ, and only contains the extracellular domains D1 and D2.
The FGFRs are known to dimer
Protein dimer
In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...
ize as heterodimer
Protein dimer
In biochemistry, a dimer is a macromolecular complex formed by two, usually non-covalently bound, macromolecules like proteins or nucleic acids...
s and homodimers.
Genes
So far, five distinct membrane FGFR have been identified in vertebrateVertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s and all of them belong to the tyrosine kinase
Tyrosine kinase
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to a protein in a cell. It functions as an "on" or "off" switch in many cellular functions....
superfamily (FGFR1 to FGFR4). (see also Fibroblast growth factor receptor 1
Fibroblast growth factor receptor 1
Fibroblast growth factor receptor 1 , also known as basic fibroblast growth factor receptor 1, fms-related tyrosine kinase-2 / Pfeiffer syndrome, and CD331, is a receptor tyrosine kinase whose ligands are specific members of the fibroblast growth factor family...
) (= CD331) (see also Fibroblast growth factor receptor 2
Fibroblast growth factor receptor 2
Fibroblast growth factor receptor 2 also known as CD332 is a protein that in humans is encoded by the FGFR2 gene residing on chromosome 10...
) (= CD332) (see also Fibroblast growth factor receptor 3) (= CD333) (see also Fibroblast growth factor receptor 4
Fibroblast growth factor receptor 4
Fibroblast growth factor receptor 4 is a protein that in humans is encoded by the FGFR4 gene. FGFR4 has also been designated as CD334 .-Interactions:...
) (= CD334)