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Results for “cell biology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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bioRxiv2017

Spectrin is a mechanoresponsive protein shaping the architecture of intercellular invasion

Spectrin is a membrane skeletal protein best known for its structural role in maintaining cell shape and protecting cells from mechanical damage1-3. Here, we report that spectrin dynamically accumulates and dissolves at the fusogenic synapse, where an attacking fusion partner mechanically invades its receiving partner with actin-propelled protrusions to promote cell-cell fusion4-7. Using genetics, cell biology, biophysics and mathematical modeling, we demonstrate that unlike myosin II that responds to dilation deformation, spectrin exhibits a mechanosensitive accumulation in response to shear deformation, which is highly elevated at the fusogenic synapse. The accumulated spectrin forms an uneven network, which functions as a \"sieve\" to constrict the invasive fingerlike protrusions, thus putting the fusogenic synapse under high mechanical tension to promote cell membrane fusion. Taken together, our study has revealed a previously unrecognized function of spectrin as a dynamic mechanoresponsive protein that shapes the architecture of intercellular invasion. These findings have general implications for understanding spectrin function in other dynamic cellular processes beyond cell-cell fusion.

cell biology↗

bioRxiv2024

Quantitative imaging of species-specific lipid transport in mammalian cells

Eukaryotic cells produce over 1000 different lipid species which tune organelle membrane properties, control signalling and store energy1,2. How lipid species are selectively sorted between organelles to maintain specific membrane identities is largely unknown due to the difficulty to image lipid transport in cells3. Here, we measured transport and metabolism of individual lipid species in mammalian cells using time-resolved fluorescence imaging of bifunctional lipid probes in combination with ultra-high resolution mass spectrometry and mathematical modelling. Quantification of lipid flux between organelles revealed that directional, non-vesicular lipid transport is responsible for fast, species-selective lipid sorting compared to slow, unspecific vesicular membrane trafficking. Using genetic perturbations, we found that coupling between active lipid flipping and passive non-vesicular transport is a mechanism for directional lipid transport. Comparison of metabolic conversion and transport rates showed that non-vesicular transport dominates the organelle distribution of lipids while species-specific phospholipid metabolism controls neutral lipid accumulation. Our results provide the first quantitative map of retrograde lipid flux in cells4. We anticipate that our pipeline for quantitative mapping of lipid flux through physical and chemical space in cells will boost our understanding of lipids in cell biology and disease.

cell biology↗

bioRxiv2022

Characterization of the HHV-6 U20 immunoevasin

Roseoloviruses (HHV-6A, -6B, and -7) infect >90% of the human population during early childhood, and are thought to remain latent or persistent throughout the life of the host. As such, these viruses are among the most pervasive and stealthy of all viruses; they must necessarily excel at escaping immune detection throughout the life of the host, and yet very little is known about how these viruses so successfully escape host defenses. Herein, we characterize the HHV6A and HHV6B U20 gene products, which are encoded within a block of genes unique to the roseoloviruses, and therefore of particular interest. Despite 92% amino acid identity, U20 proteins from HHV6A and 6B have been shown to possess different host evasion functions. Here we characterize expression, trafficking, and post-translational modifications of U20 during HHV6A infection. While U20 localized to lysosomes in HHV-6A-infected cells, HHV-6B U20 trafficked to the cell surface and was rapidly internalized. HHV-6B U20 trafficked slowly through the secretory system, receiving several post translational modifications to its N-linked glycans indicative of surface expressed glycoproteins. Interestingly, U20 is also phosphorylated on at least one Ser, Thr, or Tyr residue. These results provide a framework to understand the role(s) of U20 in evading host defenses. ImportanceHHV6A and HHV6B U20 proteins are virus-encoded integral membrane glycoproteins possessing class I MHC-like folds. As such, it is tempting to speculate that they are involved in host evasion. Indeed, although they share 92% identity, HHV6A U20 has been shown to target NK activating ligands (1) and HHV6B U20 has been shown to inhibit TNF receptor signaling and apoptosis (2). Here, we have performed cell biological and biochemical characterization of the trafficking, glycosylation, and post-translational modifications occurring on HHV6A and -6B U20, and we demonstrate U20 expression in the context of HHV6 infection.

cell biology↗

bioRxiv2024

Dissecting autonomous enzyme variability in single cells

Metabolic enzymes perform life-sustaining functions in various cellular compartments. Anecdotally, metabolic activity is observed to vary between genetically identical cells, which impacts drug resistance, differentiation, and immune cell activation. However, no large-scale resource systematically reporting metabolic cellular heterogeneity exists. Here, we leverage imaging-based single-cell spatial proteomics to reveal the extent of non-genetic variability of the human enzymatic proteome, as a proxy for metabolic states. Nearly two fifths of enzymes exhibit cell-to-cell variable expression, and half localize to multiple cellular compartments. Metabolic heterogeneity arises largely autonomously of cell cycling, and individual cells reestablish these myriad metabolic phenotypes over several cell divisions. Multiplexed imaging revealed that metabolic states are continuous and that the correlation between metabolic pathways is metabolic state dependent. These results establish cell-to-cell enzymatic heterogeneity as an organizing principle of cell biology that may rewire our understanding of drug resistance, treatment design, and other aspects of medicine.

cell biology↗

bioRxiv2025

Optimisation of skeletal muscle sampling for cultured fat production

To produce cultured meat at a commercially-relevant scale, bioprocesses must be robust, standardised and cost-efficient. In this respect, the limited in vitro lifespan of primary cells poses a major challenge, which requires regular cell sourcing by means of biopsy. We have previously shown that muscle-derived fibro-adipogenic progenitor cells (FAPs) represent a promising starting cell type for cultured fat production. These cells proliferate for a high number of population doublings (PDs) in serum-free growth medium. However, with accumulating PDs, FAPs lose their adipogenic differentiation capacity, thereby limiting the amount of cultured fat that can be produced from a given starting sample. Donor animal characteristics, including age, may affect this loss of differentiation. Here, we performed a longitudinal biopsy study to ask whether physiological differences between donor animals are reflected in FAP cell biology, and if this has an effect on loss of FAP differentiation capacity. We sampled twelve Limousin cattle over the first two years of their lives, successfully performing 144 muscle biopsies. Animals younger than six months demonstrated higher FAP yields per gram of muscle tissue, making them ideal donors for cultured fat production, but we observed little difference in the proliferation or differentiation of derived cell cultures. This work also provides valuable insights into the tissue harvesting process, highlighting the need for new, robust and standardised biopsy systems to mitigate contamination risk.

cell biology↗

bioRxiv2020

SARS-CoV-2 Requires Cholesterol for Viral Entry and Pathological Syncytia Formation

Many enveloped viruses induce multinucleated cells (syncytia), reflective of membrane fusion events caused by the same machinery that underlies viral entry. These syncytia are thought to facilitate replication and evasion of the host immune response. Here, we report that co-culture of human cells expressing the receptor ACE2 with cells expressing SARS-CoV-2 spike, results in synapse-like intercellular contacts that initiate cell-cell fusion, producing syncytia resembling those we identify in lungs of COVID-19 patients. To assess the mechanism of spike/ACE2-driven membrane fusion, we developed a microscopy-based, cell-cell fusion assay to screen [~]6000 drugs and >30 spike variants. Together with cell biological and biophysical approaches, the screen reveals an essential role for membrane cholesterol in spike-mediated fusion, which extends to replication-competent SARS-CoV-2 isolates. Our findings provide a molecular basis for positive outcomes reported in COVID-19 patients taking statins, and suggest new strategies for therapeutics targeting the membrane of SARS-CoV-2 and other fusogenic viruses. HighlightsO_LICell-cell fusion at ACE2-spike clusters cause pathological syncytia in COVID-19 C_LIO_LIDrug screen reveals critical role for membrane lipid composition in fusion C_LIO_LISpikes unusual membrane-proximal cysteines and aromatics are essential for fusion C_LIO_LICholesterol tunes relative infectivity of SARS-CoV-2 viral particles C_LI

cell biology↗

bioRxiv2024

Optimised proteomic analysis of insulin granules from MIN6 β-cells identifies Scamp3, a novel regulator of insulin secretion and content

Pancreatic {beta}-cells in the islets of Langerhans are key to maintaining glucose homeostasis, by secreting the peptide hormone insulin. Insulin is packaged within vesicles named insulin secretory granules (ISGs), that have recently been considered to have intrinsic structures and proteins that regulate insulin granule maturation, trafficking, and secretion. Previously, studies have identified a handful of novel ISG-associated proteins using different separation techniques. Here, this study combines an optimized ISG isolation technique and mass spectrometry-based proteomics, with an unbiased protein correlation profiling and targeted machine learning approach to uncover 211 ISG-associated proteins. Five of these proteins: Syntaxin-7, Synaptophysin, Synaptotagmin-13, Zinc transporter ZIP8 and SCAMP3 have not been previously ISG-associated. Through colocalization analysis of confocal imaging we validate the association of these proteins to the ISG in MIN6 and human {beta}-cells. We further validate the role for one (SCAMP3) in regulating insulin storage and secretion from {beta}-cells for the first time. SCAMP3 knock-down INS-1 cells show a reduction in insulin content and dysfunctional insulin secretion. These data provide the basis for future investigation into {beta}-cell biology and the regulation of insulin secretion. Article HighlightsO_LIWhy did we undertake this study? We undertook this study to optimize insulin granule isolation techniques alongside enhanced proteomics analyses to establish the first published murine insulin granule proteome. C_LIO_LIWhat is the specific question(s) we wanted to answer? We aimed to specifically answer and investigate what proteins are present on insulin granules from MIN6 cells to further our understanding of insulin granule biogenesis, trafficking, and secretion. C_LIO_LIWhat did we find? We find and validate the presence of 5 novel insulin granule-associated proteins. C_LIO_LIWhat are the implications of our findings? An extensive proteomics analysis of MIN6 insulin granules and implicate Scamp3 as a novel protein that regulates insulin content and secretion in beta-cells. C_LI

cell biology↗

bioRxiv2026

The Human Pancreas Cell Atlas defines a healthy reference framework for disease contextualization and translational benchmarking

A central challenge in single-cell biology is distinguishing disease-associated remodeling from normal cellular heterogeneity. Addressing this challenge requires healthy reference frameworks that capture cellular diversity across individuals, technologies, and biological contexts. Here we present the Human Pancreas Cell Atlas (HPCA), a reference atlas of the healthy human pancreas integrating 815,126 single-cell and single-nucleus transcriptomes from 109 donors across 12 studies, diverse technologies, and demographics. Using benchmarked integration and community-driven annotations, HPCA defines 94 cell types and transcriptional states spanning endocrine, exocrine, immune, and stromal compartments. The atlas identifies rare endocrine populations, including a putative, spatially supported polyhormonal alpha-beta-delta state, and provides a unified framework for interpreting pancreatic cellular variation across diverse biological and demographic covariates. Projection of disease and model-system datasets onto HPCA contextualized endocrine and epithelial remodeling relative to healthy pancreatic states. Diabetes-associated endocrine cells remained embedded within the healthy endocrine state space while exhibiting disease-specific changes, as supported by spatial and eQTL concordance analyses. Integration with a pancreatic ductal adenocarcinoma atlas resolved injury-associated and malignant epithelial ecosystem regions across donors. Finally, the HPCA enables quantitative benchmarking of murine diabetes models and stem-cell-derived islets against human pancreatic reference states. Together, the HPCA establishes a healthy transcriptional coordinate system for interpreting disease-associated pathophysiology, experimental perturbation, and regenerative fidelity, illustrating how reference atlases can function as analytical frameworks rather than static cell catalogs.

bioinformatics↗

bioRxiv2021

Kre28-Spc105 interaction is essential for their recruitment at the kinetochore

Kinetochores are macromolecular protein assemblies that attach sister chromatids to spindle microtubules and mediate accurate chromosome segregation during mitosis. The outer kinetochore consists of the KMN network, a protein super-complex comprising Knl1 (yeast Spc105), Mis12 (yeast Mtw1), and Ndc80 (yeast Ndc80), which harbors sites for microtubule binding. Within the KMN network, Spc105 acts as an interaction hub of components involved in spindle assembly checkpoint (SAC) signaling. It is known that Spc105 forms a complex with kinetochore component Kre28. However, where Kre28 physically localizes in the budding yeast kinetochore is not clear. The exact function of Kre28 at the kinetochore is also unknown. Here, we investigate how Spc105 and Kre28 interact and how they are organized within bioriented yeast kinetochores using genetics and cell biological experiments. Our microscopy data show that Spc105 and Kre28 localize at the kinetochore with a 1:1 stoichiometry. We also show that the Kre28-Spc105 interaction is important for Spc105 protein turn-over and essential for their mutual recruitment at the kinetochores. We created several truncation mutants of kre28 that affect Spc105 loading at the kinetochores. When over-expressed, these mutants sustain the cell viability, but SAC signaling and kinetochore biorientation are impaired. Therefore, we conclude that Kre28 contributes to chromosome biorientation and high-fidelity segregation at least indirectly by regulating Spc105 localization at the kinetochores.

cell biology↗

bioRxiv2025

A validated method for banking mixed glial cultures that yield responsive microglia

Microglia, the primary immune cells of the brain, orchestrate immune responses to both external and internal stimuli in health and disease. Although several cell culture methods exist to model microglia in vitro, isolating loosely adherent microglia from primary murine mixed glial cultures remains valuable for recapitulating in vivo cell states from complex transgenic lines at relatively low cost. However, these methods are constrained by limited temporal control and scalability. To address these challenges, we established a protocol for generating microglia from frozen mixed glial cultures. While freezing introduced measurable differences in microglial morphology and lipid droplet content, microglia derived from frozen cultures responded to environmental stimuli (high glucose and LPS) in the same way as those from fresh cultures. Thus, while frozen primary microglia exhibit similar functional responses, maintaining consistency in using fresh or frozen cells within a given experiment is strongly recommended. MotivationAlthough our understanding of microglias role in brain development and disease continues to grow, a standardized in vitro model of primary mouse microglia remains absent in the field. Primary cell culture systems are essential for studying microglia, enabling the empirical assessment of gene function in transgenic models and testing novel interventions before committing to time- and cost-intensive in vivo studies. However, mixed glial culture-derived primary microglia (pMG) systems are constrained by the timing of animal availability and have limited scalability. In this study, we sought to establish a protocol for freezing and subsequently reviving primary mixed glial cultures from which responsive pMG could be isolated for downstream analysis. We validated this approach by quantifying microglia responses to distinct environmental stimuli before and after a freeze-thaw cycle. Research topicsCP: Cell biology Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/693524v2_ufig1.gif" ALT="Figure 1000"> View larger version (54K): org.highwire.dtl.DTLVardef@1b0e291org.highwire.dtl.DTLVardef@1eacfb2org.highwire.dtl.DTLVardef@e9c18aorg.highwire.dtl.DTLVardef@a151a5_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

Identification and Characterization of Functional and Trans-dominant Negative HERV-K (HML-2) Rec Proteins Encoded in the Human Genome.

Human Endogenous Retroviruses K (HERV-K) of the HML-2 subgroup are the most recently integrated and biologically active retroviral elements within the human genome. The HERV-K Rec protein, a functional homolog of HIV Rev and HTLV Rex, is necessary for the nuclear export of viral mRNAs with retained introns. However, the diversity of Rec proteins encoded in the human genome and their functional capacities have remained largely unexplored. We identified full-length Rec protein sequences in the human genome and selected 23 variants for functional characterization. Using a dual-color fluorescent reporter and a complementary ELISA assay, we found that Rec proteins from only 7 genomic loci were functional. In addition, a subset of the non-functional Rec proteins exerted trans-dominant negative effects. Detailed mutational analysis of the most potent inhibitory variant, encoded by the HERV-K provirus 12q14.1, displayed only 2 amino acid changes (H2N and del34E) relative to the prototypical functional Rec protein encoded by the reconstructed consensus HERV-K (HERV-K Con). Insertion of a glutamic acid at position 34 restored the functional activity, while the substitution of histidine with asparagine at position 2 did not. Our results unveil an unexpected complexity in HERV-K (HML-2) post-transcriptional regulation, with Rec variants displaying a spectrum of activities ranging from robust nuclear export of RNA with retained introns to trans-dominant negative inhibition of Rec function. These findings expand our understanding of the regulatory landscape governing HERV-K (HML-2) expression and suggest mechanisms by which different HERV-K Rec proteins may influence host cell biology and pathology, including oncogenesis.

cell biology↗

bioRxiv2020

Non-redundant functions of H2A.Z.1 and H2A.Z.2 in chromosome segregation and cell cycle progression.

H2A.Z is a H2A-type histone variant essential for many aspects of cell biology ranging from gene expression to genome stability. From deuterostomes, H2A.Z evolved into two paralogues H2A.Z.1 and H2A.Z.2 that differ by only three amino acids and are encoded by different genes (H2AFZ and H2AFV respectively). Despite the importance of this histone variant in development and cellular homeostasis, very little is known about the individual functions of each paralogue in mammals. Here we investigated the distinct roles of two paralogues in cell cycle regulation. Using a specific siRNA approach for each paralogue in human cells, we unveiled non-redundant functions for H2A.Z.1 and H2A.Z.2 in cell division: H2A.Z.1 regulates the expression of important cell cycle genes (including Myc and Ki-67) and its depletion leads to a G1 arrest, whereas H2A.Z.2 is essential for centromere integrity and function, thus playing a key role in chromosome segregation.

cell biology↗

bioRxiv2022

Endosomal Chemokine Receptor Signalosomes Regulate Central Mechanisms Underlying Cell Migration

Chemokine receptors are GPCRs that regulate chemotactic migration of a wide variety of cells including immune and cancer cells. Most chemokine receptors contain features associated with the ability to stimulate G protein signaling during {beta}-arrestin-mediated receptor internalization into endosomes. As endosomal signaling of certain non-GPCR receptors plays a major role in cell migration, we chose to investigate the potential role of endosomal chemokine receptor signaling on mechanisms governing this function. Applying a combination of pharmacological and cell biological approaches, we demonstrate that the model chemokine receptor CCR7 recruits G protein and {beta}-arrestin simultaneously upon chemokine stimulation, which enables internalized receptors to activate G protein from endosomes. Furthermore, spatiotemporal-resolved APEX2 proteome profiling shows that endosomal CCR7 uniquely enriches specific Rho GTPase regulators as compared to plasma membrane CCR7, which is directly associated with enhanced activity of the Rho GTPase Rac1 and chemotaxis of immune T cells. As Rac1 drives the formation of membrane protrusions during chemotaxis, our findings suggest an important integrated function of endosomal chemokine receptor signaling in cell migration.

cell biology↗

bioRxiv2024

Paraptosome: A Novel Pathological Feature in Paraptotic Cell Death

Paraptosis is a novel form of programmed cell death characterized by distinct morphological features such as swelling of the endoplasmic reticulum and mitochondria, and cytoplasmic vacuolation. Unlike apoptosis, paraptosis does not involve the activation of caspases or DNA fragmentation. These unique features make paraptosis an intriguing target for cancer therapy, particularly against apoptosis-resistant cells. Here, we report a novel morphological feature of paraptosis: the formation of high-density spherical structure, which we tentatively term "paraptosome." We found that these putative paraptosomes originate from the Golgi apparatus, appearing as high-density formations under light microscopy and colocalizing with the trans-Golgi marker {beta}4GALT1-RFP. Time-lapse confocal microscopy and immunostaining demonstrated that putative paraptosomes form due to Golgi stress or disintegration, leading to severe disruption of Golgi function. Furthermore, we show that paraptosis inducers such as glabridin, morusin, and honokiol can cause significant alterations in the endoplasmic reticulum, mitochondria, autophagosomes, and lysosomes in U251MG glioblastoma cells; however, the formation of putative paraptosomes is not induced by isolated stress inducers. Collectively, these findings suggest that the putative paraptosome may be a novel characteristic structure of paraptosis. The discovery of paraptosomes provides a unique marker for defining paraptotic cell death and offers new insights into the characteristic pathological phenomena associated with multiple organelle dysfunction. This finding broadens the scope of cell biology research by introducing a new structural paradigm linked to paraptosis and may have implications for developing targeted therapies against apoptosis-resistant cancers.

cell biology↗

bioRxiv2026

Transmembrane-domain-driven heterodimer assembly licenses integrin head-domain folding in the endoplasmic reticulum

Integrins are a large family of /{beta} heterodimeric receptors whose activation is associated with the extension of the ectodomain and disruption of transient transmembrane domain (TMD) interactions. Whether the TMD interaction serves additional function(s) beyond regulating integrin activation remains unclear. Here, we report that three TMD-disruptive mutations within the integrin {beta}1-subunit activate its function while simultaneously reducing its surface expression. While a Gly744Asn ({beta}1-GN) and Gly744Leu ({beta}1-GL) TMD mutation yielded viable homozygous offspring, the more disruptive Leu748Arg ({beta}1-LR) TMD mutation caused embryonic lethality in mice and drastically reduced {beta}1-integrin surface levels. Cell biology and biochemistry studies revealed that TMD-TMD interactions drive efficient /{beta}-heterodimer assembly, thereby enabling the coupled folding of the ER-luminal {beta}I-domain. Disruption of these TMD interactions leads to endoplasmic reticulum (ER) retention and luminal domain-dependent ER-associated degradation of the monomeric, misfolded {beta}1-subunit. Moreover, mutations that disrupt the /{beta} TMD interaction of multiple integrin classes in humans similarly impair integrin cell surface expression and cause severe loss-of-function diseases. Together, our findings establish that /{beta} TMD association serves a previously unrecognized role in integrin biogenesis by promoting {beta}I-domain folding, preventing premature integrin activation in the ER, and ensuring the proper cell surface expression of activatable integrins.

cell biology↗

bioRxiv2026

COG5-mediated Golgi organization coordinates neural progenitor fate during human brain development

Apical radial glial cells (aRGs) are highly polarized epithelial cells that drive human cortical development through tightly regulated lineage progression. A distinctive feature of aRGs is their non-canonical Golgi organization, raising the possibility that specialized intracellular trafficking and secretory processes contribute to progenitor behaviour. However, how Golgi architecture contributes to human corticogenesis remains poorly understood. Here, we investigate this question in the context of COG5 deficiency, a rare congenital disorder of glycosylation associated with neurodevelopmental defects, using patient-derived fibroblasts and brain organoids, N-glycomics, glycolipidomics, and single-cell transcriptomics. We show that COG5 deficiency disrupts Golgi organization and impairs Golgi-to-ER retrograde trafficking. At the neurodevelopmental level, COG5-deficient organoids display altered ventricular organization and reduced basal progenitor abundance. Single-cell transcriptomic analysis reveals rewired developmental trajectories characterized by premature differentiation from apical progenitors with activation of neuronal pathways. Despite the absence of major abnormalities in plasma glycoproteins glycosylation, glycolipidomic analysis identified marked defects in glycosphingolipid maturation within patient-derived brain organoids, indicating selective impairment of neural lipid glycosylation. Transcriptomic and biochemical analyses further revealed dysregulation of developmental pathways, including reduced Notch signalling and altered localization of both cleaved Notch1 and the Golgi-associated protein ACBD3. Consistent with impaired progenitor maintenance, COG5-deficient organoids displayed altered cleavage plane orientation in apical progenitors. Together, our findings suggest a link between Golgi organization, intracellular trafficking, membrane glycosylation, and lineage progression in human neural progenitors, identifying Golgi architecture as an important regulator of apical radial glial cell biology and cortical development.

cell biology↗

bioRxiv2017

Force-Dependent Binding Of Vinculin To α-Catenin Regulates Cell-Cell Contacts Stability And Collective Cell Behavior

The shaping of a multicellular body and repair of adult tissues require fine-tuning of cell adhesion, cell mechanics and intercellular transmission of mechanical load. Adherens junctions (AJs) are the major intercellular junctions by which cells sense and exert mechanical force on each other. However, how AJs adapt to mechanical stress and how this adaptation contributes to cell-cell cohesion and eventually to tissue-scale dynamics and mechanics remains largely unknown. Here, by analyzing the tension-dependent recruitment of vinculin, -catenin and F-actin as a function of stiffness, as well as the dynamics of GFP-tagged wild-type and mutated -catenins, altered for their binding capability to vinculin, we demonstrate that the force-dependent binding of vinculin stabilizes -catenin and is responsible for AJ adaptation to force. Challenging cadherin complexes mechanical coupling with magnetic tweezers, and cell-cell cohesion during collective cell movements, further highlight that tension-dependent adaptation of AJs regulates cell-cell contact dynamics and coordinated collective cell migration. Altogether, these data demonstrate that the force-dependent -catenin/vinculin interaction, manipulated here by mutagenesis and mechanical control, is a core regulator of AJ mechanics and long-range cell-cell interactions.\n\nSummary statementCombining cell biology and biomechanical analysis, we show here that the coupling between cadherin complexes and actin trough tension-dependent -catenin/vinculin association is regulating AJ stability and dynamics as well as tissue-scale mechanics.

cell biology↗

bioRxiv2020

Selective targeting of non-centrosomal AURKA functions through use of a novel targeted protein degradation tool

Targeted protein degradation tools are becoming a new therapeutic modality, allowing small molecule ligands to be reformulated as heterobifunctional molecules (PROteolysis Targeting Chimeras, PROTACs) that recruit ubiquitin ligases to targets of interest, leading to ubiquitination and destruction of the targets. Several PROTACs against targets of clinical interest have been described, but detailed descriptions of the cell biology modulated by PROTACs are missing from the literature. Here we describe the functional characterization of a PROTAC derived from AURKA inhibitor MLN8237 (alisertib). We demonstrate efficient and specific destruction of both endogenous and overexpressed AURKA by Cereblon-directed PROTACs. At the subcellular level, we find differential targeting of AURKA on the mitotic spindle compared to centrosomes. The phenotypic consequences of PROTAC treatment are therefore distinct from those mediated by alisertib, and in mitotic cells differentially regulate centrosome- and chromatin-based microtubule spindle assembly pathways. In interphase cells PROTAC-mediated clearance of non-centrosomal AURKA modulates the cytoplasmic role played by AURKA in mitochondrial dynamics, whilst the centrosomal pool is refractory to PROTAC-mediated clearance. Our results point to differential sensitivity of subcellular pools of substrate, governed by substrate conformation or localization-dependent accessibility to PROTAC action, a phenomenon not previously described for this new class of degrader compounds.

cell biology↗