O-GlcNAcylation is a dynamic posttranslational modification that occurs in the serine or threonine residues of nuclear and cytosolic proteins. O-GlcNAcylation regulates various cellular events, such as a nutrient sensing, epigenetic regulation, translational regulation, and cell proliferation, as well as disease-related signal pathways. UDP-GlcNAc, a precursor of O-GlcNAcylation, is synthesized from glucose by the hexosamine biosynthetic pathway (HBP). The level of UDP-GlcNAc depends on the cellular glucose condition. For this reason, O-GlcNAcylation is called a nutrient sensor. Although O-GlcNAcylation plays a role in nutrient sensing and metabolism, the relationship between O-GlcNAcylation and autophagy remains unknown. In previous studies, decreased O-GlcNAcylation by OGT siRNA induced autophagy without starvation. In this study, we observed that a unc-51 like autophagy activating kinase 1(ULK1), a regulator of autophagy, is O-GlcNAcylated. Under glucose deprivation, O-GlcNAcylated ULk1 is increased, and increased O-GlcNAcylation induces ULK1 S757 phosphorylation, which leads to ULK1 inactivation. The ULK1 S757A mutant decreases O-GlcNAcylation on ULK1 and binding affinity with OGT compared with ULK1 wild type. These data imply that O-GlcNAcylation on ULK1 decreases ULK1 kinase activity by increasing S757 phosphorylation and reduces autophagy induction.
저자
Jin Won Pak [ Department of Integrated OMICS for Biomedical Sciences, Graduate School, Yonsei University, Seoul 120-749, Korea ]
Jin Won Cho [ Department of Integrated OMICS for Biomedical Sciences, Graduate School, Yonsei University, Seoul 120-749, Korea ]
본 학회는 화학, 생화학, 분자생물학, 미생물학, 식품공학, 의학, 약학, 유전공학 및 생물공학, 환경 및 기타 공업 등 전 분야의 탄수화물관련 이론과 기술을 연구 발전시키고 산학협동을 통해 이를 보급하여 국내 관련 산업의 발전 및 국민생활의 과학화에 기여하고자 하며, 이러한 목표와 비젼의 실현을 위해 회원들이 적극적인 참여와 활동을 전개하고자 한다.