Glycosyl-phosphatidylinositol Cleavage Products in Signal Transduction

2005 ◽  
pp. 101-119 ◽  
Author(s):  
Yolanda León ◽  
Isabel Varela-Nieto
Keyword(s):  
Signal Transduction ◽  
Glycosyl Phosphatidylinositol

scholarly journals Signal Transduction via Glycosyl Phosphatidylinositol-anchored Proteins in T Cells Is Inhibited by Lowering Cellular Cholesterol

1997 ◽  
Vol 272 (31) ◽  
pp. 19242-19247 ◽  
Author(s):  
Thomas M. Stulnig ◽  
Markus Berger ◽  
Thomas Sigmund ◽  
Hannes Stockinger ◽  
Václav Hořejšı́ ◽  
...  
Keyword(s):  
Signal Transduction ◽  
T Cells ◽  
Cellular Cholesterol ◽  
Glycosyl Phosphatidylinositol

scholarly journals Signal transduction by Fc gamma RIII (CD16) is mediated through the gamma chain.

1992 ◽  
Vol 175 (5) ◽  
pp. 1381-1390 ◽  
Author(s):  
U Wirthmueller ◽  
T Kurosaki ◽  
M S Murakami ◽  
J V Ravetch
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Cell Activation ◽  
Receptor Activation ◽  
Alpha Subunit ◽  
Wild Type ◽  
Cytoplasmic Domains ◽  
Gamma Chain ◽  
Glycosyl Phosphatidylinositol ◽  
Mutant Forms

To determine the functional role of the two isoforms of Fc gamma RIII (CD16) (IIIA, IIIB), the signal transduction capabilities of wild-type and mutant forms of these receptors were analyzed in transfected lymphoid, myeloid, and fibroblastic cell lines. Functional reconstitution of receptor signalling was observed in hematopoietic T and mast cells, and was absent in nonhematopoietic (CHO) cells. Fc gamma RIIIA, a hetero-oligomeric receptor composed of a ligand-binding subunit alpha and dimeric gamma chains, generated both proximal and distal responses in Jurkat and P815 cells, typical of what is seen in natural killer cells and macrophages upon receptor activation. In contrast, Fc gamma RIIIB, which is normally attached to the cell surface via a glycosyl-phosphatidylinositol anchor, was incapable of transducing signals. After crosslinking, Fc gamma RIIIA signalling was dependent only upon the gamma chain. Fc gamma RIIIA chimeras in which the alpha subunit transmembrane and cytoplasmic domains were substituted with the corresponding gamma chain sequences functioned as well as wild-type hetero-oligomeric receptors. These data indicate that the ability of the Fc gamma RIIIA complex to activate the appropriate pathways for cell activation is cell-type restricted and independent of the transmembrane and cytoplasmic domains of the alpha subunit. The presence of the gamma chain is responsible for the assembly of, as well as the signal transduction by, the functional cell surface complex.

scholarly journals Does oligosaccharide-phosphatidylinositol (glycosyl-phosphatidylinositol) hydrolysis mediate prolactin signal transduction in granulosa cells?

1993 ◽  
Vol 216 (3) ◽  
pp. 747-755 ◽  
Author(s):  
Luisa F. FANJUL ◽  
Isabel MARRERO ◽  
Juan GONZALEZ ◽  
Jose QUINTANA ◽  
Pino SANTANA ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Granulosa Cells ◽  
Glycosyl Phosphatidylinositol

Dengue virus nonstructural protein 1 is expressed in a glycosyl‐phosphatidylinositol‐linked form that is capable of signal transduction

2000 ◽  
Vol 14 (11) ◽  
pp. 1603-1610 ◽  
Author(s):  
Michael G. Jacobs ◽  
Peter J. Robinson ◽  
Cheryl Bletchly ◽  
Jason M. Mackenzie ◽  
Paul R. Young
Keyword(s):  
Signal Transduction ◽  
Dengue Virus ◽  
Nonstructural Protein ◽  
Glycosyl Phosphatidylinositol ◽  
Nonstructural Protein 1

scholarly journals Induction of cell migration by pro-urokinase binding to its receptor: possible mechanism for signal transduction in human epithelial cells.

1994 ◽  
Vol 126 (1) ◽  
pp. 259-270 ◽  
Author(s):  
N Busso ◽  
S K Masur ◽  
D Lazega ◽  
S Waxman ◽  
L Ossowski
Keyword(s):  
Signal Transduction ◽  
Cell Line ◽  
Solid Phase ◽  
Shape Change ◽  
Epithelial Cell Line ◽  
Cell Fractionation ◽  
Western Blots ◽  
Glycosyl Phosphatidylinositol ◽  
Cell Lysates ◽  
Pkc Epsilon

A human epithelial cell line, WISH, and a mouse cell line, LB6-uPAR, transfected with the human urokinase receptor (uPAR), both expressed high affinity uPAR but undetectable levels of urokinase (uPA). In two independent assays, binding of exogenous pro-uPA produced an up to threefold enhancement of migration. The migration was time and concentration dependent and did not involve extracellular proteolysis. This biologic response suggested that uPAR can trigger an intracellular signal. Since this receptor is a glycosyl-phosphatidylinositol-linked protein, we postulated that it must do so by interacting with other proteins, among which, by analogy to other systems, would be a kinase. To test this hypothesis, we carried out a solid phase capture of uPAR from WISH cell lysates using either antibodies against uPAR or pro-uPA adsorbed to plastic wells, followed by in vitro phosphorylation of the immobilized proteins. SDS-PAGE and autoradiography revealed two phosphorylated protein bands of 47 and 55 kD. Both proteins were phosphorylated on serine residues. Partial sequence of the two proteins showed a 100% homology to cytokeratin 18 (CK18) and 8 (CK8), respectively. A similar pattern of phosphorylation was obtained with lysates from A459 cells, a lung carcinoma, but not HL60, LB6-uPAR or HEp3 cell lysates, suggesting that the identified multiprotein uPAR-complex may be specific for simple epithelia. Moreover, immunocapture with antibody to another glycosyl-phosphatidylinositol-linked protein, CD55, which is highly expressed in WISH cells, was ineffective. The kinase was tentatively identified as protein kinase C, because it was inhibited by an analogue of staurosporine more specific for PKC and not by a PKA or tyrosine kinase inhibitors. The kinase was tentatively identified as PKC epsilon because of its resistance to PMA down-modulation, independence of Ca2+ for activity, and reaction with a specific anti-PKC epsilon antibody in Western blots. Cell fractionation into cytosolic and particulate fractions revealed that all four proteins, the kinase, uPAR, CK18, and CK8, were present in the particulate fraction. In vivo, CK8, and to a lesser degree CK18, were found to be phosphorylated on serine residues. Occupation of uPAR elicited a time-dependent increase in the phosphorylation intensity of CK8, a cell shape change and a redistribution of the cytokeratin filaments. These results strongly suggest that uPAR serves not only as an anchor for uPA but participates in a signal transduction pathway resulting in a pronounced biological response.

scholarly journals An Explanation for the Adiponectin Paradox

2021 ◽  
Vol 14 (12) ◽  
pp. 1266
Author(s):  
Hans O. Kalkman
Keyword(s):  
Insulin Resistance ◽  
Signal Transduction ◽  
Insulin Sensitivity ◽  
Phospholipase D ◽  
Functional Consequence ◽  
Glycosyl Phosphatidylinositol ◽  
Paradoxical Situation ◽  
Hydrolysis Of ◽  
Circulating Levels ◽  
Sensitivity Functional

The adipokine adiponectin improves insulin sensitivity. Functional signal transduction of adiponectin requires at least one of the receptors AdipoR1 or AdipoR2, but additionally the glycosyl phosphatidylinositol-anchored molecule, T-cadherin. Overnutrition causes a reduction in adiponectin synthesis and an increase in the circulating levels of the enzyme glycosyl phosphatidylinositol-phospholipase D (GPI-PLD). GPI-PLD promotes the hydrolysis of T-cadherin. The functional consequence of T-cadherin hydrolysis is a reduction in adiponectin sequestration by responsive tissues, an augmentation of adiponectin levels in circulation and a (further) reduction in signal transduction. This process creates the paradoxical situation that adiponectin levels are augmented, whereas the adiponectin signal transduction and insulin sensitivity remain strongly impaired. Although both hypoadiponectinemia and hyperadiponectinemia reflect a situation of insulin resistance, the treatments are likely to be different.

scholarly journals CD14-independent activation of cardiomyocyte signal transduction by bacterial endotoxin

2000 ◽  
Vol 279 (2) ◽  
pp. H619-H629 ◽  
Author(s):  
Douglas B. Cowan ◽  
Dimitrios N. Poutias ◽  
Pedro J. Del Nido ◽  
Francis X. McGowan
Keyword(s):  
Signal Transduction ◽  
Nuclear Translocation ◽  
Specific Binding ◽  
Myocardial Dysfunction ◽  
Nuclear Factor Κb ◽  
Glycosyl Phosphatidylinositol ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Lps Activation ◽  
Factor Α

In the heart, lipopolysaccharide (LPS) induces the production of proinflammatory cytokines that cause myocardial dysfunction; however, the signaling pathways involved in cardiomyocyte responses are poorly understood. We studied LPS-induced signaling by treating cardiomyocyte cultures with 0.01–10 μg/ml LPS for 0–24 h in the presence or absence of 2.5% serum. Cytosolic and nuclear proteins were analyzed for expression and activation of protein kinases. Members of the extracellular signal-regulated kinase (ERK) and signal transducer and activators of transcription (STAT) protein families were uniformly expressed and specifically phosphorylated in response to LPS. Activation was biphasic; peaking at 5–10 min and 24 h after treatment. Inhibitor experiments provided evidence that ERK proteins may regulate STAT activity. Serum did not augment endotoxin-induced phosphorylation. Although cardiomyocytes expressed low levels of CD14 and LPS-binding protein, specific enzymatic removal of glycosyl phosphatidylinositol-linked receptors or incubation with an anti-CD14 antibody had no effect on kinase activation. Treatment of cells with an excess of detoxified LPS attenuated endotoxin-induced signaling. In addition, endotoxin stimulated specific binding of nuclear factors to AP-1, nuclear factor-κB (NF-κB), STAT1 (SIE, sis-inducible element), and STAT3 consensus-binding sequences. Finally, inhibition of ERK phosphorylation reduced, and NF-κB nuclear translocation prevented, tumor necrosis factor-α production. Our results indicate that LPS-induced activation of signal transduction in cardiomyocytes occurs by a CD14-independent mechanism.

Ultrastructural aspects of olfactory signal transduction and its development

1994 ◽  
Vol 52 ◽  
pp. 142-143
Author(s):  
Bert Ph. M. Menco
Keyword(s):  
Signal Transduction ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Freeze Substitution ◽  
Luminal Surface ◽  
Tissue Sections ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Olfactory Signal ◽  
Odor Molecule

Vertebrate olfactory receptor cells are specialized neurons that have numerous long tapering cilia. The distal parts of these cilia line the interface between the external odorous environment and the luminal surface of the olfactory epithelium. The length and number of these cilia results in a large surface area that presumably increases the chance that an odor molecule will meet a receptor cell. Advanced methods of cryoprepration and immuno-gold labeling were particularly useful to preserve the delicate ultrastructural and immunocytochemical features of olfactory cilia required for localization of molecules involved in olfactory signal-transduction. We subjected olfactory tissues to freeze-substitution in acetone (unfixed tissues) or methanol (fixed tissues) followed by low temperature embedding in Lowicryl K11M for that purpose. Tissue sections were immunoreacted with several antibodies against proteins that are presumably important in olfactory signal-transduction.

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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