@article{21860, abstract = {Glutamate excitotoxicity is a cell death mechanism triggered by accumulation of glutamate in the extracellular space. The α-ketoglutarate dehydrogenase complex (αKGDHC), an enzyme of the tricarboxylic acid cycle, represents a branching point controlling glutamate formation and its consumption as a fuel. Hence, modulation of the activity of αKGDHC might alter the amount of glutamate available for excitotoxic effects. To address this hypothesis, hippocampal neurons in primary co-culture with glial cells were exposed to zero-Mg2 buffer to elicit excitotoxicity through N-methyl-D-aspartic acid (NMDA) receptor disinhibition. Pretreatment of the cultures with succinyl phosphonate, to inhibit αKGDHC, enhanced excitotoxity, whereas promotion of αKGDHC activity by pretreatment with thiamine caused an opposite action. Moreover, NMDA receptor currents – but not those mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors – were potentiated in neurons with impaired αKGDHC activity and diminished in neurons with boosted αKGDHC activity. The sensitization of NMDA receptors involved mGluR1 activation and was accompanied by enhanced neuronal discharge activity, elevated basal cytosolic Ca2+ levels, and augmented Ca2+ responses evoked by glutamate application. These results suggest that mGluR1-mediated potentiation of NMDA receptors contributes to a mechanism by which inhibition of αKGDHC might exacerbate glutamate excitotoxicity.}, author = {Goeschl, Vanessa and Hotka, Matej and Hochreiter, Bernhard and Hilber, Karlheinz and Boehm, Stefan and Kozlov, Andrey V. and Kubista, Helmut}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {8}, publisher = {The Company of Biologists}, title = {{α-ketoglutarate dehydrogenase complex activity modulates glutamate excitotoxicity via metabotropic regulation of NMDA receptors in primary cultures}}, doi = {10.1242/jcs.264420}, volume = {139}, year = {2026}, } @article{20188, abstract = {Collective cell migration is coordinated by the front-to-rear intercellular propagation of EGFR-Ras-ERK pathway activation. However, the molecular mechanisms integrating front-to-rear information into this intercellular signaling cascade, particularly the determinants of cellular front-side specification, remain elusive. We visualized the activity of EGFR, Ras, Rac1 and Rab5A (hereafter Rab5) by using FRET biosensors and chemogenetic tools. Whereas EGFR activation was uniformly observed within cells, Ras activation was biased to the front side within cells. The polarized Ras activation depended on Merlin and Rac1, which also showed front-biased activation. Furthermore, Rab5, a crucial regulator of cell migration, demonstrated similar front-biased activation and was found to function downstream of Ras while being necessary for Rac1 activation. Thus, the positive feedback loop consisting of Ras, Rab5 and Rac1 is activated primarily at the front of collectively migrating cells. These findings offer new spatio-temporal insight into processing front–rear information during collective cell migration.}, author = {Jikko, Yuya and Deguchi, Eriko and Matsuda, Kimiya and Hino, Naoya and Tsukiji, Shinya and Matsuda, Michiyuki and Terai, Kenta}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {15}, publisher = {The Company of Biologists}, title = {{Front-biased activation of the Ras-Rab5-Rac1 loop coordinates collective cell migration}}, doi = {10.1242/jcs.263779}, volume = {138}, year = {2025}, } @article{15330, abstract = {Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development by controlling plasma membrane protein composition and cargo uptake. CME relies on the precise recruitment of regulators for vesicle maturation and release. Homologues of components of mammalian vesicle scission are strong candidates to be part of the scission machinery in plants, but the precise roles of these proteins in this process are not fully understood. Here, we characterised the roles of Plant Dynamin-Related Proteins 2 (DRP2s) and SH3-domain containing protein 2 (SH3P2), the plant homologue to Dynamins’ recruiters, like Endophilin and Amphiphysin, in the CME by combining high-resolution imaging of endocytic events in vivo and characterisation of the purified proteins in vitro. Although DRP2s and SH3P2 arrive similarly late during CME and physically interact, genetic analysis of the sh3p123 triple-mutant and complementation assays with non-SH3P2-interacting DRP2 variants suggests that SH3P2 does not directly recruit DRP2s to the site of endocytosis. These observations imply that despite the presence of many well-conserved endocytic components, plants have acquired a distinct mechanism for CME.}, author = {Gnyliukh, Nataliia and Johnson, Alexander J and Nagel, MK and Monzer, Aline and Babic, David and Hlavata, Annamaria and Alotaibi, SS and Isono, E and Loose, Martin and Friml, Jiří}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {8}, publisher = {The Company of Biologists}, title = {{Role of dynamin-related proteins 2 and SH3P2 in clathrin-mediated endocytosis in Arabidopsis thaliana}}, doi = {10.1242/jcs.261720}, volume = {137}, year = {2024}, } @article{14082, abstract = {Epithelial barrier function is commonly analyzed using transepithelial electrical resistance, which measures ion flux across a monolayer, or by adding traceable macromolecules and monitoring their passage across the monolayer. Although these methods measure changes in global barrier function, they lack the sensitivity needed to detect local or transient barrier breaches, and they do not reveal the location of barrier leaks. Therefore, we previously developed a method that we named the zinc-based ultrasensitive microscopic barrier assay (ZnUMBA), which overcomes these limitations, allowing for detection of local tight junction leaks with high spatiotemporal resolution. Here, we present expanded applications for ZnUMBA. ZnUMBA can be used in Xenopus embryos to measure the dynamics of barrier restoration and actin accumulation following laser injury. ZnUMBA can also be effectively utilized in developing zebrafish embryos as well as cultured monolayers of Madin–Darby canine kidney (MDCK) II epithelial cells. ZnUMBA is a powerful and flexible method that, with minimal optimization, can be applied to multiple systems to measure dynamic changes in barrier function with spatiotemporal precision.}, author = {Higashi, Tomohito and Stephenson, Rachel E. and Schwayer, Cornelia and Huljev, Karla and Higashi, Atsuko Y. and Heisenberg, Carl-Philipp J and Chiba, Hideki and Miller, Ann L.}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {15}, publisher = {The Company of Biologists}, title = {{ZnUMBA - a live imaging method to detect local barrier breaches}}, doi = {10.1242/jcs.260668}, volume = {136}, year = {2023}, } @article{14316, abstract = {Clathrin-mediated vesicle trafficking plays central roles in post-Golgi transport. In yeast (Saccharomyces cerevisiae), the AP-1 complex and GGA adaptors are predicted to generate distinct transport vesicles at the trans-Golgi network (TGN), and the epsin-related proteins Ent3p and Ent5p (collectively Ent3p/5p) act as accessories for these adaptors. Recently, we showed that vesicle transport from the TGN is crucial for yeast Rab5 (Vps21p)-mediated endosome formation, and that Ent3p/5p are crucial for this process, whereas AP-1 and GGA adaptors are dispensable. However, these observations were incompatible with previous studies showing that these adaptors are required for Ent3p/5p recruitment to the TGN, and thus the overall mechanism responsible for regulation of Vps21p activity remains ambiguous. Here, we investigated the functional relationships between clathrin adaptors in post-Golgi-mediated Vps21p activation. We show that AP-1 disruption in the ent3Δ5Δ mutant impaired transport of the Vps21p guanine nucleotide exchange factor Vps9p transport to the Vps21p compartment and severely reduced Vps21p activity. Additionally, GGA adaptors, the phosphatidylinositol-4-kinase Pik1p and Rab11 GTPases Ypt31p and Ypt32p were found to have partially overlapping functions for recruitment of AP-1 and Ent3p/5p to the TGN. These findings suggest a distinct role of clathrin adaptors for Vps21p activation in the TGN–endosome trafficking pathway.}, author = {Nagano, Makoto and Aoshima, Kaito and Shimamura, Hiroki and Siekhaus, Daria E and Toshima, Junko Y. and Toshima, Jiro}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {17}, publisher = {The Company of Biologists}, title = {{Distinct role of TGN-resident clathrin adaptors for Vps21p activation in the TGN-endosome trafficking pathway}}, doi = {10.1242/jcs.261448}, volume = {136}, year = {2023}, } @article{14827, abstract = {Understanding complex living systems, which are fundamentally constrained by physical phenomena, requires combining experimental data with theoretical physical and mathematical models. To develop such models, collaborations between experimental cell biologists and theoreticians are increasingly important but these two groups often face challenges achieving mutual understanding. To help navigate these challenges, this Perspective discusses different modelling approaches, including bottom-up hypothesis-driven and top-down data-driven models, and highlights their strengths and applications. Using cell mechanics as an example, we explore the integration of specific physical models with experimental data from the molecular, cellular and tissue level up to multiscale input. We also emphasize the importance of constraining model complexity and outline strategies for crosstalk between experimental design and model development. Furthermore, we highlight how physical models can provide conceptual insights and produce unifying and generalizable frameworks for biological phenomena. Overall, this Perspective aims to promote fruitful collaborations that advance our understanding of complex biological systems.}, author = {Schwayer, Cornelia and Brückner, David}, issn = {1477-9137}, journal = {Journal of Cell Science}, keywords = {Cell Biology}, number = {24}, publisher = {The Company of Biologists}, title = {{Connecting theory and experiment in cell and tissue mechanics}}, doi = {10.1242/jcs.261515}, volume = {136}, year = {2023}, } @article{12282, abstract = {From a simple thought to a multicellular movement}, author = {Amberg, Nicole and Stouffer, Melissa A and Vercellino, Irene}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {8}, publisher = {The Company of Biologists}, title = {{Operation STEM fatale – how an equity, diversity and inclusion initiative has brought us to reflect on the current challenges in cell biology and science as a whole}}, doi = {10.1242/jcs.260017}, volume = {135}, year = {2022}, } @article{12283, abstract = {Neurons extend axons to form the complex circuitry of the mature brain. This depends on the coordinated response and continuous remodelling of the microtubule and F-actin networks in the axonal growth cone. Growth cone architecture remains poorly understood at nanoscales. We therefore investigated mouse hippocampal neuron growth cones using cryo-electron tomography to directly visualise their three-dimensional subcellular architecture with molecular detail. Our data showed that the hexagonal arrays of actin bundles that form filopodia penetrate and terminate deep within the growth cone interior. We directly observed the modulation of these and other growth cone actin bundles by alteration of individual F-actin helical structures. Microtubules with blunt, slightly flared or gently curved ends predominated in the growth cone, frequently contained lumenal particles and exhibited lattice defects. Investigation of the effect of absence of doublecortin, a neurodevelopmental cytoskeleton regulator, on growth cone cytoskeleton showed no major anomalies in overall growth cone organisation or in F-actin subpopulations. However, our data suggested that microtubules sustained more structural defects, highlighting the importance of microtubule integrity during growth cone migration.}, author = {Atherton, Joseph and Stouffer, Melissa A and Francis, Fiona and Moores, Carolyn A.}, issn = {1477-9137}, journal = {Journal of Cell Science}, keywords = {Cell Biology}, number = {7}, publisher = {The Company of Biologists}, title = {{Visualising the cytoskeletal machinery in neuronal growth cones using cryo-electron tomography}}, doi = {10.1242/jcs.259234}, volume = {135}, year = {2022}, } @misc{17057, abstract = {Martin Loose studied chemistry at the University of Heidelberg, Germany. He then joined Petra Schwille's group at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, where he obtained his PhD degree in 2010 for work on self-organization and pattern formation in the bacterial Min protein system. He then moved to Tim Mitchison's lab at Harvard Medical School, Boston, USA for his postdoc, funded by Human Frontier Science Program (HSFP) and European Molecular Biology Organization (EMBO) long-term fellowships; there, he discovered that the bacterial cell division proteins FtsA and FtsZ self-organize into dynamic cytoskeletal patterns. Martin established his independent research group at the Institute of Science and Technology (IST) Austria in 2015, supported by an European Research Council (ERC) starting grant and HFSP Young Investigator Grant. His lab studies the self-organization of bacterial cell division and small GTPase networks.}, author = {Loose, Martin}, booktitle = {Journal of Cell Science}, issn = {1477-9137}, number = {2}, publisher = {The Company of Biologists}, title = {{Cell scientist to watch – Martin Loose}}, doi = {10.1242/jcs.259715}, volume = {135}, year = {2022}, } @article{9952, abstract = {Proper control of division orientation and symmetry, largely determined by spindle positioning, is essential to development and homeostasis. Spindle positioning has been extensively studied in cells dividing in two-dimensional (2D) environments and in epithelial tissues, where proteins such as NuMA (also known as NUMA1) orient division along the interphase long axis of the cell. However, little is known about how cells control spindle positioning in three-dimensional (3D) environments, such as early mammalian embryos and a variety of adult tissues. Here, we use mouse embryonic stem cells (ESCs), which grow in 3D colonies, as a model to investigate division in 3D. We observe that, at the periphery of 3D colonies, ESCs display high spindle mobility and divide asymmetrically. Our data suggest that enhanced spindle movements are due to unequal distribution of the cell–cell junction protein E-cadherin between future daughter cells. Interestingly, when cells progress towards differentiation, division becomes more symmetric, with more elongated shapes in metaphase and enhanced cortical NuMA recruitment in anaphase. Altogether, this study suggests that in 3D contexts, the geometry of the cell and its contacts with neighbors control division orientation and symmetry.}, author = {Chaigne, Agathe and Smith, Matthew B. and Cavestany, R. L. and Hannezo, Edouard B and Chalut, Kevin J. and Paluch, Ewa K.}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {14}, publisher = {The Company of Biologists}, title = {{Three-dimensional geometry controls division symmetry in stem cell colonies}}, doi = {10.1242/jcs.255018}, volume = {134}, year = {2021}, } @article{8434, abstract = {Efficient migration on adhesive surfaces involves the protrusion of lamellipodial actin networks and their subsequent stabilization by nascent adhesions. The actin-binding protein lamellipodin (Lpd) is thought to play a critical role in lamellipodium protrusion, by delivering Ena/VASP proteins onto the growing plus ends of actin filaments and by interacting with the WAVE regulatory complex, an activator of the Arp2/3 complex, at the leading edge. Using B16-F1 melanoma cell lines, we demonstrate that genetic ablation of Lpd compromises protrusion efficiency and coincident cell migration without altering essential parameters of lamellipodia, including their maximal rate of forward advancement and actin polymerization. We also confirmed lamellipodia and migration phenotypes with CRISPR/Cas9-mediated Lpd knockout Rat2 fibroblasts, excluding cell type-specific effects. Moreover, computer-aided analysis of cell-edge morphodynamics on B16-F1 cell lamellipodia revealed that loss of Lpd correlates with reduced temporal protrusion maintenance as a prerequisite of nascent adhesion formation. We conclude that Lpd optimizes protrusion and nascent adhesion formation by counteracting frequent, chaotic retraction and membrane ruffling.This article has an associated First Person interview with the first author of the paper. }, author = {Dimchev, Georgi A and Amiri, Behnam and Humphries, Ashley C. and Schaks, Matthias and Dimchev, Vanessa and Stradal, Theresia E. B. and Faix, Jan and Krause, Matthias and Way, Michael and Falcke, Martin and Rottner, Klemens}, issn = {1477-9137}, journal = {Journal of Cell Science}, keywords = {Cell Biology}, number = {7}, publisher = {The Company of Biologists}, title = {{Lamellipodin tunes cell migration by stabilizing protrusions and promoting adhesion formation}}, doi = {10.1242/jcs.239020}, volume = {133}, year = {2020}, } @article{8139, abstract = {Clathrin-mediated endocytosis (CME) is a crucial cellular process implicated in many aspects of plant growth, development, intra- and inter-cellular signaling, nutrient uptake and pathogen defense. Despite these significant roles, little is known about the precise molecular details of how it functions in planta. In order to facilitate the direct quantitative study of plant CME, here we review current routinely used methods and present refined, standardized quantitative imaging protocols which allow the detailed characterization of CME at multiple scales in plant tissues. These include: (i) an efficient electron microscopy protocol for the imaging of Arabidopsis CME vesicles in situ, thus providing a method for the detailed characterization of the ultra-structure of clathrin-coated vesicles; (ii) a detailed protocol and analysis for quantitative live-cell fluorescence microscopy to precisely examine the temporal interplay of endocytosis components during single CME events; (iii) a semi-automated analysis to allow the quantitative characterization of global internalization of cargos in whole plant tissues; and (iv) an overview and validation of useful genetic and pharmacological tools to interrogate the molecular mechanisms and function of CME in intact plant samples.}, author = {Johnson, Alexander J and Gnyliukh, Nataliia and Kaufmann, Walter and Narasimhan, Madhumitha and Vert, G and Bednarek, SY and Friml, Jiří}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {15}, publisher = {The Company of Biologists}, title = {{Experimental toolbox for quantitative evaluation of clathrin-mediated endocytosis in the plant model Arabidopsis}}, doi = {10.1242/jcs.248062}, volume = {133}, year = {2020}, } @article{7420, abstract = {β1-integrins mediate cell–matrix interactions and their trafficking is important in the dynamic regulation of cell adhesion, migration and malignant processes, including cancer cell invasion. Here, we employ an RNAi screen to characterize regulators of integrin traffic and identify the association of Golgi-localized gamma ear-containing Arf-binding protein 2 (GGA2) with β1-integrin, and its role in recycling of active but not inactive β1-integrin receptors. Silencing of GGA2 limits active β1-integrin levels in focal adhesions and decreases cancer cell migration and invasion, which is in agreement with its ability to regulate the dynamics of active integrins. By using the proximity-dependent biotin identification (BioID) method, we identified two RAB family small GTPases, i.e. RAB13 and RAB10, as novel interactors of GGA2. Functionally, RAB13 silencing triggers the intracellular accumulation of active β1-integrin, and reduces integrin activity in focal adhesions and cell migration similarly to GGA2 depletion, indicating that both facilitate active β1-integrin recycling to the plasma membrane. Thus, GGA2 and RAB13 are important specificity determinants for integrin activity-dependent traffic.}, author = {Sahgal, Pranshu and Alanko, Jonna H and Icha, Jaroslav and Paatero, Ilkka and Hamidi, Hellyeh and Arjonen, Antti and Pietilä, Mika and Rokka, Anne and Ivaska, Johanna}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {11}, publisher = {The Company of Biologists}, title = {{GGA2 and RAB13 promote activity-dependent β1-integrin recycling}}, doi = {10.1242/jcs.233387}, volume = {132}, year = {2019}, } @article{11113, abstract = {The nuclear envelope (NE), a double membrane enclosing the nucleus of eukaryotic cells, controls the flow of information between the nucleoplasm and the cytoplasm and provides a scaffold for the organization of chromatin and the cytoskeleton. In dividing metazoan cells, the NE breaks down at the onset of mitosis and then reforms around segregated chromosomes to generate the daughter nuclei. Recent data from intact cells and cell-free nuclear assembly systems suggest that the endoplasmic reticulum (ER) is the source of membrane for NE assembly. At the end of mitosis, ER membrane tubules are targeted to chromatin via tubule ends and reorganized into flat nuclear membrane sheets by specific DNA-binding membrane proteins. In contrast to previous models, which proposed vesicle fusion to be the principal mechanism of NE formation, these new studies suggest that the nuclear membrane forms by the chromatin-mediated reshaping of the ER.}, author = {Anderson, Daniel J. and HETZER, Martin W}, issn = {1477-9137}, journal = {Journal of Cell Science}, keywords = {Cell Biology}, number = {2}, pages = {137--142}, publisher = {The Company of Biologists}, title = {{Shaping the endoplasmic reticulum into the nuclear envelope}}, doi = {10.1242/jcs.005777}, volume = {121}, year = {2008}, } @article{4193, abstract = {The controlled adhesion of cells to each other and to the extracellular matrix is crucial for tissue development and maintenance. Numerous assays have been developed to quantify cell adhesion. Among these, the use of atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS) has recently been established. This assay permits the adhesion of living cells to be studied in near-physiological conditions. This implementation of AFM allows unrivaled spatial and temporal control of cells, as well as highly quantitative force actuation and force measurement that is sufficiently sensitive to characterize the interaction of single molecules. Therefore, not only overall cell adhesion but also the properties of single adhesion-receptor-ligand interactions can be studied. Here we describe current implementations and applications of SCFS, as well as potential pitfalls, and outline how developments will provide insight into the forces, energetics and kinetics of cell-adhesion processes.}, author = {Helenius, Jonne and Heisenberg, Carl-Philipp J and Gaub, Hermann and Mueller, Daniel}, issn = {1477-9137}, journal = {Journal of Cell Science}, number = {11}, pages = {1785 -- 1791}, publisher = {Company of Biologists}, title = {{Single-cell force spectroscopy}}, doi = {10.1242/jcs.030999}, volume = {121}, year = {2008}, }