Fig. 1.

Structural analysis of Past-A.A, Amino acid sequences of rat Past-A. The approximate positions of the transmembrane domains are underlined. Three proline-rich regions are boxed. The leucine repeats are marked with filled circles. The sucrose–H⁺ transport motif is indicated withasterisks. Numbers to theright show amino acid positions. B, Putative membrane topology of Past-A. Three proline-rich regions areboxed. The leucine repeats are marked with dark background. The sucrose–H⁺ transport motif is indicated with asterisks. Numbers show amino acid positions. C, Phylogenic tree of a multiple alignment the Past-A with other transporters. c, Carrot;h, human; m, mouse; o,Oryzias latipes (medaka); r, rat;z, zea mays (maize).