CDKN2AIP (CDKN2A-interacting protein), also known as CARF, is a 580 amino acid protein that activates p53 via p14 ARF (alternate reading frame)-dependent and independent pathways. CDKN2AIP-dependent activation of p53, a protein that up-regulates growth arrest and apoptosis-related genes in response to stress signals, leads to an enhancement of p53 function. Expression levels of CDKN2AIP and p53 show an inverse relationship that is caused by a negative-feedback control via a proteasome-mediated degradation pathway. CDKN2AIP is expressed ubiquitously across tissue samples and, along with p14 ARF, is localized to the perinucleolar region within the nucleus.