Presentation Information
[SS17-05]Spatiotemporal control of actin network assembly in a reconstituted system
*Makito Miyazaki1,2,3 (1. RIKEN BDR (Japan), 2. RIKEN IMS (Japan), 3. Shinshu University (Japan))
Keywords:
Cytoskeleton,Actomyosin,Synthetic biology,Cell motility,Cell morphogenesis
The actin cytoskeleton forms a dynamic mesh-like network that drives cellular deformations. The structural and functional properties of actin network are defined by its density and the activity of actin-binding proteins. However, how network density impacts the penetration ability and activities of actin-binding proteins remains unclear. Here, we developed a method to spatiotemporally control actin network assembly on a supported lipid bilayer in vitro using photolithography and optogenetics. This approach enables precise manipulation of the density, thickness, and shape of Arp2/3-mediated actin network assembly. Using this reconstituted system, we investigated how network density affects the interaction of two representative actin-binding proteins: myosin and ADF/cofilin. We found that the penetration of myosin filaments into the network was strictly inhibited by only a several-fold increase in network density due to the steric hindrance. Furthermore, penetrated myosin filaments induced directional actin flow when the network has a density gradient. On the other hand, ADF/cofilin penetrated into the network regardless of network density. However, network disassembly was dramatically inhibited by only a several-fold increase in network density. These findings reveal the network-density-dependent functions of actin-binding proteins, shedding light on the mechanical regulation of cytoskeletal dynamics by actin network density.