Responsible for the transport of sucrose into the cell, with the concomitant uptake of protons (symport system). May also transport other glucosides. May be required for apoplastic phloem sucrose loading in source tissues (e.g. leaves) in order to transport it to sink tissues (e.g. roots, flowers) (By similarity). Glycan biosynthesis; sucrose metabolism. Homodimer. Belongs to the glycoside-pentoside-hexuronide (GPH) cation symporter transporter (TC 2.A.2.4) family.