@article{19404, abstract = {Cell migration is a fundamental process during embryonic development. Most studies in vivo have focused on the migration of cells using the extracellular matrix (ECM) as their substrate for migration. In contrast, much less is known about how cells migrate on other cells, as found in early embryos when the ECM has not yet formed. Here, we show that lateral mesendoderm (LME) cells in the early zebrafish gastrula use the ectoderm as their substrate for migration. We show that the lateral ectoderm is permissive for the animal-pole-directed migration of LME cells, while the ectoderm at the animal pole halts it. These differences in permissiveness depend on the lateral ectoderm being more cohesive than the animal ectoderm, a property controlled by bone morphogenetic protein (BMP) signaling within the ectoderm. Collectively, these findings identify ectoderm tissue cohesion as one critical factor in regulating LME migration during zebrafish gastrulation.}, author = {Tavano, Ste and Brückner, David and Tasciyan, Saren and Tong, Xin and Kardos, Roland and Schauer, Alexandra and Hauschild, Robert and Heisenberg, Carl-Philipp J}, issn = {2211-1247}, journal = {Cell Reports}, number = {3}, publisher = {Elsevier}, title = {{BMP-dependent patterning of ectoderm tissue material properties modulates lateral mesendoderm cell migration during early zebrafish gastrulation}}, doi = {10.1016/j.celrep.2025.115387}, volume = {44}, year = {2025}, } @article{19626, abstract = {Active regulation of gene expression, orchestrated by complex interactions of activators and repressors at promoters, controls the fate of organisms. In contrast, basal expression at uninduced promoters is considered to be a dynamically inert mode of nonfunctional “promoter leakiness,” merely a byproduct of transcriptional regulation. Here, we investigate the basal expression mode of the mar operon, the main regulator of intrinsic multiple antibiotic resistance in Escherichia coli, and link its dynamic properties to the noncanonical, yet highly conserved start codon of marR across Enterobacteriaceae. Real-time, single-cell measurements across tens of generations reveal that basal expression consists of rare stochastic gene expression pulses, which maximize variability in wildtype and, surprisingly, transiently accelerate cellular elongation rates. Competition experiments show that basal expression confers fitness advantages to wildtype across several transitions between exponential and stationary growth by shortening lag times. The dynamically rich basal expression of the mar operon has likely been evolutionarily maintained for its role in growth homeostasis of Enterobacteria within the gut environment, thereby allowing other ancillary gene regulatory roles to evolve, e.g., control of costly-to-induce multidrug efflux pumps. Understanding the complex selection forces governing genetic systems involved in intrinsic multidrug resistance is crucial for effective public health measures.}, author = {Jain, Kirti and Hauschild, Robert and Bochkareva, Olga and Römhild, Roderich and Tkačik, Gašper and Guet, Calin C}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, number = {15}, publisher = {National Academy of Sciences}, title = {{Pulsatile basal gene expression as a fitness determinant in bacteria}}, doi = {10.1073/pnas.2413709122}, volume = {122}, year = {2025}, } @article{19663, abstract = {The centrosome is a microtubule orchestrator, nucleating and anchoring microtubules that grow radially and exert forces on cargos. At the same time, mechanical stresses from the microenvironment and cellular shape changes compress and bend microtubules. Yet, centrosomes are membraneless organelles, raising the question of how centrosomes withstand mechanical forces. Here, we discover that centrosomes can deform and even fracture. We reveal that centrosomes experience deformations during navigational pathfinding within motile cells. Coherence of the centrosome is maintained by Dyrk3 and cNAP1, preventing fracturing by forces. While cells can compensate for the depletion of centriolar-based centrosomes, the fracturing of centrosomes impedes cellular function by generating coexisting microtubule organizing centers that compete during path navigation and thereby cause cellular entanglement in the microenvironment. Our findings show that cells actively maintain the integrity of the centrosome to withstand mechanical forces. These results suggest that centrosome stability preservation is fundamental, given that almost all cells in multicellular organisms experience forces.}, author = {Schmitt, Madeleine T. and Kroll, Janina and Ruiz-Fernandez, Mauricio J.A. and Hauschild, Robert and Ghosh, Shaunak and Kameritsch, Petra and Merrin, Jack and Schmid, Johanna and Stefanowski, Kasia and Thomae, Andreas W. and Cheng, Jingyuan and Öztan, Gamze Naz and Konopka, Peter and Ortega, Germán Camargo and Penz, Thomas and Bach, Luisa and Baumjohann, Dirk and Bock, Christoph and Straub, Tobias and Meissner, Felix and Kiermaier, Eva and Renkawitz, Jörg}, issn = {2375-2548}, journal = {Science Advances}, number = {17}, publisher = {AAAS}, title = {{Protecting centrosomes from fracturing enables efficient cell navigation}}, doi = {10.1126/sciadv.adx4047}, volume = {11}, year = {2025}, } @article{19704, abstract = {The information-processing capability of the brain’s cellular network depends on the physical wiring pattern between neurons and their molecular and functional characteristics. Mapping neurons and resolving their individual synaptic connections can be achieved by volumetric imaging at nanoscale resolution1,2 with dense cellular labelling. Light microscopy is uniquely positioned to visualize specific molecules, but dense, synapse-level circuit reconstruction by light microscopy has been out of reach, owing to limitations in resolution, contrast and volumetric imaging capability. Here we describe light-microscopy-based connectomics (LICONN). We integrated specifically engineered hydrogel embedding and expansion with comprehensive deep-learning-based segmentation and analysis of connectivity, thereby directly incorporating molecular information into synapse-level reconstructions of brain tissue. LICONN will allow synapse-level phenotyping of brain tissue in biological experiments in a readily adoptable manner.}, author = {Tavakoli, Mojtaba and Lyudchik, Julia and Januszewski, Michał and Vistunou, Vitali and Agudelo Duenas, Nathalie and Vorlaufer, Jakob and Sommer, Christoph M and Kreuzinger, Caroline and Oliveira, Bárbara and Cenameri, Alban and Novarino, Gaia and Jain, Viren and Danzl, Johann G}, issn = {1476-4687}, journal = {Nature}, pages = {398--410}, publisher = {Springer Nature}, title = {{Light-microscopy-based connectomic reconstruction of mammalian brain tissue}}, doi = {10.1038/s41586-025-08985-1}, volume = {642}, year = {2025}, } @inproceedings{20055, abstract = {Supercrystals represent three-dimensional orderings of colloidal nanocrystals (NCs), showcasing collective properties in photonics, phononics, and electronics applications.1,2 Recent studies have shown that such assemblies are directly produced during nanocrystal reactions.3–6 However, a fundamental understanding of in situ formed supercrystals that withstand typical NC purification processes remains underexplored, which is important for further use. Herein, we report the reaction precursor-mediated formation of stable PbTe supercrystals. Rationalizing the formation of these assemblies through small-angle x-ray scattering (SAXS) measurements, we unveil their formation mechanism. Our findings reveal that the supercrystal formation occurs in the presence of an excess of lead oleates in the crude solution. It should be noted that the formed supercrystals can be stabilized under specific conditions determined by the lead oleate cluster concentration, content of trioctylphosphine telluride (TOP-Te), NC size and the need of an annealing step at mild conditions. Furthermore, this approach allows for the continuous growth of a secondary phase within the supercrystal; for example in the case of PbTe supercrystals, a PbS shell can be grown on each PbTe NC constituent, resulting in core-shell PbTe-PbS supercrystals. Our work elucidates that reaction precursors play an important role in in situ SC formation and stabilization, implying the possibility of applying this knowledge to other NC reactions.}, author = {Lee, Seungho and Balazs, Daniel and Horta, Sharona and Rayaroth Puthiyaveettil, Aiswarya and Ibáñez, Maria}, booktitle = {Proceedings of the MATSUS Spring 2025 Conference}, location = {Sevilla, Spain}, publisher = {Fundació de la comunitat valenciana SCITO}, title = {{Reaction precursor-mediated formation of stable supercrystals in colloidal nanocrystal synthesis: PbTe case}}, doi = {10.29363/nanoge.matsusspring.2025.173}, year = {2025}, } @article{20082, abstract = {Efficient immune responses rely on the capacity of leukocytes to traverse diverse and complex tissues. To meet such changing environmental conditions, leukocytes usually adopt an ameboid configuration, using their forward-positioned nucleus as a probe to identify and follow the path of least resistance among pre-existing pores. We show that, in dense environments where even the largest pores preclude free passage, leukocytes position their nucleus behind the centrosome and organelles. The local compression imposed on the cell body by its surroundings triggers assembly of a central F-actin pool, located between cell front and nucleus. Central actin pushes outward to transiently dilate a path for organelles and nucleus. Pools of central and front actin are tightly coupled and experimental depletion of the central pool enhances actin accumulation and protrusion formation at the cell front. Although this shifted balance speeds up cells in permissive environments, migration in restrictive environments is impaired, as the unleashed leading edge dissociates from the trapped cell body. Our findings establish an actin regulatory loop that balances path dilation with advancement of the leading edge to maintain cellular coherence.}, author = {Dos Reis Rodrigues, Patricia and Avellaneda Sarrió, Mario and Canigova, Nikola and Gärtner, Florian R and Vaahtomeri, Kari and Riedl, Michael and De Vries, Ingrid and Merrin, Jack and Hauschild, Robert and Fukui, Yoshinori and Juanes Garcia, Alba and Sixt, Michael K}, issn = {1529-2916}, journal = {Nature Immunology}, pages = {1258–1266}, publisher = {Springer Nature}, title = {{Migrating immune cells globally coordinate protrusive forces}}, doi = {10.1038/s41590-025-02211-w}, volume = {26}, year = {2025}, } @techreport{20146, abstract = {This criteria catalogue and the accompanying assessment questions were developed by a working group of KEMÖ (Kooperation E-Medien Österreich, the Austrian Academic Library Consortium). They are intended to support research institutions and organisations in the evaluation of Open Science Infrastructures. The 20 criteria outlined in the catalogue provide a structured basis for making informed decisions regarding the financial support of these infrastructures. The assessment questions are intended to be completed by Open Science Infrastructures and can be shared with them accordingly.}, author = {Gredler, Paul and Kaier, Christian and Danowski, Patrick and Zoyer, Michael and Rieck, Katharina and Ferus, Andreas and Rosenberger, Elisabeth and Löffler, Alexander and Hofer, Lisa and Still, Laura}, publisher = {Zenodo}, title = {{Catalogue of criteria for assessing the funding eligibility of Open Science infrastructures}}, doi = {10.5281/zenodo.15269364}, year = {2025}, } @article{20295, abstract = {Scanning Kelvin probe microscopy (SKPM) is a powerful technique for macroscopic imaging of the electrostatic potential above a surface. Though most often used to image work-function variations of conductive surfaces, it can also be used to probe the surface charge on insulating surfaces. In both cases, relating the measured potential to the underlying signal is non-trivial. Here, general relationships are derived between the measured SKPM voltage and the underlying source, revealing either can be cast as a convolution with an appropriately scaled point spread function (PSF). For charge that exists on a thin insulating layer above a conductor, the PSF has the same shape as what would occur from a work-function variation alone, differing by a simple scaling factor. This relationship is confirmed by: (1) backing it out from finite-element simulations of work-function and charge signals, and (2) experimentally comparing the measured PSF from a small work-function target to that from a small charge spot. This scaling factor is further validated by comparing SKPM charge measurements with Faraday cup measurements for highly charged samples from contact-charging experiments. These results highlight a heretofore unappreciated connection between SKPM voltage and charge signals, offering a rigorous recipe to extract either from experimental data.}, author = {Lenton, Isaac C and Pertl, Felix and Shafeek, Lubuna B and Waitukaitis, Scott R}, issn = {2196-7350}, journal = {Advanced Materials Interfaces}, number = {19}, publisher = {Wiley}, title = {{A duality between surface charge and work function in scanning Kelvin probe microscopy}}, doi = {10.1002/admi.202500521}, volume = {12}, year = {2025}, } @article{20321, abstract = {Microsecond-to-millisecond motions are instrumental for many biomolecular functions, including enzymatic activity and ligand binding. Bloch-McConnell Relaxation Dispersion (BMRD) Nuclear Magnetic Resonance (NMR) spectroscopy is a key technique for studying these dynamic processes. While BMRD experiments are routinely used to probe protein motions in solution, the experiment is more demanding in the solid state, where dipolar couplings complicate the spin dynamics. It is believed that high deuteration levels are required and sufficient to obtain accurate and quantitative data. Here we show that even under fast magic-angle spinning and high levels of deuteration artifactual “bumps” in 15N R1ρ BMRD profiles are common. The origin of these artifacts is identified as a second-order three-spin Mixed Rotational and Rotary Resonance (MIRROR) recoupling condition. These artifacts are found to be a significant confounding factor for the accurate quantification of microsecond protein dynamics using BMRD in the solid state. We show that the application of low-power continuous wave (CW) decoupling simultaneously with the 15N spin-lock leads to the suppression of these conditions and enables quantitative measurements of microsecond exchange in the solid state. Remarkably, the application of decoupling allows the measurement of accurate BMRD even in fully protonated proteins at 100 kHz MAS, thus extending the scope of μs dynamics measurements in MAS NMR.}, author = {Tatman, Benjamin and Sridharan, Vidhyalakshmi and Uttarkabat, Motilal and Jaroniec, Christopher P. and Ernst, Matthias and Rovo, Petra and Schanda, Paul}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {32}, pages = {29315--29326}, publisher = {American Chemical Society}, title = {{Bumps on the road: The way to clean relaxation dispersion magic-angle spinning NMR}}, doi = {10.1021/jacs.5c09057}, volume = {147}, year = {2025}, } @article{17468, abstract = {Oxygen redox chemistry is central to life1 and many human-made technologies, such as in energy storage2,3,4. The large energy gain from oxygen redox reactions is often connected with the occurrence of harmful reactive oxygen species3,5,6. Key species are superoxide and the highly reactive singlet oxygen3,4,5,6,7, which may evolve from superoxide. However, the factors determining the formation of singlet oxygen, rather than the relatively unreactive triplet oxygen, are unknown. Here we report that the release of triplet or singlet oxygen is governed by individual Marcus normal and inverted region behaviour. We found that as the driving force for the reaction increases, the initially dominant evolution of triplet oxygen slows down, and singlet oxygen evolution becomes predominant with higher maximum kinetics. This behaviour also applies to the widely observed superoxide disproportionation, in which one superoxide is oxidized by another, in both non-aqueous and aqueous systems, with Lewis and Brønsted acidity controlling the driving forces. Singlet oxygen yields governed by these conditions are relevant, for example, in batteries or cellular organelles in which superoxide forms. Our findings suggest ways to understand and control spin states and kinetics in oxygen redox chemistry, with implications for fields, including life sciences, pure chemistry and energy storage.}, author = {Mondal, Soumyadip and Nguyen, Huyen T.K. and Hauschild, Robert and Freunberger, Stefan Alexander}, issn = {1476-4687}, journal = {Nature}, number = {8085}, pages = {601–605}, publisher = {Springer Nature}, title = {{Marcus kinetics control singlet and triplet oxygen evolving from superoxide}}, doi = {10.1038/s41586-025-09587-7}, volume = {646}, year = {2025}, } @unpublished{21427, abstract = {While tumor malignancy has been extensively studied under the prism of genetic and epigenetic heterogeneity, tumor cell states also critically depend on reciprocal interactions with the microenvironment. This raises the hitherto untested possibility that heterogeneity of the untransformed tumor stroma can actively fuel malignant progression. As biological heterogeneity is inherently difficult to control, we adopted a reductionist approach and let tumor cells invade micro-engineered environments harboring obstacles with precision-controlled geometry. We find that not only the presence of obstacles, but more surprisingly their spatial disorder, causes a drastic shift from a collective to a single-cell mode of invasion – comparable in strength to cadherin loss. Combining live-imaging and perturbation experiments with minimal biophysical modeling, we demonstrate that cell detachments result both from local geometrical constraints and a global integration of spatial disorder over time. We show that different types of microenvironments map onto different universality classes of invasion dynamics - homogeneous substrates follow Kardar–Parisi–Zhang (KPZ) scaling, while disordered ones exhibit exponents consistent with KPZ with quenched disorder (KPZq). Our findings highlight generic physical principles for how the mode of cancer cell invasion depends on environmental heterogeneity, with potential implications to understand tumor evolution in vivo.}, author = {Dunajova, Zuzana and Tasciyan, Saren and Majek, Juraj and Merrin, Jack and Sahai, Erik and Sixt, Michael K and Hannezo, Edouard B}, booktitle = {bioRxiv}, title = {{Substrate heterogeneity promotes cancer cell dissemination through interface roughening}}, doi = {10.1101/2025.05.20.655037}, year = {2025}, } @article{20326, abstract = {Ag2Se is a promising n-type thermoelectric material, but its performance is limited by excessive carrier concentration, compositional inhomogeneity, and phase instability, challenges rooted in a narrow homogeneity range and uncontrolled Ag+ diffusion in the superionic phase. Here, we address these issues by exploiting liquid–solid interface reactions using CdSe complexes that remove surface excess Ag to yield stoichiometric Ag2Se and generate CdSe nanodomains that inhibit Ag+ diffusion and constrain grain growth. The resulting Ag2Se-CdSe nanocomposites exhibit a reproducible, stable figure of merit (zT) of 1.04 between 300 and 390 K. Beyond demonstrating high performance, we elucidate the interfacial chemical reactions that give rise to the observed microstructure and transport properties, providing a foundation for rationally engineering interfacial chemistry to tailor transport properties across diverse thermoelectric material systems.}, author = {Liu, Yu and Kleinhanns, Tobias and Horta, Sharona and Dutkiewicz, Ewelina and Lu, Shaoqing and Spadaro, Maria Chiara and Genç, Aziz and Chen, Lei and Lim, Khak Ho and Hong, Min and Arbiol, Jordi and Ibáñez, Maria}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {35}, pages = {32199--32208}, publisher = {American Chemical Society}, title = {{Liquid-solid interface reactions drive enhanced thermoelectric performance in Ag2Se}}, doi = {10.1021/jacs.5c11435}, volume = {147}, year = {2025}, } @article{19278, abstract = {When two insulating, neutral materials are contacted and separated, they exchange electrical charge1. Experiments have long suggested that this ‘contact electrification’ is transitive, with different materials ordering into ‘triboelectric series’ based on the sign of charge acquired2. At the same time, the effect is plagued by unpredictability, preventing consensus on the mechanism and casting doubt on the rhyme and reason that series imply3. Here we expose an unanticipated connection between the unpredictability and order in contact electrification: nominally identical materials initially exchange charge randomly and intransitively, but—over repeated experiments—order into triboelectric series. We find that this evolution is driven by the act of contact itself—samples with more contacts in their history charge negatively to ones with fewer contacts. Capturing this ‘contact bias’ in a minimal model, we recreate both the initial randomness and ultimate order in numerical simulations and use it experimentally to force the appearance of a triboelectric series of our choosing. With a set of surface-sensitive techniques to search for the underlying alterations contact creates, we only find evidence of nanoscale morphological changes, pointing to a mechanism strongly coupled with mechanics. Our results highlight the centrality of contact history in contact electrification and suggest that focusing on the unpredictability that has long plagued the effect may hold the key to understanding it.}, author = {Sobarzo Ponce, Juan Carlos A and Pertl, Felix and Balazs, Daniel and Costanzo, Tommaso and Sauer, Markus and Foelske, Annette and Ostermann, Markus and Pichler, Christian M. and Wang, Yongkang and Nagata, Yuki and Bonn, Mischa and Waitukaitis, Scott R}, issn = {1476-4687}, journal = {Nature}, number = {8051}, publisher = {Springer Nature}, title = {{Spontaneous ordering of identical materials into a triboelectric series}}, doi = {10.1038/s41586-024-08530-6}, volume = {638}, year = {2025}, } @article{19795, abstract = {Super-resolution microscopy often entails long acquisition times of minutes to hours. Since drifts during the acquisition adversely affect data quality, active sample stabilization is commonly used for some of these techniques to reach their full potential. Although drifts in the lateral plane can often be corrected after acquisition, this is not always possible or may come with drawbacks. Therefore, it is appealing to stabilize sample position in three dimensions (3D) during acquisition. Various schemes for active sample stabilization have been demonstrated previously, with some reaching sub-nanometer stability in 3D. Here, we present a scheme for active drift correction that delivers the nanometer-scale 3D stability demanded by state-of-the-art super-resolution techniques and is straightforward to implement compared to previous schemes capable of reaching this level of stabilization precision. Using a refined algorithm that can handle various types of reference structure, without sparse signal peaks being mandatory, we stabilized sample position to ∼1 nm in 3D using objective lenses both with high and low numerical aperture. Our implementation requires only the addition of a simple widefield imaging path and we provide an open-source control software with graphical user interface to facilitate easy adoption of the module. Finally, we demonstrate how this has the potential to enhance data collection for diffraction-limited and super-resolution imaging techniques using single-molecule localization microscopy and cryo-confocal imaging as showcases.}, author = {Vorlaufer, Jakob and Semenov, Nikolai and Kreuzinger, Caroline and Javoor, Manjunath and Zens, Bettina and Agudelo Duenas, Nathalie and Tavakoli, Mojtaba and Suplata, Marek and Jahr, Wiebke and Lyudchik, Julia and Wartak, Andreas and Schur, Florian Km and Danzl, Johann G}, issn = {2667-0747}, journal = {Biophysical Reports}, number = {2}, publisher = {Elsevier}, title = {{Image-based 3D active sample stabilization on the nanometer scale for optical microscopy}}, doi = {10.1016/j.bpr.2025.100211}, volume = {5}, year = {2025}, } @article{18807, abstract = {Developing tissues interpret dynamic changes in morphogen activity to generate cell type diversity. To quantitatively study bone morphogenetic protein (BMP) signaling dynamics in the mouse neural tube, we developed an embryonic stem cell differentiation system tailored for growing tissues. Differentiating cells form striking self-organized patterns of dorsal neural tube cell types driven by sequential phases of BMP signaling that are observed both in vitro and in vivo. Data-driven biophysical modeling showed that these dynamics result from coupling fast negative feedback with slow positive regulation of signaling by the specification of an endogenous BMP source. Thus, in contrast to relays that propagate morphogen signaling in space, we identify a BMP signaling relay that operates in time. This mechanism allows for a rapid initial concentration-sensitive response that is robustly terminated, thereby regulating balanced sequential cell type generation. Our study provides an experimental and theoretical framework to understand how signaling dynamics are exploited in developing tissues.}, author = {Rus, Stefanie and Brückner, David and Minchington, Thomas and Greunz, Martina and Merrin, Jack and Hannezo, Edouard B and Kicheva, Anna}, issn = {1534-5807}, journal = {Developmental Cell}, number = {4}, pages = {567--580}, publisher = {Elsevier}, title = {{Self-organized pattern formation in the developing mouse neural tube by a temporal relay of BMP signaling}}, doi = {10.1016/j.devcel.2024.10.024}, volume = {60}, year = {2025}, } @article{14257, abstract = {Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here we developed Comprehensive Analysis of Tissues across Scales (CATS), a technology to densely map brain tissue architecture from millimeter regional to nanometer synaptic scales in diverse chemically fixed brain preparations, including rodent and human. CATS uses fixation-compatible extracellular labeling and optical imaging, including stimulated emission depletion or expansion microscopy, to comprehensively delineate cellular structures. It enables three-dimensional reconstruction of single synapses and mapping of synaptic connectivity by identification and analysis of putative synaptic cleft regions. Applying CATS to the mouse hippocampal mossy fiber circuitry, we reconstructed and quantified the synaptic input and output structure of identified neurons. We furthermore demonstrate applicability to clinically derived human tissue samples, including formalin-fixed paraffin-embedded routine diagnostic specimens, for visualizing the cellular architecture of brain tissue in health and disease.}, author = {Michalska, Julia M and Lyudchik, Julia and Velicky, Philipp and Korinkova, Hana and Watson, Jake and Cenameri, Alban and Sommer, Christoph M and Amberg, Nicole and Venturino, Alessandro and Roessler, Karl and Czech, Thomas and Höftberger, Romana and Siegert, Sandra and Novarino, Gaia and Jonas, Peter M and Danzl, Johann G}, issn = {1546-1696}, journal = {Nature Biotechnology}, pages = {1051--1064}, publisher = {Springer Nature}, title = {{Imaging brain tissue architecture across millimeter to nanometer scales}}, doi = {10.1038/s41587-023-01911-8}, volume = {42}, year = {2024}, } @article{14795, abstract = {Metazoan development relies on the formation and remodeling of cell-cell contacts. Dynamic reorganization of adhesion receptors and the actomyosin cell cortex in space and time plays a central role in cell-cell contact formation and maturation. Nevertheless, how this process is mechanistically achieved when new contacts are formed remains unclear. Here, by building a biomimetic assay composed of progenitor cells adhering to supported lipid bilayers functionalized with E-cadherin ectodomains, we show that cortical F-actin flows, driven by the depletion of myosin-2 at the cell contact center, mediate the dynamic reorganization of adhesion receptors and cell cortex at the contact. E-cadherin-dependent downregulation of the small GTPase RhoA at the forming contact leads to both a depletion of myosin-2 and a decrease of F-actin at the contact center. At the contact rim, in contrast, myosin-2 becomes enriched by the retraction of bleb-like protrusions, resulting in a cortical tension gradient from the contact rim to its center. This tension gradient, in turn, triggers centrifugal F-actin flows, leading to further accumulation of F-actin at the contact rim and the progressive redistribution of E-cadherin from the contact center to the rim. Eventually, this combination of actomyosin downregulation and flows at the contact determines the characteristic molecular organization, with E-cadherin and F-actin accumulating at the contact rim, where they are needed to mechanically link the contractile cortices of the adhering cells.}, author = {Arslan, Feyza N and Hannezo, Edouard B and Merrin, Jack and Loose, Martin and Heisenberg, Carl-Philipp J}, issn = {1879-0445}, journal = {Current Biology}, number = {1}, pages = {171--182.e8}, publisher = {Elsevier}, title = {{Adhesion-induced cortical flows pattern E-cadherin-mediated cell contacts}}, doi = {10.1016/j.cub.2023.11.067}, volume = {34}, year = {2024}, } @article{14846, abstract = {Contraction and flow of the actin cell cortex have emerged as a common principle by which cells reorganize their cytoplasm and take shape. However, how these cortical flows interact with adjacent cytoplasmic components, changing their form and localization, and how this affects cytoplasmic organization and cell shape remains unclear. Here we show that in ascidian oocytes, the cooperative activities of cortical actomyosin flows and deformation of the adjacent mitochondria-rich myoplasm drive oocyte cytoplasmic reorganization and shape changes following fertilization. We show that vegetal-directed cortical actomyosin flows, established upon oocyte fertilization, lead to both the accumulation of cortical actin at the vegetal pole of the zygote and compression and local buckling of the adjacent elastic solid-like myoplasm layer due to friction forces generated at their interface. Once cortical flows have ceased, the multiple myoplasm buckles resolve into one larger buckle, which again drives the formation of the contraction pole—a protuberance of the zygote’s vegetal pole where maternal mRNAs accumulate. Thus, our findings reveal a mechanism where cortical actomyosin network flows determine cytoplasmic reorganization and cell shape by deforming adjacent cytoplasmic components through friction forces.}, author = {Caballero Mancebo, Silvia and Shinde, Rushikesh and Bolger-Munro, Madison and Peruzzo, Matilda and Szep, Gregory and Steccari, Irene and Labrousse Arias, David and Zheden, Vanessa and Merrin, Jack and Callan-Jones, Andrew and Voituriez, Raphaël and Heisenberg, Carl-Philipp J}, issn = {1745-2481}, journal = {Nature Physics}, pages = {310--321}, publisher = {Springer Nature}, title = {{Friction forces determine cytoplasmic reorganization and shape changes of ascidian oocytes upon fertilization}}, doi = {10.1038/s41567-023-02302-1}, volume = {20}, year = {2024}, } @article{14979, abstract = {Poxviruses are among the largest double-stranded DNA viruses, with members such as variola virus, monkeypox virus and the vaccination strain vaccinia virus (VACV). Knowledge about the structural proteins that form the viral core has remained sparse. While major core proteins have been annotated via indirect experimental evidence, their structures have remained elusive and they could not be assigned to individual core features. Hence, which proteins constitute which layers of the core, such as the palisade layer and the inner core wall, has remained enigmatic. Here we show, using a multi-modal cryo-electron microscopy (cryo-EM) approach in combination with AlphaFold molecular modeling, that trimers formed by the cleavage product of VACV protein A10 are the key component of the palisade layer. This allows us to place previously obtained descriptions of protein interactions within the core wall into perspective and to provide a detailed model of poxvirus core architecture. Importantly, we show that interactions within A10 trimers are likely generalizable over members of orthopox- and parapoxviruses.}, author = {Datler, Julia and Hansen, Jesse and Thader, Andreas and Schlögl, Alois and Bauer, Lukas W and Hodirnau, Victor-Valentin and Schur, Florian KM}, issn = {1545-9985}, journal = {Nature Structural & Molecular Biology}, keywords = {Molecular Biology, Structural Biology}, pages = {1114--1123}, publisher = {Springer Nature}, title = {{Multi-modal cryo-EM reveals trimers of protein A10 to form the palisade layer in poxvirus cores}}, doi = {10.1038/s41594-023-01201-6}, volume = {31}, year = {2024}, } @article{15018, abstract = {The epitaxial growth of a strained Ge layer, which is a promising candidate for the channel material of a hole spin qubit, has been demonstrated on 300 mm Si wafers using commercially available Si0.3Ge0.7 strain relaxed buffer (SRB) layers. The assessment of the layer and the interface qualities for a buried strained Ge layer embedded in Si0.3Ge0.7 layers is reported. The XRD reciprocal space mapping confirmed that the reduction of the growth temperature enables the 2-dimensional growth of the Ge layer fully strained with respect to the Si0.3Ge0.7. Nevertheless, dislocations at the top and/or bottom interface of the Ge layer were observed by means of electron channeling contrast imaging, suggesting the importance of the careful dislocation assessment. The interface abruptness does not depend on the selection of the precursor gases, but it is strongly influenced by the growth temperature which affects the coverage of the surface H-passivation. The mobility of 2.7 × 105 cm2/Vs is promising, while the low percolation density of 3 × 1010 /cm2 measured with a Hall-bar device at 7 K illustrates the high quality of the heterostructure thanks to the high Si0.3Ge0.7 SRB quality.}, author = {Shimura, Yosuke and Godfrin, Clement and Hikavyy, Andriy and Li, Roy and Aguilera Servin, Juan L and Katsaros, Georgios and Favia, Paola and Han, Han and Wan, Danny and de Greve, Kristiaan and Loo, Roger}, issn = {1369-8001}, journal = {Materials Science in Semiconductor Processing}, keywords = {Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}, number = {5}, publisher = {Elsevier}, title = {{Compressively strained epitaxial Ge layers for quantum computing applications}}, doi = {10.1016/j.mssp.2024.108231}, volume = {174}, year = {2024}, }