A growth factor receptor is a

receptor Receptor may refer to: * Sensory receptor, in physiology, any neurite structure that, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and respond ...

that binds to a

growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for ...

. Growth factor receptors are the first stop in cells where the signaling cascade for cell differentiation and proliferation begins. Growth factors, which are

ligands In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's ...

that bind to the receptor are the initial step to activating the growth factor receptors and tells the cell to grow and/or divide. These receptors may use the JAK/STAT,

MAP kinase A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of serine/threonine-specific protein kinases involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammato ...

, and PI3 kinase pathways. A majority of growth factor receptors consists of receptor tyrosine kinases (RTKs). There are 3 dominant receptor types that are exclusive to research : the

epidermal growth factor receptor The epidermal growth factor receptor (EGFR; ErbB-1; HER1 in humans) is a transmembrane protein that is a receptor (biochemistry), receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligand (biochemistry ...

, the neurotrophin receptor, and the insulin receptors. All growth factor receptors are membrane bound and composed of 3 general protein domains:

extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

transmembrane A transmembrane protein is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently u ...

, and

cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...

ic. The extracellular domain region is where a

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

may bind, usually with very high specificity. In RTKs, the binding of a ligand to the extracellular ligand binding site leads to the autophosphorylation of tyrosine residues in the intracellular domain. These phosphorylations allow for other intracellular proteins to bind to with the

phosphotyrosine-binding domain In molecular biology, phosphotyrosine-binding domains are protein domains which bind to phosphotyrosine. The phosphotyrosine-binding domain (PTB, also phosphotyrosine-interaction or PI domain) in the protein tensin tends to be found at the C- ...

which results in a series of physiological responses within the cell.

Medical relevance

Research in today’s society focus on growth factor receptors in order to pinpoint cancer treatment.

Epidermal growth factor receptor The epidermal growth factor receptor (EGFR; ErbB-1; HER1 in humans) is a transmembrane protein that is a receptor (biochemistry), receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligand (biochemistry ...

s are involved heavily with oncogene activity. Once growth factors bind to their receptor, a signal transduction pathway occurs within the cell to ensure the cell is working. However, in cancerous cells, the pathway might never turn on or turn off. Furthermore, in certain cancers, receptors (such as RTKs) are often observed to be overexpressed, which corresponds to the uncontrolled proliferation and differentiation of cells. For this same reason, tyrosine receptors are often a target for

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

therapy.

References

{{Growth factor receptor modulators Receptors Single-pass transmembrane proteins