Developmental Regulation of an Organelle Tether Coordinates Mitochondrial Remodeling in Meiosis

Cellular differentiation involves remodeling cellular architecture to transform one cell type to another. By investigating mitochondrial dynamics during meiotic differentiation in budding yeast, we sought to understand how organelle morphogenesis is developmentally controlled in a system where regulators of differentiation as well as organelle architecture are known, but the interface between them remains unexplored. We found that mitochondria abruptly detach from the cell cortex shortly before segregating into gametes. Mitochondrial detachment is enabled by the programmed destruction of the mitochondria-endoplasmic reticulum-cortex anchor (MECA), an organelle tether that forms contact sites between mitochondria and the plasma membrane. MECA regulation is governed by a meiotic transcription factor, Ndt80, which promotes the activation of a conserved kinase, Ime2. We found that MECA undergoes Ime2-dependent phosphorylation. Furthermore, Ime2 promotes MECA degradation in a temporally controlled manner. Our study defines a key mechanism that coordinates mitochondrial morphogenesis with the landmark events of meiosis and demonstrates that cells can developmentally regulate tethering to induce organelle remodeling.