Oxidative Homeostasis Regulates the Response to Reductive Endoplasmic Reticulum Stress through Translation Control

Abstract

Reductive stress leads to the loss of disulfide bond formation and induces the unfolded protein response of the endoplasmic reticulum (UPR(ER)), necessary to regain proteostasis in the compartment. Here we show that peroxide accumulation during reductive stress attenuates UPR(ER) amplitude by altering translation without any discernible effect on transcription. Through a comprehensive genetic screen in Saccharomyces cerevisiae, we identify modulators of reductive stress-induced UPR(ER) and demonstrate that oxidative quality control (OQC) genes modulate this cellular response in the presence of chronic but not acute reductive stress. Using a combination of microarray and relative quantitative proteomics, we uncover a non-canonical translation attenuation mechanism that acts in a bipartite manner to selectively downregulate highly expressed proteins, decoupling the cell's transcriptional and translational response during reductive ER stress. Finally, we demonstrate that PERK, a canonical translation attenuator in higher eukaryotes, helps in bypassing a ROS-dependent, non-canonical mode of translation attenuation.

Metabolic Responses to Reductive Stress

“…NAD + , nicotinamide adenine dinucleotide; NADH, reduced NAD + ; NADP + , phosphorylated NAD + ; ReBC, redox buffer capacity; ROS, reactive oxygen species. protein response and ER stress (60). In line with this concept, we and others showed that reductive stress perturbs protein disulfide formation leading to ER stress in yeast and intracellular retention of membrane proteins in human cells (32, 60,100,113).…”

Ncl1 mediated metabolic rewiring critical during metabolic stress

“…Yeast cells were grown in presence and absence of 1 mM cysteine for 6 hrs, and then 50µg/ml of cycloheximide was added to the cultured cells and kept in ice for 5 mins to stall the ribosomes. Cells were then processed as described previously 59 . Briefly, cells were harvested at 2500 g for 5 mins at 4C, and then lysis was performed with bead beater in lysis buffer with sterile water.…”

Modern Biochemical Aspects of Xenobiotic Detoxification System. Literature Review

“…[16,23,25]. По-друге, у деяких випадках метаболіти КБ становляться, на-впаки, більш токсичними сполуками, а також й та-кими, що можуть змінити характер токсичної дії або ініціювати інший токсичний процес.…”

“…Негативним ефектом знешкодження КБ цито-хром Р450-залежною МОС є можливість генерації вільних радикалів та активних метаболітів, здатних інтенсифікувати процеси ліпопероксидації у клітин-них мембранах з наступним порушенням їх струк-тури та функцій [14,23,25]. У свою чергу, руйну-вання клітинних мембран може призвести до інак-тивації цитохрому Р450 як найбільш чутливого елементу МОС.…”