scholarly journals Plasma Membrane Organization Is Essential for Balancing Competing Pseudopod- and Uropod-promoting Signals during Neutrophil Polarization and Migration

2005 ◽  
Vol 16 (12) ◽  
pp. 5773-5783 ◽  
Author(s):  
Stéphane Bodin ◽  
Matthew D. Welch
Keyword(s):  
Plasma Membrane ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Cell Polarization ◽  
Cholesterol Depletion ◽  
Membrane Organization ◽  
And Migration ◽  
Outstanding Question ◽  
Cytoskeletal Elements ◽  
Rhoa Signaling

Exposure of neutrophils to chemoattractant induces cell polarization and migration. These behaviors require the asymmetric activation of distinct signaling pathways and cytoskeletal elements in the protruding pseudopod at the front of cells and the retracting uropod at the rear. An important outstanding question is, how does the organization of the plasma membrane participate in establishing asymmetry during polarization and migration? To answer this question, we investigated the function of cholesterol, a lipid known to influence membrane organization. Using controlled cholesterol depletion, we found that a cholesterol-dependent membrane organization enabled cell polarization and migration by promoting uropod function and suppressing ectopic pseudopod formation. At a mechanistic level, we showed that cholesterol was directly required for suppressing inappropriate activation of the pseudopod-promoting Gi/PI3-kinase signaling pathway. Furthermore, cholesterol was required for dampening Gi-dependent negative feedback on the RhoA signaling pathway, thus enabling RhoA activation and uropod function. Our findings suggest a model in which a cholesterol-dependent membrane organization plays an essential role in the establishment of cellular asymmetry by balancing the activation and segregating the localization of competing pseudopod- and uropod-inducing signaling pathways during neutrophil polarization and migration.

scholarly journals Inflammatory Immune Cytokine TNF-α Modulates Ezrin Protein Activation via FAK/RhoA Signaling Pathway in PMVECs Hyperpermeability

2021 ◽  
Vol 12 ◽  
Author(s):  
Qun Zhou ◽  
Jianjun Jiang ◽  
Guanjun Chen ◽  
Cheng Qian ◽  
Gengyun Sun
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Western Blotting ◽  
Cell Monolayer ◽  
Endothelial Barrier ◽  
Cell Periphery ◽  
Dependent Manner ◽  
Tnf Α ◽  
Microvascular Endothelial ◽  
Rhoa Signaling

Background: One of the important pathogenesis of acute respiratory distress syndrome (ARDS) is the dysfunction of pulmonary microvascular endothelial barrier induced by a hyperinflammatory immune response. However, the potential mechanisms of such an imbalance in pulmonary microvascular endothelial cells (PMVECs) are not yet understood.Purpose: Explore the molecular mechanism of endothelial barrier dysfunction induced by inflammatory immune cytokines in ARDS, and find a therapeutic target for this syndrome.Methods: Rat PMVECs were cultured to form a monolayer. Immunofluorescence, flow cytometry, and Western blotting were selected to detect the distribution and the expression level of phosphorylated Ezrin protein and Ezrin protein. Transendothelial electrical resistance (TER) and transendothelial fluxes of fluorescein isothiocyanate (FITC)-labeled bovine serum albumin (BSA) were utilized to measure the permeability of the cell monolayer. Ezrin short hairpin RNA (shRNA) and Ezrin 567-site threonine mutant (EzrinT567A) were used to examine the role of Ezrin protein and phosphorylated Ezrin protein in endothelial response induced by tumor necrosis factor-alpha (TNF-α), respectively. The function of focal adhesion kinase (FAK) and Ras homolog gene family, member A (RhoA) signaling pathways were estimated by inhibitors and RhoA/FAK shRNA in TNF-α-stimulated rat PMVECs. The activation of FAK and RhoA was assessed by Western blotting or pull-down assay plus Western blotting.Results: The TER was decreased after TNF-α treatment, while the Ezrin protein phosphorylation was increased in a time- and dose-dependent manner. The phosphorylated Ezrin protein was localized primarily at the cell periphery, resulting in filamentous actin (F-actin) rearrangement, followed by a significant decrease in TER and increase in fluxes of FITC-BSA. Moreover, FAK and RhoA signaling pathways were required in the phosphorylation of Ezrin protein, and the former positively regulated the latter.Conclusion: The phosphorylated Ezrin protein was induced by TNF-α via the FAK/RhoA signaling pathway leading to endothelial hyperpermeability in PMVECs.

scholarly journals Atypical protein kinase C (PKCζ/λ) is a convergent downstream target of the insulin-stimulated phosphatidylinositol 3-kinase and TC10 signaling pathways

2004 ◽  
Vol 164 (2) ◽  
pp. 279-290 ◽  
Author(s):  
Makoto Kanzaki ◽  
Silvia Mora ◽  
Joseph B. Hwang ◽  
Alan R. Saltiel ◽  
Jeffrey E. Pessin
Keyword(s):  
Plasma Membrane ◽  
Signaling Pathways ◽  
Membrane Lipid ◽  
Cholesterol Depletion ◽  
Insulin Stimulation ◽  
Downstream Target ◽  
Atypical Pkc ◽  
Clostridium Difficile Toxin B ◽  
Gsk 3Β ◽  
Lipid Raft Microdomains

Insulin stimulation of adipocytes resulted in the recruitment of atypical PKC (PKCζ/λ) to plasma membrane lipid raft microdomains. This redistribution of PKCζ/λ was prevented by Clostridium difficile toxin B and by cholesterol depletion, but was unaffected by inhibition of phosphatidylinositol (PI) 3-kinase activity. Expression of the constitutively active GTP-bound form of TC10 (TC10Q/75L), but not the inactive GDP-bound mutant (TC10/T31N), targeted PKCζ/λ to the plasma membrane through an indirect association with the Par6–Par3 protein complex. In parallel, insulin stimulation as well as TC10/Q75L resulted in the activation loop phosphorylation of PKCζ. Although PI 3-kinase activation also resulted in PKCζ/λ phosphorylation, it was not recruited to the plasma membrane. Furthermore, insulin-induced GSK-3β phosphorylation was mediated by both PI 3-kinase–PKB and the TC10–Par6–atypical PKC signaling pathways. Together, these data demonstrate that PKCζ/λ can serve as a convergent downstream target for both the PI 3-kinase and TC10 signaling pathways, but only the TC10 pathway induces a spatially restricted targeting to the plasma membrane.

scholarly journals Conserved Elements of the RAM Signaling Pathway Establish Cell Polarity in the BasidiomyceteCryptococcus neoformansin a Divergent Fashion from Other Fungi

2006 ◽  
Vol 17 (9) ◽  
pp. 3768-3780 ◽  
Author(s):  
Felicia J. Walton ◽  
Joseph Heitman ◽  
Alexander Idnurm
Keyword(s):  
Signaling Pathways ◽  
Signaling Pathway ◽  
Insertional Mutagenesis ◽  
Pathogenic Fungus ◽  
Cell Polarization ◽  
Targeted Deletion ◽  
Complex Processes ◽  
Capsule Production ◽  
Human Pathogenic Fungus ◽  
Differentiation And Proliferation

In eukaryotes the complex processes of development, differentiation, and proliferation require carefully orchestrated changes in cellular morphology. Single-celled eukaryotes provide tractable models for the elucidation of signaling pathways involved in morphogenesis. Here we describe a pathway regulating cell polarization and separation in the human pathogenic fungus Cryptococcus neoformans. An insertional mutagenesis screen identified roles for the ARF1, CAP60, NDH1, KIC1, CBK1, SOG2, and TAO3 genes in establishing normal colony morphology. ARF1 and CAP60 are also required for capsule production, a virulence factor, and ARF1 confers resistance to the antifungal fluconazole. KIC1, CBK1, SOG2, and TAO3 are homologues of genes conserved in other eukaryotes; in Saccharomyces cerevisiae they constitute components of the RAM (regulation of Ace2p activity and cellular morphogenesis) signaling pathway. A targeted deletion of a fifth component of RAM (MOB2) conferred identical phenotypes to kic1, cbk1, sog2, or tao3 mutations. Characterization of these genes in C. neoformans revealed unique features of the RAM pathway in this organism. Loss of any of these genes caused constitutive hyperpolarization instead of the loss of polarity seen in S. cerevisiae. Furthermore, sensitivity to the drugs FK506 and cyclosporin A demonstrates that the RAM pathway acts in parallel with the protein phosphatase calcineurin in C. neoformans but not in S. cerevisiae. These results indicate that conserved signaling pathways serve both similar and divergent cellular roles in morphogenesis in these divergent organisms.

scholarly journals Wnt11 controls cell contact persistence by local accumulation of Frizzled 7 at the plasma membrane

2006 ◽  
Vol 175 (5) ◽  
pp. 791-802 ◽  
Author(s):  
Sabine Witzel ◽  
Vitaly Zimyanin ◽  
Filipa Carreira-Barbosa ◽  
Masazumi Tada ◽  
Carl-Philipp Heisenberg
Keyword(s):  
Plasma Membrane ◽  
Planar Cell Polarity ◽  
Cell Polarization ◽  
Cell Contact ◽  
Embryonic Cells ◽  
Downstream Effectors ◽  
Local Cell ◽  
And Migration ◽  
Signaling Components ◽  
Local Accumulation

Wnt11 is a key signal, determining cell polarization and migration during vertebrate gastrulation. It is known that Wnt11 functionally interacts with several signaling components, the homologues of which control planar cell polarity in Drosophila melanogaster. Although in D. melanogaster these components are thought to polarize cells by asymmetrically localizing at the plasma membrane, it is not yet clear whether their subcellular localization plays a similarly important role in vertebrates. We show that in zebrafish embryonic cells, Wnt11 locally functions at the plasma membrane by accumulating its receptor, Frizzled 7, on adjacent sites of cell contacts. Wnt11-induced Frizzled 7 accumulations recruit the intracellular Wnt signaling mediator Dishevelled, as well as Wnt11 itself, and locally increase cell contact persistence. This increase in cell contact persistence is mediated by the local interaction of Wnt11, Frizzled 7, and the atypical cadherin Flamingo at the plasma membrane, and it does not require the activity of further downstream effectors of Wnt11 signaling, such as RhoA and Rok2. We propose that Wnt11, by interacting with Frizzled 7 and Flamingo, modulates local cell contact persistence to coordinate cell movements during gastrulation.

scholarly journals Signaling pathways involved in pancreatic stellate cells activity and interaction with pancreatic cancer cells

Morphologia ◽  
2021 ◽  
Vol 15 (2) ◽  
pp. 7-15
Author(s):  
N.V. Stanishevska
Keyword(s):  
Cancer Cells ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Tumor Cells ◽  
Translation Initiation Factor ◽  
Pancreatic Stellate Cells ◽  
Invasion And Metastasis ◽  
Pancreatic Cancer Cells ◽  
And Migration ◽  
Proliferation And Migration

Background. The activation, proliferation and migration capabilities of stellate pancreatocytes are guaranteed by a number of signaling molecular mechanisms that support the interaction of tumor cells with the PSC and determine the neoplastic process. Objective The review is a continuation of aт articles series devoted to the modern understanding of the role and functions of stellate pancreatocytes, namely, their involvement in interaction with cancer cells and signaling molecular pathways that provide synergism of the stellate pancreatocyte-cancer cell system. Methods. Data processing was carried out by the method of complex material analysis. Results. The Нedgehog signaling pathway provides interaction between PSC and tumor cells, which involves the leading mediator of this pathway - sHH (sonic hedgehog), the overexpression of which is recorded in the tumor tissue of the pancreas and ensures the formation of the tumor stroma. Stellate pancreatocytes also trigger the HGF / c-Met / survivin signaling pathway for invasion and metastasis. The activation of the PSCs themselves may be mediated by serotonin via the RhoA / ROCK signaling pathway. While the proliferation and migration of these cells, activated by alcohol, HNE (human neutrophil elastase), PDGF, IL-33 PSC are regulated by the MAP kinase and PI3K pathways. The Wnt signaling pathway promotes collagen accumulation. Through the AMPK / mTOR pathway, factor FTY720 induces apoptosis and inhibits the autophagy of stellate pancreatocytes. The interaction of PSC and tumor cells is also mediated through Notch and TGF-β, and through the Hippo signaling pathway with the participation of YAP / TAZ factors, it is possible to suppress the fibrotic activity of PSC. The interaction of stellate pancreatocytes and tumor cells is reflected in a direct correlation between a decrease in autophagy and apoptosis of stellate pancreatocytes and suppression of invasion and migration of tumor cells. This interaction can be mediated by ERK1 / 2 kinase. Among the factors secreted by tumor cells and causing PSC activation are: growth factor β1 (TGF-β1), PAI-1 protein, translation initiation factor 4E (eIF4E), sHH (involving PSC in pain deployment), Exo-Pan and Exo-Mia exosomes (engaging PSCs in carcinogenesis). Deactivation is mediated by colony stimulating factor 1 (CSF1R, cytokine). In turn, stellate pancreatocytes secrete the chemokine CXCL1, which stimulates the migration and invasion of tumor cells, exosomes with multiple miRNAs, which stimulate the proliferation and migration of cancer cells. Сonclusion. The activation of stellate pancreatocytes, which is necessary for the implementation of their fibrotic functions, is mediated through the RhoA / ROCK signaling pathway via serotonin. The Hippo pathway (activation) and AMPK / mTOR (suppression of autophagy and activation of apoptosis) are also involved in the regulation of the activity of stellate pancreatocytes. The interaction between the tumor cell and stellate pancreatocyte occurs through the Hedgehog, Notch, and TGF-β signaling pathways; regulation of invasion and metastasis of cancer cells provides the HGF / c-Met / survivin signaling pathway.

Targeted Delivery of Natural Bioactives and Lipid-nanocargos against Signaling Pathways Involved in Skin Cancer

2020 ◽  
Vol 27 ◽  
Author(s):  
Mohammad Kashif Iqubal ◽  
Aiswarya Chaudhuri ◽  
Ashif Iqubal ◽  
Sadaf Saleem ◽  
Madan Mohan Gupta ◽  
...  
Keyword(s):  
Skin Cancer ◽  
Signaling Pathways ◽  
Signaling Pathway ◽  
Targeted Delivery ◽  
Skin Pigmentation ◽  
Wnt Signaling Pathway ◽  
Human Beings ◽  
Radiation Chemical ◽  
Cell Leukemia Virus Type ◽  
Human T Cell

: At present, skin cancer is a widespread malignancy in human beings. Among diverse population types, Caucasian populations are much more prone in comparison to darker skin populations due to the comparative lack of skin pigmentation. Skin cancer is divided into malignant and non-melanoma skin cancer, which is additionally categorized as basal and squamous cell carcinoma. The exposure to ultraviolet radiation, chemical carcinogen (polycyclic aromatic hydrocarbons, arsenic, tar, etc.), and viruses (herpes virus, human papillomavirus, and human T-cell leukemia virus type-1) are major contributing factors of skin cancer. There are distinct pathways available through which skin cancer develops, such as the JAKSTAT pathway, Akt pathway, MAPKs signaling pathway, Wnt signaling pathway, to name a few. Currently, several targeted treatments are available, such as monoclonal antibodies, which have dramatically changed the line of treatment of this disease but possess major therapeutic limitations. Thus, recently many phytochemicals have been evaluated either alone or in combination with the existing synthetic drugs to overcome their limitations and have found to play a promising role in the prevention and treatment. In this review, complete tracery of skin cancer, starting from the signaling pathways involved, newer developed drugs with their targets and limitations along with the emerging role of natural products alone or in combination as potent anticancer agents and their molecular mechanism involved has been discussed. Apart from this, various nanocargos have also been mentioned here, which can play a significant role in the management and treatment of different types of skin cancer.

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