Lecture will be held in English

Hosted by

Jakub Harnoš

About the lecture

The Evolution of Wnt/beta-catenin Signaling: A View From the Bottom

Metazoans have a limited number of cell-signaling pathways that are ‘tweaked’ over evolutionary time to help generate the vast biological diversity seen on Earth. These same pathways deployed during development generate disease and death when mis regulated during adulthood. Much of our recent work is focused on the role of the bifunctional protein β-catenin, a downstream target of canonical Wnt signaling, that has fundamental roles in both developmental patterning/cell fate specification and cell adhesion in virtually all extant animals. We have focused on two early branching metazoan taxa, the cnidarian Nematostella vectensis and the ctenophore Mnemiopsis leidyi to gain insight into changes in the regulation and functional roles of this important pathway at the ‘dawn’ of animal evolution. Intracellular availability of β-catenin is tightly regulated by at least two independent pathways: sequestration at the cell membrane in the so-called Cadherin Catenin adhesion Complex (CCC), and by the Axin-APC mediated ‘destruction complex’. Despite previous bioinformatic predictions that β-catenin is not involved in cell adhesion in ctenophores, we use yeast 2-hybrid screening combined with molecular mutagenesis to show specific molecular interactions with membrane bound cadherin, 𝛼-catenin and actin cytoskeleton-associated proteins in the CCC adhesion complex. In collaboration with Dr Wikramanayake’s lab at the University of Miami we show that there are substantive dierences in the molecular interactions of ß-catenin to members of the destruction complex in ctenophores and cnidarians. These forward molecular approaches show how important these complex signaling pathways evolve and regulate cell behavior. 

Registration for lunch with the speaker /for Ph.D. students/

The sponsored lunch usually takes place in the Campus River restaurant. Please meet the speaker and other students at 12:45 at the reception desk at the main entrance (building B22, see the map below).