PROJECT SUMMARY Advances in single particle cryo-EM have transformed structural biology of ever-expanding biological systems. We request funds to purchase a Glacios 2 cryo-TEM (Thermo-Fisher) at the Icahn School of Medicine at Mount Sinai. The goal is to enable users throughout the Institution, working on different biological and disease mechanisms, to measure cryo-EM data at home, as well as provide a seamless transition for atomic resolution data collection on Titan cryo-TEMs at nearby NYSBC-MEMC and NCCAT. The microscope is equipped with a new generation Falcon 4i direct electron detection camera, and an ancillary vitrification device for the preparation of cryogenic grids. Importantly, the microscope features 200 kV X-FEG optics, and an Autoloader for cryogenic manipulation and loading of the biological samples. A suitable site for installation has already been identified, and as a proof of the Institution’s commitment to establishing cryo- EM, the Dean, Dr. Dennis Charney has agreed to lease the Glacios 2 under Thermo-Fisher’s “bridge-to-grant” mechanism with no obligation to buy, and no lease payment until 12 months after installation. Besides the construction costs, the institution is also deeply committed to all other associated costs in establishing cryo-EM at Mount Sinai, including yearly service contract, IT infrastructure, consumables, and salary for a cryo-EM manager. The success of this S10 application will help to meet a significant portion of the cost in establishing an expensive cryo-EM facility at Mount Sinai that is absolutely crucial for the continued success of our NIH-funded investigators, allowing them to fully partake in this new “resolution revolution” in structural biology. The Glacios 2 cryo-TEM majorly enhances the NIH-funded research projects of numerous investigators throughout Mount Sinai studying a wide range of biological systems that underpin human diseases.