University of New Hampshire
Mentor: Dr. John Collins, Associate Professor of Biochemistry, with Deb Audino, Research Associate
Interaction of the Oncoprotein Src with the Estrogen Receptor
The c-src gene encodes a tyrosine kinase protein (Src) which phosphorylates tyrosine residues on itself and other proteins. In its activated form, Src associates with membrane receptors such as the estrogen receptor and activates signal transduction pathways, promoting cell proliferation. The estrogen receptor (ER) binds to the hormone estrogen. The estrogen-bound form of ER binds to DNA and turns on estrogen-responsive genes. Both Src and ER are activated in signaling pathways that have been implicated in cancer, and in particular, breast cancer cells. I investigated the hypothesis that Src and ER interact directly and sought to determine if other factors are associated with the complex. To do this, I expressed both Src and ER proteins in Sf9 cells. The Src and ER coding regions had been cloned into baculovirus vectors. Sf9 cells were infected with both clones, and both proteins were synthesized in the infected cells. The Src/ER complex was isolated from these cells by “size exclusion” column chromatography, and characterized to establish the presence of each component by Western immunoblotting. If the observed size of the complex is bigger than the expected size, this implies that there are other factors associated with the complex.