Journal: eLife
Article Title: Clathrin-independent endocytosis and retrograde transport in cancer cells tune immune synapse organization and CD8 T cell response
doi: 10.7554/eLife.105821
Figure Lengend Snippet: ( A ) Confocal images of GalT-GFP-SNAP (green) and TMR-Star (red) in LB33-MEL cells stably expressing the Golgi-resident GFP-fused SNAP-tag construct (LB33-MEL GalT-GFP-SNAP). Actin (phalloidin, white) and nuclei (DAPI, blue) were also stained. The fluorescence intensity profile was made along the dashed line region in the enlarged cropped area and shows the colocalization of both signals. Scale bar: 20 μm. ( B ) Confocal images of GalT-GFP-SNAP (green) and TGN46 (red) in LB33-MEL GalT-GFP-SNAP cells. Nuclei (DAPI, blue) were also stained. The fluorescence intensity profile was made along the dashed line region in enlarged cropped area and shows the colocalization of both signals, indicating that GalT-GFP-SNAP is correctly localized at the TGN . Scale bar: 10 μm. ( C ) Quantifications of the immunoblots shown in (IB: anti-VPS35 and anti-VPS26A) confirm depletion efficiency of VPS35 and VPS26A in HeLa GalT-GFP-SNAP cells. ( D ) Retrograde transport of ICAM-1. Continuous BG-labeled anti-ICAM1 antibody uptake for 4 h at 37°C in LB33-MEL GalT-GFP-SNAP cells. Western blot analysis of LB33-MEL GalT-GFP-SNAP cells transfected with siRNAs: negative control (siCtrl) or against retromer subunits (siVPS35 and siVPS26A). Immunodetection with anti-SNAP, anti-VPS35, anti-VPS26A, and anti-α-Tubulin (loading control) antibodies. Quantification of the covalent IgG-SNAP complex is shown as fractions of siCtrl condition (histogram). Quantification of VPS35 and VPS26A depletion is shown in ( E ). ( E ) Quantifications of the immunoblots shown in ( D ) confirm depletion efficiency of VPS35 and VPS26A in LB33-MEL GalT-GFP-SNAP cells. ( F ) Retrograde transport of ALCAM. Continuous BG-labeled anti-ALCAM antibody uptake for 4 h at 37°C in HeLa GalT-GFP-SNAP cells. Western blot analysis of HeLa GalT-GFP-SNAP cells transfected for 72 h with siRNAs: negative control (siCtrl) or against Rab6 (siRab6). Immunodetection made with anti-SNAP, anti-Rab6, and anti-clathrin heavy chain (CHC, loading control) antibodies. Quantification of the covalent IgG-SNAP-GFP-GalT complex is shown as fractions of siCtrl condition (histogram). Quantification of Rab6 depletion is shown in ( G ). ( G ) Quantifications of the immunoblots shown in ( F ) confirm depletion efficiency of Rab6 in HeLa GalT-GFP-SNAP cells. ( H ) Quantifications of the immunoblots shown in (IB: anti-EndoA3) confirm depletion efficiency of EndoA3 in HeLa GalT-GFP-SNAP cells. ( I ) Retrograde transport of ALCAM. Continuous BG-labeled anti-ALCAM antibody uptake for 4 h at 37°C in LB33-MEL GalT-GFP-SNAP cells. Western blot analysis of LB33-MEL GalT-GFP-SNAP cells transfected (or not) with plasmids encoding free GFP (GFP+) or EndoA3-GFP (EndoA3+). Immunodetection with anti-SNAP, anti-EndoA3, and anti-α-Tubulin (loading control) antibodies. Quantification of the covalent IgG-SNAP-GFP-GalT complex is shown as fractions of the GFP +condition (histogram). Data information: In ( A, B ), images are from a single experiment. In ( C ), data are pooled from six independent experiments. In ( D–H ), data are pooled from three independent experiments. In ( I ), data are pooled from two independent experiments. Data are presented as mean ± SEM. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001. One-sample t test and Wilcoxon test. Figure 1—figure supplement 1—source data 1. Original files for western blot analyses displayed in . Figure 1—figure supplement 1—source data 2. PDF files containing original western blots for .
Article Snippet: First, anti-ALCAM (Bio-Rad, MCA1926) and anti-ICAM1 (Bio-Rad, MCA1615) antibodies were labeled with benzylguanine (BG) by incubating them overnight at 4°C with a threefold molar excess of BG-GLA-NHS reagent (New England Biolabs, S9151S; prepared in anhydrous DMSO).
Techniques: Stable Transfection, Expressing, Construct, Staining, Fluorescence, Western Blot, Labeling, Transfection, Negative Control, Immunodetection, Control