Continuity of Mitochondrial Budding: Insights from BS-C-1 Cells byin-situCryo-Electron Tomography

Abstract

AbstractMitochondrial division is a fundamental biological process as it is critical to cellular functionality and vitality. Following up our previous study in HeLa cells, we employedin-situCryo-Electron Tomography (Cryo-ET) to visualize mitochondrial budding in intact healthy monkey kidney cells (BS-C-1 cells). Our findings reaffirm single and multiple mitochondrial budding, supporting the hypothesis of mitochondrial division by budding. The budding regions vary significantly in diameter which may represent different stages of budding. Notably, rings, ring-like structures, or ER wrapping were not or rarely presented in the budding regions suggesting mitochondrial budding is independent from Drp1 and ER. Furthermore, we uncovered direct interactions between mitochondria and large vesicles, distinct from small mitochondrialderived vesicles and extracellular mitovesicles. We propose these interacting vesicles may have mitochondrial origins as the extracellular mitovesicles.