title: PICK1 interacts with and regulates PKC phosphorylation of mGLUR7.
abstract: The G-protein-coupled metabotropic glutamate receptor subtype 7a (mGluR7a) is a member of group III metabotropic glutamate receptors that plays an important role as a presynaptic receptor in regulating transmitter release at glutamatergic synapses. Here we report that the protein interacting with C-kinase (PICK1) binds to the C terminus (ct) of mGluR7a. In the yeast two-hybrid system, the extreme ct of mGluR7a was shown to interact with the PSD-95/Discs large/ZO-1 (PDZ) domain of PICK1. Pull-down assays indicated that PICK1 was retained by a glutathione S-transferase fusion of ct-mGluR7a. Furthermore, recombinant and native PICK1/mGluR7a complexes were coimmunoprecipitated from COS-7 cells and rat brain tissue, respectively. Confocal microscopy showed that both PICK1 and mGluR7a displayed synaptic colocalization in cultured hippocampal neurons. PICK1 has previously been shown to bind protein kinase C alpha-subunit (PKCalpha), and mGluR7a is known to be phosphorylated by PKC. We show a relationship between these three proteins using recombinant PICK1, mGluR7, and PKCalpha, where they were co-immunoprecipitated as a complex from COS-7 cells. In addition, PICK1 caused a reduction in PKCalpha-evoked phosphorylation of mGluR7a in in vitro phosphorylation assays. These results suggest a role for PICK1 in modulating PKCalpha-evoked phosphorylation of mGluR7a.
authors.affiliation: Department of Biological Sciences, Kyoto University, Faculty of Medicine, Kyoto, 606-8501, Japan.
authors.forename: K K
authors.initials: KK
authors.lastname: Dev
authors.forename: Y
authors.initials: Y
authors.lastname: Nakajima
authors.forename: J
authors.initials: J
authors.lastname: Kitano
authors.forename: S P
authors.initials: SP
authors.lastname: Braithwaite
authors.forename: J M
authors.initials: JM
authors.lastname: Henley
authors.forename: S
authors.initials: S
authors.lastname: Nakanishi
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins; D005982:Glutathione Transferase / Q000235:genetics; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding / Q000235:genetics; D020033:Protein Isoforms / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D017434:Protein Structure, Tertiary; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D007527:Isoenzymes; D009687:Nuclear Proteins; C498298:PICK1 protein, rat; D020033:Protein Isoforms; D018094:Receptors, Metabotropic Glutamate; D011993:Recombinant Fusion Proteins; C102719:metabotropic glutamate receptor 7; D005982:Glutathione Transferase; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha