scholarly journals Quantitative immunoferritin localization of [Na+,K+]ATPase on canine hepatocyte cell surface.

1984 ◽  
Vol 99 (4) ◽  
pp. 1502-1510 ◽  
Author(s):  
S Takemura ◽  
K Omori ◽  
K Tanaka ◽  
K Omori ◽  
S Matsuura ◽  
...  
Keyword(s):  
Cell Surface ◽  
Active Transport ◽  
Lateral Surface ◽  
Bile Flow ◽  
Particle Density ◽  
Transport Processes ◽  
Total Cell ◽  
Secondary Active Transport ◽  
Antibody Conjugates ◽  
Canine Kidney

Distribution of [Na+,K+]ATPase on the cell surface of canine hepatocytes was investigated quantitatively by incubating prefixed and dissociated liver cells with ferritin antibody conjugates against canine kidney holo[Na+,K+]ATPase. We found that [Na+,K+]-ATPase exists bilaterally both on the bile canalicular and sinusoid-lateral surfaces. The particle density on the bile canalicular surface was much higher (approximately 2.5 times) than that on the sinusoid-lateral surface. In the latter region, the enzyme was detected almost equally both on the sinusoidal and lateral surfaces. On all the surfaces, the distribution of the enzyme was homogeneous and no clustering of the enzyme was detected. Total number of the enzyme on the sinusoid-lateral surface was, however, approximately three times higher than that on the bile canalicular region, because the sinusoid-lateral surface represents approximately 87% of the total cell surface of a hepatocyte. We suggest that the [Na+, K+]ATPase on the bile canalicular surface is responsible for the bile acid-independent bile flow and the other transport processes on the bile canalicular cell surface, while that on the sinusoid-lateral surface is responsible not only for the active transport of Na+ but also for the secondary active transport of various substances in this region.

scholarly journals Inhibition by brefeldin A of protein secretion from the apical cell surface of Madin-Darby canine kidney cells.

1991 ◽  
Vol 266 (27) ◽  
pp. 17729-17732 ◽  
Author(s):  
S.H. Low ◽  
S.H. Wong ◽  
B.L. Tang ◽  
P. Tan ◽  
V.N. Subramaniam ◽  
...  
Keyword(s):  
Cell Surface ◽  
Protein Secretion ◽  
Apical Cell ◽  
Brefeldin A ◽  
Kidney Cells ◽  
Madin Darby Canine Kidney ◽  
Darby Canine Kidney ◽  
Canine Kidney

Retargeting of the mitochondrial protein p32/gC1Qr to a cytoplasmic compartment and the cell surface

2001 ◽  
Vol 114 (11) ◽  
pp. 2115-2123
Author(s):  
Hans C. van Leeuwen ◽  
Peter O’Hare
Keyword(s):  
Cell Surface ◽  
Protein Interactions ◽  
Mitochondrial Protein ◽  
Physiological Role ◽  
Surface Expression ◽  
Transport Processes ◽  
Cell Surface Expression ◽  
Bacterial Proteins ◽  
Er Chaperone ◽  
Cellular Compartments

p32/gC1qR is a small acidic protein that has been reported to have a broad range of distinct functions and to associate with a wide array of cellular, viral and bacterial proteins. It has been found in each of the main cellular compartments including mitochondria, nucleus and cytoplasm and is also thought to be located at the plasma membrane and secreted into the extracellular matrix. The true physiological role(s) of p32 remains controversial because it has been difficult to reconcile all of the findings on protein interactions and the seemingly disparate observations on compartmentalisation. However, it has been proposed that p32 is somehow involved in transport processes connecting diverse cellular compartments and the cell surface. Here we show that native p32 appears to be localised mainly in the mitochondria and is not detectable on the cell surface. However, addition of a short tag to the N-terminus of p32 appears to block its mitochondrial targeting, resulting in redirection into a cytoplasmic vesicular pattern, overlapping with the endoplasmic reticulum. The redirection of p32 results in an alteration in and co-localisation with ER markers including calreticulin, a lumenal ER chaperone. Furthermore, we show both by immunofluorescence and cross-linking studies that this also results in cell-surface expression of p32. These results indicate that, at least under certain circumstances, p32 can be retargeted and may help to provide an explanation for the diverse observations on its localization.

scholarly journals The Transport of Salt and Water across Isolated Rat Ileum

1967 ◽  
Vol 50 (3) ◽  
pp. 695-727 ◽  
Author(s):  
T. W. Clarkson
Keyword(s):  
Active Transport ◽  
Transport Processes ◽  
Irreversible Processes ◽  
Pressure Gradients ◽  
Ion Flow ◽  
Chemical Gradients ◽  
In Series ◽  
Frictional Coefficients ◽  
The Relationship ◽  
Active Channel

The flows of sodium, potassium, and chloride under electrical and chemical gradients and of salt and water in the presence of osmotic pressure gradients are described by phenomenological equations based on the thermodynamics of irreversible processes. The aim was to give the simplest possible description, that is to postulate the least number of active transport processes and the least number of separate pathways across the intestine. On this basis, the results were consistent with the following picture of the intestine: Two channels exist across this tissue, one allowing only passive transport of ions and the other only active. In the passive channel, the predominant resistance to ion flow is friction with the water in the channel. The electroosmotic flow indicates that the passive channel is lined with negative fixed charged groups having a surface charge density of 3000 esu cm-2. The values of the ion-water frictional coefficients, and the relationship between ionic concentrations and flows indicate that the passive channel is extracellular. The active channel behaves as two membranes in series, the first membrane being semipermeable but allowing active transport of sodium, and the second membrane being similar to the passive channel. Friction with the ions in the second "membrane" is the predominant resistance to water flow.

scholarly journals Sub-Diffusive Dynamics Lead to Depleted Particle Densities Near Cellular Borders

2018 ◽  
Author(s):  
William R. Holmes
Keyword(s):  
Particle Density ◽  
Specific Model ◽  
Transport Processes ◽  
Generalized Langevin Equation ◽  
Diffusive Motion ◽  
Protein Activation ◽  
Cellular Environment ◽  
Anomalous Particle ◽  
Canonical Type ◽  
Different Characteristics

AbstractIt has long been known that the complex cellular environment leads to anomalous motion of intracellular particles. At a gross level, this is characterized by mean squared displacements that deviate from the standard linear profile. Statistical analysis of particle trajectories has helped further elucidate how different characteristics of the cellular environment can introduce different types of anomalousness. A significant majority of this literature has however focused on characterizing the properties of trajectories that do not interact with cell borders (e.g. cell membrane or nucleus). Numerous biological processes ranging from protein activation to exocytosis however require particles to be near a membrane. This study investigates the consequences of a canonical type of sub-diffusive motion, Fractional Brownian Motion (FBM), and its physical analogue Generalized Langevin Equation (GLE) Dynamics, on the spatial localization of particles near reflecting boundaries. Results show that this type of sub-diffusive motion leads to the formation of significant zones of depleted particle density near boundaries, and that this effect is independent of the specific model details encoding those dynamics. Rather these depletion layers are a natural and robust consequence of the anti-correlated nature of motion increments that is at the core of FBM / GLE dynamics. If such depletion zones are present, it would be of profound importance given the wide array of signaling and transport processes that occur near membranes. If not, that would suggest our understanding of this type of anomalous motion may be flawed. Either way, this result points to the need to further investigate the consequences of anomalous particle motions near cell borders from both theoretical and experimental perspectives.

Effects of dinitrophenol on active-transport processes and cell membranes in the Malpighian tubule of Formica

1994 ◽  
Vol 428 (2) ◽  
pp. 150-156 ◽  
Author(s):  
S. Dijkstra ◽  
E. Lohrmann ◽  
E. Van Kerkhove ◽  
P. Steels ◽  
R. Greger
Keyword(s):  
Active Transport ◽  
Cell Membranes ◽  
Malpighian Tubule ◽  
Transport Processes

scholarly journals AMP-Activated Protein Kinase (AMPK)-Dependent Regulation of Renal Transport

2018 ◽  
Vol 19 (11) ◽  
pp. 3481 ◽  
Author(s):  
Philipp Glosse ◽  
Michael Föller
Keyword(s):  
Membrane Transport ◽  
Active Transport ◽  
Collecting Duct ◽  
Distal Tubule ◽  
Transport Processes ◽  
Acid Oxidation ◽  
Serine Threonine Kinase ◽  
Energy Deficiency ◽  
Energy Consuming ◽  
Amp Activated Protein Kinase

AMP-activated kinase (AMPK) is a serine/threonine kinase that is expressed in most cells and activated by a high cellular AMP/ATP ratio (indicating energy deficiency) or by Ca2+. In general, AMPK turns on energy-generating pathways (e.g., glucose uptake, glycolysis, fatty acid oxidation) and stops energy-consuming processes (e.g., lipogenesis, glycogenesis), thereby helping cells survive low energy states. The functional element of the kidney, the nephron, consists of the glomerulus, where the primary urine is filtered, and the proximal tubule, Henle’s loop, the distal tubule, and the collecting duct. In the tubular system of the kidney, the composition of primary urine is modified by the reabsorption and secretion of ions and molecules to yield final excreted urine. The underlying membrane transport processes are mainly energy-consuming (active transport) and in some cases passive. Since active transport accounts for a large part of the cell’s ATP demands, it is an important target for AMPK. Here, we review the AMPK-dependent regulation of membrane transport along nephron segments and discuss physiological and pathophysiological implications.

scholarly journals Microtubule-acting drugs lead to the nonpolarized delivery of the influenza hemagglutinin to the cell surface of polarized Madin-Darby canine kidney cells.

1987 ◽  
Vol 104 (2) ◽  
pp. 231-241 ◽  
Author(s):  
M J Rindler ◽  
I E Ivanov ◽  
D D Sabatini
Keyword(s):  
Golgi Apparatus ◽  
Cell Surface ◽  
G Protein ◽  
Mdck Cells ◽  
Apical Surface ◽  
Madin Darby Canine Kidney ◽  
Vesicular Stomatitis ◽  
Ha Protein ◽  
Darby Canine Kidney ◽  
Canine Kidney

The synchronized directed transfer of the envelope glycoproteins of the influenza and vesicular stomatitis viruses from the Golgi apparatus to the apical and basolateral surfaces, respectively, of polarized Madin-Darby canine kidney (MDCK) cells can be achieved using temperature-sensitive mutant viruses and appropriate temperature shift protocols (Rindler, M. J., I. E. Ivanov, H. Plesken, and D. D. Sabatini, 1985, J. Cell Biol., 100:136-151). The microtubule-depolymerizing agents colchicine and nocodazole, as well as the microtubule assembly-promoting drug taxol, were found to interfere with the normal polarized delivery and exclusive segregation of hemagglutinin (HA) to the apical surface but not with the delivery and initial accumulation of G on the basolateral surface. Immunofluorescence analysis of permeabilized monolayers of influenza-infected MDCK cells treated with the microtubule-acting drugs demonstrated the presence of substantial amounts of HA protein on both the apical and basolateral surfaces. Moreover, in cells infected with the wild-type influenza virus, particles budded from both surfaces. Viral counts in electron micrographs showed that approximately 40% of the released viral particles accumulated in the intercellular spaces or were trapped between the cell and monolayer and the collagen support as compared to less than 1% on the basolateral surface of untreated infected cells. The effect of the microtubule inhibitors was not a result of a rapid redistribution of glycoprotein molecules initially delivered to the apical surface since a redistribution was not observed when the inhibitors were added to the cells after the HA was permitted to reach the apical surface at the permissive temperature and the synthesis of new HA was inhibited with cycloheximide. The altered segregation of the HA protein that occurs may result from the dispersal of the Golgi apparatus induced by the inhibitors or from the disruption of putative microtubules containing tracks that could direct vesicles from the trans Golgi apparatus to the cell surface. Since the vesicular stomatitis virus G protein is basolaterally segregated even when the Golgi elements are dispersed and hypothetical tracks disrupted, it appears that the two viral envelope glycoproteins are segregated by fundamentally different mechanisms and that the apical surface may be incapable of accepting vesicles carrying the G protein.

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