Interaction between the glutamate transporter GLT1b and the synaptic PDZ domain protein PICK1

TY - JOUR

T1 - Interaction between the glutamate transporter GLT1b and the synaptic PDZ domain protein PICK1

AU - Bassan, Merav

AU - Liu, Hongguang

AU - Madsen, Kenneth L

AU - Armsen, Wencke

AU - Zhou, Jiayi

AU - Desilva, Tara

AU - Chen, Weizhi

AU - Paradise, Allison

AU - Brasch, Michael A

AU - Staudinger, Jeff

AU - Gether, Ulrik

AU - Irwin, Nina

AU - Rosenberg, Paul A

N1 - Keywords: Alanine; Animals; Biotinylation; Brain; Carrier Proteins; Cells, Cultured; Cercopithecus aethiops; Embryo, Mammalian; Excitatory Amino Acid Transporter 2; Glutamic Acid; Immunoprecipitation; Mutation; Neurons; Nuclear Proteins; PDZ Domains; Protein Structure, Tertiary; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; Tetradecanoylphorbol Acetate

PY - 2008

Y1 - 2008

N2 - Synaptic plasticity is implemented by the interaction of glutamate receptors with PDZ domain proteins. Glutamate transporters provide the only known mechanism of clearance of glutamate from excitatory synapses, and GLT1 is the major glutamate transporter. We show here that GLT1 interacts with the PDZ domain protein PICK1, which plays a critical role in regulating the expression of glutamate receptors at excitatory synapses. A yeast two-hybrid screen of a neuronal library using the carboxyl tail of GLT1b yielded clones expressing PICK1. The GLT1b C-terminal peptide bound to PICK1 with high affinity (K(i) = 6.5 +/- 0.4 microM) in an in vitro fluorescence polarization assay. We also tested peptides based on other variants of GLT1 and other glutamate transporters. GLT1b co-immunoprecipitated with PICK1 from rat brain lysates and COS7 cell lysates derived from cells transfected with plasmids expressing PICK1 and GLT1b. In addition, expression of GLT1b in COS7 cells changed the distribution of PICK1, bringing it to the surface. GLT1b and PICK1 co-localized with each other and with synaptic markers in hippocampal neurons in culture. Phorbol ester, an activator of protein kinase C (PKC), a known PICK1 interactor, had no effect on glutamate transport in rat forebrain neurons in culture. However, we found that exposure of neurons to a myristolated decoy peptide with sequence identical to the C-terminal sequence of GLT1b designed to block the PICK1-GLT1b interaction rendered glutamate transport into neurons responsive to phorbol ester. These results suggest that the PICK1-GLT1b interaction regulates the modulation of GLT1 function by PKC.

AB - Synaptic plasticity is implemented by the interaction of glutamate receptors with PDZ domain proteins. Glutamate transporters provide the only known mechanism of clearance of glutamate from excitatory synapses, and GLT1 is the major glutamate transporter. We show here that GLT1 interacts with the PDZ domain protein PICK1, which plays a critical role in regulating the expression of glutamate receptors at excitatory synapses. A yeast two-hybrid screen of a neuronal library using the carboxyl tail of GLT1b yielded clones expressing PICK1. The GLT1b C-terminal peptide bound to PICK1 with high affinity (K(i) = 6.5 +/- 0.4 microM) in an in vitro fluorescence polarization assay. We also tested peptides based on other variants of GLT1 and other glutamate transporters. GLT1b co-immunoprecipitated with PICK1 from rat brain lysates and COS7 cell lysates derived from cells transfected with plasmids expressing PICK1 and GLT1b. In addition, expression of GLT1b in COS7 cells changed the distribution of PICK1, bringing it to the surface. GLT1b and PICK1 co-localized with each other and with synaptic markers in hippocampal neurons in culture. Phorbol ester, an activator of protein kinase C (PKC), a known PICK1 interactor, had no effect on glutamate transport in rat forebrain neurons in culture. However, we found that exposure of neurons to a myristolated decoy peptide with sequence identical to the C-terminal sequence of GLT1b designed to block the PICK1-GLT1b interaction rendered glutamate transport into neurons responsive to phorbol ester. These results suggest that the PICK1-GLT1b interaction regulates the modulation of GLT1 function by PKC.

U2 - 10.1111/j.1460-9568.2007.05986.x

DO - 10.1111/j.1460-9568.2007.05986.x

M3 - Journal article

C2 - 18184314

SN - 0953-816X

VL - 27

SP - 66

EP - 82

JO - European Journal of Neuroscience

JF - European Journal of Neuroscience

IS - 1

ER -