FIGURE 2.

Classical mechanisms of cellular senescence. Senescent cells have unique characteristics and are known as zombie cells; It has six main features: cell cycle stagnation; SASP; organelle changes; changes in nuclear chromatin; metabolic changes; cosmetic changes. The cycle blockade of senescent cells is mainly due to the activation of ATM/ATR caused by DNA damage and the activation of p16ink4a, which are the main ways of senescence. By activating the cell cycle arrest protein, respectively, the Rb protein is dephosphorylated, and the replication of cellular DNA is prevented after binding to the E2F transcription factor, and the cell cycle is stagnant in the G1 phase.