scholarly journals Complex Proteolytic Processing Acts on Delta, a Transmembrane Ligand for Notch, during Drosophila Development

1998 ◽  
Vol 9 (7) ◽  
pp. 1709-1723 ◽  
Author(s):  
Kristin M. Klueg ◽  
Todd R. Parody ◽  
Marc A.T. Muskavitch
Keyword(s):  
Cell Fate ◽  
Cultured Cells ◽  
Cellular Responses ◽  
Proteolytic Processing ◽  
Cell Fate Specification ◽  
A Cell ◽  
Membrane Bound ◽  
Delta Functions ◽  
Intracellular Domains

Delta functions as a cell nonautonomous membrane-bound ligand that binds to Notch, a cell-autonomous receptor, during cell fate specification. Interaction between Delta and Notch leads to signal transduction and elicitation of cellular responses. During our investigations to further understand the biochemical mechanism by which Delta signaling is regulated, we have identified four Delta isoforms inDrosophila embryonic and larval extracts. We have demonstrated that at least one of the smaller isoforms, Delta S, results from proteolysis. Using antibodies to the Delta extracellular and intracellular domains in colocalization experiments, we have found that at least three Delta isoforms exist in vivo, providing the first evidence that multiple forms of Delta exist during development. Finally, we demonstrate that Delta is a transmembrane ligand that can be taken up by Notch-expressing Drosophila cultured cells. Cell culture experiments imply that full-length Delta is taken up by Notch-expressing cells. We present evidence that suggests this uptake occurs by a nonphagocytic mechanism.

scholarly journals Effect of the 3D Artificial Nichoid on the Morphology and Mechanobiological Response of Mesenchymal Stem Cells Cultured In Vitro

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1873 ◽  
Author(s):  
Andrea Remuzzi ◽  
Barbara Bonandrini ◽  
Matteo Tironi ◽  
Lorena Longaretti ◽  
Marina Figliuzzi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Cultured Cells ◽  
Three Dimensions ◽  
Nuclear Pore ◽  
Cells Cultured

Stem cell fate and behavior are affected by the bidirectional communication of cells and their local microenvironment (the stem cell niche), which includes biochemical cues, as well as physical and mechanical factors. Stem cells are normally cultured in conventional two-dimensional monolayer, with a mechanical environment very different from the physiological one. Here, we compare culture of rat mesenchymal stem cells on flat culture supports and in the “Nichoid”, an innovative three-dimensional substrate micro-engineered to recapitulate the architecture of the physiological niche in vitro. Two versions of the culture substrates Nichoid (single-layered or “2D Nichoid” and multi-layered or “3D Nichoid”) were fabricated via two-photon laser polymerization in a biocompatible hybrid organic-inorganic photoresist (SZ2080). Mesenchymal stem cells, isolated from rat bone marrow, were seeded on flat substrates and on 2D and 3D Nichoid substrates and maintained in culture up to 2 weeks. During cell culture, we evaluated cell morphology, proliferation, cell motility and the expression of a panel of 89 mesenchymal stem cells’ specific genes, as well as intracellular structures organization. Our results show that mesenchymal stem cells adhered and grew in the 3D Nichoid with a comparable proliferation rate as compared to flat substrates. After seeding on flat substrates, cells displayed large and spread nucleus and cytoplasm, while cells cultured in the 3D Nichoid were spatially organized in three dimensions, with smaller and spherical nuclei. Gene expression analysis revealed the upregulation of genes related to stemness and to mesenchymal stem cells’ features in Nichoid-cultured cells, as compared to flat substrates. The observed changes in cytoskeletal organization of cells cultured on 3D Nichoids were also responsible for a different localization of the mechanotransducer transcription factor YAP, with an increase of the cytoplasmic retention in cells cultured in the 3D Nichoid. This difference could be explained by alterations in the import of transcription factors inside the nucleus due to the observed decrease of mean nuclear pore diameter, by transmission electron microscopy. Our data show that 3D distribution of cell volume has a profound effect on mesenchymal stem cells structure and on their mechanobiological response, and highlight the potential use of the 3D Nichoid substrate to strengthen the potential effects of MSC in vitro and in vivo.

scholarly journals Stochastic antagonism between two proteins governs a bacterial cell fate switch

Science ◽  
2019 ◽  
Vol 366 (6461) ◽  
pp. 116-120 ◽  
Author(s):  
Nathan D. Lord ◽  
Thomas M. Norman ◽  
Ruoshi Yuan ◽  
Somenath Bakshi ◽  
Richard Losick ◽  
...  
Keyword(s):  
Cell Fate ◽  
Regulatory Networks ◽  
Cell Types ◽  
Feedback Loops ◽  
Cell Fate Determination ◽  
Cell Fate Decision ◽  
A Cell ◽  
Fate Decision ◽  
Antagonistic Interactions

Cell fate decision circuits must be variable enough for genetically identical cells to adopt a multitude of fates, yet ensure that these states are distinct, stably maintained, and coordinated with neighboring cells. A long-standing view is that this is achieved by regulatory networks involving self-stabilizing feedback loops that convert small differences into long-lived cell types. We combined regulatory mutants and in vivo reconstitution with theory for stochastic processes to show that the marquee features of a cell fate switch in Bacillus subtilis—discrete states, multigenerational inheritance, and timing of commitments—can instead be explained by simple stochastic competition between two constitutively produced proteins that form an inactive complex. Such antagonistic interactions are commonplace in cells and could provide powerful mechanisms for cell fate determination more broadly.

scholarly journals Abnormalities of the Genitourinary Tract in Female Mice Lacking GATA5

2000 ◽  
Vol 20 (14) ◽  
pp. 5256-5260 ◽  
Author(s):  
Jeffery D. Molkentin ◽  
Kevin M. Tymitz ◽  
James A. Richardson ◽  
Eric N. Olson
Keyword(s):  
Cell Fate ◽  
Null Allele ◽  
Cell Fate Specification ◽  
Mammalian Development ◽  
Gata Factor ◽  
Genitourinary System ◽  
Gata Factors ◽  
Developing Heart

ABSTRACT Members of the GATA family of transcription factors play important roles in cell fate specification, differentiation, and morphogenesis during mammalian development. GATA5, the only one of the six vertebrate GATA factor genes not yet inactivated in mice, is expressed in a pattern that overlaps with but is distinct from that of other GATA factor genes. During mouse embryogenesis, GATA5 is expressed first in the developing heart and subsequently in the lung, vasculature, and genitourinary system. To investigate the function of GATA5 in vivo, we created mice homozygous for a GATA5 null allele. Homozygous mutants were viable and fertile, but females exhibited pronounced genitourinary abnormalities that included vaginal and uterine defects and hypospadias. In contrast, the genitourinary system was unaffected in male GATA5 mutants. These results reveal a specific role of GATA5 in development of the female genitourinary system and suggest that other GATA factors may have functions overlapping those of GATA5 in other tissues.

Postmitotic cells fated to become rod photoreceptors can be respecified by CNTF treatment of the retina

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1055-1067 ◽  
Author(s):  
Z.D. Ezzeddine ◽  
X. Yang ◽  
T. DeChiara ◽  
G. Yancopoulos ◽  
C.L. Cepko
Keyword(s):  
Cell Fate ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Extrinsic Factors ◽  
Rod Photoreceptors ◽  
Cell Fate Decisions ◽  
Retinal Explants ◽  
A Cell

Lineage analyses of vertebrate retinae have led to the suggestions that cell fate decisions are made during or after the terminal cell division and that extrinsic factors can influence fate choices. The evidence for a role of extrinsic factors is strongest for development of rodent rod photoreceptors ('rods'). In an effort to identify molecules that may regulate rod development, a number of known factors were assayed in vitro. Ciliary neurotrophic factor (CNTF) was found to have a range of effects on retinal cells. Addition of CNTF to postnatal rat retinal explants resulted in a dramatic reduction in the number of differentiating rods. Conversly, the number of cells expressing markers of bipolar cell differentiation was increased to a level not normally seen in vivo or in vitro. In addition, a small increase in the percentage of cells expressing either a marker of amacrine cells or a marker of Muller glia was noted. It was determined that many of the cells that would normally differentiate into rods were the cells that differentiated as bipolar cells in the presence of CNTF. Prospective rod photoreceptors could make this change even when they were postmitotic, indicating that at least a subset of cells fated to be rods were not committed to this fate at the time they were born. These findings highlight the distinction between cell fate and commitment. Resistance to the effect of CNTF on rod differentiation occurred at about the time that a cell began to express opsin. The time of commitment to terminal rod differentiation may thus coincide with the initiation of opsin expression. In agreement with the hypothesis that CNTF plays a role in rod differentiation in vivo, a greater percentage of cells were observed differentiating as rod photoreceptors in mouse retinal explants lacking a functional CNTF receptor, relative to wild-type littermates.

scholarly journals Proteolytic processing of palmitoylated Hedgehog peptides specifies the 3-4 intervein region of the Drosophila wing

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Sabine Schürmann ◽  
Georg Steffes ◽  
Dominique Manikowski ◽  
Philipp Kastl ◽  
Ursula Malkus ◽  
...  
Keyword(s):  
Cell Fate ◽  
Proteolytic Processing ◽  
Wing Development ◽  
Cell Fate Determination ◽  
Site Specific ◽  
Drosophila Wing ◽  
Direct Patterning ◽  
Processing Site ◽  
Membrane Bound ◽  
Morphogen Transport

Cell fate determination during development often requires morphogen transport from producing to distant responding cells. Hedgehog (Hh) morphogens present a challenge to this concept, as all Hhs are synthesized as terminally lipidated molecules that form insoluble clusters at the surface of producing cells. While several proposed Hh transport modes tie directly into these unusual properties, the crucial step of Hh relay from producing cells to receptors on remote responding cells remains unresolved. Using wing development in Drosophila melanogaster as a model, we show that Hh relay and direct patterning of the 3–4 intervein region strictly depend on proteolytic removal of lipidated N-terminal membrane anchors. Site-directed modification of the N-terminal Hh processing site selectively eliminated the entire 3–4 intervein region, and additional targeted removal of N-palmitate restored its formation. Hence, palmitoylated membrane anchors restrict morphogen spread until site-specific processing switches membrane-bound Hh into bioactive forms with specific patterning functions.

scholarly journals Proteolytic processing of the α-subunit of rat endopeptidase-24.18 by furin

1995 ◽  
Vol 309 (2) ◽  
pp. 683-688 ◽  
Author(s):  
P E Milhiet ◽  
S Chevallier ◽  
D Corbeil ◽  
N G Seidah ◽  
P Crine ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Consensus Sequence ◽  
Proteolytic Processing ◽  
Alpha Subunit ◽  
Structural Domain ◽  
Α Subunit ◽  
Alpha Subunits ◽  
Golgi Compartment ◽  
Membrane Bound

Endopeptidase-24.18 (EC 3.4.24.18; meprin) is a multisubunit metallopeptidase of the astacin family. It is found in brush-border membranes of rodent kidney and human intestine. The membrane-bound enzyme is composed of alpha/beta dimers. Molecular cloning has shown that both subunits have a similar structural domain organization. Soluble alpha 2 dimers have also been observed in vivo and in transfected cells. The structures of all known alpha-subunits contain, upstream from the transmembrane domain, the sequence RXKR, which corresponds to the RXK/RR consensus sequence for specific cleavage by furin. In order to investigate the involvement of this putative cleavage site in the secretion process of endopeptidase-24,.18 alpha-subunit, we expressed in COS-1 cells rat alpha-subunits in which residues R655 or S656 (within the sequence R652PKRS656) were mutated to valine or leucine respectively. In contrast to the wild-type protein, the alpha R655V and alphaS656L mutants were not secreted in the culture medium. Moreover, when cells expressing the alpha-subunit were infected with a furin-encoding vaccinia virus, immunoblotting showed a shift of the major cell-associated form of endopeptidase-24.18 alpha-subunit from 98 kDa to 85 kDa and an increase in the amounts of secreted alpha-subunit. This shift in molecular mass was not observed with the mutant alpha-subunits. As observed for the 98 kDa species, the 85 kDa cell-associated protein was sensitive to endoglycosidase H treatment, suggesting that the proteolytic cleavage occurred in the endoplasmic reticulum or in an early Golgi compartment. Similar experiments using PACE4 and PC5 instead of furin showed that these enzymes were not able to generate the 85 kDa species. We conclude that furin is most probably the cellular enzyme involved in the proteolysis resulting in secretion of rat endopeptidase-24.18 alpha-subunit.

scholarly journals Small-molecule synergist of the Wnt/β-catenin signaling pathway

2007 ◽  
Vol 104 (18) ◽  
pp. 7444-7448 ◽  
Author(s):  
Qisheng Zhang ◽  
Michael B. Major ◽  
Shinichi Takanashi ◽  
Nathan D. Camp ◽  
Naoyuki Nishiya ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Small Molecules ◽  
Signaling Pathway ◽  
Cell Fate ◽  
Protein Trafficking ◽  
Purine Derivative ◽  
Pharmacological Agents ◽  
A Cell ◽  
And Behavior

The Wnt/β-catenin signaling pathway regulates cell fate and behavior during embryogenesis, adult tissue homeostasis, and regeneration. When inappropriately activated, the pathway has been linked to colorectal cancer and melanoma, and when attenuated it may contribute to Alzheimer's disease and osteoporosis. Small molecules that modulate Wnt signaling will likely provide new insights into the regulation of this key developmental pathway and ultimately provide pharmacological agents to control Wnt signaling in vivo. To this end, we screened a library of 100,000 small molecules for activity in a cell-based assay of Wnt/β-catenin signaling and discovered a purine derivative, QS11, that synergizes with Wnt-3a ligand in the activation of Wnt/β-catenin signal transduction. Through affinity chromatography and subsequent functional assays, we showed that QS11 binds and inhibits the GTPase activating protein of ADP-ribosylation factor 1 (ARFGAP1), suggesting that QS11 modulates Wnt/β-catenin signaling through an effect on protein trafficking. Consistent with its function as an ARFGAP inhibitor, QS11 inhibits migration of ARFGAP overexpressing breast cancer cells.

scholarly journals Angptl2 is a Marker of Cellular Senescence: The Physiological and Pathophysiological Impact of Angptl2-Related Senescence

2021 ◽  
Vol 22 (22) ◽  
pp. 12232
Author(s):  
Nathalie Thorin-Trescases ◽  
Pauline Labbé ◽  
Pauline Mury ◽  
Mélanie Lambert ◽  
Eric Thorin
Keyword(s):  
Cell Fate ◽  
Cellular Senescence ◽  
Cellular Response ◽  
Inflammatory Diseases ◽  
Age Related ◽  
A Cell ◽  
Future Work ◽  
The Impact

Cellular senescence is a cell fate primarily induced by DNA damage, characterized by irreversible growth arrest in an attempt to stop the damage. Senescence is a cellular response to a stressor and is observed with aging, but also during wound healing and in embryogenic developmental processes. Senescent cells are metabolically active and secrete a multitude of molecules gathered in the senescence-associated secretory phenotype (SASP). The SASP includes inflammatory cytokines, chemokines, growth factors and metalloproteinases, with autocrine and paracrine activities. Among hundreds of molecules, angiopoietin-like 2 (angptl2) is an interesting, although understudied, SASP member identified in various types of senescent cells. Angptl2 is a circulatory protein, and plasma angptl2 levels increase with age and with various chronic inflammatory diseases such as cancer, atherosclerosis, diabetes, heart failure and a multitude of age-related diseases. In this review, we will examine in which context angptl2 was identified as a SASP factor, describe the experimental evidence showing that angptl2 is a marker of senescence in vitro and in vivo, and discuss the impact of angptl2-related senescence in both physiological and pathological conditions. Future work is needed to demonstrate whether the senescence marker angptl2 is a potential clinical biomarker of age-related diseases.

scholarly journals OXPHOS Promotes Apoptotic Resistance and Persistence in TH17 cells

2021 ◽  
Author(s):  
Hanna S. Hong ◽  
Nneka E. Mbah ◽  
Mengrou Shan ◽  
Kristen Loesel ◽  
Lin Lin ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
Cell Fate ◽  
Apoptotic Cell ◽  
Metabolic Phenotype ◽  
Tumor Studies ◽  
A Cell

AbstractApoptotic cell death is a cell-intrinsic, immune tolerance mechanism that regulates the magnitude and resolution of T cell-mediated responses. Evasion of apoptosis is critical for the generation of memory T cells, as well as autoimmune T cells, and knowledge of the mechanisms that enable resistance to apoptosis will provide insight into ways to modulate their activity during protective and pathogenic responses. IL-17-producing CD4 T cells (TH17s) are long-lived, memory cells. These features enable their role in host defense, chronic inflammatory disorders, and anti-tumor immunity. A growing number of reports now indicate that TH17s in vivo require mitochondrial oxidative phosphorylation (OXPHOS), a metabolic phenotype that is poorly induced in vitro. To elucidate the role of OXPHOS in TH17 processes, we developed a system to polarize TH17s that metabolically resembled their in vivo counterparts. We discovered that directing TH17s to use OXPHOS promotes mitochondrial fitness, glutamine anaplerosis, and an anti-apoptotic phenotype marked by high BCL-XL and low BIM. Through competitive co-transfer experiments and tumor studies, we further revealed how OXPHOS protects TH17s from cell death while enhancing their persistence in the periphery and tumor microenvironment. Together, our work demonstrates a non-classical role of metabolism in regulating TH17 cell fate and highlights the potential for therapies that target OXPHOS in TH17-driven diseases.

Interchangeability of Caenorhabditis elegans DSL proteins and intrinsic signalling activity of their extracellular domains in vivo

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4275-4282 ◽  
Author(s):  
K. Fitzgerald ◽  
I. Greenwald
Keyword(s):  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Cell Interactions ◽  
Regulatory Sequences ◽  
Cell Fate Decisions ◽  
C Elegans ◽  
Dsl Ligands ◽  
Mediate Cell ◽  
Intracellular Domains

Ligands of the Delta/Serrate/lag-2 (DSL) family and their receptors, members of the lin-12/Notch family, mediate cell-cell interactions that specify cell fate in invertebrates and vertebrates. In C. elegans, two DSL genes, lag-2 and apx-1, influence different cell fate decisions during development. Here we show that APX-1 can fully substitute for LAG-2 when expressed under the control of lag-2 regulatory sequences. In addition, we demonstrate that truncated forms lacking the transmembrane and intracellular domains of both LAG-2 and APX-1 can also substitute for endogenous lag-2 activity. Moreover, we provide evidence that these truncated forms are secreted and able to activate LIN-12 and GLP-1 ectopically. Finally, we show that expression of a secreted DSL domain alone may enhance endogenous LAG-2 signalling. Our data suggest ways that activated forms of DSL ligands in other systems may be created.

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