 In 2004 has been found that one of ARF's p53-independent functions involves its binding to nucleophosmin/B23 (NPM).NPM is an acidic ribosomal chaperone (protein) involved in preribosomal processing and nuclear exportation independent of p53, and oligomerizes with itself and p14ARF.Nearly half of p14ARF is found in NPM-containing complexes with high molecular mass (2 to 5 MDa).