The Tight Junction, Intercellular Seal as a Cell Signaling Player: Protocols for Examination of Its Status

2011 ◽  
pp. 43-62
Author(s):  
Makoto Osanai
Keyword(s):  
Tight Junction ◽  
Cell Signaling ◽  
A Cell

Protein Flexibility Catalyzes a Cell Signaling Reaction of the Ras-GAP Complex

2019 ◽  
Author(s):  
Keiei Kumon ◽  
Masahiro Higashi ◽  
Shinji Saito ◽  
Shigehiko Hayashi
Keyword(s):  
Cell Signaling ◽  
Conformational Changes ◽  
Catalytic Reaction ◽  
Protein Complex ◽  
Enzyme Mechanism ◽  
Activation Free Energy ◽  
Chemical Catalysis ◽  
Simple Chemical ◽  
A Cell ◽  
Enzyme Molecules

Many enzyme molecules exhibit characteristic global and slow dynamics which furnish them with allostery realizing remarkable molecular functionalities more than simple chemical catalysis. However, molecular mechanism of a catalytic reaction associated with the molecular flexibility of enzymes is not well-understood. Here we report a hybrid molecular simulation study on GTPase activity of a Ras-GAP protein complex for cell signaling termination. We unveiled that extensive conformational changes of the protein complex and exclusion of internal water molecules are induced upon the transition state (TS) formation in the catalytic reaction and significantly lower the reaction activation free energy. We also revealed that tumor-related mutations perturb those conformational changes upon the TS formation, leading to reduction of the catalytic activity. The findings of the remarkably dynamic protein conformation directly linking to the catalytic reaction have broad implications for understanding of enzyme mechanism and for developments of allosteric drugs and novel catalysts.

C-factor: A cell-cell signaling protein required for fruiting body morphogenesis of M. Xanthus

Cell ◽  
1990 ◽  
Vol 61 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Seung K. Kim ◽  
Dale Kaiser
Keyword(s):  
Cell Signaling ◽  
Fruiting Body ◽  
Signaling Protein ◽  
A Cell ◽  
Cell Cell

scholarly journals Diffusible Signal Factor-Dependent Cell-Cell Signaling and Virulence in the Nosocomial Pathogen Stenotrophomonas maltophilia

2007 ◽  
Vol 189 (13) ◽  
pp. 4964-4968 ◽  
Author(s):  
Yvonne Fouhy ◽  
Karl Scanlon ◽  
Katherine Schouest ◽  
Charles Spillane ◽  
Lisa Crossman ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Cell Signaling ◽  
Stenotrophomonas Maltophilia ◽  
Xanthomonas Campestris ◽  
Signaling System ◽  
Nosocomial Pathogen ◽  
Diffusible Signal Factor ◽  
Dependent Cell ◽  
A Cell ◽  
Cell Cell

ABSTRACT The genome of Stenotrophomonas maltophilia encodes a cell-cell signaling system that is highly related to the diffusible signal factor (DSF)-dependent system of the phytopathogen Xanthomonas campestris. Here we show that in S. maltophilia, DSF signaling controls factors contributing to the virulence and antibiotic resistance of this important nosocomial pathogen.

scholarly journals Tetrapeptides Modelled to the Androgen Binding Site of ZIP9 Stimulate Expression of Tight Junction Proteins and Tight Junction Formation in Sertoli Cells

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Marie-Louise Möller ◽  
Ahmed Bulldan ◽  
Georgios Scheiner-Bobis
Keyword(s):  
Androgen Receptor ◽  
Tight Junction ◽  
Binding Site ◽  
Sertoli Cells ◽  
Alternative Pathway ◽  
Tight Junction Formation ◽  
Associated Proteins ◽  
A Cell ◽  
Androgen Binding

Androgens stimulate the expression of tight junction (TJ) proteins and the formation of the blood–testis barrier (BTB). Interactions of testosterone with the zinc transporter ZIP9 stimulate the expression of TJ-forming proteins and promote TJ formation in Sertoli cells. In order to investigate androgenic effects mediated by ZIP9 but not by the nuclear androgen receptor (AR), the effects of three tetrapeptides fitting the androgen binding site of ZIP9 were compared with those induced by testosterone in a Sertoli cell line expressing ZIP9 but not the AR. Three tetrapeptides and testosterone displaced testosterone-BSA-FITC from the surface of 93RS2 cells and stimulated the non-classical testosterone signaling pathway that includes the activation of Erk1/2 kinases and transcription factors CREB and ATF-1. The expression of the TJ-associated proteins ZO-1 and claudin-5 was triggered as was the re-distribution of claudin-1 from the cytosol to the membrane and nucleus. Furthermore, TJ formation was stimulated, indicated by increased transepithelial electrical resistance. Silencing ZIP9 expression by siRNA prevented all of these responses. These results are consistent with an alternative pathway for testosterone action at the BTB that does not involve the nuclear AR and highlight the significant role of ZIP9 as a cell-surface androgen receptor that stimulates TJ formation.

scholarly journals Phosphorylation and dephosphorylation of Ser852 and Ser889 control clustering, localization, and function of PAR-3

2020 ◽  
Author(s):  
Kazunari Yamashita ◽  
Keiko Mizuno ◽  
Kana Furukawa ◽  
Hiroko Hirose ◽  
Natsuki Sakurai ◽  
...  
Keyword(s):  
Tight Junction ◽  
Cell Polarity ◽  
Phosphorylation Site ◽  
Cell Junction ◽  
Unique Role ◽  
Cellular Events ◽  
A Cell ◽  
Summary Statement ◽  
And Function ◽  
Specific Membrane

AbstractCell polarity is essential for various asymmetric cellular events, where the partitioning defective (PAR) protein, PAR3, plays a unique role as a cellular landmark to establish polarity. In epithelial cells, PAR3 localizes at the subapical border such as the tight junction in vertebrates and functions as an apical determinant. Although there is much information about the regulators of PAR3 localization, the mechanism involved in PAR3 concentration and localization to the specific membrane domain remains an important question to be clarified. In this study, we demonstrate that ASPP2, a stimulator of PAR3 localization, can link PAR3 and protein phosphatase 1 (PP1). The ASPP2–PP1 complex dephosphorylates a novel phosphorylation site, Ser852, of PAR3. Furthermore, Ser852- or Ser889-unphosphorylatable PAR3 mutants form protein clusters and ectopically localize to the lateral membrane. Concomitance of clustering and ectopic localization suggests that PAR3 localization is a consequence of local clustering. We also demonstrate that unphosphorylatable forms of PAR3 are static in molecular turnover and fail to coordinate rapid reconstruction of the tight junction, supporting that both phosphorylated and dephosphorylated states are essential for the functional integrity of PAR3.Summary statementWe show that phosphorylation and dephosphorylation regulate clustering of PAR-3, a cell polarity-regulating factor, and how the clustering regulation affects localization of PAR-3 and cell-cell junction formation.

scholarly journals Five patterns of cell signaling pathways associated with cell behavior

2020 ◽  
Author(s):  
Yuji Takeda ◽  
Kazuharu Kawano ◽  
Rui Ma ◽  
Shinichi Saitoh ◽  
Hironobu Asao
Keyword(s):  
Cell Signaling ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Cell Behavior ◽  
General Strategy ◽  
Signal Transducers ◽  
Cell Signaling Pathway ◽  
Flow Cytometric Data ◽  
Phosphorylation Level ◽  
A Cell

AbstractCell signaling pathway is complex systems. Here, we present a concept for a new approach to analyze cell signaling pathway associated with cell behavior. In theoretically, cell behavior is recognized by energy and fluctuation. In this study, we measured phosphorylation level of signal transducers in a cell and fluctuation of the phosphorylation level in the cell population using flow cytometry. Flow cytometric data of mean fluorescence intensity (MFI) and coefficient variation (CV) were considered to the energy and the fluctuation, respectively. Topologically, the changes of MFI and CV were categorized into five patterns (we tentatively named as attractive, subsequent, passive, counter, and negative arbiter). In this study, we clarified the relationship between the cell behavior and the five patterns. Furthermore, combining the five patterns can define the signaling pathways, such as simple activated signal, oscillating signal, regulatory signal, robust signal, or homeostatic signal. These observations provide a proof of concept for general strategy to use the five patterns for connection between cell signaling pathway and cell behavior.

scholarly journals Semantic Mining based on graph theory and ontologies. Case Study: Cell Signaling Pathways

2016 ◽  
Author(s):  
Carlos R. Rangel ◽  
Junior Altamiranda ◽  
Jose Aguilar
Keyword(s):  
Graph Theory ◽  
Cell Signaling ◽  
Signaling Pathway ◽  
Research Area ◽  
Semantic Enrichment ◽  
Semantic Mining ◽  
A Cell ◽  
A New Technique ◽  
Two Phases ◽  
Pathway Networks

In this paper we use concepts from graph theory and cellular biology represented as ontologies, to carry out semantic mining tasks on signaling pathway networks. Specifically, the paper describes the semantic enrichment of signaling pathway networks. A cell signaling network describes the basic cellular activities and their interactions. The main contribution of this paper is in the signaling pathway research area, it proposes a new technique to analyze and understand how changes in these networks may affect the transmission and flow of information, which produce diseases such as cancer and diabetes. Our approach is based on three concepts from graph theory (modularity, clustering and centrality) frequently used on social networks analysis. Our approach consists into two phases: the first uses the graph theory concepts to determine the cellular groups in the network, which we will call them communities; the second uses ontologies for the semantic enrichment of the cellular communities. The measures used from the graph theory allow us to determine the set of cells that are close (for example, in a disease), and the main cells in each community. We analyze our approach in two cases: TGF-ß and the Alzheimer Disease.

scholarly journals The NCI-Nature Pathway Interaction Database: A cell signaling resource.

2007 ◽  
Author(s):  
Shiva Krupa ◽  
Kira Anthony ◽  
Jeffrey Buchoff ◽  
Matthew Day ◽  
Timo Hannay ◽  
...  
Keyword(s):  
Cell Signaling ◽  
Interaction Database ◽  
Pathway Interaction ◽  
Pathway Interaction Database ◽  
A Cell
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