scholarly journals The Ras Target AF-6 is a Substrate of the Fam Deubiquitinating Enzyme

1998 ◽  
Vol 142 (4) ◽  
pp. 1053-1062 ◽  
Author(s):  
Shinichiro Taya ◽  
Takaharu Yamamoto ◽  
Kyoko Kano ◽  
Yoji Kawano ◽  
Akihiro Iwamatsu ◽  
...  
Keyword(s):  
Cell Fate ◽  
Plasma Membranes ◽  
Critical Role ◽  
Amino Acid Sequences ◽  
Cell Contact ◽  
Deubiquitinating Enzyme ◽  
Intact Cells ◽  
Cell Adhesions ◽  
Fat Facets ◽  
Cell Cell

The Ras target AF-6 has been shown to serve as one of the peripheral components of cell–cell adhesions, and is thought to participate in cell–cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of ∼220 kD (p220) to investigate the function of AF-6 at cell–cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell–cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6.

scholarly journals SyNPL: Synthetic Notch pluripotent cell lines to monitor and manipulate cell interactions in vitro and in vivo

2021 ◽  
Author(s):  
Mattias Malaguti ◽  
Rosa Portero Migueles ◽  
Jennifer Annoh ◽  
Daina Sadurska ◽  
Guillaume Blin ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Lines ◽  
Modular Design ◽  
Cell Interactions ◽  
Cell Populations ◽  
Cell Contact ◽  
Pluripotent Cells ◽  
Cell Fate Decisions ◽  
Cell Cell

ABSTRACTCell-cell interactions govern differentiation and cell competition in pluripotent cells during early development, but the investigation of such processes is hindered by a lack of efficient analysis tools. Here we introduce SyNPL: clonal pluripotent stem cell lines which employ optimised Synthetic Notch (SynNotch) technology to report cell-cell interactions between engineered “sender” and “receiver” cells in cultured pluripotent cells and chimaeric mouse embryos. A modular design makes it straightforward to adapt the system for programming differentiation decisions non-cell-autonomously in receiver cells in response to direct contact with sender cells. We demonstrate the utility of this system by enforcing neuronal differentiation at the boundary between two cell populations. In summary, we provide a new tool which could be used to identify cell interactions and to profile changes in gene or protein expression that result from direct cell-cell contact with defined cell populations in culture and in early embryos, and which can be adapted to generate synthetic patterning of cell fate decisions.

scholarly journals mDia2 formin selectively interacts with catenins and not E-cadherin to regulate Adherens Junction formation

2019 ◽  
Author(s):  
Yuqi Zhang ◽  
Krista M. Pettee ◽  
Kathryn N. Becker ◽  
Kathryn M. Eisenmann
Keyword(s):  
Single Cell ◽  
Actin Polymerization ◽  
Plasma Membranes ◽  
Adherens Junctions ◽  
Single Cells ◽  
Critical Role ◽  
Cell Junctions ◽  
Hek 293 ◽  
E Cadherin ◽  
Cell Cell

AbstractBackgroundEpithelial ovarian cancer (EOC) cells disseminate within the peritoneal cavity, in part, via the peritoneal fluid as single cells, clusters, or spheroids. Initial single cell egress from a tumor can involve disruption of cell-cell adhesions as cells are shed from the primary tumor into the peritoneum. In epithelial cells, Adherens Junctions (AJs) are characterized by homotypic linkage of E-cadherins on the plasma membranes of adjacent cells. AJs are anchored to the intracellular actin cytoskeletal network through a complex involving E-cadherin, p120 catenin, β-catenin, and αE-catenin. However, the specific players involved in the interaction between the junctional E-cadherin complex and the underlying F-actin network remains unclear. Recent evidence indicates that mammalian Diaphanous-related (mDia) formins plays a key role in epithelial cell AJ formation and maintenance through generation of linear actin filaments. Binding of αE-catenin to linear F-actin inhibits association of the branched-actin nucleator Arp2/3, while favoring linear F-actin bundling. We previously demonstrated that loss of mDia2 was associated with invasive single cell egress from EOC spheroids through disruption of junctional F-actin.ResultsIn the current study, we now show that mDia2 has a role at adherens junctions (AJs) in EOC OVCA429 cells and human embryonic kidney (HEK) 293 cells through its association with αE-catenin and β-catenin. mDia2 depletion in EOC cells leads to reduction in actin polymerization and disruption of cell-cell junctions with decreased interaction between β-catenin and E-cadherin.ConclusionsOur results support a necessary role for mDia2 in AJ stability in EOC cell monolayers and indicate a critical role for mDia formins in regulating EOC AJs during invasive transitions.

Position dependent control of cell fate in the Fucus embryo: role of intercellular communication

Development ◽  
1998 ◽  
Vol 125 (11) ◽  
pp. 1999-2008 ◽  
Author(s):  
F.Y. Bouget ◽  
F. Berger ◽  
C. Brownlee
Keyword(s):  
Cell Wall ◽  
Pattern Formation ◽  
Cell Fate ◽  
Intercellular Communication ◽  
Cell Types ◽  
Early Embryo ◽  
Cell Contact ◽  
Dependent Manner ◽  
Intact Cells ◽  
Cell Fate Decisions

The early embryo of the brown alga Fucus comprises two cell types, i. e. rhizoid and thallus which are morphogically and cytologically distinguishable. Previous work has pointed to the cell wall as a source of position-dependent information required for polarisation and fate determination in the zygote and 2-celled embryo. In this study we have analysed the mechanism(s) of cell fate control and pattern formation at later embryonic stages using a combination of laser microsurgery and microinjection. The results indicate that the cell wall is required for maintenance of pre-existing polarity in isolated intact cells. However, all cell types ultimately have the capacity to re-differentiate or regenerate rhizoid cells in response to ablation of neighbouring cells. This regeneration is regulated in a position-dependent manner and is strongly influenced by intercellular communication, probably involving transport or diffusion of inhibitory signals which appear to be essential for regulation of cell fate decisions. This type of cell-to-cell communication does not involve symplastic transport or direct cell-cell contact inhibition. Apoplastic diffusible gradients appear to be involved in pattern formation in the multicellular embryo.

scholarly journals Supervillin (p205): A Novel Membrane-associated, F-Actin–binding Protein in the Villin/Gelsolin Superfamily

1997 ◽  
Vol 139 (5) ◽  
pp. 1255-1269 ◽  
Author(s):  
Kersi N. Pestonjamasp ◽  
Robert K. Pope ◽  
Julia D. Wulfkuhle ◽  
Elizabeth J. Luna
Keyword(s):  
Plasma Membranes ◽  
Adherens Junctions ◽  
Intracellular Localization ◽  
Amino Acid Sequences ◽  
Actin Binding ◽  
Striking Similarity ◽  
Cell Contact ◽  
Sequence Information ◽  
Nuclear Targeting ◽  
E Cadherin

Actin-binding membrane proteins are involved in both adhesive interactions and motile processes. We report here the purification and initial characterization of p205, a 205-kD protein from bovine neutrophil plasma membranes that binds to the sides of actin filaments in blot overlays. p205 is a tightly bound peripheral membrane protein that cosediments with endogenous actin in sucrose gradients and immunoprecipitates. Amino acid sequences were obtained from SDS-PAGE–purified p205 and used to generate antipeptide antibodies, immunolocalization data, and cDNA sequence information. The intracellular localization of p205 in MDBK cells is a function of cell density and adherence state. In subconfluent cells, p205 is found in punctate spots along the plasma membrane and in the cytoplasm and nucleus; in adherent cells, p205 concentrates with E-cadherin at sites of lateral cell–cell contact. Upon EGTA-mediated cell dissociation, p205 is internalized with E-cadherin and F-actin as a component of adherens junctions “rings.” At later times, p205 is observed in cytoplasmic punctae. The high abundance of p205 in neutrophils and suspension-grown HeLa cells, which lack adherens junctions, further suggests that this protein may play multiple roles during cell growth, adhesion, and motility. Molecular cloning of p205 cDNA reveals a bipartite structure. The COOH terminus exhibits a striking similarity to villin and gelsolin, particularly in regions known to bind F-actin. The NH2 terminus is novel, but contains four potential nuclear targeting signals. Because p205 is now the largest known member of the villin/gelsolin superfamily, we propose the name, “supervillin.” We suggest that supervillin may be involved in actin filament assembly at adherens junctions and that it may play additional roles in other cellular compartments.

scholarly journals RhoH is critical for cell-microenvironment interactions in chronic lymphocytic leukemia in mice and humans

Blood ◽  
2012 ◽  
Vol 119 (20) ◽  
pp. 4708-4718 ◽  
Author(s):  
Anja Troeger ◽  
Amy J. Johnson ◽  
Jenna Wood ◽  
William G. Blum ◽  
Leslie A. Andritsos ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Critical Role ◽  
Disease Onset ◽  
Lymphocytic Leukemia ◽  
Cell Contact ◽  
Cell Microenvironment ◽  
The Impact ◽  
Cell Cell

Abstract Trafficking of B-cell chronic lymphocytic leukemia (CLL) cells to the bone marrow and interaction with supporting stromal cells mediates important survival and proliferation signals. Previous studies have demonstrated that deletion of Rhoh led to a delayed disease onset in a murine model of CLL. Here we assessed the impact of RhoH on homing, migration, and cell-contact dependent interactions of CLL cells. Rhoh−/− CLL cells exhibited reduced marrow homing and subsequent engraftment. In vitro migration toward the chemokines CXCL12 and CXCL13 and cell-cell interactions between Rhoh−/− CLL cells and the supporting microenvironment was reduced. In the absence of RhoH the distribution of phosphorylated focal adhesion kinase, a protein known to coordinate activation of the Rho GTPases RhoA and Rac, appeared less polarized in chemokine-stimulated Rhoh−/− CLL cells, and activation and localization of RhoA and Rac was dysregulated leading to defective integrin function. These findings in the Rhoh−/− CLL cells were subsequently demonstrated to closely resemble changes in GTPase activation observed in human CLL samples after in vitro and in vivo treatment with lenalidomide, an agent with known influence on microenvironment protection, and suggest that RhoH plays a critical role in prosurvival CLL cell-cell and cell-microenvironment interactions with this agent.

Control of Cell Fate by a Deubiquitinating Enzyme Encoded by the fat facets Gene

Science ◽  
1995 ◽  
Vol 270 (5243) ◽  
pp. 1828-1831 ◽  
Author(s):  
Y. Huang ◽  
R. T. Baker ◽  
J. A. Fischer-Vize
Keyword(s):  
Cell Fate ◽  
Deubiquitinating Enzyme ◽  
Fat Facets

scholarly journals Caenorhabditis elegans β-G Spectrin Is Dispensable for Establishment of Epithelial Polarity, but Essential for Muscular and Neuronal Function

2000 ◽  
Vol 149 (4) ◽  
pp. 915-930 ◽  
Author(s):  
Suraj Moorthy ◽  
Lihsia Chen ◽  
Vann Bennett
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Expression Patterns ◽  
Cell Contact ◽  
Epithelial Polarity ◽  
Cell Stage ◽  
C Elegans ◽  
Cell Cell

The Caenorhabditis elegans genome encodes one α spectrin subunit, a β spectrin subunit (β-G), and a β-H spectrin subunit. Our experiments show that the phenotype resulting from the loss of the C. elegans α spectrin is reproduced by tandem depletion of both β-G and β-H spectrins. We propose that α spectrin combines with the β-G and β-H subunits to form α/β-G and α/β-H heteromers that perform the entire repertoire of spectrin function in the nematode. The expression patterns of nematode β-G spectrin and vertebrate β spectrins exhibit three striking parallels including: (1) β spectrins are associated with the sites of cell–cell contact in epithelial tissues; (2) the highest levels of β-G spectrin occur in the nervous system; and (3) β spec-trin-G in striated muscle is associated with points of attachment of the myofilament apparatus to adjacent cells. Nematode β-G spectrin associates with plasma membranes at sites of cell–cell contact, beginning at the two-cell stage, and with a dramatic increase in intensity after gastrulation when most cell proliferation has been completed. Strikingly, depletion of nematode β-G spectrin by RNA-mediated interference to undetectable levels does not affect the establishment of structural and functional polarity in epidermis and intestine. Contrary to recent speculation, β-G spectrin is not associated with internal membranes and depletion of β-G spectrin was not associated with any detectable defects in secretion. Instead β-G spectrin-deficient nematodes arrest as early larvae with progressive defects in the musculature and nervous system. Therefore, C. elegans β-G spectrin is required for normal muscle and neuron function, but is dispensable for embryonic elongation and establishment of early epithelial polarity. We hypothesize that heteromeric spectrin evolved in metazoans in response to the needs of cells in the context of mechanically integrated tissues that can withstand the rigors imposed by an active organism.

scholarly journals Norbin ablation results in defective adult hippocampal neurogenesis and depressive-like behavior in mice

2015 ◽  
Vol 112 (31) ◽  
pp. 9745-9750 ◽  
Author(s):  
Hong Wang ◽  
Jennifer Warner-Schmidt ◽  
Santiago Varela ◽  
Grigori Enikolopov ◽  
Paul Greengard ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Cell Fate ◽  
Adult Neurogenesis ◽  
Metabotropic Glutamate Receptors ◽  
Forced Swim Test ◽  
Critical Role ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Cell Contact

Adult neurogenesis in the hippocampus subgranular zone is associated with the etiology and treatment efficiency of depression. Factors that affect adult hippocampal neurogenesis have been shown to contribute to the neuropathology of depression. Glutamate, the major excitatory neurotransmitter, plays a critical role in different aspects of neurogenesis. Of the eight metabotropic glutamate receptors (mGluRs), mGluR5 is the most highly expressed in neural stem cells. We previously identified Norbin as a positive regulator of mGluR5 and showed that its expression promotes neurite outgrowth. In this study, we investigated the role of Norbin in adult neurogenesis and depressive-like behaviors using Norbin-deficient mice. We found that Norbin deletion significantly reduced hippocampal neurogenesis; specifically, the loss of Norbin impaired the proliferation and maturation of newborn neurons without affecting cell-fate specification of neural stem cells/neural progenitor cells (NSCs/NPCs). Norbin is highly expressed in the granular neurons in the dentate gyrus of the hippocampus, but it is undetectable in NSCs/NPCs or immature neurons, suggesting that the effect of Norbin on neurogenesis is likely caused by a nonautonomous niche effect. In support of this hypothesis, we found that the expression of a cell–cell contact gene, Desmoplakin, is greatly reduced in Norbin-deletion mice. Moreover, Norbin-KO mice show an increased immobility in the forced-swim test and the tail-suspension test and reduced sucrose preference compared with wild-type controls. Taken together, these results show that Norbin is a regulator of adult hippocampal neurogenesis and that its deletion causes depressive-like behaviors.

scholarly journals Immunohistochemical localization of cellCAM 105 in rat tissues: appearance in epithelia, platelets, and granulocytes.

1988 ◽  
Vol 36 (7) ◽  
pp. 729-739 ◽  
Author(s):  
P Odin ◽  
M Asplund ◽  
C Busch ◽  
B Obrink
Keyword(s):  
Cell Surface ◽  
Plasma Membranes ◽  
Surface Membrane ◽  
Cell Types ◽  
Cell Contact ◽  
Rat Tissues ◽  
Common Denominator ◽  
Surface Distribution ◽  
Organ Systems ◽  
Cell Cell

CellCAM 105 is an integral membrane glycoprotein, with apparent Mr 105,000, which has been purified from rat liver plasma membranes. It consists of two structurally similar, highly glycosylated polypeptide chains and is involved in cell-cell adhesion of adult rat hepatocytes in vitro. In this communication we report on the distribution and cell surface location of cellCAM 105 in rat tissues, obtained by using highly sensitive immunodetection systems based on complex formation between biotinylated antibodies, biotinylated peroxidase and avidin, or on antibodies coupled to alkaline phosphatase. CellCAM was found in many organs and organ systems, including liver, kidney, blood, blood vessels, glands, respiratory system, and gastrointestinal tract. It was mainly localized to epithelial structures but showed a varying cell surface distribution. In some cell types it was predominantly localized to cell-cell contact areas. In other cell types the highest concentrations were seen in brush-border areas containing densely packed microvilli. In addition to epithelial structures, cellCAM 105 was found in rat platelets, where it became strongly expressed on the cell surfaces after activation with ADP or collagen, suggesting that it might be involved in platelet adhesion and/or aggregation mechanisms. Granulocytes also contained cellCAM 105. By SDS-PAGE/immunoblotting, significant differences were found in the apparent Mr values of cellCAM 105 in different tissues. The collected data suggest that cellCAM 105 participates in several different cell surface membrane interactions, of which the common denominator might be membrane-membrane binding.

scholarly journals Hsp27 inhibits sublethal, Src-mediated renal epithelial cell injury

2009 ◽  
Vol 297 (3) ◽  
pp. F760-F768 ◽  
Author(s):  
Andrea Havasi ◽  
Zhiyong Wang ◽  
Jonathan M. Gall ◽  
Max Spaderna ◽  
Vikram Suri ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Organ Dysfunction ◽  
Cell Injury ◽  
Atp Depletion ◽  
Cell Contact ◽  
Intact Cells ◽  
Renal Epithelial Cells ◽  
Contact Sites ◽  
Junction Protein ◽  
Cell Cell

Disruption of cell contact sites in renal epithelial cells contributes to organ dysfunction after ischemia. We hypothesized that heat shock protein 27 (Hsp27), a known cytoprotectant protein, preserves cell architecture and cell contact site function during ischemic stress. To test this hypothesis, renal epithelial cells were subjected to transient ATP depletion, an in vitro model of ischemia-reperfusion injury. Compared with control, selective Hsp27 overexpression significantly preserved cell-cell junction function during metabolic stress as evidenced by reduced stress-mediated redistribution of the adherens junction protein E-cadherin, higher transepithelial electrical resistance, and lower unidirectional flux of lucifer yellow. Hsp27 overexpression also preserved paxillin staining within focal adhesion complexes and significantly decreased cell detachment during stress. Surprisingly, Hsp27, an F-actin-capping protein, only minimally reduced stress induced actin cytoskeleton collapse. In contrast to Hsp27 overexpression, siRNA-mediated knockdown had the opposite effect on these parameters. Since ischemia activates c-Src, a tyrosine kinase that disrupts both cell-cell and cell-substrate interactions, the relationship between Hsp27 and c-Src was examined. Although Hsp27 and c-Src did not coimmunoprecipitate and Hsp27 overexpression failed to inhibit whole cell c-Src activation during injury, manipulation of Hsp27 altered active c-Src accumulation at cell contact sites. Specifically, Hsp27 overexpression reduced, whereas Hsp27 knockdown increased active p-416Src detected at contact sites in intact cells as well as in a purified cell membrane fraction. Together, this evidence shows that Hsp27 overexpression prevents sublethal REC injury at cell contact sites possibly by a c-Src-dependent mechanism. Further exploration of the biochemical link between Hsp27 and c-Src could yield therapeutic interventions for ameliorating ischemic renal cell injury and organ dysfunction.

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