Impact of MFM disease mutations on the assembly mechanism and network formation of muscle-specific intermediate filament proteins

• Antragsteller: Professor Dr. Harald Herrmann
• Fachliche Zuordnung: Molekulare Biologie und Physiologie von Nerven- und Gliazellen
• Förderung: Förderung von 2009 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 101925924

In muscle, the intermediate filament (IF) protein desmin is one of the major components of the extra-sarcomeric cytoskeleton. During embryogenesis and later stages of development, this system is enforced and regionally functionalized by additional IF-proteins, namely vimentin, synemin and syncoilin, as these proteins all colocalize either with the entire filament or at strategically important sites such as costamers. Whereas vimentin appears to form authentic copolymers with desmin, the situation with synemin and syncoilin is not clear. For synemin we have evidence that it does not form the principal molecular complex of IFproteins, i.e. the coiled coil, neither on its own nor in complex with vimentin or desmin.Instead, it binds with high affinity to forming filaments. According to the domain organization of syncoilin, which deviates considerably from that of standard IF-proteins, we expect a similar molecular scenario for this protein too. Therefore, we want to investigate the interaction of desmin with both synemin and syncoilin at the molecular level employing analytical ultracentrifugation and chemical cross-linking techniques. For this purpose, we will generate from these two proteins specific recombinant subdomains and determine their binding properties to desmin. Starting from this investigation, we will determine the minimal peptides that still bind to desmin and determine where on the desmin molecule they bind. In addition, we will investigate if dual binding of both synemin and syncoilin as well as plectin and either of these molecules to filaments is taking place. We will then employ the binding modules of these proteins to investigate their impact on the assembly kinetics as well as the stability of desmin filaments, both in vitro and in a cellular system of myoblast-to-myotube conversion.

• DFG-Verfahren: Forschungsgruppen
• Teilprojekt zu: FOR 1228: Molecular Pathogenesis of Myofibrillar Myopathies