Dnm1 Is Required for the Focal Clustering of Fis1 on the Mitochondrial Outer Membrane

In yeast, mitochondrial fission is mediated by the dynamin-like GTPase Dnm1, which is recruited to the mitochondrial outer membrane by its receptor, Fis1. To investigate the spatial distribution of Fis1, we used the CRISPR-Cas9 system to insert the gene fragment encoding mNeonGreen into the FIS1 gene for its N-terminal tagging. Fluorescence microscopy revealed that mNeonGreen-Fis1 appeared as discrete puncta on mitochondria, in addition to a diffuse signal. Here, we show that the focal clustering of Fis1 is dependent on Dnm1. Our findings provide insight into the spatial organization of membrane proteins, highlighting a mechanism by which a downstream effector can influence the distribution of its upstream receptor.