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Identification of a novel receptor in Drosophila for both epidermal growth factor and insulin
Abstract:
The notable amino acid homology among mammalian growth factor receptors with tyrosine-specific protein kinase activity has led to speculation that these receptors derived from a common evolutionary precursor. We report the identification of a novel growth factor receptor from Drosophila cell cultures that has dual binding specificity for both insulin and epidermal growth factor (EGF). This 100-kDa protein is also related antigenically to the mammalian receptors for EGF and possibly insulin but may not correspond to the mammalian counterpart of either receptor in Drosophila. The Drosophila protein is recognized by antisera directed against the mammalian receptor for EGF in immunoblot hybridizations. It can be affinity labeled with either 125I-labeled insulin or 125I-labeled EGF after immunoprecipitation with anti-EGF receptor antiserum. Excess unlabeled EGF or insulin will block the affinity labeling with either growth factor, suggesting that both EGF and insulin share a common binding site on the 100-kDa Drosophila receptor. This Drosophila protein, therefore, may be closely related to an evolutionary precursor of the mammalian receptors for insulin and EGF.
Insights
Researchers discovered a novel Drosophila growth factor receptor with dual binding for insulin and epidermal growth factor (EGF). This finding suggests a potential evolutionary precursor to mammalian insulin and EGF receptors.
Area of Science:
- Evolutionary biology
- Molecular biology
- Cell signaling
Background:
- Mammalian growth factor receptors share amino acid homology, suggesting a common evolutionary origin.
- Tyrosine-specific protein kinase activity is a characteristic of these receptors.
Purpose of the Study:
- To identify and characterize novel growth factor receptors in Drosophila.
- To investigate the evolutionary relationship between Drosophila and mammalian growth factor receptors.
Main Methods:
- Utilized Drosophila cell cultures for protein identification.
- Employed immunoblot hybridization and affinity labeling techniques.
- Used antisera against mammalian EGF receptor for immunoprecipitation.
Main Results:
- Identified a 100-kDa Drosophila protein with dual binding specificity for insulin and epidermal growth factor (EGF).
- The protein showed antigenic relation to mammalian EGF and possibly insulin receptors.
- Both insulin and EGF competed for the same binding site on the Drosophila receptor.
Conclusions:
- The identified Drosophila protein may represent an evolutionary precursor to mammalian insulin and EGF receptors.
- This discovery provides insights into the evolutionary origins of growth factor signaling pathways.