Spindle assembly checkpoint robustness requires Tpr-mediated regulation of Mad1/Mad2 proteostasis
| Autor: | Nina Schweizer, Elsa Logarinho, Cristina Ferrás, David M Kern, Iain M. Cheeseman, Helder Maiato |
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| Přispěvatelé: | Massachusetts Institute of Technology. Department of Biology, Whitehead Institute for Biomedical Research, Kern, David Matthew, Cheeseman, Iain McPherson |
| Rok vydání: | 2013 |
| Předmět: |
Cell cycle checkpoint
Mad2 Mad1 Cell Cycle Proteins Biology Protein Serine-Threonine Kinases Cell Line 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Proto-Oncogene Proteins Report Mad2 Proteins Humans Research Articles 030304 developmental biology 0303 health sciences Kinetochore Nuclear Proteins Cell Biology Cell Cycle Checkpoints Protein-Tyrosine Kinases Cell biology Nuclear Pore Complex Proteins Spindle checkpoint Nocodazole Proteostasis chemistry 030217 neurology & neurosurgery HeLa Cells |
| Zdroj: | The Journal of Cell Biology Rockefeller University Press |
| ISSN: | 1540-8140 |
| Popis: | Tpr is a kinetochore-independent, rate-limiting factor required to mount and sustain a robust spindle assembly checkpoint response by stabilizing Mad1 and Mad2 before mitosis. Tpr is a conserved nuclear pore complex (NPC) protein implicated in the spindle assembly checkpoint (SAC) by an unknown mechanism. Here, we show that Tpr is required for normal SAC response by stabilizing Mad1 and Mad2 before mitosis. Tpr coimmunoprecipitated with Mad1 and Mad2 (hereafter designated as Tpr/Mad1/Mad2 or TM2 complex) during interphase and mitosis, and is required for Mad1–c-Mad2 recruitment to NPCs. Interestingly, Tpr was normally undetectable at kinetochores and dispensable for Mad1, but not for Mad2, kinetochore localization, which suggests that SAC robustness depends on Mad2 levels at kinetochores. Protein half-life measurements demonstrate that Tpr stabilizes Mad1 and Mad2, ensuring normal Mad1–c-Mad2 production in an mRNA- and kinetochore-independent manner. Overexpression of GFP-Mad2 restored normal SAC response and Mad2 kinetochore levels in Tpr-depleted cells. Mechanistically, we provide evidence that Tpr might spatially regulate SAC proteostasis through the SUMO-isopeptidases SENP1 and SENP2 at NPCs. Thus, Tpr is a kinetochore-independent, rate-limiting factor required to mount and sustain a robust SAC response. |
| Databáze: | OpenAIRE |
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