Small GTPase required for ciliation. Activated in a guanine nucleotide exchange factor (GEF)-independent manner via its intrinsic GDP for GTP nucleotide exchange ability (PubMed:28625565). Involved in ciliary assembly by binding the intraflagellar transport (IFT) complex B from the large pool pre-docked at the base of the cilium and thus triggers its entry into the cilia (PubMed:28428259, PubMed:28625565). . This is the function of RABL2B (RAB, member of RAS oncogene family like 2B, ENSG00000079974).