Fig. 6. Ultrastructural analysis of neuromuscular junctions (NMJ), myotendinous junctions (MTJ) and glomerular filtration barriers. (A-D) A control synapse (A) shows a Schwann cell (s) capping the vesicle-rich nerve terminal (nt) adjacent to the muscle (m) endplate containing numerous junctional folds (jf). In the Lamb2^-/- synapse (B), junctional folds are absent and the Schwann cell extends processes (arrow) between the nerve terminal and the muscle. Synaptic deposition of laminin ß2 in Lamb2^-/-; MCK-B2 mice restores synaptic architecture to normal (C). In Lamb2^-/-; NEPH-B2 mice, glomerular deposition of ß2 and prevention of proteinuria has no restorative effect on the synapse (D). (E-G) MTJ from a control (E) exhibits numerous infoldings of the muscle fiber (m) with continuous BMs. In the Lamb2^-/- MTJ (F), infoldings are less complex, and the BMs (arrows) appear fuzzy. MCK-B2 transgene-derived ß2 restores much of the normal MTJ architecture (G). (H-K) Glomerular capillary segment from a control (H) shows the interdigitated podocyte foot processes (fp) adjacent to the GBM. Effaced foot processes (efp) are evident in the Lamb2^-/- (I) and Lamb2^-/-; MCK-B2 (J) mice, which are proteinuric. Deposition of rat ß2 into the GBM in Lamb2^-/-; NEPH-B2 mice prevents proteinuria and foot process effacement (K). Scale bars in D and K are 1 µm for A-D and H-K, respectively; scale bar in G is 2 µm for E-G.