The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS...
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Transcript of The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS...
![Page 1: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/1.jpg)
![Page 2: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/2.jpg)
The major questions…
• Further refine the timing of Golgi fission in G2
• Elucidate the role of BARS in Golgi fission
• Elucidate the Golgi mitotic checkpoint model
![Page 3: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/3.jpg)
Background
Image from http://www.molecularexpressions.com/cells/golgi/golgiapparatus.html
![Page 4: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/4.jpg)
Authors’ Conclusions
• Identifies an earlier stage of Golgi partitioning, namely severing of the non-compact zones in G2 to make isolated stacks
• Identifies the role of BARS in the Golgi mitotic checkpoint
• Sets the stage for continued molecular dissection of the Golgi mitotic checkpoint pathway
![Page 5: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/5.jpg)
The Golgi begins to dissolve in G2
![Page 6: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/6.jpg)
EM based examination of Golgi fission in interphase vs. G2
![Page 7: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/7.jpg)
What is FRAP?
GalT-GFP
1. Source of Fluorescence2. Bleach with a laser3. Wait (minutes)4. Graph recovery
recovery (intact) no recovery (not intact)
![Page 8: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/8.jpg)
Is BARS required for fission during G2?
![Page 9: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/9.jpg)
Cells with isolated stacks are resistant to BARS inhibition
![Page 10: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/10.jpg)
Golgi morphology in MEFs lacking BARS
![Page 11: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/11.jpg)
Authors’ Conclusions
• Identifies an earlier stage of Golgi partitioning, namely severing of the non-compact zones in G2 to make isolated stacks
• Identifies the role of BARS in the Golgi mitotic checkpoint
• Sets the stage for continued molecular dissection of the Golgi mitotic checkpoint pathway
![Page 12: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/12.jpg)
Implications of this study
• Is there a Golgi mitotic checkpoint?– Part of the G2/M checkpoint? Is BARS inhibited
upon DNA damage?– Could Golgi disassembly simply be a requirement
for centrosome activation and separation?
• Why do you need the haze?– Shouldn’t BARS-dependent fragmentation be
sufficient for Golgi segregation to daughter cells?
![Page 13: The major questions… Further refine the timing of Golgi fission in G2 Elucidate the role of BARS in Golgi fission Elucidate the Golgi mitotic checkpoint.](https://reader035.fdocuments.in/reader035/viewer/2022062714/56649d5e5503460f94a3d8e6/html5/thumbnails/13.jpg)
Future Studies
• How is BARS regulated? – PAK1– MEK1– Others– DNA damage checkpoint???
• Does BARS get degraded at M entry?• What proteins does BARS associate with? • What are the substrates of BARS?