Byung-Ho Kang

Assistant Professor

Department of Microbiology and Cell Science 

University of Florida

Director

Electron Microscopy and Bio-Imaging Laboratory

Interdisciplinary Center for Biotechnology Research (ICBR)

University of Florida

General Interest

Plant Cell Biology, Cellular Electron Microscopy/Tomography, Bio-imaging technology.

Description of Research

Plants are essential for human existence on the Earth. Most of our food, fuel, and clothing are obtained either directly or indirectly from plants. Plant substances valuable to human are often synthesized in and transported through the secretory pathway. Our long-term goal is to understand the plant secretory pathway for engineering useful properties in plants.
The plant Golgi is enclosed in a ribosome-excluding matrix, termed the Golgi matrix. Further study has revealed that not only the Golgi but also all the sites in the secretory pathway where vesicle-mediated assembly and transformation of membrane compartments occur are encompassed by ribosome-excluding matrices. We named this cell-wide matrix system the “membrane affinity scaffold” (MAS) system, to emphasize its scaffold organization for recruiting enzymatic and regulatory proteins that are required for membrane events taking place in the enclosed compartment (Figure 1). We hypothesize that the MAS system plays crucial roles in guiding vesicular trafficking and differentiation of endomembrane compartments, and that scaffold-forming long coiled-coil proteins and proteins regulating membrane-association of the long coiled-coil proteins are major components of the MAS system. We are currently testing the hypothesis by characterizing the MAS proteins using Arabidopsis as a model system.

The ribosome-excluding scaffolds have been seen in mammalian and yeast cells indicating that the MAS is common to all eukaryotic cells. We plan to expand our MAS study to agriculturally important plants as well as to other types of eukaryotic cells that can be cultured in large scales such as algal and fungal cells.

Like other cell biology labs, our research depends heavily on microscopy. Among microscopy techniques, our specialty lies in electron tomography. By this imaging technique, cells are visualized in three-dimension (3D) with 4~7 nm resolution, which is ~40 better than achieved by most confocal microscopy. Furthermore, we can generate 3D models of organelles with complex structures for better viewing and for quantifying their spatial parameters. Data from electron tomography can complement informative time-lapse live-cell imaging data by confocal microscopy.

In addition to electron tomography, we employ high-pressure freezing to fix cells close to their native state. Even the world’s best electron microscope cannot undo artifacts introduced during sample processing. By high-pressure freezing, cells are frozen in milliseconds under high-pressure. Therefore, cellular molecules are immobilized without significant molecular rearrangement and detectable ice-crystal growth. Combined use of electron tomography and high-pressure freezing allows for cell imaging with unprecedented detail and fidelity.

We are located in the room 1012 Microbiology and Cell Science Building and are equipped with both confocal and electron microscopy capability.

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Selected Publications

Characterization and distribution of COPII- and COPIa- and COPIb-type vesicle classes surrounding plant and algal Golgi analyzed by 3D electron tomography
Donohoe, B.*, Kang, B. -H.*, and Staehelin, L. A.
Proc Natl Acad Sci U S A (2007) 1 163-168
* contributed equally to this publication.

Members of the Arabidopsis dynamin-like gene family, ADL1, are essential for plant cytokinesis and polarized cell growth.
Kang, B. -H., Busse, J. S., and Bednarek, S. Y.
Plant Cell (2003) 15, 899-913.

The dynamin-like protein, ADL1C is essential for plasma membrane maintenance during pollen grain maturation.
Kang, B. -H., Rancour, D. M., and Bednarek, S. Y.
Plant Journal (2003) 35 1-15

Three-dimensional analysis of syncytial-type cell plates during endosperm cellularization visualized by high resolution electron tomography.
Otegui, M. S., Mastronarde, D. N., Kang, B. -H., Bednarek, S. Y., and Staehelin, L. A.
Plant Cell (2001) 13, 2033-2051

The Arabidopsis cell plate-associated dynamin-like protein, ADL1Ap, is required for multiple stages of plant growth and development.
Kang, B. -H., Busse, J. S., Dickey, C., Rancour, D. M., and Bednarek, S. Y.†
Plant Physiol. (2001) 126, 47-68

Effect of thiophosphatidate on in vitro protein phosphorylation.
Kang, B. -H. and Choi, M. U.
Bull. Korean Chem. Soc. (1998) 19, 1137-40