We have designed molecules that permit the selective cross-linking (S-CROSS) of interacting proteins in cell lysates and the sensitive detection of the trapped complexes through in-gel fluorescence scanning. S-CROSS requires the expression of the putative interacting proteins as fusion to CLIP-tag or SNAP-tag, two protein tags that can be specifically labeled with synthetic probes. Bifunctional molecules that contain the substrates of the two tags connected via a fluorophore are used to selectively cross-link interacting proteins in cell lysate. The amount of trapped complex can be then quantified after SDS gel electrophoresis by in-gel fluorescence scanning. On the basis of a detailed kinetic analysis of the cross-linking reaction, we showed that the cross-linking efficiency can be used as an indicator of interaction between two proteins, allowing thereby the unambiguous identification of interacting protein pairs. We validated our approach by confirming a number of interactions through selective cross-linking and showed that it permits the quantitative and simultaneous analysis of multiple homotypic and heterotypic protein complexes and the differentiation between strong and weak protein-protein interactions.
Bruno Emanuel Ferreira De Sousa Correia, Michael Bronstein, Hamed Khakzad, Casper Alexander Goverde, Arne Schneuing, Ilia Igashov
Didier Trono, Henning Paul-Julius Stahlberg, Beat Fierz, Priscilla Turelli, Bruno Emanuel Ferreira De Sousa Correia, Elisa Oricchio, Sandrine Madeleine Suzanne Georgeon, Dongchun Ni, Michael Bronstein, Pablo Gainza Cirauqui, Zander Harteveld, Andreas Scheck, Charlène Mireille Raymonde Raclot, Anthony Marchand, Alexandra Teslenko, Casper Alexander Goverde, Aaron Simone Petruzzella, Stephen Michael Buckley, Martin Pacesa, Stéphane Rosset, Sarah Wehrle, Freyr Sverrisson, Alexandra Krina Van Hall-Beauvais, Jane Marsden