A glutamine residue conserved in the neurotransmitter:sodium:symporters is essential for the interaction of chloride with the GABA transporter GAT-1.

ABSTRACT: Neurotransmitter:sodium symporters are crucial for efficient synaptic transmission. The transporter GAT-1 mediates electrogenic cotransport of GABA, sodium, and chloride. The presence of chloride enables the transporter to couple the transport of the neurotransmitter to multiple sodium ions, thereby enabling its accumulation against steep concentration gradients. Here we study the functional impact of mutations of the putative chloride-binding residues on transport by GAT-1, with the emphasis on a conserved glutamine residue. In contrast to another putative chloride coordinating residue, Ser-331, where mutation to glutamate led to chloride-independent GABA transport, the Q291E mutant was devoid of any transport activity, despite substantial expression at the plasma membrane. Low but signif

SUBMITTER: Ben-Yona A 

PROVIDER: S-EPMC3024778 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature