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Yavuz S, Abraham TE, Houtsmuller AB, van Royen ME. Phase Separation Mediated Sub-Nuclear Compartmentalization of Androgen Receptors. Cells 2024; 13:1693. [PMID: 39451211 PMCID: PMC11506798 DOI: 10.3390/cells13201693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2024] [Revised: 10/10/2024] [Accepted: 10/11/2024] [Indexed: 10/26/2024] Open
Abstract
The androgen receptor (AR), a member of the nuclear steroid hormone receptor family of transcription factors, plays a crucial role not only in the development of the male phenotype but also in the development and growth of prostate cancer. While AR structure and AR interactions with coregulators and chromatin have been studied in detail, improving our understanding of AR function in gene transcription regulation, the spatio-temporal organization and the role of microscopically discernible AR foci in the nucleus are still underexplored. This review delves into the molecular mechanisms underlying AR foci formation, focusing on liquid-liquid phase separation and its role in spatially organizing ARs and their binding partners within the nucleus at transcription sites, as well as the influence of 3D-genome organization on AR-mediated gene transcription.
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Pascual-García M, Unkel M, Slotman JA, Bolleboom A, Bouwen B, Houtsmuller AB, Dirven C, Gao Z, Hijazi S, Kushner SA. Morphological correlates of pyramidal cell axonal myelination in mouse and human neocortex. Cereb Cortex 2024; 34:bhae147. [PMID: 38610088 PMCID: PMC11014882 DOI: 10.1093/cercor/bhae147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/16/2024] [Accepted: 03/17/2024] [Indexed: 04/14/2024] Open
Abstract
The axons of neocortical pyramidal neurons are frequently myelinated. Heterogeneity in the topography of axonal myelination in the cerebral cortex has been attributed to a combination of electrophysiological activity, axonal morphology, and neuronal-glial interactions. Previously, we showed that axonal segment length and caliber are critical local determinants of fast-spiking interneuron myelination. However, the factors that determine the myelination of individual axonal segments along neocortical pyramidal neurons remain largely unexplored. Here, we used structured illumination microscopy to examine the extent to which axonal morphology is predictive of the topography of myelination along neocortical pyramidal neurons. We identified critical thresholds for axonal caliber and interbranch distance that are necessary, but not sufficient, for myelination of pyramidal cell axons in mouse primary somatosensory cortex (S1). Specifically, we found that pyramidal neuron axonal segments with a caliber < 0.24 μm or interbranch distance < 18.10 μm are rarely myelinated. Moreover, we further confirmed that these findings in mice are similar for human neocortical pyramidal cell myelination (caliber < 0.25 μm, interbranch distance < 19.00 μm), suggesting that this mechanism is evolutionarily conserved. Taken together, our findings suggest that axonal morphology is a critical correlate of the topography and cell-type specificity of neocortical myelination.
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Koornneef L, Paul MW, Houtsmuller AB, Baarends WM, Slotman JA. Three-color dSTORM Imaging and Analysis of Recombination Foci in Mouse Spread Meiotic Nuclei. Bio Protoc 2023; 13:e4780. [PMID: 37497444 PMCID: PMC10367009 DOI: 10.21769/bioprotoc.4780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/04/2023] [Accepted: 06/13/2023] [Indexed: 07/28/2023] Open
Abstract
During the first meiotic prophase in mouse, repair of SPO11-induced DNA double-strand breaks (DSBs), facilitating homologous chromosome synapsis, is essential to successfully complete the first meiotic cell division. Recombinases RAD51 and DMC1 play an important role in homology search, but their mechanistic contribution to this process is not fully understood. Super-resolution, single-molecule imaging of RAD51 and DMC1 provides detailed information on recombinase accumulation on DSBs during meiotic prophase. Here, we present a detailed protocol of recombination foci analysis of three-color direct stochastic optical reconstruction microscopy (dSTORM) imaging of SYCP3, RAD51, and DMC1, fluorescently labeled by antibody staining in mouse spermatocytes. This protocol consists of sample preparation, data acquisition, pre-processing, and data analysis. The sample preparation procedure includes an updated version of the nuclear spreading of mouse testicular cells, followed by immunocytochemistry and the preparation steps for dSTORM imaging. Data acquisition consists of three-color dSTORM imaging, which is extensively described. The pre-processing that converts fluorescent signals to localization data also includes channel alignment and image reconstruction, after which regions of interest (ROIs) are identified based on RAD51 and/or DMC1 localization patterns. The data analysis steps then require processing of the fluorescent signal localization within these ROIs into discrete nanofoci, which can be further analyzed. This multistep approach enables the systematic investigation of spatial distributions of proteins associated with individual DSB sites and can be easily adapted for analyses of other foci-forming proteins. All computational scripts and software are freely accessible, making them available to a broad audience. Key features Preparation of spread nuclei, resulting in a flattened preparation with easy antibody-accessible chromatin-associated proteins on dSTORM-compatible coverslips. dSTORM analysis of immunofluorescent repair foci in meiotic prophase nuclei. Detailed descriptions of data acquisition, (pre-)processing, and nanofoci feature analysis applicable to all proteins that assemble in immunodetection as discrete foci. Graphical overview.
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Legerstee K, Sueters J, Abraham TE, Slotman JA, Kremers GJ, Hoogenboom JP, Houtsmuller AB. Correlative light and electron microscopy reveals fork-shaped structures at actin entry sites of focal adhesions. Biol Open 2022; 11:283176. [PMID: 36409550 PMCID: PMC9836080 DOI: 10.1242/bio.059417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 10/21/2022] [Indexed: 11/23/2022] Open
Abstract
Focal adhesions (FAs) are the main cellular structures to link the intracellular cytoskeleton to the extracellular matrix. FAs mediate cell adhesion, are important for cell migration and are involved in many (patho)-physiological processes. Here we examined FAs and their associated actin fibres using correlative fluorescence and scanning electron microscopy (SEM). We used fluorescence images of cells expressing paxillin-GFP to define the boundaries of FA complexes in SEM images, without using SEM contrast enhancing stains. We observed that SEM contrast was increased around the actin fibre entry site in 98% of FAs, indicating increases in protein density and possibly also phosphorylation levels in this area. In nearly three quarters of the FAs, these nanostructures had a fork shape, with the actin forming the stem and the high-contrast FA areas the fork. In conclusion, the combination of fluorescent and electron microscopy allowed accurate localisation of a highly abundant, novel fork structure at the FA-actin interface.
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Steurer B, Janssens RC, Geijer ME, Aprile-Garcia F, Geverts B, Theil AF, Hummel B, van Royen ME, Evers B, Bernards R, Houtsmuller AB, Sawarkar R, Marteijn J. DNA damage-induced transcription stress triggers the genome-wide degradation of promoter-bound Pol II. Nat Commun 2022; 13:3624. [PMID: 35750669 PMCID: PMC9232492 DOI: 10.1038/s41467-022-31329-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 06/10/2022] [Indexed: 01/22/2023] Open
Abstract
The precise regulation of RNA Polymerase II (Pol II) transcription after genotoxic stress is crucial for proper execution of the DNA damage-induced stress response. While stalling of Pol II on transcription-blocking lesions (TBLs) blocks transcript elongation and initiates DNA repair in cis, TBLs additionally elicit a response in trans that regulates transcription genome-wide. Here we uncover that, after an initial elongation block in cis, TBLs trigger the genome-wide VCP-mediated proteasomal degradation of promoter-bound, P-Ser5-modified Pol II in trans. This degradation is mechanistically distinct from processing of TBL-stalled Pol II, is signaled via GSK3, and contributes to the TBL-induced transcription block, even in transcription-coupled repair-deficient cells. Thus, our data reveal the targeted degradation of promoter-bound Pol II as a critical pathway that allows cells to cope with DNA damage-induced transcription stress and enables the genome-wide adaptation of transcription to genotoxic stress.
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Snaterse G, Mies R, van Weerden WM, French PJ, Jonker JW, Houtsmuller AB, van Royen ME, Visser JA, Hofland J. Androgen receptor mutations modulate activation by 11-oxygenated androgens and glucocorticoids. Prostate Cancer Prostatic Dis 2022:10.1038/s41391-022-00491-z. [PMID: 35046557 DOI: 10.1038/s41391-022-00491-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/15/2021] [Accepted: 01/07/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Androgen receptor (AR) ligand-binding domain (LBD) mutations occur in ~20% of all castration-resistant prostate cancer (CRPC) patients. These mutations confer ligand promiscuity, but the affinity for many steroid hormone pathway intermediates is unknown. In this study, we investigated the stimulation of clinically relevant AR-LBD mutants by endogenous and exogenous steroid hormones present in CRPC patients to unravel their potential contribution to AR pathway reactivation. METHODS A meta-analysis of studies reporting untargeted analysis of AR mutants was performed to identify clinically relevant AR-LBD mutations. Using luciferase reporter and quantitative fluorescent microscopy, these AR mutants were screened for sensitivity for various endogenous steroids and synthetic glucocorticoids used in the treatment of CRPC. RESULTS The meta-analysis revealed that ARL702H (3.4%), ARH875Y (4.9%), and ART878A (4.4%) were the most prevalent AR-LBD mutations across 1614 CRPC patients from 21 unique studies. Testosterone (EC50: 0.22 nmol/L) and 11-ketotestosterone (11KT, EC50: 0.74 nmol/L) displayed subnanomolar affinity for ARWT. The p.H875Y mutation selectively increased sensitivity of the AR for 11KT (EC50: 0.15 nmol/L, p < 0.05 vs ARWT), whereas p.L702H decreased sensitivity for 11KT by almost 50-fold. While cortisol and prednisolone both stimulate ARL702H, dexamethasone importantly does not. CONCLUSION Both testosterone and 11KT effectively contribute to ARWT activation, while selective sensitization positions 11KT as a more prominent activator of ARH875Y. Dexamethasone may be a suitable alternative to prednisolone and should be explored in patients bearing the ARL702H.
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Legerstee K, Houtsmuller AB. A Layered View on Focal Adhesions. BIOLOGY 2021; 10:biology10111189. [PMID: 34827182 PMCID: PMC8614905 DOI: 10.3390/biology10111189] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 12/31/2022]
Abstract
Simple Summary The cytoskeleton is a network of protein fibres within cells that provide structure and support intracellular transport. Focal adhesions are protein complexes associated with the outer cell membrane that are found at the ends of specialised actin fibres of this cytoskeleton. They mediate cell adhesion by connecting the cytoskeleton to the extracellular matrix, a protein and sugar network that surrounds cells in tissues. Focal adhesions also translate forces on actin fibres into forces contributing to cell migration. Cell adhesion and migration are crucial to diverse biological processes such as embryonic development, proper functioning of the immune system or the metastasis of cancer cells. Advances in fluorescence microscopy and data analysis methods provided a more detailed understanding of the dynamic ways in which proteins bind and dissociate from focal adhesions and how they are organised within these protein complexes. In this review, we provide an overview of the advances in the current scientific understanding of focal adhesions and summarize relevant imaging techniques. One of the key insights is that focal adhesion proteins are organised into three layers parallel to the cell membrane. We discuss the relevance of this layered nature for the functioning of focal adhesion. Abstract The cytoskeleton provides structure to cells and supports intracellular transport. Actin fibres are crucial to both functions. Focal Adhesions (FAs) are large macromolecular multiprotein assemblies at the ends of specialised actin fibres linking these to the extracellular matrix. FAs translate forces on actin fibres into forces contributing to cell migration. This review will discuss recent insights into FA protein dynamics and their organisation within FAs, made possible by advances in fluorescence imaging techniques and data analysis methods. Over the last decade, evidence has accumulated that FAs are composed of three layers parallel to the plasma membrane. We focus on some of the most frequently investigated proteins, two from each layer, paxillin and FAK (bottom, integrin signalling layer), vinculin and talin (middle, force transduction layer) and zyxin and VASP (top, actin regulatory layer). Finally, we discuss the potential impact of this layered nature on different aspects of FA behaviour.
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Zhang S, Übelmesser N, Josipovic N, Forte G, Slotman JA, Chiang M, Gothe HJ, Gusmao EG, Becker C, Altmüller J, Houtsmuller AB, Roukos V, Wendt KS, Marenduzzo D, Papantonis A. RNA polymerase II is required for spatial chromatin reorganization following exit from mitosis. SCIENCE ADVANCES 2021; 7:eabg8205. [PMID: 34678064 PMCID: PMC8535795 DOI: 10.1126/sciadv.abg8205] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Mammalian chromosomes are three-dimensional entities shaped by converging and opposing forces. Mitotic cell division induces marked chromosome condensation, but following reentry into the G1 phase of the cell cycle, chromosomes reestablish their interphase organization. Here, we tested the role of RNA polymerase II (RNAPII) in this transition using a cell line that allows its auxin-mediated degradation. In situ Hi-C showed that RNAPII is required for both compartment and loop establishment following mitosis. RNAPs often counteract loop extrusion, and in their absence, longer and more prominent loops arose. Evidence from chromatin binding, super-resolution imaging, and in silico modeling allude to these effects being a result of RNAPII-mediated cohesin loading upon G1 reentry. Our findings reconcile the role of RNAPII in gene expression with that in chromatin architecture.
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El Kharraz S, Dubois V, van Royen ME, Houtsmuller AB, Pavlova E, Atanassova N, Nguyen T, Voet A, Eerlings R, Handle F, Prekovic S, Smeets E, Moris L, Devlies W, Ohlsson C, Poutanen M, Verstrepen KJ, Carmeliet G, Launonen KM, Helminen L, Palvimo JJ, Libert C, Vanderschueren D, Helsen C, Claessens F. The androgen receptor depends on ligand-binding domain dimerization for transcriptional activation. EMBO Rep 2021; 22:e52764. [PMID: 34661369 DOI: 10.15252/embr.202152764] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/28/2023] Open
Abstract
Whereas dimerization of the DNA-binding domain of the androgen receptor (AR) plays an evident role in recognizing bipartite response elements, the contribution of the dimerization of the ligand-binding domain (LBD) to the correct functioning of the AR remains unclear. Here, we describe a mouse model with disrupted dimerization of the AR LBD (ARLmon/Y ). The disruptive effect of the mutation is demonstrated by the feminized phenotype, absence of male accessory sex glands, and strongly affected spermatogenesis, despite high circulating levels of testosterone. Testosterone replacement studies in orchidectomized mice demonstrate that androgen-regulated transcriptomes in ARLmon/Y mice are completely lost. The mutated AR still translocates to the nucleus and binds chromatin, but does not bind to specific AR binding sites. In vitro studies reveal that the mutation in the LBD dimer interface also affects other AR functions such as DNA binding, ligand binding, and co-regulator binding. In conclusion, LBD dimerization is crucial for the development of AR-dependent tissues through its role in transcriptional regulation in vivo. Our findings identify AR LBD dimerization as a possible target for AR inhibition.
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Swinkels M, Atiq F, Bürgisser PE, Slotman JA, Houtsmuller AB, de Heus C, Klumperman J, Leebeek FWG, Voorberg J, Jansen AJG, Bierings R. Quantitative 3D microscopy highlights altered von Willebrand factor α-granule storage in patients with von Willebrand disease with distinct pathogenic mechanisms. Res Pract Thromb Haemost 2021; 5:e12595. [PMID: 34532631 PMCID: PMC8440947 DOI: 10.1002/rth2.12595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Platelets play a key role in hemostasis through plug formation and secretion of their granule contents at sites of endothelial injury. Defects in von Willebrand factor (VWF), a platelet α-granule protein, are implicated in von Willebrand disease (VWD), and may lead to defective platelet adhesion and/or aggregation. Studying VWF quantity and subcellular localization may help us better understand the pathophysiology of VWD. OBJECTIVE Quantitative analysis of the platelet α-granule compartment and VWF storage in healthy individuals and VWD patients. PATIENTS/METHODS Structured illumination microscopy (SIM) was used to study VWF content and organization in platelets of healthy individuals and patients with VWD in combination with established techniques. RESULTS SIM capably quantified clear morphological and granular changes in platelets stimulated with proteinase-activated receptor 1 (PAR-1) activating peptide and revealed a large intra- and interdonor variability in VWF-positive object numbers within healthy resting platelets, similar to variation in secreted protein acidic and rich in cysteine (SPARC). We subsequently characterized VWD platelets to identify changes in the α-granule compartment of patients with different VWF defects, and were able to stratify two patients with type 3 VWD rising from different pathological mechanisms. We further analyzed VWF storage in α-granules of a patient with homozygous p.C1190R using electron microscopy and found discrepant VWF levels and different degrees of multimerization in platelets of patients with heterozygous p.C1190 in comparison to VWF in plasma. CONCLUSIONS Our findings highlight the utility of quantitative imaging approaches in assessing platelet granule content, which may help to better understand VWF storage in α-granules and to gain new insights in the etiology of VWD.
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Özgün F, Kaya Z, Morova T, Geverts B, Abraham TE, Houtsmuller AB, van Royen ME, Lack NA. DNA binding alters ARv7 dimer interactions. J Cell Sci 2021; 134:jcs258332. [PMID: 34318896 DOI: 10.1242/jcs.258332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 06/02/2021] [Indexed: 11/20/2022] Open
Abstract
Androgen receptor (AR) splice variants are proposed to be a potential driver of lethal castration-resistant prostate cancer. AR splice variant 7 (ARv7) is the most commonly observed isoform and strongly correlates with resistance to second-generation anti-androgens. Despite this clinical evidence, the interplay between ARv7 and the highly expressed full-length AR (ARfl) remains unclear. In this work, we show that ARfl/ARv7 heterodimers readily form in the nucleus via an intermolecular N/C interaction that brings the four termini of the proteins in close proximity. Combining fluorescence resonance energy transfer and fluorescence recovery after photobleaching, we demonstrate that these heterodimers undergo conformational changes following DNA binding, indicating dynamic nuclear receptor interaction. Although transcriptionally active, ARv7 can only form short-term interactions with DNA at highly accessible high-occupancy ARfl binding sites. Dimerization with ARfl does not affect ARv7 binding dynamics, suggesting that DNA binding occupancy is determined by the individual protein monomers and not the homodimer or heterodimer complex. Overall, these biophysical studies reveal detailed properties of ARv7 dynamics as both a homodimer or heterodimer with ARfl.
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Lin Z, Wu B, Paul MW, Li KW, Yao Y, Smal I, Proietti Onori M, Hasanbegovic H, Bezstarosti K, Demmers J, Houtsmuller AB, Meijering E, Hoebeek FE, Schonewille M, Smit AB, Gao Z, De Zeeuw CI. Protein Phosphatase 2B Dual Function Facilitates Synaptic Integrity and Motor Learning. J Neurosci 2021; 41:5579-5594. [PMID: 34021041 PMCID: PMC8244972 DOI: 10.1523/jneurosci.1741-20.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 04/01/2021] [Accepted: 04/23/2021] [Indexed: 11/21/2022] Open
Abstract
Protein phosphatase 2B (PP2B) is critical for synaptic plasticity and learning, but the molecular mechanisms involved remain unclear. Here we identified different types of proteins that interact with PP2B, including various structural proteins of the postsynaptic densities (PSDs) of Purkinje cells (PCs) in mice. Deleting PP2B reduced expression of PSD proteins and the relative thickness of PSD at the parallel fiber to PC synapses, whereas reexpression of inactive PP2B partly restored the impaired distribution of nanoclusters of PSD proteins, together indicating a structural role of PP2B. In contrast, lateral mobility of surface glutamate receptors solely depended on PP2B phosphatase activity. Finally, the level of motor learning covaried with both the enzymatic and nonenzymatic functions of PP2B. Thus, PP2B controls synaptic function and learning both through its action as a phosphatase and as a structural protein that facilitates synapse integrity.SIGNIFICANCE STATEMENT Phosphatases are generally considered to serve their critical role in learning and memory through their enzymatic operations. Here, we show that protein phosphatase 2B (PP2B) interacts with structural proteins at the synapses of cerebellar Purkinje cells. Differentially manipulating the enzymatic and structural domains of PP2B leads to different phenotypes in cerebellar learning. We propose that PP2B is crucial for cerebellar learning via two complementary actions, an enzymatic and a structural operation.
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Geijer ME, Zhou D, Selvam K, Steurer B, Mukherjee C, Evers B, Cugusi S, van Toorn M, van der Woude M, Janssens RC, Kok YP, Gong W, Raams A, Lo CSY, Lebbink JHG, Geverts B, Plummer DA, Bezstarosti K, Theil AF, Mitter R, Houtsmuller AB, Vermeulen W, Demmers JAA, Li S, van Vugt MATM, Lans H, Bernards R, Svejstrup JQ, Ray Chaudhuri A, Wyrick JJ, Marteijn JA. Publisher Correction: Elongation factor ELOF1 drives transcription-coupled repair and prevents genome instability. Nat Cell Biol 2021; 23:809. [PMID: 34163038 DOI: 10.1038/s41556-021-00720-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Geijer ME, Zhou D, Selvam K, Steurer B, Mukherjee C, Evers B, Cugusi S, van Toorn M, van der Woude M, Janssens RC, Kok YP, Gong W, Raams A, Lo CSY, Lebbink JHG, Geverts B, Plummer DA, Bezstarosti K, Theil AF, Mitter R, Houtsmuller AB, Vermeulen W, Demmers JAA, Li S, van Vugt MATM, Lans H, Bernards R, Svejstrup JQ, Ray Chaudhuri A, Wyrick JJ, Marteijn JA. Elongation factor ELOF1 drives transcription-coupled repair and prevents genome instability. Nat Cell Biol 2021; 23:608-619. [PMID: 34108662 PMCID: PMC7611218 DOI: 10.1038/s41556-021-00692-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 04/29/2021] [Indexed: 02/05/2023]
Abstract
Correct transcription is crucial for life. However, DNA damage severely impedes elongating RNA polymerase II, causing transcription inhibition and transcription-replication conflicts. Cells are equipped with intricate mechanisms to counteract the severe consequence of these transcription-blocking lesions. However, the exact mechanism and factors involved remain largely unknown. Here, using a genome-wide CRISPR-Cas9 screen, we identified the elongation factor ELOF1 as an important factor in the transcription stress response following DNA damage. We show that ELOF1 has an evolutionarily conserved role in transcription-coupled nucleotide excision repair (TC-NER), where it promotes recruitment of the TC-NER factors UVSSA and TFIIH to efficiently repair transcription-blocking lesions and resume transcription. Additionally, ELOF1 modulates transcription to protect cells against transcription-mediated replication stress, thereby preserving genome stability. Thus, ELOF1 protects the transcription machinery from DNA damage via two distinct mechanisms.
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Mhaskar AN, Koornneef L, Zelensky AN, Houtsmuller AB, Baarends WM. High Resolution View on the Regulation of Recombinase Accumulation in Mammalian Meiosis. Front Cell Dev Biol 2021; 9:672191. [PMID: 34109178 PMCID: PMC8181746 DOI: 10.3389/fcell.2021.672191] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/19/2021] [Indexed: 11/19/2022] Open
Abstract
A distinguishing feature of meiotic DNA double-strand breaks (DSBs), compared to DSBs in somatic cells, is the fact that they are induced in a programmed and specifically orchestrated manner, which includes chromatin remodeling prior to DSB induction. In addition, the meiotic homologous recombination (HR) repair process that follows, is different from HR repair of accidental DSBs in somatic cells. For instance, meiotic HR involves preferred use of the homolog instead of the sister chromatid as a repair template and subsequent formation of crossovers and non-crossovers in a tightly regulated manner. An important outcome of this distinct repair pathway is the pairing of homologous chromosomes. Central to the initial steps in homology recognition during meiotic HR is the cooperation between the strand exchange proteins (recombinases) RAD51 and its meiosis-specific paralog DMC1. Despite our understanding of their enzymatic activity, details on the regulation of their assembly and subsequent molecular organization at meiotic DSBs in mammals have remained largely enigmatic. In this review, we summarize recent mouse data on recombinase regulation via meiosis-specific factors. Also, we reflect on bulk “omics” studies of initial meiotic DSB processing, compare these with studies using super-resolution microscopy in single cells, at single DSB sites, and explore the implications of these findings for our understanding of the molecular mechanisms underlying meiotic HR regulation.
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Peter S, Urbanus BHA, Klaassen RV, Wu B, Boele HJ, Azizi S, Slotman JA, Houtsmuller AB, Schonewille M, Hoebeek FE, Spijker S, Smit AB, De Zeeuw CI. AMPAR Auxiliary Protein SHISA6 Facilitates Purkinje Cell Synaptic Excitability and Procedural Memory Formation. Cell Rep 2021; 31:107515. [PMID: 32294428 PMCID: PMC7175376 DOI: 10.1016/j.celrep.2020.03.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/31/2020] [Accepted: 03/23/2020] [Indexed: 12/15/2022] Open
Abstract
The majority of excitatory postsynaptic currents in the brain are gated through AMPA-type glutamate receptors, the kinetics and trafficking of which can be modulated by auxiliary proteins. It remains to be elucidated whether and how auxiliary proteins can modulate synaptic function to contribute to procedural memory formation. In this study, we report that the AMPA-type glutamate receptor (AMPAR) auxiliary protein SHISA6 (CKAMP52) is expressed in cerebellar Purkinje cells, where it co-localizes with GluA2-containing AMPARs. The absence of SHISA6 in Purkinje cells results in severe impairments in the adaptation of the vestibulo-ocular reflex and eyeblink conditioning. The physiological abnormalities include decreased presence of AMPARs in synaptosomes, impaired excitatory transmission, increased deactivation of AMPA receptors, and reduced induction of long-term potentiation at Purkinje cell synapses. Our data indicate that Purkinje cells require SHISA6-dependent modification of AMPAR function in order to facilitate cerebellar, procedural memory formation.
SHISA6 is prominently expressed in Purkinje cells in close association with AMPARs SHISA6 absence in Purkinje cells results in impaired procedural memory formation Purkinje cell synaptic baseline excitatory transmission is facilitated by SHISA6 Purkinje cell AMPAR kinetics are modulated by SHISA6
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Lu T, Haemmerich D, Liu H, Seynhaeve AL, van Rhoon GC, Houtsmuller AB, ten Hagen TL. Externally triggered smart drug delivery system encapsulating idarubicin shows superior kinetics and enhances tumoral drug uptake and response. Am J Cancer Res 2021; 11:5700-5712. [PMID: 33897876 PMCID: PMC8058728 DOI: 10.7150/thno.55163] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/09/2021] [Indexed: 12/20/2022] Open
Abstract
Rationale: Increasing the bioavailable drug level in a tumor is the key to enhance efficacy of chemotherapy. Thermosensitive smart drug delivery systems (SDDS) in combination with local hyperthermia facilitate high local drug levels, thus improving uptake in the tumor. However, inability to rapidly and efficiently absorb the locally released drug results in reduced efficacy, as well as undesired redistribution of the drug away from the tumor to the system. Methods: Based on this paradigm we propose a novel approach in which we replaced doxorubicin (DXR), one of the classic drugs for nanocarrier-based delivery, with idarubicin (IDA), a hydrophobic anthracycline used solely in the free form for treatment hematologic cancers. We established a series of in vitro and in vivo experiments to in depth study the kinetics of SDDS-based delivery, drug release, intratumor biodistribution and subsequent cell uptake. Results: We demonstrate that IDA is taken up over 10 times more rapidly by cancer cells than DXR in vitro. Similar trend is observed in in vivo online imaging and less drug redistribution is shown for IDA, together resulting in 4-times higher whole tumor drug uptake for IDA vs. DXR. Together his yielded an improved intratumoral drug distribution for IDA-SDDS, translating into superior tumor response compared to DXR-SDDS treatment at the same dose. Thus, IDA - a drug that is not used for treatment of solid cancers - shows superior therapeutic index and better outcome when administered in externally triggered SDDS. Conclusions: We show that a shift in selection of chemotherapeutics is urgently needed, away from the classic drugs towards selection based on properties of a chemotherapeutic in context of the nanoparticle and delivery mode, to maximize the therapeutic efficacy.
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Legerstee K, Abraham TE, van Cappellen WA, Nigg AL, Slotman JA, Houtsmuller AB. Growth factor dependent changes in nanoscale architecture of focal adhesions. Sci Rep 2021; 11:2315. [PMID: 33504939 PMCID: PMC7841166 DOI: 10.1038/s41598-021-81898-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 01/12/2021] [Indexed: 01/21/2023] Open
Abstract
Focal adhesions (FAs) are flat elongated structures that mediate cell migration and link the cytoskeleton to the extracellular matrix. Along the vertical axis FAs were shown to be composed of three layers. We used structured illumination microscopy to examine the longitudinal distribution of four hallmark FA proteins, which we also used as markers for these layers. At the FA ends pointing towards the adherent membrane edge (heads), bottom layer protein paxillin protruded, while at the opposite ends (tails) intermediate layer protein vinculin and top layer proteins zyxin and VASP extended further. At the tail tips, only intermediate layer protein vinculin protruded. Importantly, head and tail compositions were altered during HGF-induced scattering with paxillin heads being shorter and zyxin tails longer. Additionally, FAs at protruding or retracting membrane edges had longer paxillin heads than FAs at static edges. These data suggest that redistribution of FA-proteins with respect to each other along FAs is involved in cell movement.
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van der Burght SN, Rademakers S, Johnson JL, Li C, Kremers GJ, Houtsmuller AB, Leroux MR, Jansen G. Ciliary Tip Signaling Compartment Is Formed and Maintained by Intraflagellar Transport. Curr Biol 2020; 30:4299-4306.e5. [DOI: 10.1016/j.cub.2020.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/13/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023]
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Sierksma MC, Slotman JA, Houtsmuller AB, Borst JGG. Structure-function relation of the developing calyx of Held synapse in vivo. J Physiol 2020; 598:4603-4619. [PMID: 33439501 PMCID: PMC7689866 DOI: 10.1113/jp279976] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/07/2020] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS During development the giant, auditory calyx of Held forms a one-to-one connection with a principal neuron of the medial nucleus of the trapezoid body. While anatomical studies described that most of the target cells are temporarily contacted by multiple calyces, multi-calyceal innervation was only sporadically observed in in vivo recordings, suggesting a structure-function discrepancy. We correlated synaptic strength of inputs, identified in in vivo recordings, with post hoc labelling of the recorded neuron and synaptic terminals containing vesicular glutamate transporters (VGluT). During development only one input increased to the level of the calyx of Held synapse, and its strength correlated with the large VGluT cluster contacting the postsynaptic soma. As neither competing strong inputs nor multiple large VGluT clusters on a single cell were observed, our findings did not indicate a structure-function discrepancy. ABSTRACT In adult rodents, a principal neuron in the medial nucleus of the trapezoid (MNTB) is generally contacted by a single, giant axosomatic terminal called the calyx of Held. How this one-on-one relation is established is still unknown, but anatomical evidence suggests that during development principal neurons are innervated by multiple calyces, which may indicate calyceal competition. However, in vivo electrophysiological recordings from principal neurons indicated that only a single strong synaptic connection forms per cell. To test whether a mismatch exists between synaptic strength and terminal size, we compared the strength of synaptic inputs with the morphology of the synaptic terminals. In vivo whole-cell recordings of the MNTB neurons from newborn Wistar rats of either sex were made while stimulating their afferent axons, allowing us to identify multiple inputs. The strength of the strongest input increased to calyceal levels in a few days across cells, while the strength of the second strongest input was stable. The recorded cells were subsequently immunolabelled for vesicular glutamate transporters (VGluT) to reveal axosomatic terminals with structured-illumination microscopy. Synaptic strength of the strongest input was correlated with the contact area of the largest VGluT cluster at the soma (r = 0.8), and no indication of a mismatch between structure and strength was observed. Together, our data agree with a developmental scheme in which one input strengthens and becomes the calyx of Held, but not with multi-calyceal competition.
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21
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Slotman JA, Paul MW, Carofiglio F, de Gruiter HM, Vergroesen T, Koornneef L, van Cappellen WA, Houtsmuller AB, Baarends WM. Super-resolution imaging of RAD51 and DMC1 in DNA repair foci reveals dynamic distribution patterns in meiotic prophase. PLoS Genet 2020; 16:e1008595. [PMID: 32502153 PMCID: PMC7310863 DOI: 10.1371/journal.pgen.1008595] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 06/23/2020] [Accepted: 05/05/2020] [Indexed: 11/19/2022] Open
Abstract
The recombinase RAD51, and its meiosis-specific paralog DMC1 localize at DNA double-strand break (DSB) sites in meiotic prophase. While both proteins are required during meiotic prophase, their spatial organization during meiotic DSB repair is not fully understood. Using super-resolution microscopy on mouse spermatocyte nuclei, we aimed to define their relative position at DSB foci, and how these vary in time. We show that a large fraction of meiotic DSB repair foci (38%) consisted of a single RAD51 nanofocus and a single DMC1 nanofocus (D1R1 configuration) that were partially overlapping with each other (average center-center distance around 70 nm). The vast majority of the rest of the foci had a similar large RAD51 and DMC1 nanofocus, but in combination with additional smaller nanofoci (D2R1, D1R2, D2R2, or DxRy configuration) at an average distance of around 250 nm. As prophase progressed, less D1R1 and more D2R1 foci were observed, where the large RAD51 nanofocus in the D2R1 foci elongated and gradually oriented towards the distant small DMC1 nanofocus. D1R2 foci frequency was relatively constant, and the single DMC1 nanofocus did not elongate, but was frequently observed between the two RAD51 nanofoci in early stages. D2R2 foci were rare (<10%) and nearest neighbour analyses also did not reveal cofoci formation between D1R1 foci. However, overall, foci localized nonrandomly along the SC, and the frequency of the distance distributions peaked at 800 nm, indicating interference and/or a preferred distance between two ends of a DSB. DMC1 nanofoci where somewhat further away from the axial or lateral elements of the synaptonemal complex (SC, connecting the chromosomal axes of homologs) compared to RAD51 nanofoci. In the absence of the transverse filament of the SC, early configurations were more prominent, and RAD51 nanofocus elongation occurred only transiently. This in-depth analysis of single cell landscapes of RAD51 and DMC1 accumulation patterns at DSB repair sites at super-resolution revealed the variability of foci composition, and defined functional consensus configurations that change over time.
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Casa V, Moronta Gines M, Gade Gusmao E, Slotman JA, Zirkel A, Josipovic N, Oole E, van IJcken WFJ, Houtsmuller AB, Papantonis A, Wendt KS. Redundant and specific roles of cohesin STAG subunits in chromatin looping and transcriptional control. Genome Res 2020; 30:515-527. [PMID: 32253279 PMCID: PMC7197483 DOI: 10.1101/gr.253211.119] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 04/01/2020] [Indexed: 12/28/2022]
Abstract
Cohesin is a ring-shaped multiprotein complex that is crucial for 3D genome organization and transcriptional regulation during differentiation and development. It also confers sister chromatid cohesion and facilitates DNA damage repair. Besides its core subunits SMC3, SMC1A, and RAD21, cohesin in somatic cells contains one of two orthologous STAG subunits, STAG1 or STAG2. How these variable subunits affect the function of the cohesin complex is still unclear. STAG1- and STAG2-cohesin were initially proposed to organize cohesion at telomeres and centromeres, respectively. Here, we uncover redundant and specific roles of STAG1 and STAG2 in gene regulation and chromatin looping using HCT116 cells with an auxin-inducible degron (AID) tag fused to either STAG1 or STAG2. Following rapid depletion of either subunit, we perform high-resolution Hi-C, gene expression, and sequential ChIP studies to show that STAG1 and STAG2 do not co-occupy individual binding sites and have distinct ways by which they affect looping and gene expression. These findings are further supported by single-molecule localizations via direct stochastic optical reconstruction microscopy (dSTORM) super-resolution imaging. Since somatic and congenital mutations of the STAG subunits are associated with cancer (STAG2) and intellectual disability syndromes with congenital abnormalities (STAG1 and STAG2), we verified STAG1-/STAG2-dependencies using human neural stem cells, hence highlighting their importance in particular disease contexts.
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Roobol SJ, Hartjes TA, Slotman JA, de Kruijff RM, Torrelo G, Abraham TE, Bruchertseifer F, Morgenstern A, Kanaar R, van Gent DC, Houtsmuller AB, Denkova AG, van Royen ME, Essers J. Uptake and subcellular distribution of radiolabeled polymersomes for radiotherapy. Nanotheranostics 2020; 4:14-25. [PMID: 31911891 PMCID: PMC6940201 DOI: 10.7150/ntno.37080] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 11/06/2019] [Indexed: 12/17/2022] Open
Abstract
Polymersomes have the potential to be applied in targeted alpha radionuclide therapy, while in addition preventing release of recoiling daughter isotopes. In this study, we investigated the cellular uptake, post uptake processing and intracellular localization of polymersomes. Methods: High-content microscopy was used to validate polymersome uptake kinetics. Confocal (live cell) microscopy was used to elucidate the uptake mechanism and DNA damage induction. Intracellular distribution of polymersomes in 3-D was determined using super-resolution microscopy. Results: We found that altering polymersome size and concentration affects the initial uptake and overall uptake capacity; uptake efficiency and eventual plateau levels varied between cell lines; and mitotic cells show increased uptake. Intracellular polymersomes were transported along microtubules in a fast and dynamic manner. Endocytic uptake of polymersomes was evidenced through co-localization with endocytic pathway components. Finally, we show the intracellular distribution of polymersomes in 3-D and DNA damage inducing capabilities of 213Bi labeled polymersomes. Conclusion: Polymersome size and concentration affect the uptake efficiency, which also varies for different cell types. In addition, we present advanced assays to investigate uptake characteristics in detail, a necessity for optimization of nano-carriers. Moreover, by elucidating the uptake mechanism, as well as uptake extent and geometrical distribution of radiolabeled polymersomes we provide insight on how to improve polymersome design.
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Stedehouder J, Brizee D, Slotman JA, Pascual-Garcia M, Leyrer ML, Bouwen BL, Dirven CM, Gao Z, Berson DM, Houtsmuller AB, Kushner SA. Local axonal morphology guides the topography of interneuron myelination in mouse and human neocortex. eLife 2019; 8:48615. [PMID: 31742557 PMCID: PMC6927753 DOI: 10.7554/elife.48615] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 11/18/2019] [Indexed: 12/30/2022] Open
Abstract
GABAergic fast-spiking parvalbumin-positive (PV) interneurons are frequently myelinated in the cerebral cortex. However, the factors governing the topography of cortical interneuron myelination remain incompletely understood. Here, we report that segmental myelination along neocortical interneuron axons is strongly predicted by the joint combination of interbranch distance and local axon caliber. Enlargement of PV+ interneurons increased axonal myelination, while reduced cell size led to decreased myelination. Next, we considered regular-spiking SOM+ cells, which normally have relatively shorter interbranch distances and thinner axon diameters than PV+ cells, and are rarely myelinated. Consistent with the importance of axonal morphology for guiding interneuron myelination, enlargement of SOM+ cell size dramatically increased the frequency of myelinated axonal segments. Lastly, we confirm that these findings also extend to human neocortex by quantifying interneuron axonal myelination from ex vivo surgical tissue. Together, these findings establish a predictive model of neocortical GABAergic interneuron myelination determined by local axonal morphology.
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van den Dries K, Nahidiazar L, Slotman JA, Meddens MBM, Pandzic E, Joosten B, Ansems M, Schouwstra J, Meijer A, Steen R, Wijers M, Fransen J, Houtsmuller AB, Wiseman PW, Jalink K, Cambi A. Modular actin nano-architecture enables podosome protrusion and mechanosensing. Nat Commun 2019; 10:5171. [PMID: 31729386 PMCID: PMC6858452 DOI: 10.1038/s41467-019-13123-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/11/2019] [Indexed: 01/03/2023] Open
Abstract
Basement membrane transmigration during embryonal development, tissue homeostasis and tumor invasion relies on invadosomes, a collective term for invadopodia and podosomes. An adequate structural framework for this process is still missing. Here, we reveal the modular actin nano-architecture that enables podosome protrusion and mechanosensing. The podosome protrusive core contains a central branched actin module encased by a linear actin module, each harboring specific actin interactors and actin isoforms. From the core, two actin modules radiate: ventral filaments bound by vinculin and connected to the plasma membrane and dorsal interpodosomal filaments crosslinked by myosin IIA. On stiff substrates, the actin modules mediate long-range substrate exploration, associated with degradative behavior. On compliant substrates, the vinculin-bound ventral actin filaments shorten, resulting in short-range connectivity and a focally protrusive, non-degradative state. Our findings redefine podosome nanoscale architecture and reveal a paradigm for how actin modularity drives invadosome mechanosensing in cells that breach tissue boundaries.
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