We have developed fluorescence-based and biochemical assays to directly measure all aspects of dynamin function, including dynamin-catalyzed membrane fission from SUPER templates (Pucadyil and Schmid, Cell, 2008). Through structure-based mutagenesis studies in combination with novel FRET-based fluorescence assays and other biophysical and structural methods, we are defining the molecular mechanisms governing dynamin-catalyzed membrane fission (Schmid and Frolov, Ann Rev. Cell and Dev. Biol., 2011). This work is funded by NIH grants GM42455 and MH61345.