Cover

While the orphan nuclear estrogen-related receptors (ERRα, β, and γ) are known to be critical for mitochondrial biogenesis and energy homeostasis, an emerging theme is the regulation of the ionic composition of bodily fluids. In this issue of Molecular Endocrinology, Alaynick et al. applied physiologic genomics to examine loss of ERRγ in cardiac, gastric, and renal tissues (represented as three idealized cells in this illustration). In heart, it appears that loss of ERRγ dysregulates key potassium channel and ion transport genes, as well as ECG readings (represented by the lower cell). In stomach (represented by the cell on the upper right), altered acid production may be indicated by the down-regulation of key acid-production genes and parietal cell markers. In kidney (represented by the cell on the upper left), loss of ERRγ appears to reduce renal regulation of serum potassium, as indicated by hyperkalemia and potassium channel gene expression. From the article in this issue by Alaynick et al., pages 299–309.

The editors thank Dr. Ron Smith, Alcon Laboratories, Fort Worth, TX, for collaborating with the authors to create the figure on the cover.