Regulates cellular senescence through inhibition of PTEN translation. Acts as a pro-apoptotic regulator in response to DNA damage. Interacts with ING1 (isoform 2). Colocalizes with ING1 in the nucleolus after UV stress. Expressed at high intensities in the heart, skeletal muscle, and placenta. Down-regulated during cellular senescence. Belongs to the universal ribosomal protein uL1 family. Highly divergent.