Part of the ABC transporter complex UgpABCE involved in sn-glycerol-3-phosphate import. Responsible for energy coupling to the transport system (Probable). Can also transport glycerophosphoryl diesters. ATP + H2O + sn-glycerol 3-phosphate(out) = ADP + H(+) + phosphate + sn-glycerol 3-phosphate(in) Activated by gluconate, inhibited by fumarate and internal phosphate. Internal phosphate may bind to UgpC and reduce its affinity for UgpA and UgpE. The complex is composed of two ATP-binding proteins (UgpC), two transmembrane proteins (UgpA and UgpE) and a solute-binding protein (UgpB). Induced by phosphate starvation, via PhoB. Also induced by carbon starvation, via the cAMP receptor protein (CRP). Functional exchangeability of MalK and UgpC. But UgpC does not complement the regulatory function of MalK. Belongs to the ABC transporter superfamily. sn-glycerol-3-phosphate importer (TC 3.A.1.1.3) family. Extended N-terminus.