Iva Tolić
@ivatolic.bsky.social
Biophysics of mitosis / mitotic spindle / chromosome segregation and aneuploidy
Head of Laboratory of Cell Biophysics at @institutrb.bsky.social, previously at @mpi-cbg.de, LENS Florence, Niels Bohr Institute, @hsph.harvard.edu, Uni Zagreb.
tolic.irb.hr
Head of Laboratory of Cell Biophysics at @institutrb.bsky.social, previously at @mpi-cbg.de, LENS Florence, Niels Bohr Institute, @hsph.harvard.edu, Uni Zagreb.
tolic.irb.hr
A golden Zagreb morning before work
October 31, 2025 at 8:47 PM
A golden Zagreb morning before work
Congrats @krunovuk.bsky.social on this remarkable work! Thanks @erc.europa.eu, www.hrzz.hr, and www.srce.unizg.hr for supporting us!
October 29, 2025 at 5:09 PM
Congrats @krunovuk.bsky.social on this remarkable work! Thanks @erc.europa.eu, www.hrzz.hr, and www.srce.unizg.hr for supporting us!
We propose a kinetochore-centrosome feedback mechanism controlling chromosome movement: chromosomes near centrosomes rely on CENP-E because high Aurora A activity boosts Aurora B at kinetochores, restricting end-on attachments. CENP-E counteracts this by downregulating Aurora B.
October 29, 2025 at 5:09 PM
We propose a kinetochore-centrosome feedback mechanism controlling chromosome movement: chromosomes near centrosomes rely on CENP-E because high Aurora A activity boosts Aurora B at kinetochores, restricting end-on attachments. CENP-E counteracts this by downregulating Aurora B.
Notably, the dependence of polar chromosomes on CENP-E can be bypassed by using constitutively dephosphorylated Hec1, emphasizing the role of Aurora kinase-mediated Hec1 phosphorylation in preventing congression when CENP-E is absent.
October 29, 2025 at 5:09 PM
Notably, the dependence of polar chromosomes on CENP-E can be bypassed by using constitutively dephosphorylated Hec1, emphasizing the role of Aurora kinase-mediated Hec1 phosphorylation in preventing congression when CENP-E is absent.
Does Aurora A at spindle poles directly promote Aurora B activity at kinetochores? Yes, our results show that acute inhibition of Aurora A reduces Aurora B activity at polar kinetochores, accompanied by a decrease in the number of polar chromosomes.
October 29, 2025 at 5:09 PM
Does Aurora A at spindle poles directly promote Aurora B activity at kinetochores? Yes, our results show that acute inhibition of Aurora A reduces Aurora B activity at polar kinetochores, accompanied by a decrease in the number of polar chromosomes.
At poles that contain centrioles, high Aurora A kinase enhances Aurora B activity on kinetochores of polar chromosomes, increasing phosphorylation of microtubule-binding proteins and preventing stable microtubule attachments in the absence of CENP-E.
October 29, 2025 at 5:09 PM
At poles that contain centrioles, high Aurora A kinase enhances Aurora B activity on kinetochores of polar chromosomes, increasing phosphorylation of microtubule-binding proteins and preventing stable microtubule attachments in the absence of CENP-E.
Centrosomes inhibit the initiation of congression in the absence of CENP-E, and depletion of centrioles allows chromosomes near acentriolar poles to initiate congression independently of CENP-E.
October 29, 2025 at 5:09 PM
Centrosomes inhibit the initiation of congression in the absence of CENP-E, and depletion of centrioles allows chromosomes near acentriolar poles to initiate congression independently of CENP-E.
In our second paper, we asked why only polar chromosomes depend on CENP-E for congression. We inhibited Plk4 to generate spindles where one pole had centrioles and the other did not. Strikingly, the acentriolar pole (on the right in the movie) rarely had polar chromosomes.
October 29, 2025 at 5:09 PM
In our second paper, we asked why only polar chromosomes depend on CENP-E for congression. We inhibited Plk4 to generate spindles where one pole had centrioles and the other did not. Strikingly, the acentriolar pole (on the right in the movie) rarely had polar chromosomes.
And now… part two of our twin papers on how chromosomes find their place before division! Led by @krunovuk.bsky.social at @institutrb.bsky.social, out in @natcomms.nature.com!
doi.org/10.1038/s414...
doi.org/10.1038/s414...
Missed the thread on the first paper? Catch up:
bsky.app/profile/ivat...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
Missed the thread on the first paper? Catch up:
bsky.app/profile/ivat...
October 29, 2025 at 5:09 PM
And now… part two of our twin papers on how chromosomes find their place before division! Led by @krunovuk.bsky.social at @institutrb.bsky.social, out in @natcomms.nature.com!
doi.org/10.1038/s414...
doi.org/10.1038/s414...
Missed the thread on the first paper? Catch up:
bsky.app/profile/ivat...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
Missed the thread on the first paper? Catch up:
bsky.app/profile/ivat...
In sum, the first paper shows that chromosome congression is coupled with biorientation, with CENP-E linking the two. A thread on the second paper is coming soon! Congrats @krunovuk.bsky.social on this amazing work! We appreciate support from @erc.europa.eu, www.hrzz.hr, and www.srce.unizg.hr.
October 21, 2025 at 11:14 AM
In sum, the first paper shows that chromosome congression is coupled with biorientation, with CENP-E linking the two. A thread on the second paper is coming soon! Congrats @krunovuk.bsky.social on this amazing work! We appreciate support from @erc.europa.eu, www.hrzz.hr, and www.srce.unizg.hr.
We propose that congression operates as a negative feedback loop between the activity of Aurora kinases that oppose congression by destabilizing end-on attachments, but also activate CENP-E, which then promotes congression by opposing the activity of Aurora kinases.
October 21, 2025 at 11:14 AM
We propose that congression operates as a negative feedback loop between the activity of Aurora kinases that oppose congression by destabilizing end-on attachments, but also activate CENP-E, which then promotes congression by opposing the activity of Aurora kinases.
In our model, stabilization of end-on attachments without CENP-E is delayed due to Aurora kinase-mediated phosphorylation of microtubule-binding proteins and expansion of the fibrous corona, which obstructs attachments. CENP-E counters this by reducing phosphorylation.
October 21, 2025 at 11:14 AM
In our model, stabilization of end-on attachments without CENP-E is delayed due to Aurora kinase-mediated phosphorylation of microtubule-binding proteins and expansion of the fibrous corona, which obstructs attachments. CENP-E counters this by reducing phosphorylation.
Why can’t kinetochores start their movement without CENP-E? Is dynein holding them? No. This is due to Aurora kinases that oppose the formation of end-on attachments near the spindle poles. When Aurora B is inhibited in the absence of CENP-E, kinetochores start to move!
October 21, 2025 at 11:14 AM
Why can’t kinetochores start their movement without CENP-E? Is dynein holding them? No. This is due to Aurora kinases that oppose the formation of end-on attachments near the spindle poles. When Aurora B is inhibited in the absence of CENP-E, kinetochores start to move!
To directly test if congression is coupled with biorientation, we performed STED super-resolution imaging. Indeed, reactivation of CENP-E led to a gradual transition from lateral to end-on attachments on polar chromosomes.
October 21, 2025 at 11:14 AM
To directly test if congression is coupled with biorientation, we performed STED super-resolution imaging. Indeed, reactivation of CENP-E led to a gradual transition from lateral to end-on attachments on polar chromosomes.
Chromosome congression involves progressive capture and stabilization of end-on microtubule attachments, based on recruitment of the attachment marker Astrin, together with a gradual reduction of SAC and fibrous corona proteins on kinetochores.
October 21, 2025 at 11:14 AM
Chromosome congression involves progressive capture and stabilization of end-on microtubule attachments, based on recruitment of the attachment marker Astrin, together with a gradual reduction of SAC and fibrous corona proteins on kinetochores.
We found that without CENP-E kinetochores move in the same manner as normally, just not as frequently. Thus, CENP-E is not required for chromosome movement during congression, challenging the current view, but instead for the initiation of this movement.
October 21, 2025 at 11:14 AM
We found that without CENP-E kinetochores move in the same manner as normally, just not as frequently. Thus, CENP-E is not required for chromosome movement during congression, challenging the current view, but instead for the initiation of this movement.
@krunovuk.bsky.social pushed the limits of long-term live-cell imaging by simultaneously imaging hundreds of cells for 24 h using lattice light-sheet microscopy. By adding chemical inhibitors, he tested a time-resolved hierarchy of molecular networks working during congression.
October 21, 2025 at 11:14 AM
@krunovuk.bsky.social pushed the limits of long-term live-cell imaging by simultaneously imaging hundreds of cells for 24 h using lattice light-sheet microscopy. By adding chemical inhibitors, he tested a time-resolved hierarchy of molecular networks working during congression.
Do you know how chromosomes travel to the spindle midplane in mitosis? The motor protein CENP-E is crucial for this. Without it, some chromosomes stay trapped at the poles. The current model says it glides kinetochores along microtubules... but does it really?
October 21, 2025 at 11:14 AM
Do you know how chromosomes travel to the spindle midplane in mitosis? The motor protein CENP-E is crucial for this. Without it, some chromosomes stay trapped at the poles. The current model says it glides kinetochores along microtubules... but does it really?
Two back-to-back stories on mitosis led by my incredible postdoc @krunovuk.bsky.social at @institutrb.bsky.social, in which we challenge the gliding model of CENP-E-driven chromosome congression! Today in @natcomms.nature.com
doi.org/10.1038/s414...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
October 21, 2025 at 11:14 AM
Two back-to-back stories on mitosis led by my incredible postdoc @krunovuk.bsky.social at @institutrb.bsky.social, in which we challenge the gliding model of CENP-E-driven chromosome congression! Today in @natcomms.nature.com
doi.org/10.1038/s414...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
doi.org/10.1038/s414...
Amazing energy at our second Swiss-Croatian Bilateral Project meeting with @labmeraldi.bsky.social and Pavin Group in Srebreno near Dubrovnik! The labs teamed up instantly, with lots of brainstorming and cool ideas for new joint projects! #HRZZ @snsf-ch.bsky.social
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April 26, 2025 at 9:22 AM
Amazing energy at our second Swiss-Croatian Bilateral Project meeting with @labmeraldi.bsky.social and Pavin Group in Srebreno near Dubrovnik! The labs teamed up instantly, with lots of brainstorming and cool ideas for new joint projects! #HRZZ @snsf-ch.bsky.social
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Great memories from the joint meeting with the Meraldi Lab and Pavin Group last year in Split! Can't wait for this year's meeting, which starts tomorrow! Excited for more cool science through our Swiss-Croatian Bilateral Project #HRZZ @snsf-ch.bsky.social 🇭🇷🇨🇭
April 8, 2025 at 6:29 AM
Great memories from the joint meeting with the Meraldi Lab and Pavin Group last year in Split! Can't wait for this year's meeting, which starts tomorrow! Excited for more cool science through our Swiss-Croatian Bilateral Project #HRZZ @snsf-ch.bsky.social 🇭🇷🇨🇭
Perfect for PhD students and postdocs! www.atoutcom.com/shaping-life...
March 21, 2025 at 12:54 PM
Perfect for PhD students and postdocs! www.atoutcom.com/shaping-life...
Happy first day of spring from our Institute @institutrb.bsky.social!
March 20, 2025 at 8:52 PM
Happy first day of spring from our Institute @institutrb.bsky.social!
Join us for this small, intensive workshop in the remote Alpine town of Arolla, where we will explore the dynamics of living systems across scales, from the cytoskeleton to embryos. Let’s dive into how cellular and tissue-scale dynamics shape life itself! meetings.ls2.ch/arolla2025
March 16, 2025 at 6:38 PM
Join us for this small, intensive workshop in the remote Alpine town of Arolla, where we will explore the dynamics of living systems across scales, from the cytoskeleton to embryos. Let’s dive into how cellular and tissue-scale dynamics shape life itself! meetings.ls2.ch/arolla2025
🎉 Congrats to @lgudlin.bsky.social, @krunovuk.bsky.social, and Maja Novak for the awesome work! This was a super fun collaboration with Nenad Pavin, including our ERC Synergy team @erc.europa.eu - @kopslab.bsky.social and MIT. Special thanks to Zuzana Storchova, Josip Tambača, and Matko Ljulj! 🚀
March 10, 2025 at 4:25 PM
🎉 Congrats to @lgudlin.bsky.social, @krunovuk.bsky.social, and Maja Novak for the awesome work! This was a super fun collaboration with Nenad Pavin, including our ERC Synergy team @erc.europa.eu - @kopslab.bsky.social and MIT. Special thanks to Zuzana Storchova, Josip Tambača, and Matko Ljulj! 🚀