Micropeptides are small proteins encoded by short open reading frames mostly located in long noncoding RNAs. Mitoregulin (MOXI) is a nuclear encoded micropeptide initially identified in the inner mitochondrial membrane to regulate fatty acid β-oxidation. In this issue of Kidney International, Li et al. report that MOXI is upregulated in both human fibrotic kidneys and murine models of renal fibrosis. Remarkably, MOXI functions in the nucleus, where it forms a transcriptional complex with N-acetyltransferase 14 and c-Jun to facilitate the expression of fibrotic genes. By working in the nucleus and mitochondria, MOXI may channel the 2-way communication between these organelles, adding a new layer of complexity in the cell biology of renal fibrogenesis.
Published by Elsevier Inc.