title: Virtual and biophysical screening targeting the γ-tubulin complex--a new target for the inhibition of microtubule nucleation.
abstract: Microtubules are the main constituents of mitotic spindles. They are nucleated in large amounts during spindle assembly, from multiprotein complexes containing γ-tubulin and associated γ-tubulin complex proteins (GCPs). With the aim of developing anti-cancer drugs targeting these nucleating complexes, we analyzed the interface between GCP4 and γ-tubulin proteins usually located in a multiprotein complex named γ-TuRC (γ-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 γ-tubulin complexes.
authors.affiliation: Institut de Pharmacologie et de Biologie Structurale, UMR 5089 CNRS-Université de Toulouse, UPS, Toulouse, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Cala
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Remy
authors.forename: Valérie
authors.initials: V
authors.lastname: Guillet
authors.forename: Andreas
authors.initials: A
authors.lastname: Merdes
authors.forename: Lionel
authors.initials: L
authors.lastname: Mourey
authors.forename: Alain
authors.initials: A
authors.lastname: Milon
authors.forename: Georges
authors.initials: G
authors.lastname: Czaplicki
mesh_terms: D001665:Binding Sites; D055592:Biophysical Phenomena; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D014404:Tubulin