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Functional and structural characteristics of EGF and its receptor and their relationship to transforming proteins
Abstract:
Epidermal growth factor (EGF) is a peptide which effects the growth and/or differentiated functions of many cell types. Several pieces of evidence indicate that EGF and its receptor may play a role in carcinogenesis. Functional and structural characteristics of EGF and its receptor and their relationship to transforming proteins are discussed. EGF has extensive homology with alpha-transforming growth factor (alpha-TGF), which may actually be an embryonic form of EGF. Nevertheless, both EGF and alpha-TGF elicit transformation-associated phenotypes in target cells under certain conditions. EGF effects are mediated by a receptor present on the plasma membrane. The EGF receptor is a highly complex protein having several functions in addition to binding EGF in a highly specific manner. One of these functions is to phosphorylate tyrosyl residues on certain proteins. This activity is similar to that expressed by the src family of oncogene-encoded proteins. Besides sharing functional homology the EGF receptor also exhibits structural homology to several oncogene-encoded proteins. The v-erb-B-transforming protein has a striking extent of homology (95%) to the cytoplasmic portion of the EGF receptor. These data support the concept that some aspect of EGF-stimulated metabolism is involved in cellular transformation.
Insights
Epidermal growth factor (EGF) and its receptor are implicated in cancer development. Their structural and functional similarities to oncogenes suggest a role in cellular transformation.
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Epidermal growth factor (EGF) influences cell growth and function.
- Evidence suggests EGF and its receptor may be involved in carcinogenesis.
- EGF shares homology with alpha-transforming growth factor (alpha-TGF).
Purpose of the Study:
- To discuss the functional and structural characteristics of EGF and its receptor.
- To explore the relationship between EGF/receptor and transforming proteins.
- To investigate the role of EGF-stimulated metabolism in cellular transformation.
Main Methods:
- Review of existing evidence on EGF and its receptor.
- Comparative analysis of structural and functional homologies.
- Discussion of EGF receptor's protein phosphorylation activity.
Main Results:
- EGF and alpha-TGF can induce transformation-associated phenotypes.
- The EGF receptor phosphorylates tyrosyl residues, similar to oncogene proteins.
- Significant structural homology exists between the EGF receptor and oncogene proteins like v-erb-B.
Conclusions:
- EGF signaling pathways are implicated in the mechanisms of carcinogenesis.
- The EGF receptor's kinase activity and structural similarities to oncogenes are key.
- EGF-stimulated metabolism plays a role in cellular transformation processes.