The larval fat body tissue exhibits apical-basal cell polarity. (A) Schematic of wandering third instar larva (dorsal view and cross section on left) showing location of fat body (orange, sides a and b of fat body shown in cross section) in relation to brain (green), digestive system (blue), muscle (dark red), and epidermis (pink). Schematic and confocal images of CAAX-GFP–expressing fat body in planar view and lateral view (imaged from both sides, showing yellow surface ROIs and orange lateral ROIs used for intensity quantifications). (B–F″) Confocal images of CAAX-GFP–expressing (B–E) or Lgl-GFP–expressing (F) larval fat body immunostained for aPKC (B), Par-6 (C), Crumbs (D), and Dlg (E; imaged from side a [top] and b [bottom], shown in lateral view, with blue and orange arrowheads pointing at cell surfaces or lateral domains, respectively). Quantification of mean intensities of aPKC (B′ and B″), Par-6 (C′ and C″), Crumbs (D′ and D″), Dlg (E′ and E″), and Lgl-GFP (F′ and F″) on surface ROIs (‘, yellow background) or lateral ROIs (‘‘, orange background) on sides a and b (mean of mean intensities from several ROIs at the surface or lateral domain of the same tissue, data paired by tissue; n: 10 tissues, 3 surface or lateral ROIs per side [B′–E′ and B″–E″] and n: six tissues, two surface or lateral ROIs per side [F′ and F″]). Paired two-sided t test, ****P < 0.0001, ns P > 0.05. Scale bars: 50 µm (A—planar view image), 20 µm (A—lateral view image and B–F).