Hypoxia Associated Proteolytic Processing of OS-9 by the Metalloproteinase Meprin β

Figure 1

Immunoblot of OS-9 in kidney proteins. Meprin B degrades OS-9 present in kidney proteins. Kidney proteins were fractionated by differential centrifugation into BBM- and cytosolic-enriched fractions. Portions of the kidney tissue were homogenized in RIPA buffer to obtain nonfractionated total kidney proteins. 60 μg proteins from each fraction were loaded onto 10% gels and analyzed by Western blot analysis. (a) OS-9 was detected in total kidney proteins and cytosolic-enriched protein fraction, but not in BBM-enriched protein fractions. (b) Cytosolic-enriched kidney proteins were incubated with Tris buffer without meprins (lane 1), activated meprin B (lane 2), or activated homomeric meprin A (lane 3). Degradation of OS-9 was observed in reactions with activated meprin B, but not meprin A or Tris buffer without meprins.

(a)

(b)