ESRRA (estrogen related receptor, alpha) induces ribosomal protein RPLP1-mediated adaptive hepatic translation during...

Protein translation is an energy-intensive ribosome-driven process that is reduced during nutrient scarcity to conserve cellular resources. During prolonged starvation, cells selectively translate specific proteins to enhance their survival (adaptive translation); however, this process is poorly understood. Accordingly, we analyzed protein translation and mRNA transcription by multiple methods in vitro and in vivo to investigate adaptive hepatic translation during starvation. While acute starvation suppressed protein translation in general, proteomic analysis showed that prolonged starvation selectively induced translation of lysosome and autolysosome proteins. Significantly, the expression of the orphan nuclear receptor, ESRRA (estrogen related receptor, alpha) increased during prolonged starvation and served as a master regulator of this adaptive translation by transcriptionally stimulating Rplp1 (ribosomal protein lateral stalk subunit P1) gene expression. Overexpression or siRNA knockdown of Esrra in vitro or in vivo led to parallel changes in Rplp1 gene expression, lysosome and macroautophagy/autophagy protein translation, and autophagy activity. Remarkably, we have found that ESRRA had dual functions by not only regulating transcription but also controlling adaptive translation via the ESRRA-RPLP1-lysosome-autophagy pathway during prolonged starvation.