SNX31 co-localizes with uroplakins in the multivesicular bodies of mouse umbrella cells.

<p>(<b>A</b>) TEM of normal mouse umbrella cells showing apical plaques (P), fusiform vesicles (FV), multivesicular vesicles (MVB) and lysosomes (Lys). (<b>B–E</b>) EM localization of uroplakin IIIa using a monoclonal antibody AU1 (B and C: Lowicryl procedure; D and E: cryoEM). Note in (B) the uroplakin staining of apical plaques, fusiform vesicles, and multivesicular bodies (MVBs), in (C) and D) the presence of uroplakin not only at the limiting membranes (thick arrows), but also the intra-luminal vesicles (thin arrows), and in (E) the uroplakin association with some MVB invaginations. (<b>F</b>) EM localization of SNX31. Note the detection of SNX31 in both the limiting membranes (thick arrows) and the intra-luminal vesicles (thin arrows), but not in the neighboring fusiform vesicles. (<b>G</b>) <b>Double-labeling of UPIIIa</b> (10-nm immunogold particles; open arrows) <b>and SNX31</b> (5-nm; filled arrows). Note their co-localization at the limiting membranes of MVB. Scale bar = 1 µm (in panel A), or 0.2 µm (all others).