Single Molecule insights into Nuclear Mechanotransduction

Mechanical stimuli regulate a large number of cellular functions. However, how mechanical forces are channeled through the cytoplasm to eventually reach the nucleus and alter gene activity remains poorly understood. Here we propose to employ a combination of state-of-the-art nanomechanical techniques at different length-scales to uncover the molecular details underlying the main force propagation mechanisms of nuclear mechanotransduction. We will first study the dynamics under force of each individual protein of the LINC complex, which forms a long molecular tether between the cytoskeleton and the nuclear envelope. Secondly, we will investigate the emerging role of the nucleus as a mechanonsensor. In particular, we will test (i) the lipidome changes in the NE of cells exposed to mechanical stress; (ii) the mechanical effect of key post-translational modifications of cryptic sites in specific nuclear proteins after mechanical unfolding. Finally, we will use a combined mechanical-fluorescence approach to track the dynamics of nuclear shuttling of cytoplasmic transcription factors in order to directly test the hypothesis that mechanical unfolding of proteins accelerates their transport through the nuclear pore complex. Altogether, this multidisciplinary project will provide an integrated, mechanistic and quantitative view on how mechanical forces propagate to the cell nucleus, from a molecular perspective.