Titia Sixma
@titiasixma.bsky.social
Structural biologist and biochemist, interested in ubiquitin enzymes and DNA repair & regulation
This is wonderful!!
Many many thanks to Friedrich and everyone else for the enormous amount of work you have done to ensure the future of cryo-EM research in the Netherlands!
Many many thanks to Friedrich and everyone else for the enormous amount of work you have done to ensure the future of cryo-EM research in the Netherlands!
Very happy that NWO supports this major upgrade of our national EM infrastructure. It is great that this initiative got broad support all over NL, and it will EMPower fantastic science - looking forward to that!
www.uu.nl/en/news/33-m...
www.uu.nl/en/news/33-m...
33 million euro investment for national electron microscope facility EMPower
A major new national facility for electron microscopy, called EMPower, has been awarded to a consortium of Dutch universities and medical centers. EMPower aims to pave the way for major discoveries im...
www.uu.nl
November 4, 2025 at 7:26 AM
This is wonderful!!
Many many thanks to Friedrich and everyone else for the enormous amount of work you have done to ensure the future of cryo-EM research in the Netherlands!
Many many thanks to Friedrich and everyone else for the enormous amount of work you have done to ensure the future of cryo-EM research in the Netherlands!
Reposted by Titia Sixma
“It’s amazing to be the very first person to understand something at such a miniscule scale”.
From October 1st, junior group leader Wout Oosterheert will give a boost to fundamental cancer research at the Netherlands Cancer Institute ➡️ www.nki.nl/news-events/...
From October 1st, junior group leader Wout Oosterheert will give a boost to fundamental cancer research at the Netherlands Cancer Institute ➡️ www.nki.nl/news-events/...
September 30, 2025 at 11:50 AM
“It’s amazing to be the very first person to understand something at such a miniscule scale”.
From October 1st, junior group leader Wout Oosterheert will give a boost to fundamental cancer research at the Netherlands Cancer Institute ➡️ www.nki.nl/news-events/...
From October 1st, junior group leader Wout Oosterheert will give a boost to fundamental cancer research at the Netherlands Cancer Institute ➡️ www.nki.nl/news-events/...
Reposted by Titia Sixma
The latest work from ours and @vram142.bsky.social lab is out! True teamwork to visualize nascent chromatin with strand resolution, using a fully reconstituted system. Very proud of superstar-PhD student Bruna, and @palindromephd.bsky.social. Learning so much from Vijay’s amazing technologies! RT
Some (+)ve news to lighten another heavy weekend: our latest preprint (c/o Mattiroli + Ramani labs) is up!
www.biorxiv.org/content/10.1...
A tour-de-force by 1st authors Bruna Eckhardt & @palindromephd.bsky.social, focusing on chromatin replication. RTs welcome; tweetorial in 3,2...(1/n)
www.biorxiv.org/content/10.1...
A tour-de-force by 1st authors Bruna Eckhardt & @palindromephd.bsky.social, focusing on chromatin replication. RTs welcome; tweetorial in 3,2...(1/n)
The eukaryotic replisome intrinsically generates asymmetric daughter chromatin fibers
DNA replication is molecularly asymmetric, due to distinct mechanisms for lagging and leading strand DNA synthesis. Whether chromatin assembly on newly replicated strands is also asymmetric remains un...
www.biorxiv.org
September 21, 2025 at 7:12 AM
The latest work from ours and @vram142.bsky.social lab is out! True teamwork to visualize nascent chromatin with strand resolution, using a fully reconstituted system. Very proud of superstar-PhD student Bruna, and @palindromephd.bsky.social. Learning so much from Vijay’s amazing technologies! RT
Congratulations to everyone but especially Venda & Sylvie for this nice work and thanks to Andrea Murachelli in my lab for his analyses
Happy to share our latest research on the BRCA1-BRCTs now online.
academic.oup.com/nar/article/...
Congrats to first author Venda for putting it all together! This project was a great collaboration with the @titiasixma.bsky.social lab who helped us give structural meaning to our observations.
academic.oup.com/nar/article/...
Congrats to first author Venda for putting it all together! This project was a great collaboration with the @titiasixma.bsky.social lab who helped us give structural meaning to our observations.
Validate User
academic.oup.com
September 18, 2025 at 9:27 AM
Congratulations to everyone but especially Venda & Sylvie for this nice work and thanks to Andrea Murachelli in my lab for his analyses
Happy to see this out, great work from Niels, combining kinetic analysis, cryoEM and an unexpected gain-of-function mutant, nice work from master students Jan and Nina, from Kaustav and from Alex for the kinetics
@oncodeinstitute.bsky.social,
@nkinl.bsky.social
@oncodeinstitute.bsky.social,
@nkinl.bsky.social
I'm very proud that our paper, and with that the main project of my PhD, has just been published by @natcomms.nature.com! 🎉
Here, we reveal the unique, molecular mechanism by which USP1/UAF1 cleaves ubiquitin chains on PCNA, which may direct DNA damage tolerance.
doi.org/10.1038/s414...
Here, we reveal the unique, molecular mechanism by which USP1/UAF1 cleaves ubiquitin chains on PCNA, which may direct DNA damage tolerance.
doi.org/10.1038/s414...
USP1/UAF1 targets polyubiquitinated PCNA with an exo-cleavage mechanism that can temporarily enrich for monoubiquitinated PCNA - Nature Communications
DNA damage tolerance is regulated by ubiquitination of PCNA. Here, the authors present kinetic and structural studies showing that USP1/UAF1 prefers trimming K63- and K48-ubiquitin chains down over cl...
doi.org
July 31, 2025 at 12:38 PM
Happy to see this out, great work from Niels, combining kinetic analysis, cryoEM and an unexpected gain-of-function mutant, nice work from master students Jan and Nina, from Kaustav and from Alex for the kinetics
@oncodeinstitute.bsky.social,
@nkinl.bsky.social
@oncodeinstitute.bsky.social,
@nkinl.bsky.social
Reposted by Titia Sixma
Proud! 💙 Our scientific director Thijn Brummelkamp receives the Spinoza Prize, a prize for scientists who belong to the best researchers worldwide. A wonderful recognition for his groundbreaking research.
Congrats Thijn! 🎉 @thijnbrummel.bsky.social
Full article ➡️ bit.ly/40p4KnK
Congrats Thijn! 🎉 @thijnbrummel.bsky.social
Full article ➡️ bit.ly/40p4KnK
June 27, 2025 at 5:51 AM
Proud! 💙 Our scientific director Thijn Brummelkamp receives the Spinoza Prize, a prize for scientists who belong to the best researchers worldwide. A wonderful recognition for his groundbreaking research.
Congrats Thijn! 🎉 @thijnbrummel.bsky.social
Full article ➡️ bit.ly/40p4KnK
Congrats Thijn! 🎉 @thijnbrummel.bsky.social
Full article ➡️ bit.ly/40p4KnK
Reposted by Titia Sixma
In the context of our @reviewcommons.org revision process, I'm happy to announce Microscopy Nodes v2.2.0!
This packs lots of new fun features, including new color management 🌈, clearer transparency handling 🫥, custom default settings 🔧 and more!
Preprint at doi.org/10.1101/2025...
This packs lots of new fun features, including new color management 🌈, clearer transparency handling 🫥, custom default settings 🔧 and more!
Preprint at doi.org/10.1101/2025...
May 23, 2025 at 1:13 PM
In the context of our @reviewcommons.org revision process, I'm happy to announce Microscopy Nodes v2.2.0!
This packs lots of new fun features, including new color management 🌈, clearer transparency handling 🫥, custom default settings 🔧 and more!
Preprint at doi.org/10.1101/2025...
This packs lots of new fun features, including new color management 🌈, clearer transparency handling 🫥, custom default settings 🔧 and more!
Preprint at doi.org/10.1101/2025...
Reposted by Titia Sixma
This is accompanied by a new set of tutorials showing exactly how you can start making beautiful microscopy visualizations in @blender.org!
Following along is also easy with the example OME-Zarr @openmicroscopy.org datasets 😄
Find the tutorials here: www.youtube.com/playlist?lis...
Following along is also easy with the example OME-Zarr @openmicroscopy.org datasets 😄
Find the tutorials here: www.youtube.com/playlist?lis...
May 23, 2025 at 1:13 PM
This is accompanied by a new set of tutorials showing exactly how you can start making beautiful microscopy visualizations in @blender.org!
Following along is also easy with the example OME-Zarr @openmicroscopy.org datasets 😄
Find the tutorials here: www.youtube.com/playlist?lis...
Following along is also easy with the example OME-Zarr @openmicroscopy.org datasets 😄
Find the tutorials here: www.youtube.com/playlist?lis...
Reposted by Titia Sixma
LocScale-SURFER is now also available for quick install via the ChimeraX toolshed:
cxtoolshed.rbvi.ucsf.edu
cxtoolshed.rbvi.ucsf.edu
LocScale-2.0 is deliberately designed to optimise contrast for both high-resolution detail & weak contextual densities such as membrane/micelle or flexible/low-occupancy regions
LocScale-SURFER is a ChimeraX plugin aiding w/ visualisation of contextual structure.
cryotud.github.io/locscale-sur...
LocScale-SURFER is a ChimeraX plugin aiding w/ visualisation of contextual structure.
cryotud.github.io/locscale-sur...
May 26, 2025 at 11:10 AM
LocScale-SURFER is now also available for quick install via the ChimeraX toolshed:
cxtoolshed.rbvi.ucsf.edu
cxtoolshed.rbvi.ucsf.edu
Reposted by Titia Sixma
Harvard has set an example for other higher-ed institutions - rejecting an unlawful and ham-handed attempt to stifle academic freedom, while taking steps to make sure students can benefit from an environment of intellectual inquiry, rigorous debate and mutual respect. Let’s hope others follow suit.
April 15, 2025 at 3:52 AM
Harvard has set an example for other higher-ed institutions - rejecting an unlawful and ham-handed attempt to stifle academic freedom, while taking steps to make sure students can benefit from an environment of intellectual inquiry, rigorous debate and mutual respect. Let’s hope others follow suit.
Reposted by Titia Sixma
A must for all DNA repair aficionados!
Egmond DNA Repair Meeting → April 19–24, 2026 🇳🇱
✔️ Confirmed top speakers
✔️ Ample opportunities for talks & posters
Don’t miss it: dnarepairmeeting-egmond2026.com
Egmond DNA Repair Meeting → April 19–24, 2026 🇳🇱
✔️ Confirmed top speakers
✔️ Ample opportunities for talks & posters
Don’t miss it: dnarepairmeeting-egmond2026.com
April 9, 2025 at 8:05 AM
A must for all DNA repair aficionados!
Egmond DNA Repair Meeting → April 19–24, 2026 🇳🇱
✔️ Confirmed top speakers
✔️ Ample opportunities for talks & posters
Don’t miss it: dnarepairmeeting-egmond2026.com
Egmond DNA Repair Meeting → April 19–24, 2026 🇳🇱
✔️ Confirmed top speakers
✔️ Ample opportunities for talks & posters
Don’t miss it: dnarepairmeeting-egmond2026.com
Reposted by Titia Sixma
In what world you can justify firing Richard Youle?!? #autophagy #mitophagy www.wired.com/story/doctor...
Doctor Behind Award-Winning Parkinson’s Research Among Scientists Purged From NIH
Leading scientists at the National Institutes of Health, the US’s leading medical research agency, were swept up Tuesday in the Trump administration’s latest firing blitz.
www.wired.com
April 3, 2025 at 5:42 AM
In what world you can justify firing Richard Youle?!? #autophagy #mitophagy www.wired.com/story/doctor...
Reposted by Titia Sixma
Trump's 3/27 executive order targets the Smithsonian for advancing "the view that race is not a biological reality but a social construct."
Trump argues that the exhibit's statement, below, is unscientific. He's wrong. As a biology professor and population geneticist, I agree with every word of it.
Trump argues that the exhibit's statement, below, is unscientific. He's wrong. As a biology professor and population geneticist, I agree with every word of it.
March 31, 2025 at 11:27 PM
Trump's 3/27 executive order targets the Smithsonian for advancing "the view that race is not a biological reality but a social construct."
Trump argues that the exhibit's statement, below, is unscientific. He's wrong. As a biology professor and population geneticist, I agree with every word of it.
Trump argues that the exhibit's statement, below, is unscientific. He's wrong. As a biology professor and population geneticist, I agree with every word of it.
Reposted by Titia Sixma
Fondly remember Jan for his enthusiasm, rigorous science, and the kind person that he was.
Bauke W. Dijkstra et al.: Jan Drenth (1925–2025) @univgroningen...##IUCrhttps://journals.iucr.org/paper?S205979832500275X
Jan Drenth (1925–2025)
Jan Drenth is remembered.
journals.iucr.org
March 29, 2025 at 5:53 PM
Fondly remember Jan for his enthusiasm, rigorous science, and the kind person that he was.
great to see it out, Irina!
Two preprints!
We report extensive characterization of USP7 variants linked to Hao-Fountain syndrome AND a new allosteric activator as a potential tool to rescue USP7 activity.
A great collaboration with Sara Buhrlage’s lab.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
We report extensive characterization of USP7 variants linked to Hao-Fountain syndrome AND a new allosteric activator as a potential tool to rescue USP7 activity.
A great collaboration with Sara Buhrlage’s lab.
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Functional Spectrum of USP7 Pathogenic Variants in Hao-Fountain Syndrome: Insights into the Enzyme's Activity, Stability, and Allosteric Modulation
Hao-Fountain syndrome is a rare neurodevelopmental disorder caused by mutations in the de-ubiquitinating enzyme USP7 (Ubiquitin Specific Protease 7). Due to the novelty of the disease and its poorly u...
www.biorxiv.org
March 21, 2025 at 6:05 AM
great to see it out, Irina!
Reposted by Titia Sixma
"The rejection of grant applications or the alteration of the published record on account of the use of terms such as ‘bias’, ‘gender’, ‘ethnicity’ and even ‘female’ is unacceptable. EMBO Press joins other journals in not allowing such changes" 💪🏻👏🏻👏🏻👏🏻 www.embopress.org/doi/full/10....
Under pressure | EMBO reports
EMBO Press is an editorially independent publishing platform for the development of EMBO scientific publications.
www.embopress.org
March 20, 2025 at 8:19 AM
"The rejection of grant applications or the alteration of the published record on account of the use of terms such as ‘bias’, ‘gender’, ‘ethnicity’ and even ‘female’ is unacceptable. EMBO Press joins other journals in not allowing such changes" 💪🏻👏🏻👏🏻👏🏻 www.embopress.org/doi/full/10....
It's infinitely sad to see what is happening. the disregard of laws, advice and justice in our immigration policy plans, the total implosion of human values overseas. I feel just a bystander reeling in shock.
March 17, 2025 at 4:44 PM
It's infinitely sad to see what is happening. the disregard of laws, advice and justice in our immigration policy plans, the total implosion of human values overseas. I feel just a bystander reeling in shock.
Today Jan Drenth would have been 100 years, but sadly he passed away last week.
He was the founding father of structural biology in the Netherlands and his modesty, his gentle humor and his generosity set the spirit for the amazing environment in Groningen where i did my PhD.
He was the founding father of structural biology in the Netherlands and his modesty, his gentle humor and his generosity set the spirit for the amazing environment in Groningen where i did my PhD.
February 20, 2025 at 12:58 PM
Today Jan Drenth would have been 100 years, but sadly he passed away last week.
He was the founding father of structural biology in the Netherlands and his modesty, his gentle humor and his generosity set the spirit for the amazing environment in Groningen where i did my PhD.
He was the founding father of structural biology in the Netherlands and his modesty, his gentle humor and his generosity set the spirit for the amazing environment in Groningen where i did my PhD.
Reposted by Titia Sixma
Today, the same as every other damn day, trans rights are human rights
January 30, 2025 at 1:07 AM
Today, the same as every other damn day, trans rights are human rights
Reposted by Titia Sixma
Are you graduating this year and ready to start your career in the most meaningful way? This is your chance to get on board. #PhD #CancerResearch ➡️ nki.nl/careers-study/phd-students/nki-phd-program-2025/
January 24, 2025 at 12:09 PM
Are you graduating this year and ready to start your career in the most meaningful way? This is your chance to get on board. #PhD #CancerResearch ➡️ nki.nl/careers-study/phd-students/nki-phd-program-2025/
Reposted by Titia Sixma
I am really excited to have the opportunity to continue to do science at the Hubrecht Institute @hubrechtinstitute.bsky.social! Thank you for the support!
What if science truly is like volleyball, where teamwork and support are everything? We spoke with @fmattiroli.bsky.social, who recently earned tenure, to explore this question and more. Read her inspiring story here 👇 www.hubrecht.eu/francesca-ma...
Francesca Mattiroli got tenure: ‘Science is a team sport’ - Hubrecht Institute
She always dreamed of becoming a scientist. Francesca Mattiroli, has passed tenure evaluation with flying colors. She will expand her chromatin research.
www.hubrecht.eu
January 24, 2025 at 10:49 AM
I am really excited to have the opportunity to continue to do science at the Hubrecht Institute @hubrechtinstitute.bsky.social! Thank you for the support!
Reposted by Titia Sixma
Microscopy Nodes is now up on bioRxiv! 🚀
This is a Blender extension that seamlessly integrates and visualizes 3D microscopy data (TIF & @zarr.dev).
High-quality volume rendering for anyone, in both EM and fluorescence, regardless of computational expertise! 🔬
www.biorxiv.org/content/10.1...
This is a Blender extension that seamlessly integrates and visualizes 3D microscopy data (TIF & @zarr.dev).
High-quality volume rendering for anyone, in both EM and fluorescence, regardless of computational expertise! 🔬
www.biorxiv.org/content/10.1...
January 15, 2025 at 1:39 PM
Microscopy Nodes is now up on bioRxiv! 🚀
This is a Blender extension that seamlessly integrates and visualizes 3D microscopy data (TIF & @zarr.dev).
High-quality volume rendering for anyone, in both EM and fluorescence, regardless of computational expertise! 🔬
www.biorxiv.org/content/10.1...
This is a Blender extension that seamlessly integrates and visualizes 3D microscopy data (TIF & @zarr.dev).
High-quality volume rendering for anyone, in both EM and fluorescence, regardless of computational expertise! 🔬
www.biorxiv.org/content/10.1...
The NKI call for PhD students is now open, with more information on our project on the website, More info: bit.ly/3O4bOjq
We have an opening for a PhD student, for a cryo-EM/biochemistry project at the interface of ubiquitin and DNA repair. Enthousiasm and experience with protein biochemistry and/or structural biology really important. Recruitment will fall under the the NKI PhD program, please see below
📢 Applications for the NKI PhD program open from Jan 1 - Feb 28. Join our international research community in Amsterdam, working in cancer biology, AI research & life sciences with leading scientists and top facilities #PhD #CancerResearch More info: bit.ly/3O4bOjq
January 8, 2025 at 7:27 AM
The NKI call for PhD students is now open, with more information on our project on the website, More info: bit.ly/3O4bOjq
Despite the black picture below, we're really happy to have this illuminating story online! Careful molecular mechanistic from Niels and others in the lab work giving unexpected biological insight!
Excited to share our new paper!
Here we reveal USP1/UAF1 as a highly efficient DUB for K63- and K48 polyubiquitinated PCNA and give detailed insights into its mechanism that may drive pathway choice in DNA damage tolerance.
Preprint is available now:
www.biorxiv.org/content/10.1...
Here we reveal USP1/UAF1 as a highly efficient DUB for K63- and K48 polyubiquitinated PCNA and give detailed insights into its mechanism that may drive pathway choice in DNA damage tolerance.
Preprint is available now:
www.biorxiv.org/content/10.1...
USP1/UAF1 targets polyubiquitinated PCNA with an exo-cleavage mechanism that enriches for monoubiquitinated PCNA
DNA damage tolerance (DDT) is an important pathway that allows our cells to bypass DNA lesions during replication. DDT is orchestrated by ubiquitination of PCNA: Monoubiquitination (PCNA-Ub) initiates...
www.biorxiv.org
December 17, 2024 at 2:09 PM
Despite the black picture below, we're really happy to have this illuminating story online! Careful molecular mechanistic from Niels and others in the lab work giving unexpected biological insight!