Project Summary Our project is an exploration into the fundamental understanding of how cells sense the stiffness of the extracellular matrix (ECM), a key factor affecting cellular processes such as differentiation, proliferation, and migration. The parent grant focuses on the molecular complexities of this sensing mechanism, with a particular emphasis on the role of focal adhesions—a kind of cellular 'grip' that connects cells to the ECM. Within these adhesions, the protein talin plays a crucial role, acting as a mechanical sensor that responds to the stiffness of the surrounding tissue and, through a series of signaling events, influences the behavior of the cell. To support the intricate research outlined in the parent grant, we are proposing to enhance our experimental capabilities through the acquisition of advanced laser and LED-based fluorescence imaging equipment. This new setup includes a state-of-the-art laser system with four independent solid-state lasers and a pE-800 solid-state LED- based illuminator, both of which are critical for the high-resolution imaging needed to observe the dynamic activities of cell-matrix adhesions. The laser system is equipped with fast-switching features and precise power control, enabling us to observe rapid biological processes without the phototoxic effects that can alter or damage the samples. This is particularly important for capturing live-cell images that are fundamental to our analysis. The LED illuminator complements this by providing a less phototoxic method for FRET imaging, which is used to study protein interactions in real time. With the new equipment, we will significantly improve our imaging capabilities, achieving finer temporal resolution and reducing the phototoxicity that can impact the cells during long imaging sessions. These improvements will facilitate a deeper understanding of the mechanosensitivity signaling by focal adhesion kinase (FAK) in response to mechanical force, furthering our knowledge of how these processes contribute to cellular responses to ECM stiffness. The delays in recruitment and equipment acquisition have previously impacted our budget utilization, but with the recent onboarding of a new graduate student and the involvement of an existing Ph.D. student, we are now poised to rapidly advance our research. The insights gained from this study have the potential to inform new therapeutic strategies for diseases where tissue stiffness is a key factor, such as in cancer metastasis and fibrotic diseases. This work, supported by the NIH, aligns with the agency's mission to enhance health, lengthen life, and reduce illness and disability.