DFG Priority Programme SPP 1464

Molecular characterization of the Diaphanous-related formins dDia1 and ForC

PD Dr. Jan Faix
Cytoskeletal Dynamics Group
Institute of Biophysical Chemistry
Hannover Medical School
Carl-Neuberg-Str. 1,
30625 Hannover, Germany

phone: +49-511/532-2928
fax: +49-511/532-5966
email: faix.jan@mh-hannover.de
website : http://www.mh-hannover.de/bpc_dyncyt.html



Team



Summary
Diaphanous-related formins (DRFs) constitute a conserved family of ubiquitous multidomain proteins that act as downstream effectors of Rho GTPase signaling pathways to control numerous cellular functions depending on the cytoskeleton. Formins nucleate and elongate linear actin filaments by insertional incorporation of monomers to the filament barbed ends. The proline-rich formin homology domain1 (FH1) recruits profilin–actin complexes for filament elongation which is accomplished by the adjacent FH2 domain. In vivo formins seem to strictly depend on the recruitment of profilin-actin complexes by the FH1-domain for further assembly by the FH2 domain. Since Dictyostelium ForC is the only known formin lacking the FH1-region, we intend to study actin polymerization by this unusual formin. Our ongoing analysis of the 10 Dictyostelium formins also revealed that the elimination of the DRF dDia1 strongly accelerated cell motility, whereas migration of dDia1-overexpressing cells was significantly suppressed. The aim of this project is find out how exactly dDia1 brings about it unexpected negative effect on cell migration.



References

Schirenbeck, A., Bretschneider, T., Schleicher, M. and Faix, J. (2005). The Diaphanous-related formin dDia2 is required for the formation and maintenance of filopodia. Nature Cell Biol. 6, 619-625.

Faix, J. and Rottner, K (2006). The making of filopodia. Curr. Opin. Cell Biol. 18, 18-25.

Faix, J. and Grosse, R. (2006). Staying in shape with formins. Dev. Cell 10, 693-706.

Block, J., Stradal, T.E.B., Hänisch, J., Geffers, R., Köstler, S., Urban, E., Small, J.V., Rottner, K. and Faix, J. (2008). Filopodia formation induced by active mDia2/Drf3. J. Micros. 231, 506-517.

Breitsprecher, D., Kiesewetter A.K., Linkner, J., Urbanke, C., Resch, G.P., Small, J.V. and Faix, J. (2008). Clustering of VASP actively drives processive, WH2 domain-mediated actin filament elongation. EMBO J. 27, 2943-2954.

Faix, J., Breitspecher, D., Stradal, T.E.B. and Rottner, K. (2009). Filopodia: complex models for simple rods. Int. J. Biochem. Cell Biol. 41, 1656-1664.

Ramalingam, N., Zhao, H., Breitsprecher, D., P. Lappalainen, P., Faix, J. and Michael Schleicher. (2010). Phospholipids regulate localization and activity of mDia1 formin. Eur. J. Cell Biol. 89, 723-732.

Breitsprecher, D., Kiesewetter, A.K., Linkner, J., Vinzenz, M., Stradal, T.E.B., Small, J.V., Curth, U., Dickinson, R.B. and Faix, J. (2011). Molecular mechanism of Ena/VASP-mediated actin-filament elongation. EMBO J. 30, 456-467.