In 2002, Sally Zigmond and other UPenn/PMI scientists made the seminal discovery of formin’s ability to nucleate and elongate actin filaments (Science; DOI: 10.1126/science.1072309). Utilizing UPenn’s cryo-EM facility, Nick Palmer and Kyle Barrie, students in the Dominguez lab, have just published in Nature (https://rdcu.be/dJ8mW) the cryo-EM structures of INF2 and Dia1 that now provide a step-by-step visualization of the mechanisms of actin filament severing and elongation, bringing this story full-circle here at Penn! The implications of this study are profound since formin dysfunction is linked to pathologies, including cardiomyopathies, cancers, and neurological disorders. Mutations in the two formins studied in their paper, INF2 and Dia1, produce focal segmental glomerulosclerosis and Charcot-Marie-Tooth neuropathy (INF2), and deafness (Dia1). Please join me in congratulating the Dominguez lab on this accomplishment!