Journal: The Journal of Biological Chemistry
Article Title: A vital role for PICK1 in the differential regulation of metabotropic glutamate receptor internalization and synaptic AMPA receptor endocytosis
doi: 10.1016/j.jbc.2023.104837
Figure Lengend Snippet: PICK1 is specifically involved in the mGluR1-mediated signaling and mGluR1-mediated AMPAR endocytosis. A and B , Western blot ( A ) and quantitation of the western blots ( B ) showing that in control cells that were treated with the mGluR5 antagonist MTEP, application of 100 μM R,S-DHPG for 5 min led to the phosphorylation of MAP kinases. Furthermore, the receptors recycled to the cell surface in 2.5 h and also showed the ability to induce phosphorylation of MAP kinases on application of 100 μM R,S-DHPG for 5 min (N = 3). C and D , Western blot ( C ) and quantitation of the western blots ( D ) suggested that although in PICK1 knockdown cells, in presence of MTEP, initial application of 100 μM R,S-DHPG for 5 min led to the phosphorylation of MAP kinases, but application of 100 μM R,S-DHPG after 2.5 h did not increase the phosphorylation of MAP kinases (N = 3). E and F , representative images ( E ) and quantitation of the endocytosis index ( F ) suggested that in control cells (treated with MTEP), the receptors that recycled back to the cell surface in 2.5 h were able to induce the internalization of GluA1-containing receptors when they were stimulated with 100 μM R,S-DHPG for 5 min. Application of 100 μM R,S-DHPG did not cause endocytosis of GluA1-containing receptors when the mGluR1 recycling was inhibited with okadaic acid and FK-506 (N: control:: untreated = 30; DHPG = 32; 2.5 h untreated = 30; 2.5 h DHPG = 31; 2.5 h (OA + FK-506) untreated = 29; 2.5 h (OA + FK-506) DHPG = 29). G and H , representative images ( G ) and quantitation of the mGluR-mediated AMPAR endocytosis ( H ) showed that in shPICK1 transfected cells that were treated with mGluR5 antagonist MTEP, although initial application of 100 μM R,S-DHPG for 5 min led to the endocytosis of GluA1-containing receptors, application of 100 μM R,S-DHPG after 2.5 h did not induce the internalization of GluA1-containing receptors. Expectedly, in okadaic acid and FK-506–treated cells, 100 μM R,S-DHPG did not cause endocytosis of GluA1-containing receptors (N: shPICK1:: untreated = 31; DHPG = 32; 2.5 h untreated = 34; 2.5 h DHPG = 33; 2.5 h (OA + FK-506) untreated = 33; 2.5 h (OA + FK-506) DHPG = 32). Results are presented as means ± SD. Scale bar represents 10 μm. ∗∗∗ p < 0.001; ∗∗ p < 0.01; ∗ p < 0.05; n.s, p > 0.05. DHPG, 3, 5-dihydroxyphenylglycine; mGluR, metabotropic glutamate receptor; PICK1, protein interacting with C kinase 1; MTEP, (3-((2-methyl-1,3-thiazol-4-yl) ethynyl) pyridine).
Article Snippet: Anti-GluA1 rabbit polyclonal antibody was purchased from Millipore.
Techniques: Western Blot, Quantitation Assay, Control, Phospho-proteomics, Knockdown, Transfection