Virtual and Biophysical Screening Targeting the γ-Tubulin Complex – A New Target for the Inhibition of Microtubule Nucleation

Olivier Cala (1) , Marie-Hélène Remy (2) , Valérie Guillet (1) , Andreas Merdes (2) , Lionel Mourey (1) , Alain Milon (1) , Georges Czaplicki (1)

1 IPBS - Institut de pharmacologie et de biologie structurale
2 CBD - Centre de biologie du développement

Microtubules are the main constituents of mitotic spindles. They are nucleated in large amounts during spindle assembly, from multiprotein complexes containing c-tubulin and associated c-tubulin complex proteins (GCPs). With the aim of developing anti-cancer drugs targeting these nucleating complexes, we analyzed the interface between GCP4 and c-tubulin proteins usually located in a multiprotein complex named c-TuRC (c-Tubulin Ring Complex). 10 ns molecular dynamics simulations were performed on the heterodimers to obtain a stable complex in silico and to analyze the residues involved in persistent protein-protein contacts, responsible for the stability of the complex. We demonstrated in silico the existence of a binding pocket at the interface between the two proteins upon complex formation. By combining virtual screening using a fragment-based approach and biophysical screening, we found several small molecules that bind specifically to this pocket. Sub-millimolar fragments have been experimentally characterized on recombinant proteins using differential scanning fluorimetry (DSF) for validation of these compounds as inhibitors. These results open a new avenue for drug development against microtubule-nucleating c-tubulin complexes.

Domaines: Biologie structurale [q-bio.BM]

Olivier Cala, Marie-Hélène Remy, Valérie Guillet, Andreas Merdes, Lionel Mourey, et al.. Virtual and Biophysical Screening Targeting the γ-Tubulin Complex – A New Target for the Inhibition of Microtubule Nucleation. PLoS ONE, 2013, 8 (5), pp.e63908. ⟨10.1371/journal.pone.0063908⟩. ⟨hal-03003005⟩