In vitro reconstitution of dynamic cellular actin networks to study the interdependent roles of actin-binding proteins and myosins

• Applicant: Dr. Dennis Zimmermann
• Subject Area: Cell Biology ; Biochemistry ; Biophysics
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 277808112

The joint action of the Actin Cytoskeleton and so-called Myosin motor proteins facilitates fundamental cell biological processes including division, adhesion, differentiation and motility. The actin cytoskeleton is a highly dynamic network of actin filaments that undergoes rapid remodeling through the action of diverse actin-binding proteins. These rigid, but flexible, actin filament scaffolds enable cells to simultaneously generate and resist mechanical forces. These dynamic cytoskeletal actin networks are also utilized by Myosins, nano-machines that travel or pull on actin filaments to drive diverse cellular processes. Over the past two decades, numerous actin-binding proteins have been studied in great detail and their specific roles in regulating actin dynamics clearly defined. In parallel, the biomechanical principles for various members of the myosin super family have been successfully determined in vitro by dissecting myosins behavior on immobilized and artificially stabilized static actin filaments. However, inside the crowded cytoplasm of cells myosins interact with diverse types of highly dynamic actin filament networks that are organized by different sets of specific actin-binding proteins. Thus, the question arises: How do myosins really function under in vivo conditions, where dynamic cytoskeletal actin networks are under constant refurbishment through the action of diverse actin-binding proteins? To address this question, I propose to study the interdependent roles of different sets of myosins and ABPs on different dynamic reconstituted F-actin networks that play essential roles during cell division, cell motility and transport.I will utilize state of the art multi-color Total Internal Reflection Fluorescence (TIRF) microscopy to follow individual myosin and actin-binding protein molecules as they interact with and regulate each other on dynamic and constantly changing reconstituted cellular actin networks such as the contractile ring that an essential component during cell division. This work will pioneer our understanding of how actin-binding proteins and myosin motors work together in order to accomplish important cellular processes.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Dr. David Kovar