Nitric oxide-induced ribosome collision activates ribosomal surveillance mechanisms

Abstract

Impairment of protein translation can cause stalling and collision of ribosomes and is a signal for the activation of ribosomal surveillance and rescue pathways. Despite clear evidence that ribosome collision occurs stochastically at a cellular and organismal level, physiologically relevant sources of such aberrations are poorly understood. Here we show that a burst of the cellular signaling molecule nitric oxide (NO) reduces translational activity and causes ribosome collision in human cell lines. This is accompanied by activation of the ribotoxic stress response, resulting in ZAKα-mediated activation of p38 and JNK kinases. In addition, NO production is associated with ZNF598-mediated ubiquitination of the ribosomal protein RPS10 and GCN2-mediated activation of the integrated stress response, which are well-described responses to the collision of ribosomes. In sum, our work implicates a novel role of NO as an inducer of ribosome collision and activation of ribosomal surveillance mechanisms in human cells.

RNAi-Mediated Knockdown of Acidic Ribosomal Stalk Protein P1 Arrests Egg Development in Adult Female Yellow Fever Mosquitoes, Aedes aegypti

“…P1 is a component of the P-stalk region on the large subunit of eukaryotic ribosomes and has been shown to play an important role during the elongation stage of protein synthesis [61][62][63]. Under amino acid starvation conditions or in the presence of other cellular stressors, ribosomes collide during mRNA translation [70][71][72]. A recently published cryo-electron microscopy study revealed the structure of GCN1 bound to two colliding ribosomes [73].…”

“…Under amino acid starvation conditions or in the presence of other cellular stressors, ribosomes collide during mRNA translation [70][71][72]. A recently published cryo-electron microscopy study revealed the structure of GCN1 bound to two colliding ribosomes [73].…”

Ribosome Quality Control Mechanism Mitigates the Cytotoxic Impacts of Ribosome Collisions Induced by 5-Fluorouracil

“…RQC is a translation-dependent mechanism of quality control and more actively translated mRNAs are more prone to ribosome collisions and triggering RQC 20–22 , due to the higher chance of presence of trailing ribosomes that collide into a stalled ribosome. Metabolic stress and oxidative agents such as nitric oxide and reactive oxygen species, which are common in cancer cells and directly damage ribonucleotide bases, impede the transition of translating ribosomes and cause ribosome stalling 14,15,56,57 . Furthermore, following oncogenic transformation, overall translation activity is often elevated, partly due to mutation and activation of signalling pathways such as PI3K/mTOR 58 , which stimulate mRNA translation 12 .…”

“…Significant progress has been made in our understanding of the mechanism of RQC 26 , its important role in maintenance of homeostasis 31,32 and triggering global reprogramming of gene expression in response to stress 15,25,32,56,61 . Yet, important gaps exist in our understanding of how the RQC mechanism itself is regulated in response to environmental stimuli that impact cellular metabolism and mRNA translation, including the antimetabolites such as 5FU.…”

Emerging Role of GCN1 in Disease and Homeostasis

“…These reagents and UV leave the A-site vacant during translation inhibition. Furthermore, the signaling molecule nitric oxide also activates ISR and RSR via ribosome collision (see below) [ 85 ]. Thus, GCN1–GCN2 and other eIF2α kinases function as sentinels that monitor translational defects and proteostasis via ISR.…”