Involvement of threonine 258 and serine 259 motif in amphetamine‐induced norepinephrine transporter endocytosis

• DOI: 10.1111/j.1471-4159.2010.06898.x
• Publication Date: 2010-07-08T20:26:49Z
• Authors: Balasubramaniam A...; Padmanabhan Manna...; Obulakshmi Arapul...; Sammanda Ramamoorthy; Lankupalle D. Jay...
• Keywords: Norepinephrine transporter

D-amphetamine (AMPH) down-regulates the norepinephrine transporter (NET), although exact trafficking pathways altered and motifs involved are not known. Therefore, we examined cellular molecular mechanisms in AMPH-induced NET regulation human placental trophoblast cells expressing wild-type (WT)-hNET hNET double mutant (DM)-bearing protein kinase C (PKC)-resistant T258A + S259A motif. function surface expression were significantly reduced WT-hNET but hNET-DM following AMPH treatment. inhibited plasma membrane recycling of both hNET-DM. In contrast, stimulated endocytosis WT-hNET, did affect endocytosis. Although PKC or calcium/calmodulin- dependent kinase-II (CaMKII) inhibition depletion calcium failed to block AMPH-mediated down-regulation NET-specific blocker desipramine completely prevented down-regulation. Furthermore, treatment had no effect on phospho-CaMKII immunoreactivity. The inhibitory potency was highest hNET-DM, intermediary single mutants lowest WT-hNET. Single exhibited partial resistance accumulation similar results demonstrate that insertion enhanced account for down-regulation, provide first evidence T258/S259 motif is only desipramine-sensitive, CaMKII independent.