scholarly journals An Association between Mitochondria and the Endoplasmic Reticulum in Cells of the Pseudobranch Gland of a Teleost

1959 ◽  
Vol 5 (3) ◽  
pp. 393-396 ◽  
Author(s):  
D. E. Copeland ◽  
A. J. Dalton
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Carbonic Anhydrase ◽  
Basement Membrane ◽  
The Other ◽  
Secretory Cells ◽  
Specific Cell ◽  
Primary Products ◽  
In Cells

An elaborate and apparently unique specialization of the endoplasmic reticulum having the form of tubules and a precise orientation with respect to the mitochondria has been described for the specific cell of the pseudobranch gland. The tubules also are concentrated near the vascular border of the cell where they show continuity with the plasma membrane and open directly against the basement membrane. On the other side of the basement membrane, the endothelial cells of the sinusoid show openings or discontinuities characteristically associated with secretory cells. The pseudobranch gland is presumed to have carbonic anhydrase as one of its primary products, if not its only one, and the elaborate ultrastructure is thought to be associated with the special problems of secreting this enzyme.

scholarly journals Compartmentalization of intracellular membrane glycocomponents is revealed by fracture-label.

1984 ◽  
Vol 98 (1) ◽  
pp. 29-34 ◽  
Author(s):  
M R Torrisi ◽  
P Pinto da Silva
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Secretory Granules ◽  
The Other ◽  
Rat Tissues ◽  
Intracellular Membrane ◽  
Definition Of

We used thin-section fracture-label to determine the distribution of wheat-germ agglutinin binding sites in intracellular membranes of secretory and nonsecretory rat tissues as well as in human leukocytes. In all cases, analysis of the distribution of wheat germ agglutinin led to the definition of two endomembrane compartments: one, characterized by absence of the label, includes the membranes of mitochondria and peroxisomes as well as those of the endoplasmic reticulum and nuclear envelope; the other, strongly labeled, comprises the membrane of lysosomes, phagocytic vacuoles, and secretory granules, as well as the plasma membrane. The Golgi apparatus was weakly labeled in all studied tissues.

Cytosolic phospholipase A2-α associates with plasma membrane, endoplasmic reticulum and nuclear membrane in glomerular epithelial cells

2000 ◽  
Vol 353 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Jianhong LIU ◽  
Tomoko TAKANO ◽  
Joan PAPILLON ◽  
Abdelkrim KHADIR ◽  
Andrey V. CYBULSKY
Keyword(s):  
Endoplasmic Reticulum ◽  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Phospholipase A2 ◽  
Cytosolic Phospholipase A2 ◽  
Membrane Association ◽  
Cytosolic Phospholipase ◽  
Glomerular Epithelial Cells ◽  
In Cells

Eicosanoids mediate complement-dependent glomerular epithelial injury in experimental membranous nephropathy. The release of arachidonic acid from phospholipids by cytosolic phospholipase A2 (cPLA2) is the rate-limiting step in eicosanoid synthesis. The present study examines the association of cPLA2 with membranes of organelles. Glomerular epithelial cells were disrupted by homogenization in Ca2+-free buffer; organelles were separated by gradient centrifugation. The distribution of cPLA2 and organelles was analysed by immunoblotting with antibodies against cPLA2 and organelle markers, or by enzyme assay. In cells incubated with or without the Ca2+ ionophore ionomycin plus PMA, cPLA2 co-localized with plasma membrane, endoplasmic reticulum and nuclei, but not with mitochondria or Golgi. A greater amount of cPLA2 was associated with membranes in stimulated cells, but membrane-associated cPLA2 was readily detectable under resting conditions. The pattern of association of cPLA2 with membrane in cells treated with antibody and complement was similar to that in cells stimulated with ionomycin plus PMA; however, complement did not enhance the membrane association of cPLA2 protein. To determine the functional role of membrane association of cPLA2, phospholipids were labelled with [3H]arachidonic acid. Cells were then incubated with or without antibody and complement and were fractionated. Complement induced a loss of radioactivity from the plasma membrane, endoplasmic reticulum and nuclei, but not from the mitochondrial fraction. Thus the release of arachidonic acid by cPLA2 is due to the hydrolysis of phospholipids at multiple subcellular membrane sites, including the endoplasmic reticulum, plasma membrane and nucleus.

Freeze-Fracture Replication of Rough Endoplasmic Reticulum of Mouse Liver Cells

1972 ◽  
Vol 11 (2) ◽  
pp. 477-489
Author(s):  
A. S. BREATHNACH ◽  
C. STOLINSKI ◽  
M. GROSS
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Mouse Liver ◽  
Freeze Fracture ◽  
The Other ◽  
Fracture Face ◽  
Mitochondrial Membranes ◽  
En Face

Fresh, chemically unfixed, glycerinated specimens of mouse liver were examined by the technique of freeze-fracture replication without sublimation (i.e. they were not ‘etched’). Where extensive areas of fractured lamellar membranes of the rough endoplasmic reticulum are revealed en face, 2 types of fracture face are distinguishable. One of these fracture faces (A) is directed towards the cytoplasm, and the other (B) towards the cisternal cavity. A characteristic mosaic, or patchwork pattern of flat areas circumscribed by particles, is evident on both faces, and more clearly so on face B, due to a greater number of more prominent particles. Similar mosaic patterns are revealed on convex faces of the nuclear membrane, and on concave fracture faces of mitochondrial membranes, but are not evident on fracture faces of the plasma membrane. Uncertainty in establishing the exact plane of fracture of membranes in this material, since glycerol is virtually non-sublimable, makes it difficult to assess the significance of these mosaic patterns. The fact that ribosomes are not identifiable on either face of fractured endoplasmic reticulum membranes, gives no certain indication of the plane of fracture.

Localisation des activités de la p-nitrophénylphosphatase et de la phosphatase alcaline dans les cellules de transfert du noeud cotylédonaire du pois nain

1983 ◽  
Vol 61 (5) ◽  
pp. 1476-1490
Author(s):  
A. Nougarède ◽  
P. Landré ◽  
J. Rembur
Keyword(s):  
Alkaline Phosphatase ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Cotyledonary Node ◽  
Ultrastructural Localization ◽  
Transfer Cells ◽  
The Other ◽  
Reaction Products ◽  
Weak Reaction ◽  
Phosphatase Alcaline

The ultrastructural localization of the K+-dependent nitrophenylphosphatase (NPPase) and alkaline phosphatase (ALPase) activities were determined in the transfer cells of the pea cotyledonary node. These two types of activities were generally associated and located essentially on the plasma membrane. NPPase and ALPase activities were also detected along the nuclear membrane of the xylem and phloem transfer cells and along the endoplasmic reticulum profiles (internal face) of phloem transfer cells. Mitochondrial NNPase activity was confined to the outer membrane and cristae. The partial inhibition of the NPPase reaction products by L-p-bromotetramisole and cysteine, the weak reaction observed after deletion of K+, and the suppression of the reaction in the presence of L-p-bromotetramisole are best explained by the concomitant activity of a K+-dependent NPPase and of an ALPase partially inhibited by K+. On the basis of sensitivity to inhibitors, two plasma membrane ALPase isoenzymes were detected. One, extramembranous, was bromotetramisole and cysteine insensitive but inhibited by L-phenylalanine; the other, intramembranous, was bromotetramisole and cysteine sensitive, but insensitive to L-phenylalanine. The other sites of ALPase activities were substantially inhibited by all treatments.

scholarly journals Effect of microtubule assembly status on the intracellular processing and surface expression of an integral protein of the plasma membrane.

1984 ◽  
Vol 99 (3) ◽  
pp. 1101-1109 ◽  
Author(s):  
A A Rogalski ◽  
J E Bergmann ◽  
S J Singer
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
G Protein ◽  
Rough Endoplasmic Reticulum ◽  
Intracellular Transport ◽  
Temperature Shift ◽  
Surface Expression ◽  
Microtubule Assembly ◽  
In Cells

We studied the effects of changes in microtubule assembly status upon the intracellular transport of an integral membrane protein from the rough endoplasmic reticulum to the plasma membrane. The protein was the G glycoprotein of vesicular stomatitis virus in cells infected with the Orsay-45 temperature-sensitive mutant of the virus; the synchronous intracellular transport of the G protein could be initiated by a temperature shift-down protocol. The intracellular and surface-expressed G protein were separately detected and localized in the same cells at different times after the temperature shift, by double-immunofluorescence microscopic measurements, and the extent of sialylation of the G protein at different times was quantitated by immunoprecipitation and SDS PAGE of [35S]methionine-labeled cell extracts. Neither complete disassembly of the cytoplasmic microtubules by nocodazole treatment, nor the radical reorganization of microtubules upon taxol treatment, led to any perceptible changes in the rate or extent of G protein sialylation, nor to any marked changes in the rate or extent of surface appearance of the G protein. However, whereas in control cells the surface expression of G was polarized, at membrane regions in juxtaposition to the perinuclear compact Golgi apparatus, in cells with disassembled microtubules the surface expression of the G protein was uniform, corresponding to the intracellular dispersal of the elements of the Golgi apparatus. The mechanisms of transfer of integral proteins from the rough endoplasmic reticulum to the Golgi apparatus, and from the Golgi apparatus to the plasma membrane, are discussed in the light of these observations, and compared with earlier studies of the intracellular transport of secretory proteins.

scholarly journals UNE FORME MICROTUBULAIRE ET PARACRISTALLINE DE RETICULUM ENDOPLASMIQUE DANS LES PHOTOCYTES DES ANNELIDES POLYNOINÆ

1966 ◽  
Vol 31 (1) ◽  
pp. 135-158 ◽  
Author(s):  
J. M. Bassot
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Nuclear Envelope ◽  
Contact Surface ◽  
Special Kind ◽  
The Other ◽  
Cytoplasmic Organelle ◽  
Specialized Form

Luminous cells of polynoid worm elytra have been examined by methods of electron microscopy, with special attention focused on the fine structure of photogenic grains. These cells send apical prolongations into the mid-part of the elytra. The plasma membrane is very sinuous, and a special kind of desmosome links two portions of the same membrane. In addition to all the organelles which can be found in nonluminescent epithelial cells of the elytra, numerous photogenic grains are contained in their cytoplasm. These grains are composed of undulating microtubules measuring 200 A in diameter; their disposition in the grain is highly regular, and the grains appear as paracrystals. At the borders of the grains, the walls of the microtubules are often in continuity with those of the endoplasmic reticulum and with the external membrane of the nuclear envelope. Because of this fact, the microtubules of the grains may be considered a cytoplasmic organelle, representing a specialized form of the endoplasmic reticulum. The microtubules permit the repartition, inside and outside their walls, of two different products, one being forty-three times more abundant than the other; thus, the contact surface, in comparison to the volume, is greatly increased. The induction of the luminous reaction by change in the permeability of the microtubule walls, allowing contact between the two substances, is suggested as a working hypothesis. There is an evolution of the grains along the axis of the photocytes. The grains are often surrounded by progressively increasing amounts of glycogen. Their paracrystalline disposition is altered at the apex of the luminous cells.

scholarly journals Spatial and temporal translocation of PKCα in single endothelial cell in response to focal mechanical stimulus

2017 ◽  
Author(s):  
Masataka Aarai ◽  
Toshihiro Sera ◽  
Takumi Hasegawa ◽  
Susumu Kudo
Keyword(s):  
Endothelial Cells ◽  
Endoplasmic Reticulum ◽  
Endothelial Cell ◽  
Mechanical Stress ◽  
Mechanical Stimulus ◽  
The Other ◽  
Protein Kinase Cα ◽  
Intracellular Ca ◽  
Summary Statement ◽  
Kinetics Of

AbstractWe observed the kinetics of protein kinase Cα (PKCα) and the intracellular Ca2+ wave in endothelial cells (ECs) in response to microscopic mechanical stress to investigate the effect of mechanical stress on PKCα translocation. The results show that a focal mechanical stimulus induced biphasic and directional PKCα translocation; PKCα initially translocated toward distinct spots near or at the membrane and then accumulated at the stimulus point. The low initial translocation occurred simultaneously in parallel with the increase in Ca2+. Initial translocation was inhibited in spite of Ca2+ increase when the diacylglycerol (DAG) binding domain of PKCα was inhibited, suggesting that translocation requires intracellular Ca2+ increase and DAG. On the other hand, high secondary translocation was delayed, occurring after the Ca2+ wave; however, this secondary translocation occurred even when Ca2+ release from the endoplasmic reticulum was inhibited, while it did not occur when the mechanosensitive (MS) channel was inhibited. These results indicated that at least Ca2+ influx through MS channels is required. Our results support the implication of PKCα in the Ca2+ signaling pathway in response to mechanical stress in ECs.Summary statementIn response to a focal mechanical stimulus, PKCα in an endothelial cell was initially translocated toward distinct spots near or at the membrane and then accumulated at the stimulus point.

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