The function of RHOU (ras homolog family member U, Ensembl gene identifier ENSG00000116574) is as follows. Binds to and activates protein kinase PAK1 (PubMed:11459829). Plays a role in the regulation of cell morphology, cytoskeletal organization and focal adhesion assembly during cell migration (PubMed:11459829, PubMed:17620058, PubMed:18086875, PubMed:21834987). Also stimulates quiescent cells to reenter the cell cycle (PubMed:11459829). Has no detectable GTPase activity but its high intrinsic guanine nucleotide exchange activity suggests it is constitutively GTP-bound (PubMed:16472646). {ECO:0000269|PubMed:11459829, ECO:0000269|PubMed:16472646, ECO:0000269|PubMed:17620058, ECO:0000269|PubMed:18086875, ECO:0000269|PubMed:21834987}.