The larval fat body has distinct apical and basal BMs. (A–A″) Transmission electron microscopy images at different magnifications of WT larval fat body showing the BM (black arrowheads) near the cell surface on opposite sides of the tissue. Note the presence of microridge protrusions at the cell surface (A″). (B–F′) Confocal images of Viking-GFP–expressing (B), Dystroglycan-GFP–expressing (C), Laminin B1-GFP–expressing (D), Trol (Perlecan)-GFP–expressing (E), or Nidogen-GFP–expressing (F) larval fat body (side a [top] and b [bottom], lateral view, blue arrowheads pointing at cell surface). Quantification of mean intensity of Viking-GFP (B′), Dystroglycan-GFP (C′), Laminin B1-GFP (D′), Trol-GFP (E′), or Nidogen-GFP (F′) on surfaces on side a and b (mean intensities from several ROIs, data paired by tissue; n: six tissues, three surface ROIs per side). Unpaired two-sided t test, ****P < 0.0001, ns P > 0.05. (G–G″) Confocal images of CAAX-GFP–expressing larval fat body immunostained for Mys. (G, side a [top] and b [bottom], lateral view, blue and orange arrowheads pointing at cell surface or lateral domain, respectively). Quantification of mean intensity of Mys on surfaces (‘, yellow) or lateral domain (‘’, orange) on sides a and b (mean of mean intensities from several ROIs, data paired by tissue; n: 10 tissues, 6 surface ROIs [G′] or 10 lateral ROIs [G″] per side). Paired two-sided t test, ****P < 0.0001. Scale bars: 50 µm (A), 2 µm (A′), 500 nm (A″), and 20 µm (B–G).