Education and Training
- 2001-2003, Research Associate Harvard Medical School & Dana-Farber Cancer Institute, Boston, USA
- 1999-2001, Postdoctoral Fellow Max-Planck-Institut für Biochemie, Martinsried, Germany
- 1997-1999, Postdoctoral Fellow Research Institute for Basic Sciences, Seoul National University
- 1993-1997, Ph.D. in Chemistry Seoul National University, Seoul, Korea
- 1991-1993, M.S. in Chemistry Seoul National University, Seoul, Korea
- 1987-1991, B.S. in Agricultural Chemistry Seoul National University, Seoul, Korea
- 2011-Present, Professor Division of Life Sciences, Korea University, Seoul, Korea
- 2013-2015, Division Chair Division of Life Sciences, Korea University, Seoul, Korea
- 2010-2011, Visiting Professor Harvard Medical School & Dana-Farber Cancer Institute, Boston, USA
- 2004-2011, Assistant & Associate Professor Division of Life Sciences, Korea University, Seoul, Korea
- 2003-2004, Senior Researcher Division of Basic Sciences, National Cancer Center, Ilsan, Korea
Structural biology is the essential part of modern biology for understanding the fascinating molecular events within the cell and for developing novel therapeutics. We are particularly interested in the structure-function relationship of the protein complexes involved in protein degradation and autophagy pathways. A myriad of proteins and organelles in cell have their own life-span. Problems in protein and/or organelle turn-over cause defects in cellular processes and subsequently numerous diseases in general. Accordingly, to understand structure-function relationship on the target proteins and related molecule diseases, it is important to recognize protein degradation signals, activation mechanism of proteases, and molecular events in the autophagic pathways. The below three sections sketch our key research activities.
1. Autophagic molecules Autophagy, a bulk degradation process of cell’s own proteins or oranelles by lysosomes (or vacuoles in fungi), is tightly regulated to maintain a balance between synthesis and degradation of cellular products. It is an important mechanism for recycling cellular building blocks under metabolically stressful conditions. We have expanded our research to whole autophagic pathways including several selective autophagy pathways (including xenophagy [autophagy for bacterial clearance] and aggrephagy [autophagy for protein aggregates]), ubiquitylation-like enzymatic mechanism, and autophagosome maturation.
2. Ubiquitin Biology Ubiquitin (Ub) is a small protein composed of 76 amino acids found only in eukaryotes. It plays as a key signal for proteasome-dependent protein degradation pathway by a covalent modification of target proteins. Ub-dependent degradation regulates diverse cellular processes including cell cycle progression, muscle differentiation, and transcriptional regulation. Interestingly, proteins containing specific amino acid residues at the N-terminus are discarded within a few minutes, which is called “N-degron pathway” mediated by N-recognins including the first characterized Ub E3-ligase, Ubr1. The N-degron pathway, especially Arg/N-degron pathway possesses the hierarchical enzymatic steps to degrade the N-degron substrates. We are working on the structure-function study of proteins involved in the N-degron pathway.
3. Bacterial Degradation Signal Recognition Intracellular protein degradation is a highly regulated process. The proteolytic machinery must select the right substrate in the right place at the right time. Unlike eukaryotes, prokaryotes utilize several protease complexes for intracellular protein degradation as they lack the ubiquitin-proteosome system. However, despite a wealth of structural information on prokaryotic proteosome homologs, the detailed mechanism for their substrate recognition is still mysterious. For unveiling it, we conduct research on the target selection steps by bacterial degradation machineries including ClpXP and HslVU.