Journal: The Journal of Biological Chemistry
Article Title: Small GTPase Rab17 Regulates the Surface Expression of Kainate Receptors but Not α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors in Hippocampal Neurons via Dendritic Trafficking of Syntaxin-4 Protein *
doi: 10.1074/jbc.M114.550632
Figure Lengend Snippet: Rab17 is required for dendritic trafficking of endogenous Syntaxin-4. A, HEK293T cells were transfected with pFIV-Control ( lanes 1, 4, and 6 ), pFIV-shStx4-1 ( lanes 2, 5, and 7 ), or pFIV-shStx4-2 ( lane 3 ) together with pCMV-Myc-ratStx4 ( lanes 1–3 ), pCMV-Myc-Stx4 SR ( lanes 4 and 5 ), or pCMV-Myc-Stx-3 ( lanes 6 and 7 ). Two days after transfection, the cells were lysed and subjected to immunoblot analysis with anti-Myc antibody ( upper panel ) and anti-GAPDH antibody ( lower panel ). B, Neuro2A cells were transfected with pFIV-Control ( lane 1 ), pFIV-shStx4-1 ( lane 2 ), or pFIV-shStx4-2 ( lane 3 ). Two days after transfection the cells were lysed and subjected to immunoblot analysis with anti-Syntaxin-4 antibody ( upper panel ) and anti-GAPDH antibody ( lower panel ). C, quantification of endogenous Syntaxin-4 of control-shRNA, Stx4 -shRNA-1 and Stx4 -shRNA-2 as shown in B. A.U. , arbitrary units. **, p < 0.0025. D, representative images of Myc-Syntaxin-4-expressing neurons in the presence and absence of Stx4 -shRNA. At 8 DIV, rat hippocampal neurons were transfected with pCMV-Myc-ratStx4 together with pFIV-Control, pFIV-shStx4-1, or pFIV-shStx4-2, and at 11 DIV, the neurons were fixed. The neurons were stained by Myc ( red ). Bar, 10 μm. E, quantification of the Myc-Syntaxin-4 of control-shRNA-transfected neurons ( n = 10), Stx4 -shRNA-1-transfected neurons ( n = 10), and Stx4 -shRNA-2-transfected neurons ( n = 10) as shown in B. A.U. , arbitrary units. **, p < 0.0025. F, representative images of Myc-Syntaxin-4-expressing neurons stained by Syntaxin-4 antibody. At 8 DIV, rat hippocampal neurons were transfected with pCMV-Myc-Stx4, and at 11 DIV, the neurons were fixed. The neurons were stained by Myc ( green ), Syntaxin-4 ( black ), and MAP2 ( red ). Bar, 10 μm. G, representative images of endogenous Syntaxin-4 in the presence and absence of Stx4 -shRNA. At 8 DIV, rat hippocampal neurons were transfected with pFIV-Control and pFIV-shStx4-1, and at 11 DIV, the neurons were fixed. The neurons were stained by Syntaxin-4 ( black ) and MAP2 ( red ). Bar, 10 μm. H, quantification of endogenous Syntaxin-4 of control-shRNA-transfected neurons ( n = 10) and Stx4 -shRNA-1-transfected neurons ( n = 10) shown in G. A.U., arbitrary units. **, p < 0.0025. I, representative images of endogenous Syntaxin-4 in the Rab17 -shRNA-transfected neurons. At 8 DIV, mouse hippocampal neurons were transfected with pSilencer-CMV-EGFP-Control or pSilencer-CMV-EGFP-shRab17, and at 11 DIV, the neurons were fixed and subjected to immunocytochemistry with antibodies against Syntaxin-4 ( black ), GFP ( green ), and MAP2 ( red ). The arrows and arrowheads point to axons and dendrites, respectively. The lower three panels a–c are magnified views of the boxed areas in the top right panels. Bar, 10 μm. J, quantification of the proportion of endogenous Syntaxin-4 in the control neurons ( n = 10) and Rab17 -shRNA-transfected neurons ( n = 10) at the dendrites, shown in I . The rate of translocated level of Syntaxin-4 was calculated by dividing the dendrite Syntaxin-4 fluorescence intensity by the total Syntaxin-4 fluorescence intensity. *, p < 0.025.
Article Snippet: Commercially obtained antibodies were as follows: anti-c-Myc (9E10) mouse monoclonal antibody (Santa Cruz Biotechnology); anti-calcium/calmodulin-dependent protein kinase II α (6G9) mouse monoclonal antibody, anti-GAPDH (6C5) mouse monoclonal antibody, and anti-MAP2 chick polyclonal antibody (Millipore Corp.); anti-GFP (clones 7.1 and 13.1) mouse monoclonal antibody (Roche Applied Science); anti-Syntaxin-4 rabbit polyclonal antibody (Synaptic Systems); IRDye®680RD/800CW-conjugated anti-mouse/rabbit IgG donkey antibody (LI-COR Biotechnology); horseradish peroxidase (HRP)-conjugated anti-mouse antibody (Sigma); and Cy2/Cy3/Cy5 or Alexa Fluor® 488/594/647-conjugated anti-mouse/rabbit/chick/sheep IgG donkey antibody (Jackson ImmunoResearch).
Techniques: Transfection, Western Blot, shRNA, Expressing, Staining, Immunocytochemistry, Fluorescence