Fig. 7.

Meprins degrade actin present in kidney proteins. I: Western blots of actin in kidney proteins. Cytosolic-enriched proteins (90 μg) from meprin αβ double KO mice were incubated with 40 nM activated homomeric meprin A or meprin B for 0–4 h. II: cytosolic-enriched kidney proteins from meprin αβ double KO mice were incubated with 40 nM of either meprin A or meprin B for 4 h. The following control reactions were included: Tris buffer (lane 1), activated meprins (lane 2), latent meprins (lane 3), active meprins preincubated with 20 mM EDTA for 1 h (lane 4), and meprin activation buffer processed with trypsin (lane 5). The actin band was only degraded in reactions with activated meprins and was blocked by the meprin inhibitor EDTA.