This is a family of 5 evolutionarily related proteins. Their structural similarities suggest that they are transporters. Biochemical evidence supports transporter activity for SLC66A1 (LAAT1) and SLC66A4 (CTNS; Cystinosin). The functions of the 3 remaining members of the family are undetermined.

* Key recommended reading is highlighted with an asterisk

* Jézégou A, Llinares E, Anne C, Kieffer-Jaquinod S, O'Regan S, Aupetit J, Chabli A, Sagné C, Debacker C, Chadefaux-Vekemans B et al.. (2012) Heptahelical protein PQLC2 is a lysosomal cationic amino acid exporter underlying the action of cysteamine in cystinosis therapy. Proc Natl Acad Sci U S A, 109 (50): E3434-43. [PMID:23169667]

* Kalatzis V, Cherqui S, Antignac C, Gasnier B. (2001) Cystinosin, the protein defective in cystinosis, is a H(+)-driven lysosomal cystine transporter. EMBO J, 20 (21): 5940-9. [PMID:11689434]

* Kandasamy P, Gyimesi G, Kanai Y, Hediger MA. (2018) Amino acid transporters revisited: New views in health and disease. Trends Biochem Sci, 43 (10): 752-789. [PMID:30177408]

* Liu B, Du H, Rutkowski R, Gartner A, Wang X. (2012) LAAT-1 is the lysosomal lysine/arginine transporter that maintains amino acid homeostasis. Science, 337 (6092): 351-4. [PMID:22822152]

* Ruivo R, Bellenchi GC, Chen X, Zifarelli G, Sagné C, Debacker C, Pusch M, Supplisson S, Gasnier B. (2012) Mechanism of proton/substrate coupling in the heptahelical lysosomal transporter cystinosin. Proc Natl Acad Sci U S A, 109 (5): E210-7. [PMID:22232659]

1. Kalatzis V, Cherqui S, Antignac C, Gasnier B. (2001) Cystinosin, the protein defective in cystinosis, is a H(+)-driven lysosomal cystine transporter. EMBO J, 20 (21): 5940-9. [PMID:11689434]

2. Liu B, Du H, Rutkowski R, Gartner A, Wang X. (2012) LAAT-1 is the lysosomal lysine/arginine transporter that maintains amino acid homeostasis. Science, 337 (6092): 351-4. [PMID:22822152]

3. Ruivo R, Bellenchi GC, Chen X, Zifarelli G, Sagné C, Debacker C, Pusch M, Supplisson S, Gasnier B. (2012) Mechanism of proton/substrate coupling in the heptahelical lysosomal transporter cystinosin. Proc Natl Acad Sci U S A, 109 (5): E210-7. [PMID:22232659]