Figure 1From: Alterations in the ribosomal machinery in cancer and hematologic disordersLoss of ribosomal proteins activats p53: In a normal cell, MDM2 binds to p53 in the nucleoplasm, leading to p53 ubiquination and degradation. Defective ribosome biogenesis leads free ribosomal proteins moving out of the nucleolus and binding MDM2, thereby preventing the degradation of p53 which then causes G1 cell cycle arrest.Back to article page