Related Experiment Videos
Heregulin-dependent translocation and hyperphosphorylation of ErbB-2
1Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, TN 37232-0146, USA.
Oncogene
|July 6, 2001
Summary
Heregulin rapidly moves ErbB-2 and ErbB-4 proteins to insoluble cell membranes, where they become highly phosphorylated. This suggests a new mechanism for receptor signaling in T47 D mammary carcinoma cells.
Area of Science:
- Cell biology
- Molecular oncology
- Signal transduction
Background:
- Previous studies indicated heregulin induces ErbB-4 translocation and hyperphosphorylation in tumor cells.
- ErbB-2 is a known heterodimerization partner for ErbB-4.
Purpose of the Study:
- To investigate the effect of heregulin and betacellulin on ErbB-2 and ErbB-4 localization and phosphorylation in T47 D mammary carcinoma cells.
- To determine if ErbB-2 and ErbB-4 translocation to detergent-insoluble fractions is ligand-dependent.
Main Methods:
- Treatment of T47 D cells with heregulin, betacellulin, or EGF.
- Analysis of ErbB-2 and ErbB-4 protein localization via detergent solubility fractionation.
- Assessment of tyrosine phosphorylation levels of ErbB-2 and ErbB-4.
Main Results:
- Heregulin and betacellulin, but not EGF, caused rapid translocation of ErbB-2 and ErbB-4 to detergent-insoluble membrane fractions in T47 D cells.
- Translocation occurred within 2 minutes of heregulin addition.
- ErbB-2 in the insoluble fraction showed a fourfold increase in tyrosine phosphorylation compared to the soluble fraction.
- ErbB-3 did not show significant translocation.
Conclusions:
- Ligand-dependent formation of hyperphosphorylated ErbB-4/ErbB-2 dimers is suggested.
- These dimers coordinate with translocation to putative membrane microdomains, indicating a novel signaling mechanism.