Fig. 2. In vitro binding of type 1-fimbriated E. coli and FimH-FimC protein complex to mouse and bovine uroplakins. Purified bovine (A) and mouse (B) urothelial plaque proteins were resolved by SDS-PAGE and transferred to nitrocellulose membranes. Lane 1: coomassie blue staining showing the positions of uroplakins Ia, Ib, II and III; note the excellent resolution of the mouse 24 kDa uroplakin Ia and 29 kDa uroplakin Ib, in comparison with the poorly resolved bovine 27 kDa uroplakin Ia and 28 kDa uroplakin Ib. Lane 2: binding of biotinylated FimH-FimC to uroplakins; note the selective binding to mouse uroplakin Ia with no detectable binding to uroplakin Ib. Lane 3: same as in lane 2 but the binding was carried out in the presence of 1 mM -D-mannose; note the complete inhibition of the FimH-FimC binding to uroplakin Ia. Lane 4: same as in lane 2 but done in the presence of 1 mM galactose; note the lack of inhibition. Lane 5: binding of ³⁵S-labeled, type 1-piliated E. coli (strain SH48) to urothelial plaque proteins; note again the selective binding to mouse uroplakin Ia. Lane 6: binding of a similarly labeled, but nonfimbriated E. coli (strain P678) to urothelial proteins; note the complete lack of binding. Positions of uroplakins Ia, Ib, II and III are marked. MW: molecular weight standards.