The absence of the ribosomal protein Rpl2702 elicits the MAPK-mTOR signaling to modulate mitochondrial morphology and functions

• Published in: Redox biology Vol. 73; p. 103174
• Main Authors: Liu, Ling, Wu, Yifan, Liu, Ke, Zhu, Mengdan, Guang, Shouhong, Wang, Fengsong, Liu, Xing, Yao, Xuebiao, He, Jiajia, Fu, Chuanhai
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2024; Elsevier
• Subjects: MAP Kinase Signaling System; MAPK; Membrane Potential, Mitochondrial; Mitochondria; Mitochondria - metabolism; Mitogen-Activated Protein Kinases - metabolism; mTOR; Reactive Oxygen Species - metabolism; Ribosomal Proteins - genetics; Ribosomal Proteins - metabolism; Ribosome; Ribosomes - metabolism; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; Signal Transduction; TOR Serine-Threonine Kinases - metabolism; mTOR; Schizosaccharomyces pombe; Mitochondria; Ribosome; MAPK
• ISSN: 2213-2317; 2213-2317
• DOI: 10.1016/j.redox.2024.103174

Ribosomes mediate protein synthesis, which is one of the most energy-demanding activities within the cell, and mitochondria are one of the main sources generating energy. How mitochondrial morphology and functions are adjusted to cope with ribosomal defects, which can impair protein synthesis and affect cell viability, is poorly understood. Here, we used the fission yeast Schizosaccharomyces Pombe as a model organism to investigate the interplay between ribosome and mitochondria. We found that a ribosomal insult, caused by the absence of Rpl2702, activates a signaling pathway involving Sty1/MAPK and mTOR to modulate mitochondrial morphology and functions. Specifically, we demonstrated that Sty1/MAPK induces mitochondrial fragmentation in a mTOR-independent manner while both Sty1/MAPK and mTOR increases the levels of mitochondrial membrane potential and mitochondrial reactive oxygen species (mROS). Moreover, we demonstrated that Sty1/MAPK acts upstream of Tor1/TORC2 and Tor1/TORC2 and is required to activate Tor2/TORC1. The enhancements of mitochondrial membrane potential and mROS function to promote proliferation of cells bearing ribosomal defects. Hence, our study reveals a previously uncharacterized Sty1/MAPK-mTOR signaling axis that regulates mitochondrial morphology and functions in response to ribosomal insults and provides new insights into the molecular and physiological adaptations of cells to impaired protein synthesis. [Display omitted] •Ribosomal insults cause mitochondrial fragmentation and increase mitochondrial membrane potential and mitochondrial ROS.•Ribosomal defects caused by the absence of the ribosomal protein Rpl2702 activate MAPK and mTOR signaling pathways.•MAPK acts upstream of mTOR in cells bearing ribosomal defects caused by the absence of Rpl2702.•Cells increase mitochondrial membrane potential and the level of mitochondrial ROS to cope with ribosomal stresses.