Randall Seminar: Prof. Klemens Rottner. Wednesday 7^th October 2026. 13:00pm - 14:00pm. NHH G.8. In-Person Only.

Please join us for the exciting Randall Seminar talk from Prof. Klemens Rottner. Details of the seminar can be seen below:

 

Speaker: Prof. Klemens Rottner

Host: Prof. Peter Bieling

Title: Defining profilin functions in mammalian actin dynamics and cell behaviour

Abstract: Cell migration and proliferation as well as communication and trafficking, all depend on the fine-tuned and continuous remodeling of actin filaments, which are nucleated and elongated by addition of monomers, regulated in turn by several monomer-binding factors. The most prominent of those certainly constitutes profilin 1, the largely ubiquitous family member in mammals, and profilin 2, enriched in the nervous system. Profilins are well established as both inhibiting spontaneous actin filament nucleation and promoting formin-dependent actin filament elongation, but their precise cell biological roles are less clear.

 

In this seminar, I will provide evidence establishing that the presence of any profilin is obligatory for cell growth in both mammals and Dictyostelium amoeba, although minute amounts of the protein are sufficient for mediating migration and actin turnover. I will also show that aside from being essential for formin-dependent filopodia and microspike formation, profilin is also crucial for Arp2/3 complex-dependent processes. Mathematical modeling reveals how this can be explained. Our data thus also refute previous suggestions of antagonistic connections between profilin and Arp2/3 complex. Instead, profilin emerges as master regulator of both formin- and Arp2/3 complex-dependent actin assembly pathways operating directly and indirectly, respectively.