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Updated: Jun 19, 2026

Isolation of Primary Mouse Hepatocytes for Nascent Protein Synthesis Analysis by Non-radioactive L-azidohomoalanine Labeling Method
Published on: October 23, 2018
AMP-activated protein kinase adapts rRNA synthesis to cellular energy supply
Sven Hoppe1, Holger Bierhoff, Ivana Cado
1Molecular Biology of the Cell II, German Cancer Research Center, DKFZ-ZMBH Alliance, INF 581, D-69120 Heidelberg, Germany.
Abstract:
AMP-activated protein kinase (AMPK) senses changes in the intracellular AMP/ATP ratio, switching off energy-consuming processes and switching on catabolic pathways in response to energy depletion. Here, we show that AMPK down-regulates rRNA synthesis under glucose restriction by phosphorylating the RNA polymerase I (Pol I)-associated transcription factor TIF-IA at a single serine residue (Ser-635). Phosphorylation by AMPK impairs the interaction of TIF-IA with the TBP-containing promoter selectivity factor SL1, thereby precluding the assembly of functional transcription initiation complexes. Mutation of Ser-635 compromises down-regulation of Pol I transcription in response to low energy supply, supporting that activation of AMPK adapts rRNA synthesis to nutrient availability and the cellular energy status.
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