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Growth factor receptor

These receptors may use the JAK/STAT, MAP kinase, and PI3 kinase pathways.^[2]

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 neurotrophin receptor, and the insulin receptors.^[3] All growth factor receptors are membrane bound and composed of 3 general protein domains: extracellular, transmembrane, and cytoplasmic.^[4] The extracellular domain region is where a ligand may bind, usually with very high specificity.^[5]InRTKs, the binding of a ligand to the extracellular ligand binding site leads to the autophosphorylation of tyrosine residues in the intracellular domain.^[6] These phosphorylations allow for other intracellular proteins to bind to with the phosphotyrosine-binding domain which results in a series of physiological responses within the cell.^[6]

Research in today’s society focus on growth factor receptors in order to pinpoint cancer treatment. Epidermal growth factor receptors are involved heavily with oncogene activity.^[7] 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.^[7] Furthermore, in certain cancers, receptors (such as RTKs) are often observed to be overexpressed, which corresponds to the uncontrolled proliferation and differentiation of cells.^[8] For this same reason, tyrosine receptors are often a target for cancer therapy.^[8]