An intracellular interaction network regulates conformational transitions in the dopamine transporter.
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An intracellular interaction network regulates conformational transitions in the dopamine transporter. / Kniazeff, Julie; Shi, Lei; Løland, Claus Juul; Javitch, Jonathan A; Weinstein, Harel; Gether, Ulrik.
In: Journal of Biological Chemistry, Vol. 283, No. 25, 2008, p. 17691-701.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - An intracellular interaction network regulates conformational transitions in the dopamine transporter.
AU - Kniazeff, Julie
AU - Shi, Lei
AU - Løland, Claus Juul
AU - Javitch, Jonathan A
AU - Weinstein, Harel
AU - Gether, Ulrik
N1 - Keywords: Amino Acid Sequence; Animals; COS Cells; Cercopithecus aethiops; Cytoplasm; Dopamine Plasma Membrane Transport Proteins; Gene Expression Regulation; Humans; Models, Biological; Molecular Sequence Data; Mutagenesis, Site-Directed; Neurotransmitter Agents; Protein Conformation; Sequence Homology, Amino Acid; Sodium
PY - 2008
Y1 - 2008
N2 - Neurotransmitter:sodium symporters (NSS)(1) mediate sodium-dependent reuptake of neurotransmitters from the synaptic cleft and are targets for many psychoactive drugs. The crystal structure of the prokaryotic NSS protein, LeuT, was recently solved at high resolution; however, the mechanistic details of regulation of the permeation pathway in this class of proteins remain unknown. Here we combine computational modeling and experimental probing in the dopamine transporter (DAT) to demonstrate the functional importance of a conserved intracellular interaction network. Our data suggest that a salt bridge between Arg-60 in the N terminus close to the cytoplasmic end of transmembrane segment (TM) 1 and Asp-436 at the cytoplasmic end of TM8 is stabilized by a cation-pi interaction between Arg-60 and Tyr-335 at the cytoplasmic end of TM6. Computational probing illustrates how the interactions may determine the flexibility of the permeation pathway, and mutagenesis within the network and results from assays of transport, as well as the state-dependent accessibility of a substituted cysteine in TM3, support the role of this network in regulating access between the substrate binding site and the intracellular milieu. The mechanism that emerges from these findings may be unique to the NSS family, where the local disruption of ionic interactions modulates the transition of the transporter between the outward- and inward-facing conformations.
AB - Neurotransmitter:sodium symporters (NSS)(1) mediate sodium-dependent reuptake of neurotransmitters from the synaptic cleft and are targets for many psychoactive drugs. The crystal structure of the prokaryotic NSS protein, LeuT, was recently solved at high resolution; however, the mechanistic details of regulation of the permeation pathway in this class of proteins remain unknown. Here we combine computational modeling and experimental probing in the dopamine transporter (DAT) to demonstrate the functional importance of a conserved intracellular interaction network. Our data suggest that a salt bridge between Arg-60 in the N terminus close to the cytoplasmic end of transmembrane segment (TM) 1 and Asp-436 at the cytoplasmic end of TM8 is stabilized by a cation-pi interaction between Arg-60 and Tyr-335 at the cytoplasmic end of TM6. Computational probing illustrates how the interactions may determine the flexibility of the permeation pathway, and mutagenesis within the network and results from assays of transport, as well as the state-dependent accessibility of a substituted cysteine in TM3, support the role of this network in regulating access between the substrate binding site and the intracellular milieu. The mechanism that emerges from these findings may be unique to the NSS family, where the local disruption of ionic interactions modulates the transition of the transporter between the outward- and inward-facing conformations.
U2 - 10.1074/jbc.M800475200
DO - 10.1074/jbc.M800475200
M3 - Journal article
C2 - 18426798
VL - 283
SP - 17691
EP - 17701
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 25
ER -
ID: 5772558