Prof. Hyokeun Park received his Ph.D. in Chemical Physics at University of Illinois at Urbana-Champaign in 2006. He worked at Stanford University as a postdoctoral fellow until 2013. He became a joint professor in the division of Life Science and department of Physics in 2014. He has worked on neuroscience and single-molecule biophysics. His research focuses on the synaptic transmission in living neurons and dynamics of single-molecules using advanced real-time nanometer-accuracy tracking of single molecules and organelles.

Research Question

Neurons communicate with each other by releasing neurotransmitters inside synaptic vesicles in the presynaptic terminal and subsequently activating postsynaptic neurotransmitter receptors. Owing to the tiny size of synapses (~1 micrometer), studying mechanisms underlying neuronal communication is very challenging. To overcome this challenge, we built the state-of-the-art tracking setup and have tracked single presynaptic single synaptic vesicles and postsynaptic receptors in living neurons with an accuracy of nanometers in real time. Using advanced tracking, we are studying the exocytosis and dynamics of inhibitory synaptic vesicles during inhibitory synaptic transmission which is crucial in maintaining balance between excitation and inhibition in the brain but is poorly understood. We are also studying the neurodegeneration mechanisms in neurodegenerative diseases such as Huntington’s disease and Alzheimer’s disease, which tens of millions of people are suffering from. Additionally, we are working on dynamics of single molecules and single cells using advanced imaging techniques and magnetic tweezers. Here are our research projects.

1. Investigating exocytosis and dynamics of inhibitory synaptic vesicles and receptors during inhibitory synaptic transmission. 
2. Discovering neurodegeneration mechanisms in neurodegenerative diseases. 
3. Exploring the stepping mechanism and dynamics of single myosin X. 
4. Examining the mechanobiology of cancer cells 
5. Developing new fluorescent techniques for biological applications. 

Representative Publications

1. Sidong Chen, Hanna Yoo, Chun Hei Li, Chungwon Park, Gyu Nam Park, Li Yang Tan, Sangyong Jung & Hyokeun Park Real-time three-dimensional tracking of single vesicles reveals abnormal motion and pools of synaptic vesicles in neurons of Huntington’s disease mice, iScience 24 (10), 103181 (2021)
2. Xingxiang Chen, Teng Liu, Xianan Qin, Sang Kwon Lee, Chanwoo Lee, Yaguang Ren, Jun Chu, Guang Zhu, Tae-Young Yoon, Chan Young Park,& Hyokeun Park, Simultaneous Measurement of Real-Time Three-Dimensional Localization and FRET of Two Distinct Particles, Nano Letters 21 (18), 7479-7485 (2021)
   
3. Chungwon Park, Xingxiang Chen, Chong-Li Tian, Gyu Nam Park, Nicolas Chenouard, Hunki Lee, Xin Yi Yeo,Sangyong Jung, Richard W. Tsien, Guoqiang Bi, & Hyokeun Park, Unique dynamics and exocytosis properties of GABAergic synaptic vesicles revealed by three-dimensional single vesicle tracking, PNAS  118 (9) e2022133118 (2021)
   
4. Fang Tian, Tsung-Cheng Lin, Liang Wang, Sidong Chen, Xingxiang, Chen, Pak Man Yiu, Ophelia K. C. Tsui, Jun Chu, Ching-Hwa, Kiang & Hyokeun Park, Mechanical responses of breast cancer cells to substrates of varying stiffness revealed by single-cell measurements. The Journal of Physical Chemistry Letters, 11, 7643–7649 (2020)
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5. Park H, Li Y and Tsien RW. Influence of synaptic vesicle position on release probability and exocytotic fusion mode. Science335, 1362-1366 (2012).