Proteolytic degradation of IκBα and p105 in plasmin-stimulated monocytes.

(A,B) Kinetic study. Cells were either unstimulated (control) or treated with LPS 1 μg/mL (positive control) or plasmin 0.43 CTA U/mL for the times indicated. (C) Detailed time- and concentration-dependent effects of plasmin from 0.043 to 0.43 CTA U/mL on p105 degradation. Cell extracts were prepared and used for immunoblots with specific anti-IκBα (A) and anti-p50 (B,C) antibodies. Because p105 contains the complete sequence of p50, it is also recognized by anti-p50 antibodies. Positions of IκBα (37 kd), p105 and p50 (105 kd and 50 kd, respectively) are indicated. In each case, a representative blot of 3 independent experiments is shown.