Hormone Receptors and the Nuclear Matrix

Abstract

The induction by steroid hormones of a wide variety of biological actions has been visualized to result from the interaction of steroids with specific cytoplasmic receptor proteins and their translocation into the nucleus (see reviews by Gorski and Gannon 1976; Thrall et al. 1978; Jensen 1979; Liao et al. 1979). In spite of the progress that has been made to elucidate various aspects of these events, there remain many unknowns in our understanding of how hormones actually bring about their effects. New concepts and techniques may be needed to provide new insights. In this regard, recent studies of the binding of receptor hormone complexes to specific gene sequences promises to yield fruitful new information (Mulvihill et al. 1982). At present it appears that steroid receptor complexes may bind both to DNA and to nuclear proteins. While insight is being gained on possible DNA sequences to which the steroid receptor complex may bind, there is little agreement on the identification of specific nuclear proteins that may interact with the steroid-receptor complex. These nuclear proteins have been collectively referred to as acceptors, but their exact location and nature have not been fully resolved. We have chosen to focus on nuclear structural proteins as important elements in hormone action, for several reasons.