| 1. |
- Lock, John G, et al.
(författare)
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Reticular adhesions are a distinct class of cell-matrix adhesions that mediate attachment during mitosis
- 2018
-
Ingår i: Nature Cell Biology. - Stockholm : Karolinska Institutet, Dept of Biosciences and Nutrition. - 1465-7392 .- 1476-4679.
-
Tidskriftsartikel (refereegranskat)abstract
- Adhesion to the extracellular matrix persists during mitosis in most cell types. However, while classical adhesion complexes, such as focal adhesions, do and must disassemble to enable mitotic rounding, the mechanisms of residual mitotic cell-extracellular matrix adhesion remain undefined. Here, we identify 'reticular adhesions', a class of adhesion complex that is mediated by integrin alpha v beta 5, formed during interphase, and preserved at cell-extracellular matrix attachment sites throughout cell division. Consistent with this role, integrin beta 5 depletion perturbs mitosis and disrupts spatial memory transmission between cell generations. Reticular adhesions are morphologically and dynamically distinct from classical focal adhesions. Mass spectrometry defines their unique composition, enriched in phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P-2)-binding proteins but lacking virtually all consensus adhesome components. Indeed, reticular adhesions are promoted by PtdIns(4,5)P-2, and form independently of talin and F-actin. The distinct characteristics of reticular adhesions provide a solution to the problem of maintaining cell-extracellular matrix attachment during mitotic rounding and division.
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| 2. |
- Poch, Christine M, et al.
(författare)
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Migratory and anti-fibrotic programmes define the regenerative potential of human cardiac progenitors
- 2022
-
Ingår i: Nature Cell Biology. - Stockholm : Karolinska Institutet, Dept of Cell and Molecular Biology. - 1465-7392 .- 1476-4679.
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Tidskriftsartikel (refereegranskat)abstract
- Heart regeneration is an unmet clinical need, hampered by limited renewal of adult cardiomyocytes and fibrotic scarring. Pluripotent stem cell-based strategies are emerging, but unravelling cellular dynamics of host–graft crosstalk remains elusive. Here, by combining lineage tracing and single-cell transcriptomics in injured non-human primate heart biomimics, we uncover the coordinated action modes of human progenitor-mediated muscle repair. Chemoattraction via CXCL12/CXCR4 directs cellular migration to injury sites. Activated fibroblast repulsion targets fibrosis by SLIT2/ROBO1 guidance in organizing cytoskeletal dynamics. Ultimately, differentiation and electromechanical integration lead to functional restoration of damaged heart muscle. In vivo transplantation into acutely and chronically injured porcine hearts illustrated CXCR4-dependent homing, de novo formation of heart muscle, scar-volume reduction and prevention of heart failure progression. Concurrent endothelial differentiation contributed to graft neovascularization. Our study demonstrates that inherent developmental programmes within cardiac progenitors are sequentially activated in disease, enabling the cells to sense and counteract acute and chronic injury.
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| 3. |
- Alvarado-Kristensson, Maria, et al.
(författare)
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SADB phosphorylation of gamma-tubulin regulates centrosome duplication.
- 2009
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 11:9, s. 86-1081
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Tidskriftsartikel (refereegranskat)abstract
- Symmetrical cell division requires duplication of DNA and protein content to generate two daughter cells. Centrosomes also duplicate during cell division, but the mechanism controlling this process is incompletely understood. We describe an alternative splice form of SadB encoding a short SADB Ser/Thr kinase whose activity fluctuates during the cell cycle, localizes to centrosomes, and controls centrosome duplication. Reduction of endogenous SADB levels diminished centrosome numbers, whereas enhanced SADB expression induced centrosome amplification. SADB exerted this action through phosphorylation of gamma-tubulin on Ser 131, as expression of a phosphomimetic Ser 131-to-Asp gamma-tubulin mutant alone increased centrosome numbers, whereas non-phosphorylatable Ala 131-gamma-tubulin impaired centrosome duplication. We propose that SADB kinase activity controls centrosome homeostasis by regulating phosphorylation of gamma-tubulin.
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| 4. |
- Andrews, B., et al.
(författare)
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Imaging cell biology
- 2022
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Ingår i: Nature Cell Biology. - : Springer Nature. - 1465-7392 .- 1476-4679. ; 24:8, s. 1180-1185
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Apostolou, E, et al.
(författare)
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Progress and challenges in stem cell biology
- 2023
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 25:2, s. 203-206
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Apostolou, E, et al.
(författare)
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Progress and challenges in stem cell biology
- 2023
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 25:2, s. 203-206
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Tidskriftsartikel (refereegranskat)
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| 8. |
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| 9. |
- Bai, Ming, et al.
(författare)
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ARFGAP1 promotes AP-2-dependent endocytosis
- 2011
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 13:5, s. 559-U144
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Tidskriftsartikel (refereegranskat)abstract
- COPI (coat protein I) and the clathrin-AP-2 (adaptor protein 2) complex are well-characterized coat proteins, but a component that is common to these two coats has not been identified. The GTPase-activating protein (GAP) for ADP-ribosylation factor 1 (ARF1), ARFGAP1, is a known component of the COPI complex. Here, we show that distinct regions of ARFGAP1 interact with AP-2 and coatomer (components of the COPI complex). Selectively disrupting the interaction of ARFGAP1 with either of these two coat proteins leads to selective inhibition in the corresponding transport pathway. The role of ARFGAP1 in AP-2-regulated endocytosis has mechanistic parallels with its roles in COPI transport, as both its GAP activity and coat function contribute to promoting AP-2 transport.
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| 10. |
- Baietti, Maria Francesca, et al.
(författare)
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Syndecan-syntenin-ALIX regulates the biogenesis of exosomes
- 2012
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 14:7, s. 677-685
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Tidskriftsartikel (refereegranskat)abstract
- The biogenesis of exosomes, small secreted vesicles involved in signalling processes, remains incompletely understood. Here, we report evidence that the syndecan heparan sulphate proteoglycans and their cytoplasmic adaptor syntenin control the formation of exosomes. Syntenin interacts directly with ALIX through LYPX(n)L motifs, similarly to retroviral proteins, and supports the intraluminal budding of endosomal membranes. Syntenin exosomes depend on the availability of heparan sulphate, syndecans, ALIX and ESCRTs, and impact on the trafficking and confinement of FGF signals. This study identifies a key role for syndecan-syntenin-ALIX in membrane transport and signalling processes.
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| 11. |
- Bakhiet, M, et al.
(författare)
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RANTES promotes growth and survival of human first-trimester forebrain astrocytes
- 2001
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 3:2, s. 150-157
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Tidskriftsartikel (refereegranskat)abstract
- We have examined the role of alpha and beta chemokines in the promotion of the ontogenetic development of the brain. RANTES was expressed preferentially in human fetal astrocytes in an age-dependent manner. Astrocytes from 5-week-old brains showed high proliferation and reduced survival, whereas 10-week-old astrocytes exhibited opposite effects. These effects were suppressed by anti-RANTES or anti-RANTES receptor antibodies and were enhanced by recombinant RANTES. RANTES induced tyrosine phosphorylation of several cellular proteins and nuclear translocation of STAT-1 in astrocytes. Interferons (IFN-gamma) was required for RANTES effects because RANTES induced IFN-gamma, and only 10-week-old astrocytes expressed the IFN-gamma receptor. Blocking of IFN-gamma with antibody reversed the effects of RANTES, indicating that cytokine/chemokine networks are critically involved in brain development.
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| 12. |
- Bentley, Katie, et al.
(författare)
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The role of differential VE-cadherin dynamics in cell rearrangement during angiogenesis
- 2014
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 16:4, s. 309-321
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial cells show surprising cell rearrangement behaviour during angiogenic sprouting; however, the underlying mechanisms and functional importance remain unclear. By combining computational modelling with experimentation, we identify that Notch/VEGFR-regulated differential dynamics of VE-cadherin junctions drive functional endothelial cell rearrangements during sprouting. We propose that continual flux in Notch signalling levels in individual cells results in differential VE-cadherin turnover and junctional-cortex protrusions, which powers differential cell movement. In cultured endothelial cells, Notch signalling quantitatively reduced junctional VE-cadherin mobility. In simulations, only differential adhesion dynamics generated long-range position changes, required for tip cell competition and stalk cell intercalation. Simulation and quantitative image analysis on VE-cadherin junctional patterning in vivo identified that differential VE-cadherin mobility is lost under pathological high VEGF conditions, in retinopathy and tumour vessels. Our results provide a mechanistic concept for how cells rearrange during normal sprouting and how rearrangement switches to generate abnormal vessels in pathologies.
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| 13. |
- Bergsten, Erika, et al.
(författare)
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PDGF-D is a specific, protease-activated ligand for the PDGF beta-receptor
- 2001
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Ingår i: Nature Cell Biology. - : Macmillan Magazines Ltd. - 1465-7392 .- 1476-4679. ; 3:5, s. 512-516
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Tidskriftsartikel (refereegranskat)abstract
- The term 'platelet-derived growth factor' (PDGF) refers to a family of disulphide-bonded dimeric isoforms that are important for growth, survival and function in several types of connective tissue cell. So far, three different PDGF chains have been identified - the classical PDGF-A and PDGF-B and the recently identified PDGF-C. PDGF isoforms (PDGF-AA, AB, BB and CC) exert their cellular effects by differential binding to two receptor tyrosine kinases. The PDGF alpha-receptor (PDGFR-alpha) binds to all three PDGF chains, whereas the beta-receptor (PDGFR-beta) binds only to PDGF-B. Gene-targeting studies using mice have shown that the genes for PDGF-A and PDGF-B, as well as the two PDGFR genes, are essential for normal development. Furthermore, overexpression of PDGFs is linked to different pathological conditions, including malignancies, atherosclerosis and fibroproliferative diseases. Here we have identify and characterize a fourth member of the PDGF family, PDGF-D. PDGF-D has a two-domain structure similar to PDGF-C and is secreted as a disulphide-linked homodimer, PDGF-DD. Upon limited proteolysis, PDGF-DD is activated and becomes a specific agonistic ligand for PDGFR-beta. PDGF-DD is the first known PDGFR-beta-specific ligand, and its unique receptor specificity indicates that it may be important for development and pathophysiology in several organs.
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| 14. |
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| 15. |
- Boström, Pontus, 1982, et al.
(författare)
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SNARE proteins mediate fusion between cytosolic lipid droplets and are implicated in insulin sensitivity.
- 2007
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 9:11, s. 1286-93
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of cytosolic lipid droplets in muscle and liver cells has been linked to the development of insulin resistance and type 2 diabetes. Such droplets are formed as small structures that increase in size through fusion, a process that is dependent on intact microtubules and the motor protein dynein. Approximately 15% of all droplets are involved in fusion processes at a given time. Here, we show that lipid droplets are associated with proteins involved in fusion processes in the cell: NSF (N-ethylmaleimide-sensitive-factor), alpha-SNAP (soluble NSF attachment protein) and the SNAREs (SNAP receptors), SNAP23 (synaptosomal-associated protein of 23 kDa), syntaxin-5 and VAMP4 (vesicle-associated membrane protein 4). Knockdown of the genes for SNAP23, syntaxin-5 or VAMP4, or microinjection of a dominant-negative mutant of alpha-SNAP, decreases the rate of fusion and the size of the lipid droplets. Thus, the SNARE system seems to have an important role in lipid droplet fusion. We also show that oleic acid treatment decreases the insulin sensitivity of heart muscle cells, and this sensitivity is completely restored by transfection with SNAP23. Thus, SNAP23 might be a link between insulin sensitivity and the inflow of fatty acids to the cell.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
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| 20. |
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| 21. |
- Cockburn, K, et al.
(författare)
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Gradual differentiation uncoupled from cell cycle exit generates heterogeneity in the epidermal stem cell layer
- 2022
-
Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 24:12, s. 1692-
-
Tidskriftsartikel (refereegranskat)abstract
- Highly regenerative tissues continuously produce terminally differentiated cells to replace those that are lost. How they orchestrate the complex transition from undifferentiated stem cells towards post-mitotic, molecularly distinct and often spatially segregated differentiated populations is not well understood. In the adult skin epidermis, the stem cell compartment contains molecularly heterogeneous subpopulations1–4 whose relationship to the complete trajectory of differentiation remains unknown. Here we show that differentiation, from commitment to exit from the stem cell layer, is a multi-day process wherein cells transit through a continuum of transcriptional changes with upregulation of differentiation genes preceding downregulation of typical stemness genes. Differentiation-committed cells remain capable of dividing to produce daughter cells fated to further differentiate, demonstrating that differentiation is uncoupled from cell cycle exit. These cell divisions are not required as part of an obligate transit-amplifying programme but help to buffer the differentiating cell pool during heightened demand. Thus, instead of distinct contributions from multiple progenitors, a continuous gradual differentiation process fuels homeostatic epidermal turnover.
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| 22. |
- Costa, Guilherme, et al.
(författare)
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Asymmetric division coordinates collective cell migration in angiogenesis
- 2016
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 18:12, s. 1292-
-
Tidskriftsartikel (refereegranskat)abstract
- The asymmetric division of stem or progenitor cells generates daughters with distinct fates and regulates cell diversity during tissue morphogenesis. However, roles for asymmetric division in other more dynamic morphogenetic processes, such as cell migration, have not previously been described. Here we combine zebrafish in vivo experimental and computational approaches to reveal that heterogeneity introduced by asymmetric division generates multicellular polarity that drives coordinated collective cell migration in angiogenesis. We find that asymmetric positioning of the mitotic spindle during endothelial tip cell division generates daughters of distinct size with discrete 'tip' or 'stalk' thresholds of pro-migratory Vegfr signalling. Consequently, post-mitotic Vegfr asymmetry drives Dll4/Notch-independent self-organization of daughters into leading tip or trailing stalk cells, and disruption of asymmetry randomizes daughter tip/stalk selection. Thus, asymmetric division seamlessly integrates cell proliferation with collective migration, and, as such, may facilitate growth of other collectively migrating tissues during development, regeneration and cancer invasion.
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| 23. |
- De Luca, Michele, et al.
(författare)
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Advances in stem cell research and therapeutic development
- 2019
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 21:7, s. 801-811
-
Forskningsöversikt (refereegranskat)abstract
- Despite many reports of putative stem-cell-based treatments in genetic and degenerative disorders or severe injuries, the number of proven stem cell therapies has remained small. In this Review, we survey advances in stem cell research and describe the cell types that are currently being used in the clinic or are close to clinical trials. Finally, we analyse the scientific rationale, experimental approaches, caveats and results underpinning the clinical use of such stem cells.
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| 24. |
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| 25. |
- Eroglu, E, et al.
(författare)
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Epicardium-derived cells organize through tight junctions to replenish cardiac muscle in salamanders
- 2022
-
Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 24:5, s. 645-
-
Tidskriftsartikel (refereegranskat)abstract
- The contribution of the epicardium, the outermost layer of the heart, to cardiac regeneration has remained controversial due to a lack of suitable analytical tools. By combining genetic marker-independent lineage-tracing strategies with transcriptional profiling and loss-of-function methods, we report here that the epicardium of the highly regenerative salamander species Pleurodeles waltl has an intrinsic capacity to differentiate into cardiomyocytes. Following cryoinjury, CLDN6+ epicardium-derived cells appear at the lesion site, organize into honeycomb-like structures connected via focal tight junctions and undergo transcriptional reprogramming that results in concomitant differentiation into de novo cardiomyocytes. Ablation of CLDN6+ differentiation intermediates as well as disruption of their tight junctions impairs cardiac regeneration. Salamanders constitute the evolutionarily closest species to mammals with an extensive ability to regenerate heart muscle and our results highlight the epicardium and tight junctions as key targets in efforts to promote cardiac regeneration.
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| 26. |
- Eroglu, E, et al.
(författare)
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PHF7 directs cardiac reprogramming
- 2021
-
Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 23:5, s. 440-442
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Tidskriftsartikel (refereegranskat)
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Gerber, Julia P., et al.
(författare)
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Aberrant chromatin landscape following loss of the H3.3 chaperone Daxx in haematopoietic precursors leads to Pu.1-mediated neutrophilia and inflammation
- 2021
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 23:12, s. 1224-1239
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Tidskriftsartikel (refereegranskat)abstract
- Defective silencing of retrotransposable elements has been linked to inflammageing, cancer and autoimmune diseases. However, the underlying mechanisms are only partially understood. Here we implicate the histone H3.3 chaperone Daxx, a retrotransposable element repressor inactivated in myeloid leukaemia and other neoplasms, in protection from inflammatory disease. Loss of Daxx alters the chromatin landscape, H3.3 distribution and histone marks of haematopoietic progenitors, leading to engagement of a Pu.1-dependent transcriptional programme for myelopoiesis at the expense of B-cell differentiation. This causes neutrophilia and inflammation, predisposing mice to develop an autoinflammatory skin disease. While these molecular and phenotypic perturbations are in part reverted in animals lacking both Pu.1 and Daxx, haematopoietic progenitors in these mice show unique chromatin and transcriptome alterations, suggesting an interaction between these two pathways. Overall, our findings implicate retrotransposable element silencing in haematopoiesis and suggest a cross-talk between the H3.3 loading machinery and the pioneer transcription factor Pu.1.
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| 31. |
- Grebe, Markus, 1967-
(författare)
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Out of the shade and into the light
- 2011
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 13:4, s. 347-349
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Tidskriftsartikel (refereegranskat)abstract
- Plants reach for the sun by avoiding the shade and by directly growing towards the light. Two studies now suggest that the polar relocation of PIN3, a transporter directing the flow of the plant hormone auxin, drives both growth processes. PIN3 repolarization occurs downstream of shade perception through phytochrome photoreceptors, whereas blue light perceived by phototropin initiates polar recycling of PIN3 and growth towards the light.
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| 32. |
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| 33. |
- Guzzi, Nicola, et al.
(författare)
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Pseudouridine-modified tRNA fragments repress aberrant protein synthesis and predict leukaemic progression in myelodysplastic syndrome
- 2022
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 24:3, s. 299-306
-
Tidskriftsartikel (refereegranskat)abstract
- Transfer RNA-derived fragments (tRFs) are emerging small noncoding RNAs that, although commonly altered in cancer, have poorly defined roles in tumorigenesis1. Here we show that pseudouridylation (Ψ) of a stem cell-enriched tRF subtype2, mini tRFs containing a 5′ terminal oligoguanine (mTOG), selectively inhibits aberrant protein synthesis programmes, thereby promoting engraftment and differentiation of haematopoietic stem and progenitor cells (HSPCs) in patients with myelodysplastic syndrome (MDS). Building on evidence that mTOG-Ψ targets polyadenylate-binding protein cytoplasmic 1 (PABPC1), we employed isotope exchange proteomics to reveal critical interactions between mTOG and functional RNA-recognition motif (RRM) domains of PABPC1. Mechanistically, this hinders the recruitment of translational co-activator PABPC1-interacting protein 1 (PAIP1)3 and strongly represses the translation of transcripts sharing pyrimidine-enriched sequences (PES) at the 5′ untranslated region (UTR), including 5′ terminal oligopyrimidine tracts (TOP) that encode protein machinery components and are frequently altered in cancer4. Significantly, mTOG dysregulation leads to aberrantly increased translation of 5′ PES messenger RNA (mRNA) in malignant MDS-HSPCs and is clinically associated with leukaemic transformation and reduced patient survival. These findings define a critical role for tRFs and Ψ in difficult-to-treat subsets of MDS characterized by high risk of progression to acute myeloid leukaemia (AML).
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| 34. |
- Gängel, Konstantin, et al.
(författare)
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Endocytosis regulates VEGF signalling during angiogenesis
- 2013
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 15:3, s. 233-235
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Endocytosis has proved to be a versatile mechanism regulating diverse cellular processes, ranging from nutrient uptake to intracellular signal transduction. New work reinforces the importance of endocytosis for VEGF receptor signalling and angiogenesis in the developing eye, and describes a mechanism for its differential regulation in angiogenic versus quiescent endothelial cells.
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| 35. |
- Haglund, Kaisa, et al.
(författare)
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Multiple monoubiquitination of RTKs is sufficient for their endocytosis and degradation
- 2003
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 5:5, s. 461-466
-
Tidskriftsartikel (refereegranskat)abstract
- Many cellular proteins are post-translationally modified by the addition of a single ubiquitin or a polyubiquitin chain. Among these are receptor tyrosine kinases (RTKs), which undergo ligand-dependent ubiquitination. The ubiquitination of RTKs has become recognized as an important signal for their endocytosis and degradation in the lysosome; however, it is not clear whether ubiquitination itself is sufficient for this process or simply participates in its regulation. The issue is further complicated by the fact that RTKs are thought to be polyubiquitinated - a modification that is linked to protein degradation by the proteasome. By contrast, monoubiquitination has been associated with diverse proteasome-independent cellular functions including intracellular protein movement. Here we show that the epidermal growth factor and platelet-derived growth factor receptors are not polyubiquitinated but rather are monoubiquitinated at multiple sites after their ligand-induced activation. By using different biochemical and molecular genetics approaches, we show that a single ubiquitin is sufficient for both receptor internalization and degradation. Thus, monoubiquitination is the principal signal responsible for the movement of RTKs from the plasma membrane to the lysosome.
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| 36. |
- Heldin, Carl-Henrik, et al.
(författare)
-
Tony Pawson 1952-2013
- 2013
-
Ingår i: Nature Cell Biology. - : Springer Nature. - 1465-7392 .- 1476-4679. ; 15:10
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 37. |
- Hosono, Chie, et al.
(författare)
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Transient junction anisotropies orient annular cell polarization in the Drosophila airway tubes
- 2015
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 17:12, s. 1569-1576
-
Tidskriftsartikel (refereegranskat)abstract
- In contrast to planes, three-dimensional (3D) structures such as tubes are physically anisotropic. Tubular organs exhibit a striking orientation of landmarks according to the physical anisotropy of the 3D shape(1-4), in addition to planar cell polarization(5,6). However, the influence of 3D tissue topography on the constituting cells remains underexplored(7-9). Here, we identify a regulatory network polarizing cellular biochemistry according to the physical anisotropy of the 3D tube geometry (tube cell polarization) by a genome-wide, tissue-specific RNAi screen. During Drosophila airway remodelling, each apical cellular junction is equipotent to establish perpendicular actomyosin cables, irrespective of the longitudinal or transverse tube axis. A dynamic transverse enrichment of atypical protein kinase C (aPKC) shifts the balance and transiently targets activated small GTPase RhoA, myosin phosphorylation and Rab11 vesicle trafficking to longitudinal junctions. We propose that the PAR complex translates tube physical anisotropy into longitudinal junctional anisotropy, where cell cell communication aligns the contractile cytoskeleton of neighbouring cells.
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| 38. |
- Ikeda, Yoshihisa, et al.
(författare)
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Local auxin biosynthesis modulates gradient-directed planar polarity in Arabidopsis
- 2009
-
Ingår i: Nature Cell Biology. - : Nature Publishing Group. - 1465-7392 .- 1476-4679. ; 11:6, s. 731-738
-
Tidskriftsartikel (refereegranskat)abstract
- The coordination of cell polarity within the plane of a single tissue layer (planar polarity) is a crucial task during development of multicellular organisms. Mechanisms underlying establishment of planar polarity, however, differ substantially between plants and animals. In Arabidopsis thaliana, planar polarity of root-hair positioning along epidermal cells is coordinated towards maximum concentration of an auxin gradient in the root tip. This gradient has been hypothesized to be sink-driven and computational modelling suggests that auxin efflux carrier activity may be sufficient to generate the gradient in the absence of auxin biosynthesis in the root. Here, we demonstrate that the Raf-like kinase CONSTITUTIVE TRIPLE RESPONSE1 (CTR1; Refs 8, 9) acts as a concentration-dependent repressor of a biosynthesis-dependent auxin gradient that modulates planar polarity in the root tip. We analysed auxin biosynthesis and concentration gradients in a variety of root-hair-position mutants affected in CTR1 activity, auxin biosynthesis and transport. Our results reveal that planar polarity relies on influx- and efflux-carrier-mediated auxin redistribution from a local biosynthesis maximum. Thus, a local source of auxin biosynthesis contributes to gradient homeostasis during long-range coordination of cellular morphogenesis.
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| 39. |
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| 40. |
- Jiang, Dongsheng, et al.
(författare)
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Two succeeding fibroblastic lineages drive dermal development and the transition from regeneration to scarring
- 2018
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 20:4, s. 422-431
-
Tidskriftsartikel (refereegranskat)abstract
- During fetal development, mammalian back-skin undergoes a natural transition in response to injury, from scarless regeneration to skin scarring. Here, we characterize dermal morphogenesis and follow two distinct embryonic fibroblast lineages, based on their history of expression of the engrailed 1 gene. We use single-cell fate-mapping, live three dimensional confocal imaging and in silico analysis coupled with immunolabelling to reveal unanticipated structural and regional complexity and dynamics within the dermis. We show that dermal development and regeneration are driven by engrailed 1-history-naive fibroblasts, whose numbers subsequently decline. Conversely, engrailed 1-history-positive fibroblasts possess scarring abilities at this early stage and their expansion later on drives scar emergence. The transition can be reversed, locally, by transplanting engrailed 1-naive cells. Thus, fibroblastic lineage replacement couples the decline of regeneration with the emergence of scarring and creates potential clinical avenues to reduce scarring.
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| 41. |
- Jin, Yi, et al.
(författare)
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Endoglin prevents vascular malformation by regulating flow-induced cell migration and specification through VEGFR2 signalling
- 2017
-
Ingår i: Nature Cell Biology. - : NATURE PUBLISHING GROUP. - 1465-7392 .- 1476-4679. ; 19:6, s. 639-652
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Tidskriftsartikel (refereegranskat)abstract
- Loss-of-function (LOF) mutations in the endothelial cell (EC)-enriched gene endoglin (ENG) cause the human disease hereditary haemorrhagic telangiectasia-1, characterized by vascular malformations promoted by vascular endothelial growth factor A (VEGFA). How ENG deficiency alters EC behaviour to trigger these anomalies is not understood. Mosaic ENG deletion in the postnatal mouse rendered Eng LOF ECs insensitive to flow-mediated venous to arterial migration. Eng LOF ECs retained within arterioles acquired venous characteristics and secondary ENG-independent proliferation resulting in arteriovenous malformation (AVM). Analysis following simultaneous Eng LOF and overexpression (OE) revealed that ENG OE ECs dominate tip-cell positions and home preferentially to arteries. ENG knockdown altered VEGFA-mediated VEGFR2 kinetics and promoted AKT signalling. Blockage of PI(3)K/AKT partly normalized flow-directed migration of ENG LOF ECs in vitro and reduced the severity of AVM in vivo. This demonstrates the requirement of ENG in flow-mediated migration and modulation of VEGFR2 signalling in vascular patterning.
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| 42. |
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| 43. |
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| 44. |
- Kalinina, Iana, et al.
(författare)
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Pivoting of microtubules around the spindle pole accelerates kinetochore capture.
- 2013
-
Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 15:1, s. 82-7
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Tidskriftsartikel (refereegranskat)abstract
- During cell division, spindle microtubules attach to chromosomes through kinetochores, protein complexes on the chromosome. The central question is how microtubules find kinetochores. According to the pioneering idea termed search-and-capture, numerous microtubules grow from a centrosome in all directions and by chance capture kinetochores. The efficiency of search-and-capture can be improved by a bias in microtubule growth towards the kinetochores, by nucleation of microtubules at the kinetochores and at spindle microtubules, by kinetochore movement, or by a combination of these processes. Here we show in fission yeast that kinetochores are captured by microtubules pivoting around the spindle pole, instead of growing towards the kinetochores. This pivoting motion of microtubules is random and independent of ATP-driven motor activity. By introducing a theoretical model, we show that the measured random movement of microtubules and kinetochores is sufficient to explain the process of kinetochore capture. Our theory predicts that the speed of capture depends mainly on how fast microtubules pivot, which was confirmed experimentally by speeding up and slowing down microtubule pivoting. Thus, pivoting motion allows microtubules to explore space laterally, as they search for targets such as kinetochores.
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| 45. |
- Karkkainen, Marika J, et al.
(författare)
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Lymphatic endothelium : a new frontier of metastasis research.
- 2002
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- The vascular endothelium is a dynamic tissue with many active functions. Until recently, endothelial cell (EC) biology studies have used cultured ECs from various organs; these cell lines are considered representative of the blood vascular endothelium. Very few lymphatic EC lines have been available, and these were derived from lymphatic tumours or large collecting lymphatic ducts. In the past, lymphatic vessels were defined largely by the lack of erythrocytes in their lumen, a lack of junctional complexes and the lack of a well-defined basement membrane. Now that lymphatic-specific vascular endothelial growth factors (VEGF-C and VEGF-D) and molecular cell surface markers such as the VEGFR-3 receptor have been identified, this definition needs to be updated. Recent developments have highlighted the importance of lymphatic ECs, and they could become the next focus for angiogenesis and metastasis research.
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| 46. |
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| 47. |
- Koltowska, Katarzyna, et al.
(författare)
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The RNA helicase Ddx21 controls Vegfc-driven developmental lymphangiogenesis by balancing endothelial cell ribosome biogenesis and p53 function
- 2021
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Ingår i: Nature Cell Biology. - : Springer Nature. - 1465-7392 .- 1476-4679. ; 23:11, s. 1136-1147
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Tidskriftsartikel (refereegranskat)abstract
- Hogan and colleagues report that the RNA helicase Ddx21 mediates Vegfc-stimulated lymphangiogenesis during zebrafish development through controlling rDNA transcription and ribosome biogenesis in endothelial cells. The development of a functional vasculature requires the coordinated control of cell fate, lineage differentiation and network growth. Cellular proliferation is spatiotemporally regulated in developing vessels, but how this is orchestrated in different lineages is unknown. Here, using a zebrafish genetic screen for lymphatic-deficient mutants, we uncover a mutant for the RNA helicase Ddx21. Ddx21 cell-autonomously regulates lymphatic vessel development. An established regulator of ribosomal RNA synthesis and ribosome biogenesis, Ddx21 is enriched in sprouting venous endothelial cells in response to Vegfc-Flt4 signalling. Ddx21 function is essential for Vegfc-Flt4-driven endothelial cell proliferation. In the absence of Ddx21, endothelial cells show reduced ribosome biogenesis, p53 and p21 upregulation and cell cycle arrest that blocks lymphangiogenesis. Thus, Ddx21 coordinates the lymphatic endothelial cell response to Vegfc-Flt4 signalling by balancing ribosome biogenesis and p53 function. This mechanism may be targetable in diseases of excessive lymphangiogenesis such as cancer metastasis or lymphatic malformation.
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| 48. |
- Krastev, DB, et al.
(författare)
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The ubiquitin-dependent ATPase p97 removes cytotoxic trapped PARP1 from chromatin
- 2022
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 24:1, s. 62-
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Tidskriftsartikel (refereegranskat)abstract
- Poly (ADP-ribose) polymerase (PARP) inhibitors elicit antitumour activity in homologous recombination-defective cancers by trapping PARP1 in a chromatin-bound state. How cells process trapped PARP1 remains unclear. Using wild-type and a trapping-deficient PARP1 mutant combined with rapid immunoprecipitation mass spectrometry of endogenous proteins and Apex2 proximity labelling, we delineated mass spectrometry-based interactomes of trapped and non-trapped PARP1. These analyses identified an interaction between trapped PARP1 and the ubiquitin-regulated p97 ATPase/segregase. We found that following trapping, PARP1 is SUMOylated by PIAS4 and subsequently ubiquitylated by the SUMO-targeted E3 ubiquitin ligase RNF4, events that promote recruitment of p97 and removal of trapped PARP1 from chromatin. Small-molecule p97-complex inhibitors, including a metabolite of the clinically used drug disulfiram (CuET), prolonged PARP1 trapping and enhanced PARP inhibitor-induced cytotoxicity in homologous recombination-defective tumour cells and patient-derived tumour organoids. Together, these results suggest that p97 ATPase plays a key role in the processing of trapped PARP1 and the response of tumour cells to PARP inhibitors.
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| 49. |
- Kumar, B, et al.
(författare)
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Polycomb repressive complex 2 shields naïve human pluripotent cells from trophectoderm differentiation
- 2022
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1476-4679 .- 1465-7392. ; 24:6, s. 845-
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Tidskriftsartikel (refereegranskat)abstract
- The first lineage choice in human embryo development separates trophectoderm from the inner cell mass. Naïve human embryonic stem cells are derived from the inner cell mass and offer possibilities to explore how lineage integrity is maintained. Here, we discover that polycomb repressive complex 2 (PRC2) maintains naïve pluripotency and restricts differentiation to trophectoderm and mesoderm lineages. Through quantitative epigenome profiling, we found that a broad gain of histone H3 lysine 27 trimethylation (H3K27me3) is a distinct feature of naïve pluripotency. We define shared and naïve-specific bivalent promoters featuring PRC2-mediated H3K27me3 concomitant with H3K4me3. Naïve bivalency maintains key trophectoderm and mesoderm transcription factors in a transcriptionally poised state. Inhibition of PRC2 forces naïve human embryonic stem cells into an ‘activated’ state, characterized by co-expression of pluripotency and lineage-specific transcription factors, followed by differentiation into either trophectoderm or mesoderm lineages. In summary, PRC2-mediated repression provides a highly adaptive mechanism to restrict lineage potential during early human development.
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| 50. |
- Kvist, Anders, et al.
(författare)
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Promoter usage of BRCA1-IRIS
- 2005
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 7:4, s. 325-326
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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