Predicted to enable guanyl-nucleotide exchange factor activity and small GTPase binding activity. Involved in endosomal vesicle fusion and molting cycle. Located in early endosome. Is expressed in several structures, including coelomocyte; distal tip cell; neurons; ventral nerve cord; and vulva. Orthologous to human RABGEF1 (RAB guanine nucleotide exchange factor 1).
WB Description
rabx-5 encodes a protein containing a zinc-finger domain and a Vps9 domain that is the C. elegans ortholog of the Rabex-5 Rab5 guanine-nucleotide exchange factor (GEF); RABX-5 activity is required for homotypic endosomal fusion, and genetic studies indicate that rabx-5 functions redundantly with rme-6 to regulate RAB-5 localization to endosomes and, more generally, nematode larval development, particularly with respect to regulation of the molting cycle; RABX-5 physically interacts with RABN-5, the C. elegans ortholog of Rabaptin-5, a Rab5 effector protein and with the RAB-5 GTPase (likely the GDP-bound form).