Figure 1. A model for the link between sumoylation and Sir2-related aging pathway. Various factors stabilize rDNA to affect lifespan extension in S. cerevisiae. TORC1 inhibition, Sir2 and several epigenetic regulators of rDNA promote rDNA stability and longevity. Sumoylation may regulate the activity of Sir2 and contribute to maintaining stable rDNA structure, leading to lifespan extension.