scholarly journals Roles for Ndel1 in keratin organization and desmosome function

2021 ◽  
pp. mbc.E21-02-0087
Author(s):  
Yong-Bae Kim ◽  
Daniel Hlavaty ◽  
Jeff Maycock ◽  
Terry Lechler
Keyword(s):  
Cell Cycle ◽  
Cell Adhesion ◽  
Polymer Networks ◽  
Mouse Genetics ◽  
Cell Type ◽  
Intermediate Filament Proteins ◽  
Differentiated Cells ◽  
Keratin Filaments ◽  
Local Assembly ◽  
Keratin Intermediate Filaments

Keratin intermediate filaments form dynamic polymer networks that organize in specific ways dependent on the cell type, the stage of the cell cycle, and the state of the cell. In differentiated cells of the epidermis, they are organized by desmosomes, cell-cell adhesion complexes which provide essential mechanical integrity to this tissue. Despite this, we know little about how keratin organization is controlled and whether desmosomes locally regulate keratin dynamics in addition to binding pre-assembled filaments. Ndel1 is a desmosome-associated protein in the differentiated epidermis, though its function at these structures has not been examined. Here, we show that Ndel1 binds directly to keratin subunits through a motif conserved in all intermediate filament proteins. Further, Ndel1 was necessary for robust desmosome-keratin association and sufficient to reorganize keratins at distinct cellular sites. Lis1, a Ndel1 binding protein, was required for desmosomal localization of Ndel1, but not for its effects on keratin filaments. Finally, we use mouse genetics to demonstrate that loss of Ndel1 results in desmosome defects in the epidermis. Our data thus identifies Ndel1 as a desmosome-associated protein which promotes local assembly/reorganization of keratin filaments and is essential for robust desmosome formation.

scholarly journals Ndel1 promotes keratin assembly and desmosome stability

2020 ◽  
Author(s):  
Yong-Bae Kim ◽  
Daniel Hlavaty ◽  
Jeff Maycock ◽  
Terry Lechler
Keyword(s):  
Cell Cycle ◽  
Cell Adhesion ◽  
Polymer Networks ◽  
Mouse Genetics ◽  
Cell Type ◽  
Intermediate Filament Proteins ◽  
Differentiated Cells ◽  
Keratin Filaments ◽  
Local Assembly ◽  
Keratin Intermediate Filaments

ABSTRACTKeratin intermediate filaments form dynamic polymer networks that organize in specific ways dependent on the cell type, the stage of the cell cycle, and the state of the cell. In differentiated cells of the epidermis, they are organized by desmosomes, cell-cell adhesion complexes which provide essential mechanical integrity to this tissue. Despite this, we know little about how keratin organization is controlled and whether desmosomes actively promote keratin assembly in addition to binding pre-assembled filaments. We recently discovered that Ndel1 is a desmosome-associated protein in differentiated epidermis. Here, we show that Ndel1 binds directly to keratin subunits through a motif conserved in all intermediate filament proteins. Further, Ndel1 is necessary for robust desmosome-keratin association and sufficient to reorganize keratins to distinct cellular sites. Lis1, a Ndel1 binding protein, is required for desmosomal localization of Ndel1, but not for its effects on keratin filaments. Finally, we use mouse genetics to demonstrate that loss of Ndel1 results in desmosome defects in the epidermis. Our data thus identify Ndel1 as a desmosome-associated protein which promotes local assembly/organization of keratin filaments and is essential for both robust cell adhesion and epidermal barrier function.

scholarly journals Histone modifications form a cell-type-specific chromosomal bar code that persists through the cell cycle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
John A. Halsall ◽  
Simon Andrews ◽  
Felix Krueger ◽  
Charlotte E. Rutledge ◽  
Gabriella Ficz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Histone Modifications ◽  
Expression Patterns ◽  
Cell Types ◽  
Cell Type ◽  
Bar Code ◽  
Genes Encoding ◽  
Cell Type Specific ◽  
Rolling Windows

AbstractChromatin configuration influences gene expression in eukaryotes at multiple levels, from individual nucleosomes to chromatin domains several Mb long. Post-translational modifications (PTM) of core histones seem to be involved in chromatin structural transitions, but how remains unclear. To explore this, we used ChIP-seq and two cell types, HeLa and lymphoblastoid (LCL), to define how changes in chromatin packaging through the cell cycle influence the distributions of three transcription-associated histone modifications, H3K9ac, H3K4me3 and H3K27me3. We show that chromosome regions (bands) of 10–50 Mb, detectable by immunofluorescence microscopy of metaphase (M) chromosomes, are also present in G1 and G2. They comprise 1–5 Mb sub-bands that differ between HeLa and LCL but remain consistent through the cell cycle. The same sub-bands are defined by H3K9ac and H3K4me3, while H3K27me3 spreads more widely. We found little change between cell cycle phases, whether compared by 5 Kb rolling windows or when analysis was restricted to functional elements such as transcription start sites and topologically associating domains. Only a small number of genes showed cell-cycle related changes: at genes encoding proteins involved in mitosis, H3K9 became highly acetylated in G2M, possibly because of ongoing transcription. In conclusion, modified histone isoforms H3K9ac, H3K4me3 and H3K27me3 exhibit a characteristic genomic distribution at resolutions of 1 Mb and below that differs between HeLa and lymphoblastoid cells but remains remarkably consistent through the cell cycle. We suggest that this cell-type-specific chromosomal bar-code is part of a homeostatic mechanism by which cells retain their characteristic gene expression patterns, and hence their identity, through multiple mitoses.

scholarly journals Effect of Placental Extract on Omentum Mesenchymal Stem Cells Differentiation in NMRI Mice

2017 ◽  
Vol 7 (1) ◽  
pp. 176
Author(s):  
Maryam Sadat Nezhadfazel ◽  
Kazem Parivar ◽  
Nasim Hayati Roodbari ◽  
Mitra Heydari Nasrabadi
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Flow Cytometry ◽  
Endothelial Cells ◽  
Mesenchymal Stem Cells ◽  
Control Group ◽  
Fat Cell ◽  
Nmri Mice ◽  
Differentiated Cells ◽  
Placental Extract

Omentum mesenchymal stem cells (OMSCs) could be induced to differentiate into cell varieties under certain conditions. We studied differentiation of OMSCs induced by using placenta extract in NMRI mice. Mesenchymal stem cells (MSCs) were isolated from omentum and cultured with mice placenta extract. MSCs, were assessed after three passages by flow cytometry for CD90, CD44, CD73, CD105, CD34 markers and were recognized their ability to differentiate into bone and fat cell lines. Placenta extract dose was determined with IC50 test then OMSCs were cultured in DMEM and 20% placenta extract.The cell cycle was checked. OMSCs were assayed on 21 days after culture and differentiated cells were determined by flow cytometry and again processed for flow cytometry. CD90, CD44, CD73, CD105 markers were not expressed, only CD34 was their marker. OMSCs were morphologically observed. Differentiated cells are similar to the endothelial cells. Therefore, to identify differentiated cells, CD31 and FLK1 expression were measured. This was confirmed by its expression. G1 phase of the cell cycle shows that OMSCs compared to the control group, were in the differentiation phase. The reason for the differentiation of MSCs into endothelial cells was the sign of presence of VEGF factor in the medium too high value of as a VEGF secreting source.

scholarly journals Discovery of keratin function and role in genetic diseases: the year that 1991 was

2016 ◽  
Vol 27 (18) ◽  
pp. 2807-2810 ◽  
Author(s):  
Pierre A. Coulombe
Keyword(s):  
Intermediate Filaments ◽  
Cell Biology ◽  
Essential Role ◽  
Genetic Diseases ◽  
Structure And Function ◽  
Mechanical Support ◽  
25Th Anniversary ◽  
Keratin Filaments ◽  
And Function ◽  
Keratin Intermediate Filaments

In 1991, a set of transgenic mouse studies took the fields of cell biology and dermatology by storm in providing the first credible evidence that keratin intermediate filaments play a unique and essential role in the structural and mechanical support in keratinocytes of the epidermis. Moreover, these studies intimated that mutations altering the primary structure and function of keratin filaments underlie genetic diseases typified by cellular fragility. This Retrospective on how these studies came to be is offered as a means to highlight the 25th anniversary of these discoveries.

scholarly journals Talin mechanosensitivity is modulated by a direct interaction with cyclin-dependent kinase-1

2021 ◽  
Author(s):  
Rosemarie E. Gough ◽  
Matthew C. Jones ◽  
Thomas Zacharchenko ◽  
Shimin Le ◽  
Miao Yu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Adhesion ◽  
Cell Division ◽  
Mechanical Response ◽  
Direct Interaction ◽  
Cyclin Dependent Kinase ◽  
Cell Cycle Regulator ◽  
Direct Binding

AbstractTalin is a mechanosensitive component of adhesion complexes that directly couples integrins to the actin cytoskeleton. In response to force, talin undergoes switch-like behaviour of its multiple rod domains that modulate interactions with its binding partners. Cyclin-dependent kinase-1 (CDK1) is a key regulator of the cell cycle, exerting its effects through synchronised phosphorylation of a large number of protein targets. CDK1 activity also maintains adhesion during interphase, and its inhibition is a prerequisite for the tightly choreographed changes in cell shape and adhesiveness that are required for successful completion of mitosis. Using a combination of biochemical, structural and cell biological approaches, we demonstrate a direct interaction between talin and CDK1 that occurs at sites of integrin-mediated adhesion. Mutagenesis demonstrated that CDK1 contains a functional talin-binding LD motif, and the binding site within talin was pinpointed to helical bundle R8 through the use of recombinant fragments. Talin also contains a consensus CDK1 phosphorylation motif centred on S1589; a site that was phosphorylated by CDK1in vitro. A phosphomimetic mutant of this site within talin lowered the binding affinity of KANK and weakened the mechanical response of the region, potentially altering downstream mechanotransduction pathways. The direct binding of the master cell cycle regulator, CDK1, to the primary integrin effector, talin, therefore provides a primordial solution for coupling the cell proliferation and cell adhesion machineries, and thereby enables microenvironmental control of cell division in multicellular organisms.SummaryThe direct binding of the master cell cycle regulator, CDK1, to the primary integrin effector, talin, provides a primordial solution for coupling the cell proliferation and cell adhesion machineries, and thereby enables microenvironmental control of cell division.

scholarly journals Src kinase activity coordinates cell adhesion and spreading with activation of mammalian target of rapamycin in pancreatic endocrine tumour cells

2011 ◽  
Vol 18 (5) ◽  
pp. 541-554 ◽  
Author(s):  
Alessia Di Florio ◽  
Laura Adesso ◽  
Simona Pedrotti ◽  
Gabriele Capurso ◽  
Emanuela Pilozzi ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Adhesion ◽  
Microarray Analysis ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Inhibitors ◽  
Target Of Rapamycin ◽  
Cell Cycle Regulators ◽  
Inhibition Of Proliferation ◽  
Pancreatic Endocrine Tumours ◽  
Independent Marker

Pancreatic endocrine tumours (PETs) are rare and heterogeneous neoplasms, often diagnosed at metastatic stage, for which no cure is currently available. Recently, activation of two pathways that support proliferation and invasiveness of cancer cells, the Src family kinase (SFK) and mammalian target of rapamycin (mTOR) pathways, was demonstrated in PETs. Since both pathways represent suitable targets for therapeutic intervention, we investigated their possible interaction in PETs. Western blot and immunofluorescence analyses indicated that SFK and mTOR activity correlate in PET cell lines. We also found that SFKs coordinate cell adhesion and spreading with activation of the mTOR pathway in PET cells. Live cell metabolic labelling and biochemical studies demonstrated that SFK activity enhance mTOR-dependent translation initiation. Furthermore, microarray analysis of the mRNAs associated with polyribosomes revealed that SFKs regulate mTOR-dependent translation of specific transcripts, with an enrichment in mRNAs encoding cell cycle proteins. Importantly, a synergic inhibition of proliferation was observed in PET cells concomitantly treated with SFK and mTOR inhibitors, without activation of the phosphatidylinositol 3-kinase/AKT pro-survival pathway. Tissue microarray analysis revealed activation of Src and mTOR in some PET samples, and identified phosphorylation of 4E-BP1 as an independent marker of poor prognosis in PETs. Thus, our work highlights a novel link between the SFK and mTOR pathways, which regulate the translation of mRNAs for cell cycle regulators, and suggest that crosstalk between these pathways promotes PET cell proliferation.

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