SUMMARY Cell division is a complex and specifically orchestrated set of events that culminates in the equal segregation of sister chromatids into two cells. It relies on a multitude of protein complexes, protein- protein interactions, and regulatory mechanisms driven by the activities of posttranslational modification enzymes. The Torres lab investigates the enzymes and regulatory mechanisms that are necessary to carry out human cell division with high fidelity, which are often dysregulated in diseases like cancer. Our research requires a microscope capable of imaging fixed and living cells with high spatial and temporal resolution. This supplement requests funds to purchase a Leica MICA Widefield Live Cell microscope, manufactured by Leica Microsystems, to replace the current broken microscope in the Torres lab that has been continually used for over 12 years. The requested microscope is necessary to continue to successfully complete the aims of the parent R35GM139539 grant, which still has over three years of funding.