Hwang, Inhwan, Ph.D.

Professor
Department of Life Science
Division of Molecular and Life Sciences
Plant Molecular Cell Biology

Publications Abstract
E-mail ihhwang@postech.ac.kr
Phone +82-54-279-2128(office)
          +82-54-279-8160(lab.)
Laboratory Cellular Systems Biology

Profile |  Research Interests |  Selected Publications

Profile

Research Interests

Plant Molecular Cell Biology
The main objectives of the laboratory are to elucidate and understand the molecular mechanisms of 1) how a higher eukarytic cell coordiate and maintain its multicompartmental organization (cellular organelles), 2) how a large number of proteins and lipids are transported between these compartments, and 3) how a multicellular organism can be developed from a single cell. Since inevitably an array of complex cellular activities are necessary to regulate and coordinate these compartments to function as a single unit cell a large number of  molecules must be involved in these complex processes. Therefore, the main stream of research is focused on isolation and characterization of important molecular players of these processes by the molecular, biochemical, and cellular approaches.  The important players we are currently characterizing include 1) proteins involved in biogenesis and maintanace of the organelles such as the ER, Golgi apparatus, chloroplasts, vacuoles, 2) proteins involved in transportations of molecules between these organelles, 3) regulator proteins such as small G proteins (Arf, Rab, and Sar), kinases (PI3-K, PI4-K), lipid binding proteins (EEA1 homolog), and various interacting proteins(Seh1h, Tmp170), 4) regulator lipids such as various phosphoinositides (PI3P, PI4P, PI4,5P2), and 5) signal motifs and domains of transported proteins. For these purposes we use Arabidopsis, a small model plant as an experimental system.
In addition we are currently investigating whether environmental stresses such as high salt stress, cold stress, and dehydration stresses can modulate organogenesis and maintenance of subcellular compartments, and intracellular trafficking of molecules between these organelles. For these purposes we aim to elucidate the signal perception and signal transduction mechanisms of osmotic stress responses in plant cells by isolating and characterizing genes involved in osmotic stress responses.
Finally, based on informations such as the principles of cellular organizations, cellular systems on the biosynthesis, transportation, and storage of proteins we are currently investigating whether we can improve the cells by cellular engineering to use as environmentally friendly production systems for valuable medicinal and industrial proteins and secondary metabolites.

Selected Publications 

• Yong Jik Lee, Wonsil Bae, Soojin Kim, Dae Heon Kim, Eun Ju Sohn, Inhwan Hwang. (2008) AKR2A-mediated biogenesis of chloroplast outer membrane proteins is essential for chloroplast development. Nature Cell Biology 10: 200-207
• Lee Y, Kim YW, Jeon BW, Park KY, Suh SJ, Seo J, Kwak JM, Martinoia E, Hwang I, Lee Y. (2007) Phosphatidylinositol 4,5-bisphosphate is important for stomatal opening. Plant J. 52: 803-816.
• Lee GJ, Kim H, Kang H, Jang M, Lee DW, Lee S, Hwang I. (2007). EpsinR2 Interacts with Clathrin, Adaptor Protein-3, AtVTI12, and Phosphatidylinositol-3-Phosphate. Implications for EpsinR2 Function in Protein Trafficking in Plant Cells. Plant Physiol.  143: 1561-1575.
• Min MK, Kim SJ, Miao Y, Shin J, Jiang L, Hwang I. (2007). Overexpression of Arabidopsis AGD7 Causes Relocation of Golgi-Localized Proteins to the Endoplasmic Reticulum and Inhibits Protein Trafficking in Plant Cells. Plant Physiol., 143:1601-1614
• Dhonukshe P, Aniento F, Hwang I, Robinson DG, Mravec J, Stierhof YD, Friml J. (2007). Clathrin-Mediated Constitutive Endocytosis of PIN Auxin Efflux Carriers in Arabidopsis.Curr Biol. 17:520-527.
• Jung KH, Han MJ, Lee DY, Lee YS, Schreiber L, Franke R, Faust A, Yephremov A, Saedler H, Kim YW, Hwang I, An G. (2006). Wax-deficient anther1 is involved in cuticle and wax production in rice anther walls and is required for pollen development. Plant Cell. 18:3015-3032.
• Lee, K.H., Piao, H. L.,Kim, H.-Y., Choi, S.M., Jiang, F., Hartung, W., Hwang, I., Kwak,  J.M., Lee, I.-J., and Hwang, I. (2006). Activation of glucosidase via dehydration-induced polymerization rapidly increases active pools of abscisic acid. Cell.  126, 1109-1120.
• Lee MH, Lee SH, Kim H, Jin JB, Kim DH, and Hwang I. (2006). A WD40 Repeat Protein, Arabidopsis Sec13 Homolog 1, May Play a Role in Vacuolar Trafficking by Controlling the Membrane Association of AtDRP2A. Mol Cells. 22:210-219.
• Yangsong Miao, Pak Kan Yan, Hyeran Kim, Inhwan Hwang, Liwen Jiang (2006). Localization of GFP fusions with the seven Arabidopsis sorting receptors to the prevacuolar compartments in BY-2 cells. Plant Physiol. 142:945-962.
• Jinhee Song, Myoung Hui Lee, Gil-Je Lee, Cheol Min Yoo, and Inhwan Hwang (2006). An Arabidopsis epsin homolog AtEpsin1 plays a critical role in vacuolar trafficking of soluble proteins via interaction with clathrin, AtVTI11, AP1 and AtVSR1. Plant Cell, 18: 2258-2274.
• Yi-Shan Teng, Yi-shin Su, Lih-Jen Chen, Yong Jik Lee, Inhwan Hwang, and Hsou-min Li (2006). Tic21 Is an Essential Translocon Component for Protein Translocation across the Chloroplast Inner Envelope Membrane. Plant Cell 18: 2247-2257
• Lee, D.W., Lee, S., Lee, G.-J., Lee, K.-H., and Hwang, I. (2006) Functional characterization of sequence motifs in the transit peptide of RbcS. Plant Physiol.140:466-483.
• Bae, H.J., Lee, D.S., and Hwang, I (2006). Simultaneous targeting of a protein to chloroplasts and peroxisomes as an approach to express heterologous proteins at the high level. J Experimental Botany, 57:161-169.
• Park, M., Lee, D. Lee G-J and Hwang, I. (2005). The Ring-H2 finger domain-bearing RMR protein functions as a cargo receptor for a protein trafficked to the protein storage vacuole. J Cell Biol. 170:757-767
• Joo, J.H., Yoo, H.J., Hwang, I., Lee, J.S., Nam, K.H., and Bae, Y.S. (2005). Auxin-induced reactive oxygen species production requires the activation of phosphatidylinositol 3-kinase. FEBS Lett. 579:1243-1248.
• Kim, H., Park, M., Kim, S.J. and Hwang, I. (2005). Actin filaments play a critical role in vacuolar trafficking at the Golgi complex in plant cells. Plant Cell 17:888-902
• Lim, Y.G., Sohn, E.J., S대, J., Lee,K.-J., Lee, H.-S., Hwang, I., Sacher, W.M.,and  Oh, B.-H. (2005). The crystal structure of mammalian bet3 reveals a novel mechanism for Golgi localization of the tethering factor TRAPP. Nature Structural and Mol. Biol. 12(1):38-45.
• Lee H-Y, Bahn SC, Shin JS, Hwang I, Back K, Doelling JH, Ruy SB (2005). Multiple forms of secretory phospholipase A2 in Plants. Progress in lipid research 44:52-67.
• Lee J, Shim D, Song WY, Hwang I, Lee Y (2004). Arabidopsis metallothioneins 2a and 3 enhance resistance to cadmium when expressed in Vicia faba guard cells.Plant Mol Biol. 54:805-815.
• Gil-Je Lee, Eun Ju Sohn, Myong Hui Lee, Inhwan Hwang. (2004). The Arabidopsis Rab5 homologs Rha1 and Ara7 localize to the prevacuolar compartment. Plant Cell Physiology 45:1211-1220.
• Song, W..Y., Martinoia, E.., Lee, J., Kim, D., Kim, D..Y.., Vogt, E., Shim, D.., Choi, K.S., Hwang, I., and Lee, Y. (2004). A novel family of cys-rich membrane proteins mediates cadmium resistance in Arabidopsis. Plant Physiol. 135:1027-1039.
• Cho HS, Lee SS, Kim KD, Hwang I, Lim JS, Park YI, Pai HS. (2004). DNA Gyrase Plays a Role in DNA Metabolism in Chloroplasts and Mitochondria of Higher Plants. Plant Cell 16:2665-2682
• Lee YJ, Sohn EJ, Lee KH, Lee DW, Hwang I. (2004). The transmembrane domain of AtToc64 and its C-terminal lysine-rich flanking region are targeting signals to the chloroplast outer envelope membrane. Mol Cells. 17:281-291
• Park, M., Kim, S.J., Vitale, A., and Hwang, I. (2004). Identification of the protein storage vacuole and protein targeting to the vacuole in leaf cells of three plant species. Plant Physiol. 134:625-639.
• Cho, C.H., Lee, C.S., Chang, M., Jang, I.H., Kim, S.J., Hwang, I.., Ryu, S.H., Lee, C.O., and Koh, G.Y. (2004) Localization of VEGFR-2 and Phospholipase D2 in Endothelial Caveolae is Involved in VEGF-induced Phosphorylation of MEK and ERK. Am J Physiol Heart Circ Physiol. 286:H1881-1888.
• Kim, Y.J., Kim, J.E., Lee, J.H., Lee, M.H., Jung, H.W., Bahk, Y.Y., Hwang, B.K., Hwang, I., and Kim, W.T. (2004). The Vr-PLC3 gene encodes a putative plasma membrane-localized phosphoinositide-specific phospholipase C whose expression is induced by abiotic stress in mung bean (Vigna radiata L. FEBS Lett. 556:127-136.

Division of Molecular & Life Sciences| POSTECH