Acts as a growth inhibitor. Can activate p53/TP53, causes G1 arrest and collaborates with CDKN2A to restrict proliferation, but does not require either protein to inhibit DNA synthesis. Redistributes CDKN2A into the nucleoplasm. Involved in maintaining chromosomal stability. Interacts with CDKN2A and MDM2. Induced in cells undergoing arrest in response to DNA damage and TGFB1 treatment. Ubiquitinated; mediated by MDM2 and leading to its subsequent proteasomal degradation. Belongs to the TBRG1 family.