<unk>  (also called ARF tumor suppressor, ARF,<unk>  is an alternate reading frame protein product of the CDKN2A locus (i.e. INK4a/ARF locus).<unk>  is induced in response to elevated mitogenic stimulation, such as aberrant growth signaling from MYC and Ras (protein). It accumulates mainly in the nucleolus where it forms stable complexes with NPM or Mdm2. These interactions allow<unk>  to act as a tumor suppressor by inhibiting ribosome biogenesis or initiating p53-dependent cell cycle arrest and apoptosis, respectively.<unk>  is an atypical protein, in terms of its transcription, its amino acid composition, and its degradation: it is transcribed in an alternate reading frame of a different protein, it is highly basic, and it is polyubiquinated at the N-terminus. Both p16INK4a and<unk>  are involved in cell cycle regulation.<unk>  inhibits mdm2, thus promoting p53, which promotes p21 activation, which then binds and inactivates certain cyclin-CDK complexes, which would otherwise promote transcription of genes that would carry the cell through the G1/S checkpoint of the cell cycle. Loss of<unk>  by a homozygous mutation in the CDKN2A (INK4A) gene will lead to elevated levels in mdm2 and, therefore, loss of p53 function and cell cycle control. The equivalent in mice is<unk> .
P14arf
AP-7 
IPrEx
BGR-34
FITkit
VIR-576
C-KAD
BBV154