Serotonin transporter (SERT) is responsible for lowering serotonin (5-HT) levels in the vicinity of synapses that release this neurotransmitter. In this process, 5-HT is transported into the cell from which it was released, where it is available for repackaging into synaptic vesicles. Drugs that inhibit SERT increase the level of synaptic 5-HT and lengthen the duration of its action. These drugs include abused substances such as cocaine, and therapeutic drugs such as antidepressants. Some drugs that are substrates for SERT, such as 3,4-methylenedioxymethamphetamine (a.k.a. """"""""ecstasy""""""""), act through SERT to release 5-HT from neurons. From the profound behavioral consequences of these drugs, it is clear that regulation of SERT activity is likely to be a key event in normal brain physiology. An important new tool in understanding SERT regulation is a mutant form of the transporter found in patients with obsessive-compulsive disorder. This mutant is apparently activated in a constitutive fashion by a pathway normally involving cyclic GMP (cGMP). As part of the long-term goal to understand the structure and function of neurotransmitter transporters, this proposal outlines plans to investigate the activation of SERT by cGMP and the way that this process is disrupted in the mutant. The studies will approach these issues in three ways: 1) One approach will be to determine the pathway by which cGMP activates SERT. 2) The structural and mechanistic features of SERT that participate in the activation will be investigated. 3) The proposal also explores the nature of the SERT mutation to determine how it leads to constitutive activation of transport activity. If successful, this plan will identify the specific cGMP-dependent protein kinase responsible for SERT activation and will determine if the phosphorylation site is on SERT or another protein. The mechanism of activation through modification of SERT structure and conformation will also be investigated. The effect of environmental and behavioral influences on modification of SERT will be examined. All of these studies are directed to testing the hypothesis that production of cGMP activates a protein kinase that phosphorylates SERT with the consequent increase in turnover rate and ligand affinity. This hypothesis also predicts that the mutant form of SERT is defective as a substrate for a protein phosphatase.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA008213-12
Application #
7009916
Study Section
Molecular, Cellular and Developmental Neurosciences 2 (MDCN)
Program Officer
Pilotte, Nancy S
Project Start
1993-05-01
Project End
2009-01-31
Budget Start
2006-02-01
Budget End
2007-01-31
Support Year
12
Fiscal Year
2006
Total Cost
$279,400
Indirect Cost
Name
Yale University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Zhang, Yuan-Wei; Tavoulari, Sotiria; Sinning, Steffen et al. (2018) Structural elements required for coupling ion and substrate transport in the neurotransmitter transporter homolog LeuT. Proc Natl Acad Sci U S A 115:E8854-E8862
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
Zhang, Yuan-Wei; Turk, Benjamin E; Rudnick, Gary (2016) Control of serotonin transporter phosphorylation by conformational state. Proc Natl Acad Sci U S A 113:E2776-83
Tavoulari, Sotiria; Margheritis, Eleonora; Nagarajan, Anu et al. (2016) Two Na+ Sites Control Conformational Change in a Neurotransmitter Transporter Homolog. J Biol Chem 291:1456-71
Fenollar-Ferrer, Cristina; Stockner, Thomas; Schwarz, Thomas C et al. (2014) Structure and regulatory interactions of the cytoplasmic terminal domains of serotonin transporter. Biochemistry 53:5444-60
Rudnick, Gary; Krämer, Reinhard; Blakely, Randy D et al. (2014) The SLC6 transporters: perspectives on structure, functions, regulation, and models for transporter dysfunction. Pflugers Arch 466:25-42
Porton, B; Greenberg, B D; Askland, K et al. (2013) Isoforms of the neuronal glutamate transporter gene, SLC1A1/EAAC1, negatively modulate glutamate uptake: relevance to obsessive-compulsive disorder. Transl Psychiatry 3:e259
Rudnick, Gary (2013) How do transporters couple solute movements? Mol Membr Biol 30:355-9
Bulling, Simon; Schicker, Klaus; Zhang, Yuan-Wei et al. (2012) The mechanistic basis for noncompetitive ibogaine inhibition of serotonin and dopamine transporters. J Biol Chem 287:18524-34
Wong, Albert; Zhang, Yuan-Wei; Jeschke, Grace R et al. (2012) Cyclic GMP-dependent stimulation of serotonin transport does not involve direct transporter phosphorylation by cGMP-dependent protein kinase. J Biol Chem 287:36051-8

Showing the most recent 10 out of 25 publications