In the closing talk of #SpindleCroatia2026, Helder Maiato discussed how dividing cells adapt to karyotype evolution. Using Indian muntjac (2N=6/7) and Chinese muntjac (2N=46) cells, they showed that high chromosome number is a critical mitotic vulnerability.

Monica Gobran showed that when CDK1 is partially inhibited, nuclear pores begin to disassemble, but the overall structure of the nuclear envelope remains intact, similar to closed mitosis. The spindle forms outside the nucleus. #SpindleCroatia2026

Jacques Pécréaux used FRAP of the half-spindle in C. elegans and revealed that only kinetochore microtubules exhibit flux, sliding along pole-anchored ones. The flux is larger on the posterior side, reflecting the imbalance in cortical pulling forces. #SpindleCroatia2026

Régis Giet showed that, in Drosophila neural stem cells, the number of astral microtubules nucleated by each centrosome determines the spindle position. Asymmetric pushing forces, rather than cortical pulling, dominate spindle positioning. #SpindleCroatia2026

Arp Schnittger @schnittger-lab.bsky.social examined kinetochores in plant meiosis, focusing on how mono‑orientation of sister kinetochores is achieved. Arabidopsis has a homolog of Csm1, a monopolin component, with a function in kinetochore organization and mono‑orientation. #SpindleCroatia2026

Gautam Dey @gautamdey.bsky.social discussed spindle evolutionary dynamics. In Chlamy, an MTOC forms in prophase to nucleate the spindle, but remains tethered to the basal bodies. By using ExM, they plan to expand every microbial eukaryote on Earth! #SpindleCroatia2026

Marija Žanić @zaniclab.bsky.social used EB1 imaging to determine the relationship between microtubule GTP-cap size and growth rate throughout the cell cycle. GTP-cap size for matching growth rates drops during mitosis, suggesting active regulation of the hydrolysis rate. #SpindleCroatia2026

Ana Pinto Teixeira @carlos-conde.bsky.social showed that excessive MPS1 activity drives CIN by promoting an untimely expansion of the fibrous corona, providing a structural basis for merotely and chromosome missegregation in colon cancer. #SpindleCroatia2026

Verena Cmentowski @vcmentowski.bsky.social explored the mechanism that triggers dynein activation at kinetochores. CENP‑E facilitates the recruitment of dynein-dynactin and cofactors to kinetochores and regulates dynein motility. #SpindleCroatia2026

Tarun Kapoor developed a chemical genetic approach to analyze the functions of VPS4, a key protein required for nuclear envelope repair in human cells. Upon VPS4 inhibition, CHMP7 persists, and inner nuclear membrane defects form, leading to DNA damage. #SpindleCroatia2026

Julie Welburn @jwelburn.bsky.social showed the molecular basis for how PRC1 recruits CENP-E to the central spindle in anaphase. She also explored how drug binding varies with beta-tubulin isotypes, showing that human meiotic beta8-tubulin has a reduced sensitivity to nocodazole. #SpindleCroatia2026

Marin Barišić @barisiclab.bsky.social showed that acentrosomal cells often divide with uncongressed chromosomes. Lack of Aurora A at the poles of acentrosomal spindles is the main cause of chromosome missegregation. #SpindleCroatia2026

Spindle squad #SpindleCroatia2026 #Dubrovnik www.phy.pmf.unizg.hr/~mitosis/

Ryota Uehara identified TPX2 as an adaptive factor for mitotic control after whole-genome duplication. TPX2 depletion caused multipolar spindles selectively in tetraploids. These cells required longer spindles to maintain their bipolarity than diploids. #SpindleCroatia2026

Véronique Marthiens asked how tissue properties affect mitosis. In the mammalian embryonic brain, biomechanical constraints enhance neural stem cell vulnerability by increasing microtubule growth and chromosome missegregation via cortical tension. #SpindleCroatia2026

Gerben Vader @vaderlab.bsky.social discussed mitotic vulnerabilities in chromosomally unstable cancer cells. KIF18A is a selective target causing chromosome misalignment and prolonged mitosis. “KIF18A-like” vulnerabilities are now being explored to expand anti-mitotic therapies. #SpindleCroatia2026

Beth Weaver explored the effect of microtubule-targeting agents on cancer cells and found that paclitaxel induces multipolar spindles without mitotic arrest in breast cancer. Pole focusing is a major mechanism of resistance. #SpindleCroatia2026

Geert Kops @kopslab.bsky.social showed beautiful fibrous coronas in bovine oocytes, which extend far beyond the kinetochores. The corona nucleates microtubules and promotes spindle assembly, but it may also be a liability if it completely encapsulates the chromosome. #SpindleCroatia2026

Ido Lavi developed a kinetic model in which RanGTP-regulated nucleators bind to microtubules and induce branching, while the microtubules polymerize at (+) ends and are transported poleward by Eg5. Multistep branching is important to get the right polarity. #SpindleCroatia2026

Martin Würtz @wuertzmartin.bsky.social explored augmin-microtubule interactions and showed that stable microtubule anchoring is mediated by the calponin homology domain of HAUS6, which determines the orientation of the augmin complex during microtubule branching. #SpindleCroatia2026

Ivana Gašić @ivanagasic.bsky.social showed that gamma-tubulin is regulated by the same machinery that regulates alpha-beta-tubulin levels, including TTC5, SCAPER, and CCR4-NOT. Disruption of this regulation compromises mitotic fidelity. #SpindleCroatia2026

Day3 of #SpindleCroatia2026! Arshad Desai @odlab.bsky.social showed that TRIM37 loss restores rapid spindle assembly in acentriolar cells by enabling the formation of pseudo-centrosomes. CDK5RAP2 was dispensable for this, but PLK4's CPB was required.

Kristjana Skendo from @labmeraldi.bsky.social showed that HURP, NuSAP, and Kid localize to bridging fibers in metaphase and, together with HAUS6/Augmin, act downstream of TPX2. Combined depletions lead to shorter overlaps, chromosome misalignment, and segregation errors. #SpindleCroatia2026

William Conway used cryo-electron tomography to map microtubule polarity in human metaphase spindles, and found that microtubules form locally antiparallel bundles with 8 nm wall-to-wall spacing. The spacing scaled inversely with microtubule density. #SpindleCroatia2026

Zachary Mullin-Bernstein from @dumontlabucsf.bsky.social used microneedle manipulation to pull on anaphase midzone bundles. The bundles locally transmit force to each other in the spindle’s short axis, and globally, leading to spindle shortening. #SpindleCroatia2026

Tomomi Kiyomitsu showed that short metaphase asters create a halo-like cytoplasmic concentration of dynein around aster tips in medaka early embryos. In anaphase, dynein relocates from the halo to growing asters, promoting successful cytokinesis. #SpindleCroatia2026

Andrew McAinsh showed that the first mitosis in human embryos is highly error-prone. MCAK agonist reduces multipolar divisions and those with multiple lagging chromosomes. Mosaicism is normal physiology in humans, and it may promote implantation. #SpindleCroatia2026

Tomoya Kitajima is designing different bead-based artificial kinetochores with the selected capabilities of microtubule attachment, force sensing, and spindle checkpoint activation in cells. They used NDC80-NUF2 beads as a tool to reduce errors in oocytes. #SpindleCroatia2026

Samya Aich asked what the minimal components for building a centriole are. He developed a synthetic phase-separated condensate platform, where Cep63 was sufficient for cartwheel assembly, and STIL overexpression led to procentriole assembly. #SpindleCroatia2026

Rita Tewari @ritatewari.bsky.social presented the unconventional mitosis in the malaria parasite. The Aurora-related kinase ARK1 is part of a highly divergent chromosomal passenger complex, whereas ARK2 interacts with EB1 and Myosin-K. #SpindleCroatia2026