PROJECT SUMMARY We are requesting funding to purchase a Marianas spinning disk confocal microscope with six laser lines from Intelligent Imaging Innovations to enable fast, multichannel, live cell imaging of fluorescent samples by NIH supported investigators at UT Southwestern Medical Center in Dallas, TX. For optimum spatial and temporal resolution, the instrument is configured with the Yokogawa CSU W1 SoRa spinning disk head and a Hamamatsu Orca Fusion sCMOS camera. An Andor iXON 888 EMCCD also is included to support fast timelapse imaging of samples that are too dim to be imaged with the Fusion camera. For FRAP and photoactivation experiments, the requested instrument is configured with a Vector high speed point scanner. The instrument will be housed in and maintained by the institutional imaging core facility and will be available to all investigators on campus. The microscope will replace an eleven-year old Andor spinning disk confocal that experiences frequent communication issues, extended downtime, and lags far behind current spinning disk confocal and camera technology. The existing instrument is used an average of 35 hr/week despite these issues. Five of the nine major users listed in this application use the existing instrument daily or weekly, while the others have used it intensively at regular intervals over the past five years and plan to use it again in the near future. There is no other spinning disk confocal microscope on the UT Southwestern campus that is available to this user group and no other microscope of any kind that is capable of FRAP and photoactivation with sufficient time resolution to support the needs of these users. Health related research that will benefit from the requested instrument includes studies of nuclear import and export, the mechanism of tubulogenesis during development of organs such as kidney and pancreas, characterization of metastatic phenotypes, mechanisms of lipid biogenesis and metabolism, the causes of developmental abnormalities of the heart and skeletal muscle, and virus interactions with the innate immune system.