CAREER: Mechanical Forces on the Nuclear Linker of Nucleoskeleton to Cytoskeleton (LINC) Complex

Animal cells respond to mechanical forces both in health and during mechanically caused diseases. The forces change cell signaling through a process known as mechanotransduction. Mechanical forces are known to influence fundamental cellular and tissue level functions, but the cellular sites for mechanotransduction remain poorly understood. The nucleus is the largest and perhaps most critical structure of a mammalian cell since most of the DNA is stored there. Proteins located on the outside of the nucleus experience mechanical force, and the nucleus can be seen deforming when a cell is loaded. Deformation of the nucleus by forces suggests that the nucleus could be a site for mechanotransduction. This Faculty Early Career Development (CAREER) Program research project will determine how and when the nucleus experiences mechanical force using a new kind of force transducer, and then determine how these forces regulate cellular functions. These studies have the potential to identify a new fundamental mechanism of mechanotransduction that would be present in all animals cells. Research opportunities for undergraduate and graduate students to engage in interdisciplinary research projects are planned, as well as K-12 outreach activities, and using research results to improved graduate engineering education. The nucleus is directly connected to the cytoplasmic cytoskeleton by a group of proteins that form the LINC (linker of nucleoskeleton to cytoskeleton) complex. Mutations in LINC complex proteins are associated with impaired development, human genetic diseases, and cancer; thus the linkage of the cytoskeleton to the nucleus appears to be essential to cell function and homeostasis. Proteins in the LINC complex experience mechanical force, suggesting that the LINC complex could be an important structure for mechanotransduction. The goal of this CAREER project is to develop novel force biosensors for LINC complex proteins nesprin and SUN, and then use these sensors to study the mechanical and force-dependent biochemical processes associated with the LINC complex. Identification of the relationship between nuclear force and the forces on the outside of the cell will provide a better understanding of how forces are transmitted within a cell, helping to validate or advance theories of cellular biomechanics. Additionally, the force biosensors used in this project are expressed with plasmid DNA and imaged using fluorescent microscopy, allowing for other laboratories to adopt this force measurement technique