Identification of Novel Nuclear Hormone Receptor Ligands by Activity-Guided Purification

Abstract

Publisher Summary This chapter focuses on the analysis of nuclear receptor ligands. The members of the nuclear hormone receptor superfamily share a common architecture typically including a highly conserved DNA-binding domain (DBD) and a ligand-binding domain (LBD). Many of these ligand-modulated transcription factors have specific endogenous ligands and act as ligand sensors that regulate gene expression during development, cellular differentiation, reproduction, and lipid homeostasis. Those receptors lacking known endogenous ligands are termed as ‘‘orphan receptors.’’ The identification of natural ligands for this class of nuclear receptors is an important goal in understanding their biology. It is thought that nearly all nuclear receptors evolved from an ancestral estrogen receptor. Based on this observation and the existence of conserved LBD sequences, it is not unreasonable to hypothesize that many orphan receptors are ligand-dependent. The strategy applied successfully in identifying novel nuclear receptor ligands is based on the key principle of activity-guided purification followed by structure determination. A particular benefit of the modular structure of nuclear receptors is the ability to construct chimeras that retain the specific ligand-dependent nature of a receptor, but facilitate high-throughput screening by utilizing a common reporter construct.