- Epidermal growth factor
Epidermal growth factor or EGF is a
growth factor that plays an important role in the regulation ofcell growth ,proliferation , and differentiation by binding to its receptor EGFR. Human EGF is a 6045-Daprotein with 53 amino acid residues and three intramoleculardisulfide bond s. [cite journal | author =Carpenter G, and Cohen S. | title =Epidermal growth factor | journal =J. Biol. Chem. | year=1990 | volume=265 | issue=14 | pages=7709–7712 | pmid = 2186024]History
The discovery of EGF won Dr. Stanly Cohen a Nobel Prize in Physiology and Medicine in 1986 [ [http://nobelprize.org/nobel_prizes/medicine/laureates/1986/presentation-speech.html The Nobel Prize in Physiology or Medicine 1986 - Presentation Speech ] ] and was patented for cosmetic use by Dr. Greg Brown in 1989 [ [http://www.freepatentsonline.com/5618544.html Method of decreasing cutaneous senescence - Patent 5618544 ] ] .
Function
EGF results in cellular proliferation, differentiation, and survival. cite journal |author=Herbst RS |title=Review of epidermal growth factor receptor biology |journal=Int. J. Radiat. Oncol. Biol. Phys. |volume=59 |issue=2 Suppl |pages=21–6 |year=2004 |pmid=15142631 |doi=10.1016/j.ijrobp.2003.11.041]
Mechanism
EGF acts by binding with high
affinity toepidermal growth factor receptor (EGFR) on the cell surface and stimulating the intrinsic protein-tyrosine kinase activity of the receptor (see the second diagram). Thetyrosine kinase activity, in turn, initiates asignal transduction cascade that results in a variety of biochemical changes within the cell - a rise in intracellularcalcium levels, increasedglycolysis andprotein synthesis , and increases in the expression of certaingene s including the gene for EGFR - that ultimately lead to DNA synthesis and cell proliferation. [cite journal | author =Fallon JH, Seroogy KB."et al" | title=Epidermal growth factor immunoreactive material in the central nervous system: location and development | journal =Science | year=1984 | volume=224 | issue=4653 | pages=1107–1109 | pmid = 6144184 | doi=10.1126/science.6144184]EGF-family
EGF is the founding member of the EGF-family of proteins. Members of this protein family have highly similar structural and functional characteristics. Besides EGF itself other family members include:cite journal | author =Dreux AC, Lamb DJ. "et al." | title =The epidermal growth factor receptors and their family of ligands: their putative role in atherogenesis | journal =Atherosclerosis | year=2006 | volume=186 | issue=1 | pages=38–53 | pmid = 16076471 | doi =10.1016/j.atherosclerosis.2005.06.038]
*
Heparin-binding EGF-like growth factor (HB-EGF)
*transforming growth factor-α (TGF-α)
*Amphiregulin (AR)
*Epiregulin (EPR)
*Epigen
*Betacellulin (BTC)
*neuregulin-1 (NRG1)
*neuregulin-2 (NRG2)
*neuregulin-3 (NRG3)
*neureguline-4 (NRG4).All family members contain one or more repeats of the conserved amino acid sequence:
Where X represents any
amino acid .This sequence contains 6
cysteine residues that form three intramoleculardisulfide bond s. Disulfide bond formation generates three structural loops that are essential for high-affinity binding between members of the EGF-family and theircell-surface receptors.cite journal | author =Harris RC, Chung E, and Coffey RJ. | title =EGF receptor ligands | journal =Exp. Cell. Res. | year=2003 | volume=284 | issue=1 | pages=2–13 | pmid = 12648462 | doi =10.1016/S0014-4827(02)00105-2]EGF therapy
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