Functional Sites of the erbB-2 Receptor and Its Activator Heregulin
Abstract
Over expression of the erbB-2 (HER-2/neu) receptor occurs in up to 30% of cases of human breast cancers and correlates with aggressive disease and poor prognosis for therapy and survival. The growth factor heregulin (HRG) binds to erbB-3 or erbB-4 receptors, promotes dimer formation with erbB-2 and induces autophosphorylation and activation of erbB-2 signaling. It is generally accepted that HRG and erbB-2 do not interact directly. Depending on its concentration HRG can either inhibit or stimulate cell proliferation in cell lines that overexpress erbB-2. This suggests some type of direct interaction between HRO and erbB-2. Solution structure of HRO and other data support the existence of a low-affinity binding site within the EGF-like domain of HRG. The goal of the proposed experiments is to define the predicted sites of interaction between HRG and the erbB-2 receptor, through generation of HRG and erbB-2 deletion mutants. During the second year of funding, I maintained the timeline outlined in the statement of work: a) transduced deletion mutants of erbB-2 lacking either the putative heregulin binding site or the site important for receptor heterodimerization into Ba/F3 cells and established 8 cell lines expressing different variants of erbB-2 and b) generated 5 different point mutations of the heregulin beta1 gene and confirmed them by sequencing, and started to work on recombinant protein induction and purification. The main result of my work was to generate 8 cell lines expressing the erbB-2 receptor containing different deletions in the extracellular domain, and 5 different point mutations within the EGF-like domain of HRG. These mutants will be used in the experiments designed to determine the mechanism of interaction between ErbB-2 and heregulin.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2001
- Accession Number
- ADA404611
Entities
People
- Joanna E. Mroczkowska-jasinska
Organizations
- University of California, Berkeley