Mechanical connection between the actin cytoskeleton and the nucleus – Actin2Nucleus

In eukaryotic cells, the nucleus is physically connected to the cytoskeleton, which is fundamental for mechanical force transmission and required for multiple nucleus and chromosomes functions. A transmembrane protein of the nuclear envelope, nesprin-2, interacts with the actin cytoskeleton and is thought to play a key role in the mechanical connection with the nucleus. The mechanical properties of nesprin-2 and its interaction with the actin cytoskeleton are, however, poorly understood. We propose to combine a range of biophysical approaches to characterize quantitatively the mechanics of nesprin-actin complexes in minimal systems. We will use optical tweezers, micro-functionalized microfluidic chambers and reconstituted actin gels to exert forces on cell-extracted nuclei, and genetically encoded molecular force probes to measure molecular tensions in nesprins. This will determine the mechanical properties of nesprins, and how these properties integrate at the nucleus-actin contact to transmit or buffer mechanical signals between the actin network and the nucleus.