Regulator of rDNA transcription. Acts in cooperation UBF/UBTF and positively regulates RNA polymerase I transcription (By similarity). GTP + H2O = GDP + H(+) + phosphate Interacts with UBF/UBTF. Associates with rDNA transcription unit throughout the cell cycle. Widely expressed. Down-regulated in prostate tumors compared to normal prostate tissue. High levels found in colon tumor and normal colon tissue followed by small intestine, liver, jejunum, ileum, bladder and aorta. Lowest levels observed in endothelial cells. Down-regulated during development of THP-1 monocytes into macrophages. Down-regulated by TGFB1. Belongs to the small GTPase superfamily. Ras family. Although highly related to the Ras family, lacks the conserved prenylation motif at the C-terminus, which serves to target Ras proteins to membrane compartments.