The long-term objective of this project is to elucidate mechanisms supporting acute modulation of the norepinephrine (NE) transporter (NET) as established by coordinated trafficking and intrinsic activity modulation. NE signaling at PNS and CNS noradrenergic synapses regulates a variety of physiological functions including attention, motivation, vasoconstriction and heart rate. The NET dictates the magnitude and duration of NE signaling. For decades, the main focus on NET has been as a target for antidepressant and psychostimulant (e.g. amphetamine (AMPH), cocaine, and methylphenidate (Ritalin)) action. Our recent findings indicate that the stability of NET protein-protein associations, including interactions with syntaxin (SYN) 1A and protein phosphatase 2A (PP2A), dictate NET cell surface distribution and NET intrinsic activities, including transport rates, NET-gated currents and efflux potential. This renewal application unites two laboratories at the forefront of neurotransmitter transporter research, linking methods in biochemistry and molecular biology with real-time imaging and biophysical approaches, and includes studies on neuronal cell lines expressing NET and NET mutants as well as an evaluation of native noradrenergic neurons. We focus our efforts on three distinct, but coordinated, aspects of modulated NET behavior: the exocytosis of NET proteins, the endocytosis of NET proteins and the modulation of NET associated ion/substrate flux properties.
Our specific aims are to: 1) Determine whether activity-dependent changes in NET surface density reflect increased insertion of cytoplasmic transporters or reduced transporter endocytosis (or both) and define the sites supporting SYN 1A/PP2Ac associations and their functional consequences with respect to NET localization and surface insertion; 2) Elucidate structural and signaling determinants of NET endocytic trafficking as triggered by GPCRs and AMPH; and 3) Determine relationships between NET/associated proteins/Ca2+ and AMPH-triggered NE efflux. Our overall goal then is to develop a more sophisticated understanding of the nature of acute NET regulation and to determine how the formation/dissolution of NET protein complexes promotes the coordination of NE clearance with NE release and clarifies intrinsic mechanisms by which psychostimulants impact NET mediated ion and NE flux.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
2R01MH058921-11A1
Application #
6870669
Study Section
Neurotransporters, Receptors, and Calcium Signaling Study Section (NTRC)
Program Officer
Desmond, Nancy L
Project Start
2004-09-30
Project End
2009-06-30
Budget Start
2004-09-30
Budget End
2005-06-30
Support Year
11
Fiscal Year
2004
Total Cost
$339,750
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Physiology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Sung, Uhna; Binda, Francesca; Savchenko, Valentina et al. (2017) Ca2+ dependent surface trafficking of norepinephrine transporters depends on threonine 30 and Ca2+ calmodulin kinases. J Chem Neuroanat 83-84:19-35
Erickson, Susan L; Gandhi, Anjalika R; Asafu-Adjei, Josephine K et al. (2011) Chronic desipramine treatment alters tyrosine hydroxylase but not norepinephrine transporter immunoreactivity in norepinephrine axons in the rat prefrontal cortex. Int J Neuropsychopharmacol 14:1219-32
Robertson, Sabrina D; Matthies, Heinrich J G; Owens, W Anthony et al. (2010) Insulin reveals Akt signaling as a novel regulator of norepinephrine transporter trafficking and norepinephrine homeostasis. J Neurosci 30:11305-16
Bowton, Erica; Saunders, Christine; Erreger, Kevin et al. (2010) Dysregulation of dopamine transporters via dopamine D2 autoreceptors triggers anomalous dopamine efflux associated with attention-deficit hyperactivity disorder. J Neurosci 30:6048-57
Siuta, Michael A; Robertson, Sabrina D; Kocalis, Heidi et al. (2010) Dysregulation of the norepinephrine transporter sustains cortical hypodopaminergia and schizophrenia-like behaviors in neuronal rictor null mice. PLoS Biol 8:e1000393
Matthies, Heinrich J G; Han, Qiao; Shields, Angela et al. (2009) Subcellular localization of the antidepressant-sensitive norepinephrine transporter. BMC Neurosci 10:65
Steiner, Jennifer A; Carneiro, Ana Marin D; Wright, Jane et al. (2009) cGMP-dependent protein kinase Ialpha associates with the antidepressant-sensitive serotonin transporter and dictates rapid modulation of serotonin uptake. Mol Brain 2:26
Robertson, S D; Matthies, H J G; Galli, A (2009) A closer look at amphetamine-induced reverse transport and trafficking of the dopamine and norepinephrine transporters. Mol Neurobiol 39:73-80
Lute, Brandon J; Khoshbouei, Habibeh; Saunders, Christine et al. (2008) PI3K signaling supports amphetamine-induced dopamine efflux. Biochem Biophys Res Commun 372:656-61
Binda, Francesca; Dipace, Concetta; Bowton, Erica et al. (2008) Syntaxin 1A interaction with the dopamine transporter promotes amphetamine-induced dopamine efflux. Mol Pharmacol 74:1101-8

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