O-GlcNAcase (OGA) is the enzyme that catalyzes the elimination of O-GlcNAc moiety on its substrates. It has two isoforms, full OGA and variant OGA that has alternative stop codon within intron10, which is not spliced-out. As a result, variant OGA lacks C-terminal HAT (histone acetyl transferase) domain and contains additional 15 amino acids. It is known that full OGA exists both in cytosol and nucleus, primarily to the cytoplasm, however, there are two opposite reports about the subcellular localization of two OGA isoforms by different research groups. The first group figured out that full OGA localizes in cytoplasm, whereas variant OGA exists within nucleus in 2001. However, recently the other group reported that full OGA localized diffusely throughout the nucleus and cytoplasm, whereas variant OGA resides with lipid droplets in cytosol. So these two finding motivates our laboratory to commence this study as to nucleocytoplasmic shuttling mechanism of two OGA isoforms. We also focus on the various post-translational modifications on OGAs. Full OGA should weigh 103 kDa, but it weighs approximately 130kDa in reality. So we speculate that various modifications might be related to OGA’s subcellular distribution. To verify and get the answers to several issues about OGAs, we first overexpressed two FLAG tagged-OGA isoforms in HeLa cells to trace the subcellular localization of them. Then we made three C-terminal domain deletion mutants to know the critical domain for its localization. And we also check modification occurred on OGAs by using immune-precipitation. Consequentially we can get schematic drawing as to OGA’s nucleocytoplasmic shuttling, and we expect that this research makes it easy to understand and approach O-GlcNAc modification.
저자
Yeon Jung Kim [ Department of Biology, Yonsei University, Seoul, 120-749, Korea ]
Jin Won Cho [ Department of Biology, Yonsei University, Department of integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University ]
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.