Size does matter: 18 amino acids at the N-terminal tip of an amino acid transporter in Leishmania determine substrate specificity.

ABSTRACT: Long N-terminal tails of amino acid transporters are known to act as sensors of the internal pool of amino acids and as positive regulators of substrate flux rate. In this study we establish that N-termini of amino acid transporters can also determine substrate specificity. We show that due to alternative trans splicing, the human pathogen Leishmania naturally expresses two variants of the proline/alanine transporter, one 18 amino acid shorter than the other. We demonstrate that the longer variant (LdAAP24) translocates both proline and alanine, whereas the shorter variant (∆18LdAAP24) translocates just proline. Remarkably, co-expressing the hydrophilic N-terminal peptide of the long variant with ∆18LdAAP24 was found to recover alanine transport. This restoration of alanine transport could

SUBMITTER: Schlisselberg D 

PROVIDER: S-EPMC4637868 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature