FIG. 8.

Cleavage of plectin precedes cleavage of CK18, lamin B, and gelsolin during CD95-mediated apoptosis. (A) MCF7-Fas cells were stimulated with anti-CD95 (2 μg/ml) for the indicated time periods or treated with 20 μM zVAD-fmk prior to addition of 2 μg of anti-CD95 per ml. The corresponding IF preparations were analyzed by Western blotting using the anti-plectin-C antiserum. (B to D) Cells were treated as for panel A, but Triton X-100 cell lysates were prepared (see Materials and Methods). Western blots were developed with anti-CK 8 (B), anti-CK 18 (C), or anti-lamin B (D) antibody. (E to F) Jurkat T cells were stimulated with anti-CD95 (2 μg/ml) for the indicated time periods. Plectin IF preparations (E) or Triton X-100 cell lysates (F) were analyzed for plectin or gelsolin. Migration positions of the full-length proteins are indicated by filled arrowheads; migration positions of the cleavage products are marked by open arrowheads. Molecular masses of the cleavage products: plectin, 200 kDa; CK18, 28 kDa; lamin B, 28 and 21 kDa; gelsolin, 48 kDa.