- 作者: Yu-Wen Hung, Ching Ouyang, Xiaoli Ping, Yue Qi, Yi-Chang Wang, Hsing-Jien Kung & David K. Ann
- 作者服務機構: 1.Cancer Center, School of Medicine, University of California, Davis, CA, 95817, USA 2.Department of Computational and Quantitative Medicine, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA 3.Department of Diabetes Complications and Metabolism, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of City of Hope, City of Hope Comprehensive Cancer Center, Duarte, CA, 91010-3000, USA 4.Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
- 中文摘要:
- 英文摘要:
Background Nutrient limitations often lead to metabolic stress during cancer initiation and progression. To combat
this stress, the enzyme heme oxygenase 1 (HMOX1, commonly known as HO-1) is thought to play a key role as an
antioxidant. However, there is a discrepancy between the level of HO-1 mRNA and its protein, particularly in cells
under stress. O-linked β-N-acetylglucosamine (O-GlcNAc) modifcation of proteins (O-GlcNAcylation) is a recently
discovered cellular signaling mechanism that rivals phosphorylation in many proteins, including eukaryote translation
initiation factors (eIFs). The mechanism by which eIF2α O-GlcNAcylation regulates translation of HO-1 during extracel‑
lular arginine shortage (ArgS) remains unclear.
Methods We used mass spectrometry to study the relationship between O-GlcNAcylation and Arg availability in
breast cancer BT-549 cells. We validated eIF2α O-GlcNAcylation through site-specifc mutagenesis and azido sugar
N-azidoacetylglucosamine-tetraacylated labeling. We then evaluated the efect of eIF2α O-GlcNAcylation on cell
recovery, migration, accumulation of reactive oxygen species (ROS), and metabolic labeling during protein synthesis
under diferent Arg conditions.
Results Our research identifed eIF2α, eIF2β, and eIF2γ, as key O-GlcNAcylation targets in the absence of Arg.
We found that O-GlcNAcylation of eIF2α plays a crucial role in regulating antioxidant defense by suppressing the
translation of the enzyme HO-1 during Arg limitation. Our study showed that O-GlcNAcylation of eIF2α at specifc
sites suppresses HO-1 translation despite high levels of HMOX1 transcription. We also found that eliminating eIF2α
O-GlcNAcylation through site-specifc mutagenesis improves cell recovery, migration, and reduces ROS accumula‑
tion by restoring HO-1 translation. However, the level of the metabolic stress efector ATF4 is not afected by eIF2α
O-GlcNAcylation under these conditions.
Conclusions Overall, this study provides new insights into how ArgS fne-tunes the control of translation initiation
and antioxidant defense through eIF2α O-GlcNAcylation, which has potential biological and clinical implications. - 中文關鍵字:
- 英文關鍵字: Arginine, O-GlcNAcylation, Eukaryotic initiation factor 2α, Protein translation, Heme oxygenase 1, Antioxidant defense