Excited about #ubiquitin and #TPD ?
Then join us tomorrow for the latest instalment of the @danafarber.bsky.social ‬ Targeted Protein Degradation Webinar where Kimberly Stegmaier and I will present our latest work.
dfci.zoom.us/webinar/regi...

Schulman lab is ready for the GRK2243 Symposium: Understanding ubiquitination: from molecular mechanisms to disease in würzburg

#wUeBI2025 @grk2243.bsky.social
@jakobfarnung.bsky.social @samuelmaiwald.bsky.social @hannahbkmpr.bsky.social

Had a wonderful time at #ubfriends2025
Thanks again @sfb-tpd-vienna.bsky.social for giving me a short talk slot to present UbiREAD and for all the great conversations! #ubiquitin

In addition, 𝗯𝗿𝗮𝗻𝗰𝗵𝗶𝗻𝗴 𝗼𝗳𝗳 𝗮 𝗞48-𝗰𝗵𝗮𝗶𝗻 𝘄𝗶𝘁𝗵 𝗞63 didn’t enhance but 𝗽𝘂𝘁 𝗮 𝘀𝗺𝗮𝗹𝗹 𝗽𝗲𝗻𝗮𝗹𝘁𝘆 𝗼𝗻 𝗱𝗲𝗴𝗿𝗮𝗱𝗮𝘁𝗶𝗼𝗻.

So already lots of exciting and surprising findings. Can’t wait to go further with UbiREAD!

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But how about 𝗞48/𝗞63-𝗯𝗿𝗮𝗻𝗰𝗵𝗲𝗱 𝘂𝗯𝗶𝗾𝘂𝗶𝘁𝗶𝗻 𝗰𝗵𝗮𝗶𝗻𝘀?

Surprisingly, we found that branching K63 chains into K48 does not transform these into degradation signals. The 𝘀𝘂𝗯𝘀𝘁𝗿𝗮𝘁𝗲-𝗮𝗻𝗰𝗵𝗼𝗿𝗲𝗱 𝗰𝗵𝗮𝗶𝗻 𝗵𝗮𝘀 𝘁𝗵𝗲𝗿𝗲𝗳𝗼𝗿𝗲 𝗽𝗿𝗶𝗼𝗿𝗶𝘁𝘆 𝗼𝘃𝗲𝗿 𝘁𝗵𝗲 𝗯𝗿𝗮𝗻𝗰𝗵𝗲𝗱 𝗰𝗵𝗮𝗶𝗻.

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What about K63 ubiquitin chains?

They cannot induce degradation inside cells. Instead, 𝗞63 𝗰𝗵𝗮𝗶𝗻𝘀 𝗮𝗿𝗲 𝗱𝗲𝘂𝗯𝗶𝗾𝘂𝗶𝘁𝗶𝗻𝗮𝘁𝗲𝗱 𝗮𝘁 𝗵𝗶𝗴𝗵 𝘀𝗽𝗲𝗲𝗱.

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How long does a K48 ubiquitin chain have to be to induce degradation?

We tested 𝗞48-𝘂𝗯𝗶𝗾𝘂𝗶𝘁𝗶𝗻𝗮𝘁𝗲𝗱 𝗚𝗙𝗣 with up to a hexa-Ub and found that 𝗮 𝗰𝗵𝗮𝗶𝗻 𝗹𝗲𝗻𝗴𝘁𝗵 𝗼𝗳 3 𝗶𝘀 𝗲𝗳𝗳𝗶𝗰𝗶𝗲𝗻𝘁𝗹𝘆 𝘁𝘂𝗿𝗻𝗶𝗻𝗴 𝗼𝗻 𝗱𝗲𝗴𝗿𝗮𝗱𝗮𝘁𝗶𝗼𝗻, by switching the equilibrium from deubiqutination to degradation.

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With UbiREAD, we can establish causation between ubiquitin chains of defined linkage, length and topology and their intracellular fates.

Now, we can ask many questions!

How fast are ubiquitinated proteins degraded inside cells?

We see 𝗱𝗲𝗴𝗿𝗮𝗱𝗮𝘁𝗶𝗼𝗻 𝘄𝗶𝘁𝗵 𝗮 𝗵𝗮𝗹𝗳-𝗹𝗶𝗳𝗲 𝗼𝗳 𝗷𝘂𝘀𝘁 1 𝗺𝗶𝗻.

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We wanted to translate specific ubiquitin chains into cellular phenotypes. So, we synthesized GFP, added a K48-Ub4 and delivered it into cells.

GFP alone was stable, but ubiquitinated GFP was degraded.

Welcome to 𝗨𝗯𝗶𝗥𝗘𝗔𝗗 (𝗨𝗯𝗶quitinated 𝗥eporter 𝗘valuation 𝗔fter intracellular 𝗗elivery)

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