Table 1.
Chromatin-releasing mitotic regulators.
| Protein | Interphase localization | Interphase function | Mitosis localization | Mitotic function | In vitro | RanGTP regulation |
|---|---|---|---|---|---|---|
| ISWI | Nucleus, chromatin (12, 14) | Unknown, no effect on chromatin decondensation and DNA replication (12, 14) | The spindle, enrichment on poles and chromosomes (15) | Spindle maintenance, RanGTP-dependent microtubule stabilization in anaphase (15); no effect on chromosome condensation and sister chromatid cohesion (12) | Chromatin-remodeling (44); RanGTP-dependent MAP, inhibited by importin α/β (15) | Yes (15) |
| Ino80 | Nucleus (45); chromatin (20) | Transcription (17–19); DNA repair (46); DNA replication (47) | Spindle microtubules (20) | Spindle assembly (20) | Chromatin-remodeling (48); MAP (21) | Not determined |
| Pontin/RuvBL1 | Nucleus, chromatin (49) | Transcription, DNA repair (50) | Spindle poles and microtubules (22, 49) | Spindle assembly, interact with γ-tubulin (22) | Chromatin-remodeling (48) | Not determined |
| Rae1/Gle2 | NPCs (27) | mRNA export through the NPC (27) | The spindle, enrichment on poles chromosomes (26) | Spindle assembly, functions as a rebonucleoprotein complex, RanGTP-dependent microtubule nucleation/stabilization (26) | MAP (26) | Yes (26) |
| Nup98 | NPCs (51) | NPC assembly, essential for assembling the permeability barrier (52) | The mitotic cytoplasm (53) | Spindle assembly, counteract MCAK (28) | Recombinant Nup98 forms the permeability barrier (52); MAP (28) | Not determined |
| Nup107-160 complex | NPCs (54, 55) | NPC assembly (54, 55) | Kinetochores and spindle microtubules (29, 30) | Spindle assembly in Xenopus egg extracts (30); γ-tubulin recruitment and microtubule nucleation at unattached kinetochores in human cells (31) | Immunoprecipitates from Xenopus egg extracts nucleate microtubules in vitro in RanGTP-dependent manner (31) | Yes (31) |
| RanBP2/Nup358 | NPCs (56, 57) | Nuclear transport through the NPC (58) | Kinetochores and spindle microtubules (59) | Required for microtubule-kinetochore interaction (32, 33); recruited to kinetochores dependent on RanGTP and Crm1 (34) | Protein sumoylation (60) | Yes (34) |