Insights into Bud Morphogenesis Dynamics in Aging Yeast

Understanding cellular aging is crucial for extending organismal lifespan and studying age-related degenerative diseases. In budding yeast recent experiments revealed two aging modes—nucleolar and mitochondrial decline. Bud dimensions measured over a cell cycle show linear growth in both modes. In one, cells maintain bud size and spherical shape, whereas bud size increases and shape becomes tubular in the other. We introduce a chemical-mechanical coupled model predicting that linear bud growth results from delivering new cell surface materials to Cdc42 polarization at a constant rate. Simulations confirm the generation of elongated buds by locally inserting materials at the bud tip. These findings suggest cellular aging may impact the maintenance of chemical signaling polarization that directs the delivery of new materials. Our aim now is to simulate aging under varying environmental conditions with cellular signalling and determine the role played by the septin neck ring and actin cables.