Fig. 2
Fluorescence detection of lipid droplets and mitochondria at the extremities of melanoma cells. A-F Native FEMX-I cells (A-E) or COX-8-mCherry-transfected cells (F) growing either on poly-L-lysine (A) or fibronectin-coated (B-F) supports were processed for CLSM (A, C-F) or live-cell phase-contrast/fluorescence video microscopy (B). PFA-fixed and saponin-permeabilized cells were immunolabeled with an anti-adipophilin (A, F) or anti-60-kDa mitochondrial antigen (E) antibody and/or stained with fluorescent dyes BODIPYâ„¢ 493/503 (A, D, E) or LipidSpotâ„¢ 610 (B, C). Alternatively, cells were co-stained with MitoTrackerâ„¢ Red CMXRos (C) or MitoViewâ„¢ Fix 640 (D). Cells were counterstained with DAPI (A, C, blue) or fluorescence-conjugated WGA (C, F) to highlight nuclei and glycoconjugates at the cell membrane, respectively. LipidSpot-stained cells were observed alive and elapsed time in minutes is shown on the top-right corner (B). Samples were pseudo-colored with a given marker as indicated. The images presented in panel B are excerpted from the Additional file 2: Video S1. Asterisks indicate the enrichment of lipid droplets at the cell extremities (A, B), while the symbol @ shows a cell changing from a bipolar to a tripolar morphology over time (B). The arrow points to a small EV containing lipid droplets (A). DIC, differential interference contrast. Scale bars are indicated