Energy-dependent uptake of glycine betaine in response to high salinity. Uptake is activated by NaCl, KCl or mannose gradients across the cell membrane. Inhibited by the protonophore 3,3',4',5-tetrachlorosalicylanilide (TCS). Deletion of the gene completely abolishes glycine betaine transport. Belongs to the BCCT transporter (TC 2.A.15) family.