Cellular Interactome Dynamics during Paclitaxel Treatment

Cell-cycle inhibitors, including paclitaxel, are among the most widely used and effective cancer therapies. However, several challenges limit the success of paclitaxel, including drug resistance and toxic side effects. Paclitaxel is thought to act primarily by stabilizing microtubules, locking cells in a mitotic state. However, the resulting cytotoxicity and tumor shrinkage rates observed cannot be fully explained by this mechanism alone. Here we apply quantitative chemical cross-linking with mass spectrometry analysis to paclitaxel-treated cells. Our results provide large-scale measurements of relative protein levels and, perhaps more importantly, changes to protein conformations and interactions that occur upon paclitaxel treatment. Drug concentration-dependent changes are revealed in known drug targets including tubulins, as well as many other proteins and protein complexes involved in apoptotic signaling and cellular homeostasis. As such, this study provides insight into systems-level changes to protein structures and interactions that occur with paclitaxel treatment. [Display omitted] •Quantitative cross-linking/mass spectrometry analysis of mitotic inhibitor-treated cells•Cross-links reflect paclitaxel stabilization of microtubules•Drug-specific changes to intermediate and microfilament structures•Paclitaxel treatment alters mitochondrial respiration and ATP synthase structure Chavez et al. reveal interactome changes in cells treated with mitotic inhibitors using quantitative cross-linking and mass spectrometry. Cross-links reflect interaction/conformational changes specific for drug type and concentration, which are not evident by protein expression levels. Microtubule stabilization, cytoskeletal alteration, and changes to mitochondrial function are visualized in cross-link levels.