Figure 5

Vps34 deletion in PTCs disrupts the Rab11-labeled, apical recycling endosomal compartment. Kidney sections from WT and Vps34^∆/∆ P14 pups were double-immunolabeled for megalin (red) and Rab11 (green). Broken white lines delineate PTC contours. The pair of radial broken yellow lines defines in the upper field unusual PTCs with normal appearance in Vps34^∆/∆ mice, attributed to mosaicism (notice preservation of continuous megalin layer without dotty cytoplasmic redistribution, contrasting to other PTCs of the same tubule). Boxed rectangles are enlarged below. In WT PTCs, Rab11 antibodies produce a specific finely dotty apical signal in the most apical half of the continuous megalin layer (Lu, PTC lumen), labelling the apical, rapidly recycling endosomal compartment. In Vps34^∆/∆ PTCs showing megalin mislocalization into deep cytoplasmic dots (lower cells, best visible below the yellow broken line in the enlargements), the Rab11 signal is not detectable, indicating disruption of the apical recycling endosomal compartment.