Recognizes the ribosomal RNA gene promoter and activates transcription mediated by RNA polymerase I through cooperative interactions with the transcription factor SL1/TIF-IB complex. It binds specifically to the upstream control element. Homodimer (By similarity). Interacts with TBP (PubMed:7982918). Interacts with TAF1A (PubMed:7491500). Interacts with RASL11A (By similarity). Binds to IRS1 and PIK3CA (By similarity). Interacts with DHX33 (PubMed:21930779). Interacts with PHF6 (PubMed:23229552). Interacts with CEBPA (isoform 1 and isoform 4) (PubMed:20075868). Interacts with DDX11 (PubMed:26089203). Interacts with NOP53 (PubMed:27729611). Interacts with ALKBH2. Phosphorylated and activated by PIK3CA. The disease is caused by variants affecting the gene represented in this entry.