Research

In the very crowded inner environment of a cell, most macromolecules function in the form of complexes, many being described as "molecular machines." To understand the machines' structures and structural changes that occur during the working cycle, we employ cryo-electron microscopy to visualize molecules as "single particle" or ordered functional assemblies. The micrographs are analyzed by computational image processing to reveal the structure and conformational variations of molecules. We then combine the structural information with data from accompanying biophysical and biochemical techniques to elucidate the mechanisms of these large macromolecular machines. Our current research focuses on (1) RNA degradation, (2) microtubule dynamics, and (3) RNA interference.

The mechanism and regulations of the exosome- mediated RNA processing and degradation

The multisubunit exosome complex is a key player in eukaryotic cells' RNA quality control systems. In order to fully understand the mechanisms and regulation of this important cellular machinery, we utilize electron microscopy and single particle reconstruction techniques to reveal the structure of the exosome in complex with its different cofactors, and with and without the RNA substrate.
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The regulation of microtubule's dynamics at cell cortexes

The dynamic properties of microtubules' plus ends at the cellular boundary are essential in the definition of cell shape and polarity, which in turn influence other important cellular processes, such as cellular differentiation and migration. Using cryo-EM, we study the interactions between microtubule plus ends and the cell membrane, actin network and other cellular structures at the cell cortex, as well as the regulation of these interactions.
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The architecture and mechanism of the RISC- loading complex in RNA interference pathways

RISC-loading complex is at the core of the RNA- interference pathways, responsible for the generating of siRNAs and miRNAs and loading them into the RNA- interference silencing complex for gene-silencing effects. We use electron microscopy to reveal the structure of the RISC-loading complex and the mechanism of RNA substrates processing by this complex.
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