Research Description:


Eukaryotic actin filament assembly powers diverse cellular processes in endocytosis, polarized cell growth in either physiological or disease states. At different developmental stages or stress conditions, intracellular actin filaments polymerize the filaments and organize the shapes of actin array in precisely controlled manner.

Actin filament networks are formed in crowd cytoplasm through dynamic protein-protein interaction by actin-binding proteins (ABPs). Well-folded functional domain and flexible disorder regions of ABPs coordinate the ABPs activity through protein-protein interactions, either high or weak interaction. The intrinsically disordered proteins (IDPs) are frequently targeted by post-translational modifications (PTMs), such as phosphorylation and ubiquitination. PTMs are implicated in regulating protein function by modulating the protein dynamics, protein conformation, protein-protein interactions, and the transition between order and disorder states of IDPs.

We studied the molecular mechanism by which signal transductions regulated ABPs activities in actin cytoskeleton assembly in different cell states, using integrated approaches, including biochemical, cell imaging, genetics, structural biology, mathematical simulation and modelling.


 

Reconstitution of Actin Assembly in Cell-free Extract

reconsitution Figure 3        Reconstitution of Actin Cable

Reconstitution of F-actin assembly in yeast cell-free extracts. Branched actin patch structures are assembled by microsphere coated with nucleation-promoting factors for Arp2/3 complex (up-left), and unbranched actin cables are assembled with formin protein (up-right).


 

Advanced Cell Imaging of Actin Cytoskeleton

 Fig 2-1             Actin bundling example

Cell cycle and F-actin assembly (3D-SIM)         Bundling of actin filaments (TEM)

 

Sac6 for NTU1

Cdk1 phospho-regulates fimbrin Sac6 in budding yeast

 

Actin Cytoskeleton Assembly in Biochemical Assays       IMG_20140527_155501-M1        

Fluorescent actin-binding protein                         Pyrene actin assembly assay