Novel Intracellular Proteins Associated with Cellular Vitamin D Action

Work with vitamin D–resistant New World primates has revealed novel cellular proteins involved in vitamin D action. An "intracellular vitamin D–binding protein" functions to bind vitamin D metabolites in the cell and enhances vitamin D action. By contrast, a "vitamin D response element–binding protein" inhibits vitamin D receptor binding to the DNA and is responsible for vitamin D resistance in New World primates.