Top: BLAST of protein sequence between human and woodchuck (marmot) ASCT2. The upper bars highlight the trans-membrane segments, and the blue boxed are the key motifs involved in amino acid transport. The red letters represent the differences between the two species in amino acid residues. Bottom: membrane model of ASCT2 towards the C-terminal. While segments 7 and 10 are helices, 8 and 9 form a re-entrant loop-pore structure with conserved motifs (A, B, C, and D), adapted from Ref.