Amino acid residues that control pH modulation of transport-associated current in mammalian serotonin transporters.

ABSTRACT: The rat and human serotonin transporters (rSERT and hSERT, respectively) were expressed in Xenopus oocytes and studied using site-directed mutagenesis, electrophysiological recordings, and [3H]5-HT uptake measurements. rSERT, but not hSERT, displayed increased transport-associated current at low pH. Chimeras and point mutations showed that, of the 52 nonidentical residues, a single residue at position 490 (threonine in rSERT and lysine in hSERT) governs this difference. Furthermore, potentiation required the glutamate residue at position 493. Cysteine substitution and alkylation experiments showed that residue 493 is extracellular. Cysteine at 493 increased, whereas aspartate decreased, the net charge movement per transported 5-HT molecule. The mutations at this region did not significantl

SUBMITTER: Cao Y 

PROVIDER: S-EPMC6793029 | biostudies-literature | 1998 Oct

REPOSITORIES: biostudies-literature