Probable UDP-L-arabinose mutase involved in the biosynthesis of cell wall non-cellulosic polysaccharides (By similarity). Was initially shown to possess an autoglycosylating activity which is dependent on the presence of UDP-glucose and manganese (Probable) (PubMed:10580281). UDP-beta-L-arabinofuranose = UDP-beta-L-arabinopyranose Homopentamer or homohexamer. Cell wall-associated, with highest concentrations on plasmodesmata. Also located in the Golgi apparatus (By similarity). Expressed in all tissues tested, including root, tuber, leaf, petiole, shoot, stolon and stem. The conserved DXD motif is involved in enzyme activity. Reversibly glycosylated by UDP-glucose, UDP-xylose and UDP-galactose, but not UDP-mannose. Belongs to the RGP family.