scholarly journals Signaling Enzymes and Ion Channels Being Modulated by the Actin Cytoskeleton at the Plasma Membrane

2021 ◽  
Vol 22 (19) ◽  
pp. 10366
Author(s):  
Filip Vasilev ◽  
Yulia Ezhova ◽  
Jong Tai Chun

A cell should deal with the changing external environment or the neighboring cells. Inevitably, the cell surface receives and transduces a number of signals to produce apt responses. Typically, cell surface receptors are activated, and during this process, the subplasmalemmal actin cytoskeleton is often rearranged. An intriguing point is that some signaling enzymes and ion channels are physically associated with the actin cytoskeleton, raising the possibility that the subtle changes of the local actin cytoskeleton can, in turn, modulate the activities of these proteins. In this study, we reviewed the early and new experimental evidence supporting the notion of actin-regulated enzyme and ion channel activities in various cell types including the cells of immune response, neurons, oocytes, hepatocytes, and epithelial cells, with a special emphasis on the Ca2+ signaling pathway that depends on the synthesis of inositol 1,4,5-trisphosphate. Some of the features that are commonly found in diverse cells from a wide spectrum of the animal species suggest that fine-tuning of the activities of the enzymes and ion channels by the actin cytoskeleton may be an important strategy to inhibit or enhance the function of these signaling proteins.

2019 ◽  
Author(s):  
Eleanor M Denham ◽  
Michael I Barton ◽  
Susannah M Black ◽  
Marcus J Bridge ◽  
Ben de Wet ◽  
...  

AbstractDose-response experiments are a mainstay of receptor biology studies and can reveal valuable insights into receptor function. Such studies of receptors that bind cell surface ligands are currently limited by the difficulty in manipulating the surface density of ligands at a cell-cell interface. Here we describe a generic cell surface ligand system that allows precise manipulation of cell surface ligand densities over several orders of magnitude. We validate the system for a range of immunoreceptors, including the T cell receptor (TCR), and show that this generic ligand stimulates via the TCR at a similar surface density as its native ligand. This system allows the effect of surface density, valency, dimensions, and affinity of the ligand to be manipulated. It can be readily extended to other receptor-cell surface ligand interactions, and will facilitate investigation into the activation of, and signal integration between, cell surface receptors.


1975 ◽  
Vol 64 (3) ◽  
pp. 719-724 ◽  
Author(s):  
GL Campbell ◽  
LT Goldstein ◽  
BB Knowles

Quantitation of the expression of cell surface antigens has hitherto been limited to analysis by either cytotoxicity tests or radioimmune assays (5, 15). We report here the use of a new methodology to analyze and quantitate the expression of mouse histocompabililty antigens (H-2 locus) in hybrid clones and parental cell types. The binding of fluorescein-tagged antibody is measured on a cell-to-cell basis in large viable cell populations using flow microfluorimetric techniques. These techniques have been used to measure hapten and immunoglobulin binding to lymphocyte populations (8, 9, 14). However, this is the first report in which these techniques have been used to examine the expression of the H-2 locus. The advantage of this approach is twofold: first, a large and statistically significant sample population may be analyzed one cell at a time, thus revealing the fine detail of heterogeneity in the expression of the cell surface markers within a population. Second, as has been demonstrated for analysis of specific components of the immune system, this method does permit fluorescence-activated sorting of cell types according to their different surface populations (8, 9, 14).


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Rainer Ebid ◽  
Julia Lichtnekert ◽  
Hans-Joachim Anders

Glomerular mesangial cells (MC), like most cell types secrete hyaluronan (HA), which attached to the cell surface via CD44, is the backbone of a hydrophilic gel matrix around these cells. Reduced extracellular matrix thickness and viscosity result from HA cleavage during inflammation. HA fragments were reported to trigger innate immunity via Toll-like receptor-(TLR-) 2 and/or TLR4 in immune cells. We questioned whether HA fragments also regulate the immunostimulatory capacity of smooth muscle cell-like MC. LPS (TLR4-ligand) and PAM3CysSK4 (TLR2-ligand) induced IL-6 secretion in MC; highly purified endotoxin-free HA < 3000 Da up to 50 μg/mL did not. Bovine-testis-hyaluronidase from was used to digest MC-HA into HA fragments of different size directly in the cell culture. Resultant HA fragments did not activate TLR4-deficient MC, while TLR2-deficient MC responded to LPS-contamination of hyaluronidase, not to produced HA fragments. Hyaluronidase increased the stimulatory effect of TLR2-/-3/-5 ligands on their TLR-receptors in TLR4-deficient MC, excluding any effect by LPS-contamination. Supplemented heparin suppressed every stimulatory effect in a dose-dependent manner. We conclude that the glycosaminoglycan HA creates a pericellular jelly barrier, which covers surface receptors like the TLRs. Barrier-thickness and viscosity balanced by HA-synthesis and degradation and the amount of HA-receptors on the cell surface regulate innate immunity via the accessibility of the receptors.


1979 ◽  
Vol 12 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Robert L. Simmer ◽  
Joffre B. Baker ◽  
Dennis D. Cunningham

1985 ◽  
Vol 100 (3) ◽  
pp. 826-834 ◽  
Author(s):  
M D Snider ◽  
O C Rogers

The intracellular movement of cell surface transferrin receptor (TfR) after internalization was studied in K562 cultured human erythroleukemia cells. The sialic acid residues of the TfR glycoprotein were used to monitor transport to the Golgi complex, the site of sialyltransferases. Surface-labeled cells were treated with neuraminidase, and readdition of sialic acid residues, monitored by isoelectric focusing of immunoprecipitated TfR, was used to assess the movement of receptor to sialyltransferase-containing compartments. Asialo-TfR was resialylated by the cells with a half-time of 2-3 h. Resialylation occurred in an intracellular organelle, since it was inhibited by treatments that allow internalization of surface components but block transfer out of the endosomal compartment. Moreover, roughly half of the resialylated molecules were cleaved when cells were retreated with neuraminidase after culturing, indicating that this fraction of the molecules had returned to the cell surface. These results suggest that TfR is transported from the cell surface to the Golgi complex, the intracellular site of sialyltransferases, and then returns to the cell surface. This pathway, which has not been previously described for a cell surface receptor, may be different from the route followed by TfR in iron uptake, since reported rates of transferrin uptake and release are significantly more rapid than the resialylation of asialo-TfR.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Huaping Chen ◽  
Ming Yuan ◽  
Chunji Huang ◽  
Zhi Xu ◽  
Mingchun Li ◽  
...  

Rab26 GTPase modulates the trafficking of cell surface receptors, such as G protein-coupled receptors including α2-adrenergic receptors in some cell types. However, the effect of Rab26 on β2-adrenergic receptor (β2-AR) trafficking or/and Toll-like receptor 4 (TLR4) expression in human pulmonary microvascular endothelial cells (HPMECs) is still unclear. Here, we investigated the role of Rab26 in regulating the expression of β2-ARs and TLR4 in HPMECs and the effect of these receptors’ imbalance on endothelial cell barrier function. The results showed that there was unbalance expression in these receptors, where β2-AR expression was remarkably reduced, and TLR4 was increased on the cell membrane after lipopolysaccharide (LPS) treatment. Furthermore, we found that Rab26 overexpression not only upregulated β2-ARs but also downregulated TLR4 expression on the cell membrane. Subsequently, the TLR4-related inflammatory response was greatly attenuated, and the hyperpermeability of HPMECs also was partially relived. Taken together, these data suggest that basal Rab26 maintains the balance between β2-ARs and TLR4 on the cell surface, and it might be a potential therapeutic target for diseases involving endothelial barrier dysfunction.


Author(s):  
L. B. Grabel ◽  
G. R. Martin ◽  
S. D. Rosen

A major research interest is the identification of the cell surface molecules responsible for the selective intercellular adhesion of various cell types. Initially it was believed that cell-cell adhesion was mediated by tissue specific lock and key molecules present on adjacent cells; a single molecular recognition system would be sufficient to generate the desired selectivity. In the past few years it has become apparent that although specific recognition molecules are certainly involved in mediating intercellular adhesion, the idea of each cell type having a single unique molecular system of recognition is an oversimplification. The available data suggest that multiple systems of adhesion function simultaneously in any given cell type, and that the same or similar molecules may be involved in adhesion within different tissues.We have been studying the intercellular adhesion of teratocarcinoma stem cells, and review here evidence that at least two separable components are involved in their intercellular adhesion; one requiring the presence of divalent cations, and the other one involving recognition by a cell surface fucan/mannan specific lectin.


1996 ◽  
Vol 319 (3) ◽  
pp. 865-872 ◽  
Author(s):  
M. Grazia MALABARBA ◽  
Hallgeir RUI ◽  
Harald H. J. DEUTSCH ◽  
Johanna CHUNG ◽  
Frank S. KALTHOFF ◽  
...  

The lymphocyte growth factors interleukin-2 (IL2), IL4, IL7, IL9 and IL15 use the common IL2 receptor-γ (IL2Rγ) and activate the IL2Rγ-associated tyrosine kinase JAK3 (Janus kinase 3). IL13 is structurally related to IL4, competes with IL4 for binding to cell surface receptors and exhibits many similar biological effects. The molecular basis for this functional overlap between IL4 and IL13 has been attributed mainly to a shared use of the 140 kDa IL4Rα, since these cytokines appear to be uniquely different in that, according to several recent reports, IL13 does not recruit the IL2Rγ or JAK3. This notion has been supported by the identification of a novel 70 kDa IL13 receptor in certain IL13-responsive cell lines that lack IL2Rγ. The present study sheds new light on the issue of functional overlap between IL13 and IL4, by demonstrating for the first time that, in cells that express both IL2Rγ and IL4Rα, IL13 can mimic IL4-induced heterodimerization of IL2Rγ and IL4Rα, with consequent marked activation of JAK3 and the transcription factor STAT6 (IL4-STAT). Reconstitution experiments in BA/F3 cells showed that both cytokines require the simultaneous presence of IL4Rα and IL2Rγ to mediate JAK3 and proliferative responses, and analysis of 12 IL4Rα variants showed that IL4 and IL13 signals were equally affected by mutations of the cytoplasmic domain. We conclude that IL13 activates the IL2Rγ-associated JAK3 tyrosine kinase in appropriate cell types, and propose that IL13 is capable of interacting with multiple receptor subunits in a cell-dependent and combinatorial manner. Consequently, we predict that partial disruption of IL13 signal transduction also contributes to the severe combined immunodeficiency syndromes associated with inactivation of the IL2Rγ or JAK3 genes.


Oncogene ◽  
2001 ◽  
Vol 20 (44) ◽  
pp. 6403-6417 ◽  
Author(s):  
Wei Li ◽  
Jianhua Fan ◽  
David T Woodley

2001 ◽  
Vol 360 (3) ◽  
pp. 579-587 ◽  
Author(s):  
Dieter KÜBLER

A variety of cell membrane proteins become phosphorylated in their ecto-domains by cell-surface protein kinase (ecto-PK) activities, as detected in a broad spectrum of cell types. This study reports the isolation and identification of a frequent ecto-PK substrate, ecto-p120, using HeLa cells as a model. Data from MS and further biochemical and immunochemical means identified ecto-p120 as a cell-surface homologue of human nucleolar phosphoprotein p140 (hNopp140), which belongs to the family of argyrophilic (AgNOR-stainable) proteins. The superposition of 32P-labelled ecto-nucleolar phosphoprotein p140 (ecto-Nopp140) with anti-Nopp140 immunostaining could be demonstrated in a wide range of cell lines without any exceptions, suggesting a nearly universal occurrence of cell-surface Nopp140. A previous, tentative association of ecto-p120 with the nucleoplasmic pre-mRNA-binding protein hnRNP U has thus been supplanted, since improved purification techniques have allowed unambiguous identification of this ecto-PK cell-surface substrate. Furthermore, we have shown that rapid suppression of ecto-hNopp140 phosphorylation resulted upon a rise in the free extracellular calcium, while lowering the calcium concentrations returned ecto-Nopp140 phosphorylation to the original level. It is important to note that these Ca2+-dependent effects on ecto-Nopp140 phosphorylation are not accompanied by alterations in the phosphorylation of other ecto-PK substrates. Our results indicate that, in addition to nucleolin, a further nucleolar protein, which was considered initially to be strictly intracellular, is identified as a cell-surface phosphoprotein.


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