Table 1.
Proteolysis of some substrates in neural staurosporine-induced apoptosis
| Substrate | Function | Proteolytic fragments |
|---|---|---|
| Nuclear substrates | ||
| DNA topoisomerase I (Topo I) | Modification of DNA topology (Liu, 1989) | 100 → 70 kDa |
| Lamin B | Nuclear envelope formation; anchoring chromatin to nuclear matrix (Lazebnik et al., 1995) | 68 → 45 kDa |
| NuMA | Involved in nuclear structure and nuclear re-formation (Compton and Cleveland, 1994) | 210 → 160, 180 kDa |
| PARP | DNA repair; interaction with chromatin in the nuclear matrix (Lazebnik et al., 1994) | 110 → 85 kDa |
| U1–70 kDa | pre-mRNA splicing (Casciola-Rosen et al., 1994) | 70 → 40 kDa |
| PCNA | Proliferation-associated DNA replication (Bravo et al., 1987) | Not cleaved |
| Ku | DNA repair (Ajmani et al., 1995) | Not cleaved |
| Cytosolic substrates | ||
| Jo-1 | his tRNA synthetase (Casiano et al., 1996) | Not cleaved |
| rRNP | Ribosomal proteins P0,P1,P2 (Casiano et al., 1996) | Not cleaved |
| Fodrin | Cytoskeletal protein (Martin et al., 1995b) | 240 → 150, 120 kDa |
| Nuclear/cytosolic substrates | ||
| PKC-δ | Signal transduction; activated in apoptosis; blocked by Bcl-2 (Emoto et al., 1995) | 78 → 40 kDa |