Table 1 Summary of subfamilies identified within the NSS family.¹

Osmolytes

Two distinct groups of GABA transporters (11 and 12, respectively). Also includes: creatine (6), taurine (9), and betaine transporters (6). Two remain ORFans.

46

Biogenic amines

Two distinct groups of dopamine transporters (13 and 6, respectively). Also includes: norepinephrine (13), epinephrine (1), and serotonin (11) transporters.

44

Renal system

Only 7 sequences are characterized, of which: 5 are isolated from the renal system; 1 is an intestinal brush border proline transporter; and the last was found in the brain. Due to the location of the branch point, the sequences highlighted in dark purple in Figure 1 are also included; however, no experimental evidence is available to confirm or refute this.

24

Amino acid #1

Mainly includes proline (5) and glycine (10) transporters; 3 are generically annotated as "amino acid" transporters.

18

Amino acid #2

3 generically annotated as "amino acid" transporters and 2 ORFans.

5

Prokaryotic

Bacterial and archaeal transporters (includes LeuT_Aa). Nearly all are from genome sequencing projects and lack robust biophysical characterization of functional specificity.

44