Epiregulin (EPR) is a protein that in humans is encoded by the EREGgene.[5][6]
Structure
Epiregulin consists of 46 amino acid residues. Its secondary structure contains approximately 30 percent of β-sheet in the strand.[7] Some of the residues form loops and turns due to the hydrogen bonding.[7] The percentage of β-sheet in epiregulin depends on the domain and the secondary structures that they occupy. The polymeric molecules of epiregulin has the formula weight of 5280.1 g/mol with a polypeptide(L), a polymer type.[7]
Structural motifs in most proteins have typical connections in an all β motif. Meaning that the polypeptide chains do not make a crossover connection or in so far as this type of connection has not been observed. Epiregulin is one of the proteins that occupies a typical connection in all β motif. Furthermore, as the structure of epiregulin forms a chain in an all β motif, it also forms β hairpinstructural motif. A β hairpin is when the two adjacent anti-parallel β strands connected by a β-turn.
Function
Epiregulin is a member of the epidermal growth factor family. Epiregulin can function as a ligand of epidermal growth factor receptor (EGFR), as well as a ligand of most members of the ERBB (v-erb-b2 oncogene homolog) family of tyrosine-kinase receptors.[6] The secondary structure at the C-terminus epiregulin is different from other epidermal growth factor family ligands because of the lack of hydrogen bonds. The structural difference at the C-terminus may provide an explanation for the reduced binding affinity of epiregulin to the ERBB receptors.[7]
^ abcdSato K, Nakamura T, Mizuguchi M, Miura K, Tada M, Aizawa T, Gomi T, Miyamoto K, Kawano K (October 2003). "Solution structure of epiregulin and the effect of its C-terminal domain for receptor binding affinity". FEBS Lett. 553 (3): 232–8. doi:10.1016/s0014-5793(03)01005-6. PMID14572630. S2CID24761378.
Further reading
Yamamoto T, Akisue T, Marui T, et al. (2004). "Expression of betacellulin, heparin-binding epidermal growth factor and epiregulin in human malignant fibrous histiocytoma". Anticancer Res. 24 (3b): 2007–10. PMID15274392.
Cho MC, Choi HS, Lee S, et al. (2008). "Epiregulin expression by Ets-1 and ERK signaling pathway in Ki-ras-transformed cells". Biochem. Biophys. Res. Commun. 377 (3): 832–7. doi:10.1016/j.bbrc.2008.10.053. PMID18948081.
Lindvall C, Hou M, Komurasaki T, et al. (2003). "Molecular characterization of human telomerase reverse transcriptase-immortalized human fibroblasts by gene expression profiling: activation of the epiregulin gene". Cancer Res. 63 (8): 1743–7. PMID12702554.
Morita S, Shirakata Y, Shiraishi A, et al. (2007). "Human corneal epithelial cell proliferation by epiregulin and its cross-induction by other EGF family members". Mol. Vis. 13: 2119–28. PMID18079685.
Freimann S, Ben-Ami I, Dantes A, et al. (2004). "EGF-like factor epiregulin and amphiregulin expression is regulated by gonadotropins/cAMP in human ovarian follicular cells". Biochem. Biophys. Res. Commun. 324 (2): 829–34. doi:10.1016/j.bbrc.2004.09.129. PMID15474502.
Ben-Ami I, Armon L, Freimann S, et al. (2009). "EGF-like growth factors as LH mediators in the human corpus luteum". Hum. Reprod. 24 (1): 176–84. doi:10.1093/humrep/den359. PMID18835871.
Draper BK, Komurasaki T, Davidson MK, Nanney LB (2003). "Epiregulin is more potent than EGF or TGFalpha in promoting in vitro wound closure due to enhanced ERK/MAPK activation". J. Cell. Biochem. 89 (6): 1126–37. doi:10.1002/jcb.10584. PMID12898511. S2CID24643892.
Takahashi M, Hayashi K, Yoshida K, et al. (2003). "Epiregulin as a major autocrine/paracrine factor released from ERK- and p38MAPK-activated vascular smooth muscle cells". Circulation. 108 (20): 2524–9. doi:10.1161/01.CIR.0000096482.02567.8C. PMID14581411. S2CID8012969.
