Yeast RNA exosome activity is necessary for maintaining cell wall stability through proper protein glycosylation

• Published in: Molecular biology of the cell Vol. 32; no. 5; pp. 363 - 375
• Main Authors: Novačić, Ana, Beauvais, Valentin, Oskomić, Marina, Štrbac, Lucija, Dantec, Aurélia Le, Rahmouni, A Rachid, Stuparević, Igor
• Format: Journal Article
• Language: English
• Published: United States American Society for Cell Biology 01-03-2021; The American Society for Cell Biology
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Catalytic Domain; Cell Wall - metabolism; Cell Wall - physiology; DNA-Binding Proteins - metabolism; Exosome Multienzyme Ribonuclease Complex - genetics; Exosome Multienzyme Ribonuclease Complex - metabolism; Exosomes - genetics; Exosomes - metabolism; Gene Expression; Glycosylation; Life Sciences; Nuclear Proteins - metabolism; RNA Stability; RNA-Binding Proteins - metabolism; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - metabolism; Rrp6; RNA exosome regulates cell wall structure RNA exosome; yeast cell wall; protein glycosylation; Psa1; Dis3; RNA exosome cofactors; Saccharomyces cerevisiae
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E20-08-0544-T

Nuclear RNA exosome is the main 3'→5' RNA degradation and processing complex in eukaryotic cells and its dysregulation therefore impacts gene expression and viability. In this work we show that RNA exosome activity is necessary for maintaining cell wall stability in yeast
. While the essential RNA exosome catalytic subunit Dis3 provides exoribonuclease catalytic activity, the second catalytic subunit Rrp6 has a noncatalytic role in this process. RNA exosome cofactors Rrp47 and Air1/2 are also involved. RNA exosome mutants undergo osmoremedial cell lysis at high temperature or at physiological temperature upon treatment with cell wall stressors. Finally, we show that a defect in protein glycosylation is a major reason for cell wall instability of RNA exosome mutants. Genes encoding enzymes that act in the early steps of the protein glycosylation pathway are down-regulated at high temperature in cells lacking Rrp6 protein or Dis3 exoribonuclease activity and overexpression of the essential enzyme Psa1, that catalyzes synthesis of the mannosylation precursor, suppresses temperature sensitivity and aberrant morphology of these cells. Furthermore, this defect is connected to a temperature-dependent increase in accumulation of noncoding RNAs transcribed from loci of relevant glycosylation-related genes.