Expression of a Novel Estrogen Receptor, GPR30, During Development and Differentiation

Abstract

Estrogen regulates growth, development, and homeostasis of several tissues in the human body. Estrogen actions are thought to be mediated through the well-characterized estrogen receptors, ERα and ERβ. However, a novel estrogen receptor belonging to the G-protein coupled receptor class of membrane proteins, called GPR30, which has been recently identified. We hypothesize that GPR30 is responsible for multiple estrogen-dependent biological responses in estrogen-responsive tissues. The goal of this study is to characterize GPR30 expression during development using immunofluorescence, Western immunoblotting, and immunohistochemistry techniques. GPR30 is expressed in a wide variety of organs and tissues throughout the body including the female reproductive tract and is enriched in epithelia and smooth muscle. Ongoing experiments are aimed at characterizing spatio-temporal changes in GPR30 expression during development. The results from these studies will form the basis for functional studies designed to understand the role of GPR30 in estrogen-dependent cellular responses, including proliferation and differentiation. Because estrogen is important not only for normal development and homeostasis, but also promotes proliferation of estrogen-dependent cancers, it is critical to understand how GPR30 mediates estrogen-dependent signaling. Furthermore, ER-antagonists are extensively used for breast cancer treatment, and unlike the classic ERs, GPR30 is activated rather than suppressed by ER-antagonists. Understanding GPR30 function will further our understanding of estrogen-induced growth and proliferation in both normal and neoplastic tissues.