ARF tumor suppression in the nucleolus.

Since its discovery close to twenty years ago, the ARF tumor suppressor has played a pivotal role in the field of cancer biology. Elucidating ARF's basal physiological function in the cell has been the focal interest of numerous laboratories throughout the world for many years. Our current understanding of ARF is constantly evolving to include novel frameworks for conceptualizing the regulation of this critical tumor suppressor.

A non-tumor suppressor role for basal p19ARF in maintaining nucleolar structure and function.

The nucleolus is the center of ribosome synthesis, with the nucleophosmin (NPM) and p19(ARF) proteins antagonizing one another to either promote or inhibit growth. However, basal NPM and ARF proteins form nucleolar complexes whose functions remain unknown. Nucleoli from Arf(-/)(-) cells displayed increased nucleolar area, suggesting that basal ARF might regulate key nucleolar functions.