May play a role in stationary phase survival. alpha-D-glucose 1-phosphate + H(+) + UTP = diphosphate + UDP-alpha-D-glucose Bacterial outer membrane biogenesis; lipopolysaccharide biosynthesis. Homotetramer or homopentamer. A transposon mutant in galU (only the first 220 residues could be expressed) allows HeLa cell invasion but no cell spreading. Shows decreased secretion of IscA, a protein required for cell spreading. The lipopolysaccharide produced is of a size consistent with it containing only lipid A and a single core component. Belongs to the UDPGP type 2 family.