scholarly journals HISTOCHEMICAL LOCALIZATION OF ADENYL CYCLASE IN THE FUNGUS PHYCOMYCES BLAKESLEEANUS

1973 ◽  
Vol 21 (12) ◽  
pp. 1041-1046 ◽  
Author(s):  
J. C. TU ◽  
S. K. MALHOTRA
Keyword(s):  
Plasma Membrane ◽  
Sodium Fluoride ◽  
Stage Iv ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Adenyl Cyclase ◽  
Mitochondrial Membranes ◽  
Phycomyces Blakesleeanus ◽  
Nuclear Membranes

The presence of adenyl cyclase in Phycomyces blakesleeanus has been investigated in situ histochemically by lead precipitation of pyrophosphate liberated by conversion of adenosine triphosphate to cyclic adenosine monophosphate. Dormant spores, heat-shocked spores, germinating spores and the growing zone of sporangiophore (stage IV) of the fungus were studied. Electron-dense lead precipitate was localized in association with plasma membrane and between the mitochondrial membranes and nuclear membranes in all stages investigated. This reaction product is not inhibited by sodium fluoride, and adenyl cyclase is the only known enzyme stimulated by sodium fluoride. Comparable studies on the hepatocytes of mouse liver showed the reaction product in association with plasma membrane only.

A Study of the Neurohumoral Control of Glycolysis in the Mouse Brain in vivo: Role of Noradrenaline and Dopamine

1975 ◽  
Vol 30 (5-6) ◽  
pp. 385-391 ◽  
Author(s):  
B. E. Leonard
Keyword(s):  
Mouse Brain ◽  
Sodium Fluoride ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Adenyl Cyclase ◽  
Membrane Bound ◽  
Adenyl Cyclase System ◽  
Neurohumoral Control

Abstract Noradrenaline, Dopamine, Glycolysis, Adenyl Cyclase Intraventricularly injected noradrenaline, dopamine and isoprenaline increased glycolysis as shown by the decrease in the concentration of “free” glycogen and increase in the concentration of lactate. The effects of noradrenaline and isoprenaline were reduced in mice which had been pretreated with α-methyl-p-tyrosine. ʟᴅ-Propranolol blocked the increase in glycolysis caused by noradrenaline, isoprenaline, sodium fluoride and analogues of 3,5-cyclic adenosine monophosphate. It is suggested that the results of this investigation can be explained by the various drugs and neurohormones acting on the adenyl cyclase system in vivo, either by blocking the action of the neurohormone on the membrane bound enzyme or monophosphate on glycolysis.

Lithium administration and phosphate excretion

1976 ◽  
Vol 231 (4) ◽  
pp. 1140-1146 ◽  
Author(s):  
JA Arruda ◽  
JM Richardson ◽  
JA Wolfson ◽  
L Nascimento ◽  
DR Rademacher ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Renal Cortex ◽  
Cyclic Adenosine Monophosphate ◽  
Fractional Excretion ◽  
Adenosine Monophosphate ◽  
Adenyl Cyclase ◽  
Phosphate Excretion ◽  
Camp System

The phosphaturic effect of parathyroid hormone (PTH), cyclic adenosine monophosphate (cAMP), acetazolamide (Az), and HCO3 loading was studied in normal, thyroparathyroidectomized (TPTX), and Li-treated dogs. PTH administration to normal animals markedly increased fractional excretion (F) of PO4 but had a blunted effect on FPO4 in the Li-treated animals. Cyclic AMP likewise markedly increased FPO4 in the normal animals but had a markedly blunted effect in the Li-treated animals. Az led to a significant increase in FNa, FHCO3, and FPO4 in the normal animals. In the Li-treated dogs, Az induced a significant natriuresis and bicarbonaturia but failed to increase phosphaturia. HCO3 loading in normal dogs caused a significant phosphaturia while having little effect on FPO4 in Li-treated dogs. HCO3 loading to TPTX dogs was associated with a lower FPO4 as compared to normal HCO3-loaded animals. These data suggest that Li administration not only blocks the adenyl cyclase-cAMP system in the renal cortex, but it may also interfere with a step distal to the formation of cAMP, since the phosphaturic effect of both PTH and cAMP was markedly diminished in Li-treated animals.

scholarly journals Effects of integrin-mediated cell adhesion on plasma membrane lipid raft components and signaling

2011 ◽  
Vol 22 (18) ◽  
pp. 3456-3464 ◽  
Author(s):  
Andrés Norambuena ◽  
Martin A. Schwartz
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Lipid Raft ◽  
Rho Gtpases ◽  
Cancer Metastasis ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Membrane Lipid ◽  
Cell Detachment ◽  
Suspended Cells

Anchorage dependence of cell growth, which is mediated by multiple integrin-regulated signaling pathways, is a key defense against cancer metastasis. Detachment of cells from the extracellular matrix triggers caveolin-1–dependent internalization of lipid raft components, which mediates suppression of Rho GTPases, Erk, and phosphatidylinositol 3-kinase in suspended cells. Elevation of cyclic adenosine monophosphate (cAMP) following cell detachment is also implicated in termination of growth signaling in suspended cells. Studies of integrins and lipid rafts, however, examined mainly ganglioside GM1 and glycosylphosphatidylinositol-linked proteins as lipid raft markers. In this study, we examine a wider range of lipid raft components. Whereas many raft components internalized with GM1 following cell detachment, flotillin2, connexin43, and Gαs remained in the plasma membrane. Loss of cell adhesion caused movement of many components from the lipid raft to the nonraft fractions on sucrose gradients, although flotillin2, connexin43, and H-Ras were resistant. Gαs lost its raft association, concomitant with cAMP production. Modification of the lipid tail of Gαs to increase its association with ordered domains blocked the detachment-induced increase in cAMP. These data define the effects of that integrin-mediated adhesion on the localization and behavior of a variety of lipid raft components and reveal the mechanism of the previously described elevation of cAMP after cell detachment.

Evaluation of the effect of incorporation of dibutyryl cyclic adenosine monophosphate in an in situ-forming hydrogel wound dressing based on oxidized alginate and gelatin

Biomaterials ◽  
2006 ◽  
Vol 27 (8) ◽  
pp. 1355-1361 ◽  
Author(s):  
Biji Balakrishnan ◽  
Mira Mohanty ◽  
Adelaide C. Fernandez ◽  
Parayanthara V. Mohanan ◽  
A. Jayakrishnan
Keyword(s):  
Wound Dressing ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
In Situ Forming

scholarly journals Visualization of β-adrenergic receptor dynamics and differential localization in cardiomyocytes

2021 ◽  
Vol 118 (23) ◽  
pp. e2101119118
Author(s):  
Marc Bathe-Peters ◽  
Philipp Gmach ◽  
Horst-Holger Boltz ◽  
Jürgen Einsiedel ◽  
Michael Gotthardt ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Adrenergic Receptor ◽  
Cardiac Contractility ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Receptor Subtypes ◽  
Specific Cell ◽  
Adult Cardiomyocytes ◽  
Outer Plasma Membrane

A key question in receptor signaling is how specificity is realized, particularly when different receptors trigger the same biochemical pathway(s). A notable case is the two β‐adrenergic receptor (β‐AR) subtypes, β1 and β2, in cardiomyocytes. They are both coupled to stimulatory Gs proteins, mediate an increase in cyclic adenosine monophosphate (cAMP), and stimulate cardiac contractility; however, other effects, such as changes in gene transcription leading to cardiac hypertrophy, are prominent only for β1‐AR but not for β2-AR. Here, we employ highly sensitive fluorescence spectroscopy approaches, in combination with a fluorescent β‐AR antagonist, to determine the presence and dynamics of the endogenous receptors on the outer plasma membrane as well as on the T-tubular network of intact adult cardiomyocytes. These techniques allow us to visualize that the β2‐AR is confined to and diffuses within the T-tubular network, as opposed to the β1‐AR, which is found to diffuse both on the outer plasma membrane as well as on the T-tubules. Upon overexpression of the β2‐AR, this compartmentalization is lost, and the receptors are also seen on the cell surface. Such receptor segregation depends on the development of the T-tubular network in adult cardiomyocytes since both the cardiomyoblast cell line H9c2 and the cardiomyocyte-differentiated human-induced pluripotent stem cells express the β2‐AR on the outer plasma membrane. These data support the notion that specific cell surface targeting of receptor subtypes can be the basis for distinct signaling and functional effects.

A comparison of membrane fracture faces of fixed and unfixed glycerinated tissue

1976 ◽  
Vol 21 (3) ◽  
pp. 437-448
Author(s):  
A.S. Breathnach ◽  
M. Gross ◽  
B. Martin ◽  
C. Stolinski
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Freeze Fracture ◽  
Particle Aggregation ◽  
Buccal Epithelium ◽  
Mitochondrial Membranes ◽  
Nuclear Membranes ◽  
General Plasma

Fixed (glutaraldehyde, 3%) and unfixed specimens of rat buccal epithelium, striated muscle, and liver, were cryoprotected with glycerol, freeze-fractured, and replicated without sublimation. A comparison of fracture faces of general plasma membranes, nuclear membranes, mitochondrial membranes, and membranes of rough endoplasmic reticulum revealed no significant differences as between fixed and unfixed material. Apart from some membranes of liver endoplasmic reticulum, there was no evidence of aggregation or redistribution of intramembranous particles in the unfixed material. The results demonstrate that chemical prefixation of tissues for freeze-fracture is not always necessary, or even desirable, and that glycerol may not be as deeply or directly implicated in particle aggregation as previously thought. Fixation with glutaraldehyde alters the cleaving behaviour of plasma membrane at desmosomes and tight junctions, but not at gap junctions.

Components of the mitochondrial cAMP signalosome

2017 ◽  
Vol 45 (1) ◽  
pp. 269-274 ◽  
Author(s):  
Stefania Monterisi ◽  
Manuela Zaccolo
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Signalling Pathway ◽  
Intermembrane Space ◽  
Mitochondrial Membranes ◽  
The Matrix ◽  
Extracellular Stimuli ◽  
Kinase A

3′-5′-Cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signalling is activated by different extracellular stimuli and mediates many diverse processes within the same cell. It is now well established that in order to translate into the appropriate cellular function multiple extracellular inputs, which may act simultaneously on the same cell, the cAMP/PKA signalling pathway is compartmentalised. Multimolecular complexes are organised at specific subcellular sites to generate spatially confined signalosomes, which include effectors, modulators and targets of the pathway. In recent years, it has become evident that mitochondria represent sites of compartmentalised cAMP signalling. However, the exact location and the molecular composition of distinct mitochondria signalosomes and their function remain largely unknown. In this review, we focus on individual components of the cAMP/PKA signalling pathway at distinct mitochondria subdomains represented by the outer and inner mitochondrial membranes, the intermembrane space and the matrix, highlighting some of the questions that remain unanswered.

scholarly journals Cyclic AMP modulates the rate of ‘constitutive’ exocytosis of apical membrane proteins in Madin-Darby canine kidney cells

1995 ◽  
Vol 108 (5) ◽  
pp. 1931-1943 ◽  
Author(s):  
M. Brignoni ◽  
O.P. Pignataro ◽  
M.L. Rodriguez ◽  
A. Alvarez ◽  
D.E. Vega-Salas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Apical Membrane ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Apical Plasma Membrane ◽  
Madin Darby Canine Kidney ◽  
Cell Contacts ◽  
Darby Canine Kidney ◽  
Canine Kidney

Madin-Darby canine kidney and other epithelial cell lines (e.g. Caco-2, MCF-10A and MCF-7) develop intracellular vacuoles composed of apical membrane displaying microvilli (VACs) when impaired from forming normal cell-to-cell contacts. In a previous publication, we showed that VACs are rapidly exocytosed upon treatment with 8-Br-3′,5′-cyclic adenosine monophosphate (8-Br-cAMP), a membrane-permeable analog of cAMP, and that this exocytosis correlates with variations in the cellular cAMP concentration in response to the cell-cell contacts. In the present work, we tested the hypothesis that cAMP may be a positive modulator of the ‘constitutive’ exocytic pathway. To mimic conditions in cells with incomplete intercellular contacts, the intracellular levels of cAMP were decreased by means of two independent approaches: (i) pores were induced in the plasma membrane with the polypeptidic antibiotic subtilin, thus allowing small molecules (including cAMP) to permeate and move out of the cytoplasm; and (ii) adenylate cyclase and protein kinase A were blocked with specific inhibitors. In all cases, the intracellular levels of cAMP were measured and, in porated cells, equilibrated to simulate the corresponding physiological intracellular concentrations. The decrease in cAMP within the physiological range resulted in a decreased rate of transport of an apical marker of the constitutive pathway (influenza virus hemagglutinin) from the trans-Golgi network to the apical plasma membrane. Likewise, the delivery of a number of cellular apical proteins to the plasma membrane was retarded at low cAMP concentrations. The inhibitors of adenylate cyclase failed to block basolateral delivery of vesicular stomatitis virus G protein. This differential modulatory effect may represent a differentiation-dependent control of the insertion of apical membrane in epithelial cells.

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