Figure 2.

Possible nucleolar functions of APUM23. APUM23 is required for rRNA processing (1) and affects ribosome biogenesis (2). Because APUM23 is a nucleolar protein, it is possible that it has also other nucleolar functions such as rRNA byproduct degradation by exosome (3), a direct role in translation (4) or an indirect role via its role in ribosome biogenesis (5). Further, auxin and ribosome biogenesis are linked with each other such that defective ribosomes inhibit auxin biosynthesis⁵⁴–⁵⁶ (6) and a local auxin accumulation can translationally repress ribosomal genes (7).⁵⁷