SPP 1464: Principles and Evolution of Actin-nucleator Complexes
Final Report Abstract
Actin/myosin-dependent force generation is a central mechanism of cells providing motility at both microscopic and macroscopic scales. Motor proteins of the myosin family pulling on actin filaments mediate muscle contractions and allow animals to move. At the cellular level, myosin motors sliding along actin filaments enable processes as diverse as migration, cell shape changes and morphological dynamics or cytokinesis during cell division, but also subcellular, motile processes such as organelle movements and vesicle trafficking. At the cell membrane, the polymerisation of actin filaments by itself can generate forces to push membranes forward for shape changes and the formation if protrusions accompanying cell migration. In the decade preceding the priority programme, distinct mechanisms have been identified to generate actin filaments from free actin monomers (actin nucleation). The complexity of the nucleation mechanisms mirrors the diversity of cellular actin structures and functions. In a very successful interdisciplinary approach, the priority programme has addressed in the past roughly 8 years the biochemistry, biophysics and cell biological functions of actin nucleation. The cooperative approach provided the knowledge to link the diversity of nucleation mechanisms to defined cellular functions. Outstanding discoveries made by researchers of the priority programme include the discovery of how actin filament nucleation, elongation and motor protein activation can be coordinated in specific subcellular structures, as well as the mechanistic elucidation of various, distinct aspects of cell edge protrusion. These discoveries will provide basic cell biological textbook knowledge. In addition, the priority programme very much influenced the international venture to mechanistically understand the generation and function of actin structures. By including international collaborators (PIs, coworkers and students) into the meetings and summer school training courses of the programme, we have established a trustful and very collaborative international network, which extends beyond the period of the priority programme. The three international conferences on "Actin Dynamics" organised by members of the priority programme (Kerkhoff, Rottner, Stradal) were internationally well recognized and acknowledged, last not least illustrated by the attraction of numerous leading researchers from all over the world. Both, the summer school and the international conferences on Actin Dynamics have subsequently been continued as an EMBO conference and course, respectively. In summary, the priority programme has executed and published excellent research with general, cell biological significance, and has constituted a vivid platform for the fruitful integration of German, particularly young and medium-aged actin researchers into the international cytoskeleton community. The numerous connections and friendships established throughout the programme period will be of invaluable benefit to us for many years to come.
