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Physics of Memory and Learning: From the Perspective of Interacting Biomolecules

Thursday, August 22, 2019

11:30 am - 1:00 pm

Abstract: Calcium (Ca2+) signaling is a dynamic system where Ca2+ concentration fluctuates in range of 0.1-10μM with time. These 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.

This presentation focuses on the binding mechanism of CaM and its target, which requires mutually and conformationally-induced changes in both participants and two unique and distinct CaM binding targets, neurogranin (Ng) and CaM-dependent kinase II (CaMKII), which are abundant in postsynaptic neuronal cells and are biochemically known to tune CaM’s affinity for Ca2+ in opposite directions.

Additional topics discussed include: CaM binding and target selection in the context of evolution and in a crowded environment and a presentation of an integrative approach of quantum mechanical calculations, all-atomistic molecular dynamics, and coarse-grained molecular simulations to investigate the molecular mechanisms of CaM’s reciprocal interaction between target binding and Ca2+binding.

Pizza will be available

Speaker: Margaret S. Cheung - Department of Physics, University of Houston

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.