Retinoic acid receptors at 35: molecular convergence of vitamin A and steroid hormone action.

Abstract

The fields of vitamins and steroid hormones emerged in parallel in the early parts of the twentieth century. Scientists in both fields were initially interested in the purification of natural compounds present respectively in food stuff and extracts from organs and biological fluids that had profound effects on reproduction, development, and general maintenance of a healthy organism. Coincidently, the chemical structure of vitamin A and the steroid hormones oestradiol and progesterone were resolved around the same time in the mid 1930s. From these early common grounds, the fields of vitamin A and steroid hormones then diverged into their respective branches of biological sciences, mainly nutrition/vision and endocrinology for the next several decades. Yet, 50 years later, it is the surprising discovery that retinoic acid (RA), an active metabolite of vitamin A, exerts its biological effects via a member of the superfamily of steroid receptors that led to the improbable reunification of vitamin A and steroid hormones action. We celebrate the scientific milestone of the discovery of the retinoic acid receptor (RAR) with a special issue of the Journal of Molecular Endocrinology. This issue comprises chronicles reminiscing how that discovery was achieved independently by two young Canadian scientists working in the laboratories of Ronald Evans and Pierre Chambon separated by a continent and an ocean, and reviews by international experts describing distinct aspects of RAR-dependent biology and mode of action.