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Seminars

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  • Title:Physics of Memory and Learning – from the Perspective of Interacting Molecules
  • Start Date/Time:2019-09-30 / 14:00
  • End Date/Time :2019-09-30 / 16:00
    • Speaker:Prof Margaret S Cheung(University of Houston)
    • Place:P512 of NCTS, 5F, General 3rd Building, Nat'l Tsing Hua Univ.
    • Host:Prof. Lee-Wei Yang (NTHU)
    • Abstract:Physics of Memory and Learning – from the Perspective of Interacting Biomolecules
      Margaret S. Cheung
      Department of Physics, University of Houston
      The calcium (Ca2+) signaling pathway is integral to learning and memory formation in neurons. Short transient Ca2+ around the entry sites activate Ca2+-binding proteins such as calmodulin (CaM). The prototypical pathway describes CaM as encoding a Ca2+ signal by selectively activating downstream CaM-dependent proteins through molecular binding. However, CaM’s intrinsic Ca2+-binding properties alone appear insufficient to decode rapidly fluctuating Ca2+ signals. It has been proposed that the temporally varying mechanism for producing target selectivity requires CaM-target interactions that directly tune the Ca2+-binding properties of CaM through reciprocal interactions, thus making a distinctive signaling decision in a cell. In this presentation, I will first focus on the binding mechanism of CaM and its target, which requires mutually and conformationally-induced changes in both participants Then, I will reveal how a target mechanistically tunes CaM’s affinity for Ca2+ by examining its binding with neurogranin (Ng) and CaM-dependent kinase II (CaMKII). These two targets are biochemically known to tune CaM’s affinity for Ca2+ in opposite directions in postsynaptic neuronal cells. I will further discuss about the active role of CaM/CaMKII in organizing the structure and dynamics of actin networks in a dendritic spine, underlying how a chemical reaction at a molecular scale transmits to a designated mechanical response at a micron scale. My group has employed an integrative approach of quantum mechanical calculations, all-atomistic molecular dynamics, and coarse-grained molecular simulations to investigate these problems across a wide scale in both space and time.

      Short Bio:
      Dr. Cheung is the Moores Professor of Physics at the University of Houston. She graduated from the National Taiwan University with a bachelor’s degree in chemistry and received her Ph.D. in physics from the University of California, San Diego. She carried out theoretical biological physics and bioinformatics research as a Sloan Postdoctoral Fellow at the University of Maryland and started her lab at the University of Houston in 2006. Dr. Cheung’s research focuses on protein folding inside a cell, calmodulin dependent calcium signaling, protein motors, actomyosin dynamics, and quantum efficiency in organic photovoltaics. She is particularly interested in developing multi-physics models that bridge the dynamics across wide temporal and spatial scales in subcellular biology and materials, and designing computational algorithms that integrate high-performance computing resources across heterogeneous systems. She is a fellow of the American Physical Society, a Senior Scientist at the Center for Theoretical Biological Physics and an Adjunct Professor of Bioengineering at Rice University.

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