Required for formation and/or maintenance of proper nucleolar structure and function (PubMed:26164235). Plays a dual role in the regulation of ribosomal DNA (rDNA) transcription (By similarity). In the presence of high glucose, maintains active rDNA transcription through H2A.Z deposition and under glucose starvation, is required for the repression of rDNA transcription, and this function may be independent of H2A.Z (By similarity).