Syntaxin 1A regulates dopamine transporter activity, phosphorylation and surface expression.
We investigated the functional relationship between the soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) protein syntaxin 1A (syn 1A) and the dopamine transporter (DAT) by treating rat striatal tissue with Botulinum Neurotoxin C (BoNT/C) and co-transfecting syn 1A with DAT in non-neuronal cells, followed by analysis of DAT activity, phosphorylation, and regulation. Treatment of striatal slices with BoNT/C resulted in elevated dopamine (DA) transport Vmax and reduced DAT phosphorylation, while heterologous co-expression of syn 1A led to reduction in DAT surface expression and transport Vmax. Syn 1A was present in DAT immunoprecipitation complexes, supporting a direct or indirect interaction between the proteins. Phorbol ester regulation of DA transport activity was retained in BoNT/C-treated synaptosomes and syn 1A transfected cells, demonstrating that protein kinase C (PKC) and syn 1A effects occur through independent processes. These findings reveal a novel mechanism for regulation of DAT activity and phosphorylation, and suggest the potential for syn 1A to impact DA neurotransmission through effects on reuptake.
Cervinski
M A
MA
Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
Foster
J D
JD
Vaughan
R A
RA
D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D018374:LLC-PK1 Cells; D008297:Male; D010703:Phorbol Esters / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects*; D021381:Protein Transport / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020239:Receptor Cross-Talk / Q000187:drug effects*; D013552:Swine; D013574:Synaptosomes / Q000378:metabolism; D050827:Syntaxin 1 / Q000378:metabolism*; D014162:Transfection / Q000379:methods
D050483:Dopamine Plasma Membrane Transport Proteins; D010703:Phorbol Esters; C494213:Stx1a protein, rat; D050827:Syntaxin 1; D001905:Botulinum Toxins; C096324:botulinum toxin type C