Sa Kan Yoo

We study tissue and organismal homeostasis using the fruit fly Drosophila at RIKEN in Japan.
Journal club @Yoolab_JC
Tweet in Japanese @SaKanYoo1

[Sa Kan Yoo @Yoo_Lab_RIKEN]

1. Our erebosis paper is out @PLOSBiology. PhD students Hanna and @HIroshi5Nishida contributed. Apoptosis has been believed to mediate the gut turnover. We discovered a new cell death, erebosis, mediates the gut cell turnover. Erebos means "deep darkness".
https://t.co/Tfx7ndCD8D

[Sa Kan Yoo @Yoo_Lab_RIKEN]

Erebosis of Neurons May Exist in the Brain with Alzheimer’s Disease. 🤯
https://t.co/G11B8MCgCh

[Sa Kan Yoo @Yoo_Lab_RIKEN]

Motohiro, a grad student in my lab gave a fantastic talk at the fly meeting in San Diego😀

[Sa Kan Yoo @Yoo_Lab_RIKEN]

We propose that behind the proliferation signals, there is an insidious chromatin change with a propensity to exhaust cells during aging.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

What is a mechanism of intestinal stem cell exhaustion during aging? Saki Naito, a PhD student, addressed this question focusing on changes of chromatin and transcription during aging.
https://t.co/q3KrWMlxJC

[Sa Kan Yoo @Yoo_Lab_RIKEN]

Good bye, Dr Shivakshi Sulekh @sulekh_shiva. It was fantastic to work with you. Good luck on your postdoc endeavor in France!

[Sa Kan Yoo @Yoo_Lab_RIKEN]

I also enjoyed the RIKEN-UPF joint symposium a lot! The UPF campus was gorgeous.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

Many thanks for hosting my visit to IRB @MarcoMilanIRB. I really enjoyed insightful discussion with scientists at IRB!

[Sa Kan Yoo @Yoo_Lab_RIKEN]

I really look forward to visiting Spain for the first time in life! And, many many thanks for hosting my seminar ! @MarcoMilanIRB

[IRB Barcelona @IRBBarcelona]

🗣️Join us next week in our seminar by Sa Kan Yoo, MD, PhD (@Yoo_Lab_RIKEN-@Yoolab_JC) from @RIKEN_BDR👇

📜"Erebosis, a new cell death mechanism during homeostatic turnover of gut enterocytes"

🤝Host: Dr. @MarcoMilanIRB

Register here➡️https://t.co/7nJfdpo1n8

#BarcelonaBiomed

[Sa Kan Yoo @Yoo_Lab_RIKEN]

7. I forgot to add a link:
https://t.co/x98Krwha0r

[Sa Kan Yoo @Yoo_Lab_RIKEN]

5. GALDAR1/2 is relatively slow due to its dependency on transcription/translation/maturation. So, @hitsujican came up with GALDAR3, where 1) Gal3 is localized in the nucleus, 2) Gal80 is fused with GFP, 3) Gal80 mutant that can't bind to Gal4 was used.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

6. In addition to using GALDAR as a biosensor, GALDAR1/2 can be used a gene-inducible system in cells that uptake galactose readily (in fact, that was the original, initial purpose of this project).

GALDARs were sent to the Bloomington stock center, and will be available soon!

[Sa Kan Yoo @Yoo_Lab_RIKEN]

4. Using GALDAR1/2, we found that ISCs (arrows below) don't uptake galactose. We also confirmed ISCs don't uptake glucose either. Since the same transporters transport galactose/glucose, in some situations demonstrated here, GALDAR can be used for glucose flux analysis.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

3. Feeding galactose to flies induces GALDAR signals.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

1. GALDAR, a genetically encoded galactose sesor in flies @PlosBiology. A PhD student @hitsujican did a great job! GALDAR1/2 incorporates the yeast's Gal system Gal3/Gal4/Gal80. GALDAR3 doesn't depend on Gal4-UAS. With GALDAR, we found that ISCs don't uptake galactose/glucose!

[Sa Kan Yoo @Yoo_Lab_RIKEN]

2. In flies, Gal4-UAS was introduced in 1993 (Perrimon lab), followed by introduction of Gal80 in 1998 (Luo lab). We transferred the yeast whole Gal system, by adding Gal3/galactose, to flies. This is the basis of GALDAR1/2.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

One year ago, a student at my lab was not confident whether she could handle fruit flies because she's not a fan of bugs. Today, she attended a graduation ceremony with a fly on her head (Cyo wings!) 🥳

[Sa Kan Yoo @Yoo_Lab_RIKEN]

Now our Necrosensor stocks are available at the Bloomington stock center. With this simple sensor, you don't have to hassle with live staining with propidium iodide anymore!

[Sa Kan Yoo @Yoo_Lab_RIKEN]

A proofed version of our necrosensor paper is published now. I've already received multiple requests of the stocks. They will be available at the Bloomington stock center within a few weeks. I guarantee this simple necrosis sensor will be super useful
https://t.co/eHr0RYzkCe

[Sa Kan Yoo @Yoo_Lab_RIKEN]

7. This study has 2 major findings:
1. caspase-JNK feedback loop that promotes cell death and proliferation simultaneously
2. A defect of the feedback leads to resistance of ISCs to apoptosis.

Many thanks for helping FACS of ISCs! @IchiroHiratani

[Sa Kan Yoo @Yoo_Lab_RIKEN]

4. On the other hand, we found that ISCs have a defect in this positive feedback loop of caspase activation. With weak caspase activation, cells cannot die, so they end up proliferating.

[Sa Kan Yoo @Yoo_Lab_RIKEN]

6. Finally, we examined effects of "ISCizing" wing disc cells (making wing disc cells similar to ISCs): combination of the feedback loop inhibition and caspase activation induced overproliferation in wing disc, which is similar to ISCs.