Association of kinesin with the Golgi apparatus in rat hepatocytes

1994 ◽  
Vol 107 (9) ◽  
pp. 2417-2426 ◽  
Author(s):  
D.L. Marks ◽  
J.M. Larkin ◽  
M.A. McNiven
Keyword(s):  
Golgi Apparatus ◽  
Immunofluorescence Microscopy ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Immunoblot Analysis ◽  
Subcellular Fractionation ◽  
Rat Hepatocyte ◽  
Membranous Structure ◽  
Microtubule Disruption ◽  
Motor Enzymes

The Golgi apparatus is a dynamic membranous structure, which has been observed to alter its location and morphology during the cell cycle and after microtubule disruption. These dynamics are believed to be supported by a close structural interaction of the Golgi with the microtubule cytoskeleton and associated motor enzymes. One microtubule-dependent motor enzyme, kinesin, has been implicated in Golgi movement and function although direct evidence supporting this interaction is lacking. In this study, we utilized two well-characterized kinesin antibodies in conjunction with subcellular fractionation techniques, immunoblot analysis and immunofluorescence microscopy to conduct a detailed study on the association of kinesin with the Golgi and other membranous organelles in a polarized epithelial cell, the primary rat hepatocyte. We found that kinesin represents approximately 0.3% of total protein in rat liver homogenates, with approximately 30% membrane-associated and the remainder in the cytosol. Among membrane fractions, kinesin was concentrated markedly in Golgi-enriched fractions, which were prepared using two independent techniques. Kinesin was also abundant in fractions enriched in transcytotic carriers and secretory vesicles, with lower levels detected on fractions enriched in endosomes, endoplasmic reticulum, lysosomes and mitochondria. Immunofluorescence microscopy showed that kinesin is concentrated on Golgi-like structures in both primary cultured hepatocytes and rat hepatocyte-derived clone 9 cells. Double-label immunofluorescence demonstrated that kinesin staining colocalizes with the Golgi marker, alpha-mannosidase II, in both cell types. These results provide compelling evidence showing that kinesin is associated with the Golgi complex in cells and implicate this motor enzyme in Golgi structure, function and dynamics.

scholarly journals The Golgi apparatus remains associated with microtubule organizing centers during myogenesis.

1985 ◽  
Vol 101 (2) ◽  
pp. 630-638 ◽  
Author(s):  
A M Tassin ◽  
M Paintrand ◽  
E G Berger ◽  
M Bornens
Keyword(s):  
Golgi Apparatus ◽  
Nuclear Periphery ◽  
Spatial Relationship ◽  
Cell Types ◽  
Microtubule Depolymerization ◽  
Animal Cells ◽  
Microtubule Organizing Center ◽  
Microtubule Disruption ◽  
Tight Association

In vitro myogenesis involves a dramatic reorganization of the microtubular network, characterized principally by the relocalization of microtubule nucleating sites at the surface of the nuclei in myotubes, in marked contrast with the classical pericentriolar localization observed in myoblasts (Tassin, A. M., B. Maro, and M. Bornens, 1985, J. Cell Biol., 100:35-46). Since a spatial relationship between the Golgi apparatus and the centrosome is observed in most animal cells, we have decided to follow the fate of the Golgi apparatus during myogenesis by an immunocytochemical approach, using wheat germ agglutinin and an affinity-purified anti-galactosyltransferase. We show that Golgi apparatus in myotubes displays a perinuclear distribution which is strikingly different from the polarized juxtanuclear organization observed in myoblasts. As a result, the Golgi apparatus in myotubes is situated close to the microtubule organizing center (MTOC), the cis-side being situated at a fixed distance from the nuclear envelope, a situation which suggests the existence of a structural association between the Golgi apparatus and the nuclear periphery. This is supported by experiments of microtubule depolymerization by nocodazole, in which a minimal effect was observed on Golgi apparatus localization in myotubes in contrast with the dramatic scattering observed in myoblasts. In both cell types, electron microscopy reveals that microtubule disruption generates individual dictyosomes; this suggests that the connecting structures between dictyosomes are principally affected. This structural dependency of the Golgi apparatus upon microtubules is not apparently accompanied by a reverse dependency of MTOC structure or function upon Golgi apparatus activity. Golgi apparatus modification by monensin, as effective in myotubes as in myoblasts, is without apparent effect on MTOC localization or activity and on microtubule stability. The main result of our study is to show that in a cell type where the MTOC is dissociated from centrioles and where antero-posterior polarity has disappeared, the association between the Golgi apparatus and the MTOC is maintained. The significance of such a tight association is discussed.

scholarly journals The Water Channel Aquaporin-8 Is Mainly Intracellular in Rat Hepatocytes, and Its Plasma Membrane Insertion Is Stimulated by Cyclic AMP

2001 ◽  
Vol 276 (15) ◽  
pp. 12147-12152 ◽  
Author(s):  
Fabiana Garcı́a ◽  
Arlinet Kierbel ◽  
M. Cecilia Larocca ◽  
Sergio A. Gradilone ◽  
Patrick Splinter ◽  
...  
Keyword(s):  
Water Transport ◽  
Water Permeability ◽  
Plasma Membranes ◽  
Water Channel ◽  
Rat Hepatocytes ◽  
Immunoblot Analysis ◽  
Subcellular Fractionation ◽  
Bile Secretion ◽  
Confocal Immunofluorescence Microscopy ◽  
Microsomal Membranes

We previously found that water transport across hepatocyte plasma membranes occurs mainly via a non-channel mediated pathway. Recently, it has been reported that mRNA for the water channel, aquaporin-8 (AQP8), is present in hepatocytes. To further explore this issue, we studied protein expression, subcellular localization, and regulation of AQP8 in rat hepatocytes. By subcellular fractionation and immunoblot analysis, we detected anN-glycosylated band of ∼34 kDa corresponding to AQP8 in hepatocyte plasma and intracellular microsomal membranes. Confocal immunofluorescence microscopy for AQP8 in cultured hepatocytes showed a predominant intracellular vesicular localization. Dibutyryl cAMP (Bt2cAMP) stimulated the redistribution of AQP8 to plasma membranes. Bt2cAMP also significantly increased hepatocyte membrane water permeability, an effect that was prevented by the water channel blocker dimethyl sulfoxide. The microtubule blocker colchicine but not its inactive analog lumicolchicine inhibited the Bt2cAMP effect on both AQP8 redistribution to cell surface and hepatocyte membrane water permeability. Our data suggest that in rat hepatocytes AQP8 is localized largely in intracellular vesicles and can be redistributed to plasma membranes via a microtubule-depending, cAMP-stimulated mechanism. These studies also suggest that aquaporins contribute to water transport in cAMP-stimulated hepatocytes, a process that could be relevant to regulated hepatocyte bile secretion.

Lipoproteins in Golgi Apparatus and GERL of Rat Hepatocytes: A CytoChemical Study

1977 ◽  
Vol 35 ◽  
pp. 432-433
Author(s):  
P.M. Novikoff ◽  
A. Yam
Keyword(s):  
Golgi Apparatus ◽  
Orotic Acid ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Very Low Density Lipoproteins ◽  
Hepatocyte Ultrastructure ◽  
Cytochemical Study ◽  
Thiamine Pyrophosphatase

Our laboratory has recently reported that the marked fatty liver induced in rats by feeding a purine-free diet with 1% orotic acid (OA) can be reversed by addition of ethyl chlorophenoxyiso- butyrate (clofibrate or CPIB) to the OA diet (1). Hepatocyte ultrastructure returns to normal, as do the triacylglycerol levels in liver and serum. During reversal, GERL becomes prominent, distended with particles interpreted as lipoproteins undergoing degradation.This communication reports cytochemical observations on such hepatocytes. Thiamine pyrophosphatase (TPPase) activity in hepatocytes, as in various cell types (2), is localized to the inner (trans) element of the Golgi apparatus (Figure 1). GERL, in contrast, shows no TPPase activity but displays acid phosphatase (AcPase) activity (Figure 2). Particles resembling very low density lipoproteins (VLDL) are found in both GERL and elements of the Golgi apparatus. The presence of both AcPase activity and VLDL-like particles strengthens our earlier suggestion that lipoproteins may undergo transformations in GERL.

A Comparison of Plasminogen Activators Derived from Rat Plasma, Primary Rat Hepatocytes and Isolated Perfused Rat Liver

1982 ◽  
Vol 47 (02) ◽  
pp. 166-172 ◽  
Author(s):  
Yoav Sharoni ◽  
Maria C Topal ◽  
Patricia R Tuttle ◽  
Henry Berger
Keyword(s):  
Rat Liver ◽  
Isoelectric Point ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Plasminogen Activators ◽  
Rat Plasma ◽  
Isolated Perfused Rat Liver ◽  
Perfused Rat Liver ◽  
Molecular Weights ◽  
Physiological Relevance

SummaryOf the two cell types it was possible to culture from the dissociated rat liver, hepatocytes and Kupffer cells, only the former were fibrinolytically active. Rat hepatocytes during the first 24 hr in culture secreted two plasminogen activators with molecular weights identical to those found in rat plasma, an 80,000-dalton form (PA-80) and a 45,000-dalton form (PA-45). Partially purified preparations of plasminogen activators from both sources were subjected to isoelectric focusing (IEF) to compare characteristics further. There were three distinct peaks of PA-45 in each preparation with isoelectric points of 7.1, 7.2 and 7.4; all electrophoretic forms had the same low affinity to fibrin. PA-80 from both sources displayed similar IEF profiles with forms ranging from pH values of 7 to 8, all with the same high affinity to fibrin. The major form of PA-80 in the plasma preparation had an isoelectric point of 7.9 whereas that in the hepatocyte preparation had an isoelectric point of 7.6. The isolated perfused rat liver was also shown to produce both PA-80 and PA-45 emphasizing the physiological relevance of the findings with hepatocytes. It is concluded that in the rat hepatocytes contribute to the plasma profile with regard to the plasminogen activator content.

scholarly journals Effects of taurolithocholate, a Ca2+-mobilizing agent, on cell Ca2+ in rat hepatocytes, human platelets and neuroblastoma NG108-15 cell line

1991 ◽  
Vol 273 (1) ◽  
pp. 153-160 ◽  
Author(s):  
J F Coquil ◽  
B Berthon ◽  
N Chomiki ◽  
L Combettes ◽  
P Jourdon ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acid ◽  
Cell Line ◽  
Rat Liver ◽  
Neuronal Cell ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
Liver Cells ◽  
Human Platelets ◽  
Rat Liver Cells

The monohydroxy bile acid taurolithocholate permeabilizes the endoplasmic reticulum to Ca2+ in rat liver cells. To assess whether this action on the endoplasmic reticulum was restricted to this tissue, the effects of bile acid were investigated in two cell types quite unrelated to rat hepatocyte, namely human platelets and neuronal NG108-15 cell line. The results showed that taurolithocholate (3-100 microM) had no effect on free cytosolic [Ca2+] in human platelets and NG108-15 cells. whereas it increased it from 180 to 520 nM in rat hepatocytes. In contrast, in cells permeabilized by saponin, taurolithocholate initiated a profound release of the stored Ca2+ from the internal Ca2+ pools in the three cell types. The bile acid released 90% of the Ca2+ pools, with rate constants of about 5 min-1 and half-maximal effects at 15-30 microM. The results also showed that, in contrast with liver cells, which displayed an influx of [14C]taurolithocholate of 2 nmol/min per mg, human platelets and the neuronal cell line appeared to be resistant to [14C]taurolithocholate uptake. The influx measured in these latter cells was about 100-fold lower than in rat liver cells. Taken together, these data suggest that human platelets and NG108-15 cells do not possess the transport system for concentrating monohydroxy bile acids into cells. However, they show that human platelets and neuronal NG108-15 possess, in common with liver cells, the intracellular system responsible for taurolithocholate-mediated Ca2+ release from internal stores.

scholarly journals Cell-substratum interaction of cultured avian osteoclasts is mediated by specific adhesion structures.

1984 ◽  
Vol 99 (5) ◽  
pp. 1696-1705 ◽  
Author(s):  
P C Marchisio ◽  
D Cirillo ◽  
L Naldini ◽  
M V Primavera ◽  
A Teti ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Intermediate Filaments ◽  
Immunofluorescence Microscopy ◽  
Laying Hens ◽  
Cell Types ◽  
Medullary Bone ◽  
Transformed Cell ◽  
The Core ◽  
Low Calcium Diet

The cell-substratum interaction was studied in cultures of osteoclasts isolated from the medullary bone of laying hens kept on low calcium diet. In fully spread osteoclasts, cell-substratum adhesion mostly occurred within a continuous paramarginal area that corresponded also to the location of a thick network of intermediate filaments of the vimentin type. In this area, regular rows of short protrusions contacting the substratum and often forming a cup-shaped adhesion area were observed in the electron microscope. These short protrusions showed a core of F-actin-containing material presumably organized as a network of microfilaments and surrounded by a rosette-like structure in which vinculin and alpha-actinin were found by immunofluorescence microscopy. Rosettes were superposable to dark circles in interference-reflection microscopy and thus represented circular forms of close cell-substratum contact. The core of ventral protrusions also contained, beside F-actin, fimbrin and alpha-actinin. Villin was absent. This form of cell-substratum contact occurring at the tip of a short ventral protrusion differed from other forms of cell-substratum contact and represented an osteoclast-specific adhesion device that might also be present in in vivo osteoclasts as well as in other normal and transformed cell types.

The transcytotic pathway of an apical plasma membrane protein (B10) in hepatocytes is similar to that of IgA and occurs via a tubular pericentriolar compartment

1996 ◽  
Vol 109 (6) ◽  
pp. 1215-1227 ◽  
Author(s):  
I. Hemery ◽  
A.M. Durand-Schneider ◽  
G. Feldmann ◽  
J.P. Vaerman ◽  
M. Maurice
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Apical Membrane ◽  
Rat Hepatocytes ◽  
Apical Plasma Membrane ◽  
Apical Surface ◽  
Plasma Membrane Protein ◽  
Microtubule Disruption

In hepatocytes, newly synthesized apical plasma membrane proteins are first delivered to the basolateral surface and are supposed to reach the apical surface by transcytosis. The transcytotic pathway of apical membrane proteins and its relationship with other endosomal pathways has not been demonstrated morphologically. We compared the intracellular route of an apical plasma membrane protein, B10, with that of polymeric IgA (pIgA), which is transcytosed, transferrin (Tf) which is recycled, and asialoorosomucoid (ASOR) which is delivered to lysosomes. Ligands and anti-B10 monoclonal IgG were linked to fluorochromes or with peroxidase. The fate of each ligand was followed by confocal and electron microscopy in polarized primary monolayers of rat hepatocytes. When fluorescent anti-B10 IgG and fluorescent pIgA were simultaneously endocytosed for 15–30 minutes, they both uniformly labelled a juxtanuclear compartment. By 30–60 minutes, they reached the bile canaliculi. Tf and ASOR were also routed to the juxtanuclear area, but their fluorescence patterns were more punctate. Microtubule disruption prevented all ligands from reaching the juxtanuclear area. This area corresponded, at least partially, to the localization of the mannose 6-phosphate receptor, an endosomal marker. By electron microscopy, the juxtanuclear compartment was made up of anastomosing tubules connected to vacuoles, and was organized around the centrioles. B10 and pIgA were mainly found in the tubules, whereas ASOR was segregated inside the vacuolar elements and Tf within thinner, recycling tubules. In conclusion, transcytosis of the apical membrane protein B10 occurs inside tubules similar to those carrying pIgA, and involves passage via the pericentriolar area. In the pericentriolar area, the transcytotic tubules appear to maintain connections with other endosomal elements where sorting between recycled and degraded ligands occurs.

scholarly journals Channelling of intermediates in the biosynthesis of phosphatidylcholine and phosphatidylethanolamine in mammalian cells

1998 ◽  
Vol 334 (3) ◽  
pp. 511-517 ◽  
Author(s):  
Bellinda A. BLADERGROEN ◽  
Math J. H. GEELEN ◽  
A. Ch. Pulla REDDY ◽  
Peter E. DECLERCQ ◽  
Lambert M. G. VAN GOLDE
Keyword(s):  
Staphylococcus Aureus ◽  
Mammalian Cells ◽  
Glioma Cells ◽  
Rat Hepatocytes ◽  
Cell Types ◽  
General Phenomenon ◽  
Rat Glioma ◽  
Permeabilized Cells ◽  
Metabolic Compartmentation ◽  
Choline Incorporation

Previous studies with electropermeabilized cells have suggested the occurrence of metabolic compartmentation and Ca2+-dependent channeling of intermediates of phosphatidylcholine (PC) biosynthesis in C6 rat glioma cells. With a more accessible permeabilization technique, we investigated whether this is a more general phenomenon also occurring in other cell types and whether channeling is involved in phosphatidylethanolamine (PE) synthesis as well. C6 rat glioma cells, C3H10T½ fibroblasts and rat hepatocytes were permeabilized with Staphylococcus aureus α-toxin, and the incorporation of the radiolabelled precursors choline, phosphocholine (P-choline), ethanolamine and phosphoethanolamine (P-EA) into PC and PE were measured both at high and low Ca2+ concentrations. In glioma cells, permeabilization at high Ca2+ concentration did not affect [14C]choline or [14C]P-choline incorporation into PC. However, reduction of free Ca2+ in the medium from 1.8 mM to < 1 nM resulted in a dramatic increase in [14C]P-choline incorporation into permeabilized cells, whereas [14C]choline incorporation remained unaffected. Also, in fibroblasts, reduction of extracellular Ca2+ increased [14C]P-choline and [14C]P-EA incorporation into PC and PE respectively. In hepatocytes, a combination of α-toxin and low Ca2+ concentration severely impaired [14C]choline incorporation into PC. Therefore, α-toxin-permeabilized hepatocytes are not a good model in which to study channeling of intermediates in PC biosynthesis. In conclusion, our results indicate that channeling is involved in PC synthesis in glioma cells and fibroblasts. PE synthesis in fibroblasts is also at least partly dependent on channeling.

scholarly journals The effects of low temperatures on intracellular transport of newly synthesized albumin and haptoglobin in rat hepatocytes

1986 ◽  
Vol 237 (1) ◽  
pp. 33-39 ◽  
Author(s):  
E Fries ◽  
I Lindström
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Low Temperatures ◽  
Intracellular Transport ◽  
Rat Hepatocytes ◽  
Subcellular Fractionation ◽  
Isolated Rat Hepatocytes ◽  
Different Temperatures ◽  
Lag Period ◽  
Time Courses

Isolated rat hepatocytes were pulse-labelled with [35S]methionine at 37 degrees C and subsequently incubated (chased) for different periods of time at different temperatures (37-16 degrees C). The time courses for the secretion of [35S]methionine-labelled albumin and haptoglobin were determined by quantitative immunoprecipitation of the detergent-solubilized cells and of the chase media. Both proteins appeared in the chase medium only after a lag period, the length of which increased markedly with decreasing chase temperature: from about 10 and 20 min at 37 degrees C to about 60 and 120 min at 20 degrees C for albumin and haptoglobin respectively. The rates at which the proteins were externalized after the lag period were also strongly affected by temperature, the half-time for secretion being 20 min at 37 degrees C and 200 min at 20 degrees C for albumin; at 16 degrees C no secretion could be detected after incubation for 270 min. Analysis by subcellular fractionation showed that part of the lag occurred in the endoplasmic reticulum and that the rate of transfer to the Golgi complex was very temperature-dependent. The maximum amount of the two pulse-labelled proteins in Golgi fractions prepared from cells after different times of chase decreased with decreasing incubation temperatures, indicating that the transport from the Golgi complex to the cell surface was less affected by low temperatures than was the transport from the endoplasmic reticulum to the Golgi complex.

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