FIG 3.

Mapping of exons to protein structure of GLUT8. (A) Schematic diagram showing the GLUT8 locus. Exon and intron base size (in base pairs) are indicated. (B) Schematic of GLUT8 variant 1, indicating the exon boundaries within the putative protein structure, where each of the transmembrane (TM) domains is numbered in black, 1 to 12. Key functional domains are indicated, including the glycosylation site in the ecto-loop between transmembrane domains 9 and 10 and the dileucine ER retention and sorting motifs. (C) Comparison of GLUT8 protein sequence conservation, between human GLUT8 (Uniprot ID Q9NY64, Homo sapiens) and three other mammalian species, Mus musculus (Q9JIF3), Rattus norvegicus (Q9JJZ1), and Bos taurus (P63010). Transmembrane domains are 20 amino acids long. Internal cytoplasmic domains include both N and C termini and a large loop between transmembrane domains 6 and 7.