scholarly journals Distribution of an asialoglycoprotein receptor on rat hepatocyte cell surface.

1982 ◽  
Vol 95 (3) ◽  
pp. 864-875 ◽  
Author(s):  
S Matsuura ◽  
H Nakada ◽  
T Sawamura ◽  
Y Tashiro
Keyword(s):  
Cell Surface ◽  
Control Level ◽  
Liver Homogenate ◽  
Asialoglycoprotein Receptor ◽  
Lateral Face ◽  
Rabbit Antibody ◽  
Rat Hepatocyte ◽  
Antibody Conjugates ◽  
Rapid Clearance ◽  
Polygonal Shape

Direct ferritin immunoelectron microscopy was applied to visualize the distribution of the hepatocyte cell surface of the asialoglycoprotein receptor which is responsible for the rapid clearance of serum glycoproteins and lysosomal catabolism. For this purpose, rabbit antibody against the purified hepatic binding protein specific for asialoglycoproteins was prepared and coupled to ferritin by glutaraldehyde. The specific antibody conjugates were incubated with the hepatocytes, which were isolated from rat liver homogenate after fixation by glutaraldehyde perfusion. These cells preserved well the original polygonal shape and polarity, and it was easy to identify the sinusoidal, lateral, and bile canalicular faces. The surface density of the ferritin particles bound to the sinusoidal face was about four times higher than that of particles bound to the lateral face, while the bile canalicular face was hardly labeled and almost at the control level. Using the surface area of hepatocyte measured by morphometrical analyses, it was estimated that approximately 90% of bound ferritin particles were at the sinusoidal face, approximately 10% at the lateral face, and approximately 1% at the bile canalicular face. Nonhepatic cells such as endothelial and Kupffer cells had no receptor specific for asialoglycoproteins.

scholarly journals Human IgA as a heterovalent ligand: switching from the asialoglycoprotein receptor to secretory component during transport across the rat hepatocyte.

1986 ◽  
Vol 102 (3) ◽  
pp. 920-931 ◽  
Author(s):  
J M Schiff ◽  
M M Fisher ◽  
A L Jones ◽  
B J Underdown
Keyword(s):  
Secretory Component ◽  
Binding Activity ◽  
Asialoglycoprotein Receptor ◽  
Galactose Oxidase ◽  
Rat Hepatocyte ◽  
Binding Properties ◽  
Affinity Adsorption ◽  
Switching Event ◽  
Transit Times

Asialoglycoproteins are taken up by the rat liver for degradation; rat polymeric IgA is taken up via a separate receptor, secretory component (SC), for quantitative delivery to bile. There is negligible uptake of these ligands by the converse receptor, and only a low level of missorting of ligands to opposite destinations. The two pathways are not cross-inhibitable and operate independently (Schiff, J.M., M. M. Fisher, and B. J. Underdown, 1984, J. Cell Biol., 98:79-89). We report here that when human IgA is presented as a ligand in the rat, it is processed using elements of both pathways. To study this in detail, different IgA fractions were prepared using two radiolabeling methods that provide separate probes for degradation or re-secretion. Behavior of intravenously injected human polymeric IgA in the rat depended on its binding properties. If deprived of SC binding activity by affinity adsorption or by reduction and alkylation, greater than 80% of human IgA was degraded in hepatic lysosomes; radioactive catabolites were released into bile by a leupeptin-inhibitable process. If prevented from binding to the asialoglycoprotein receptor by competition or by treatment with galactose oxidase, human IgA was cleared and transported to bile directly via SC, but its uptake was about fivefold slower than rat IgA. Untreated human IgA was taken up rapidly by the asialoglycoprotein receptor, but depended on SC binding to get to bile: the proportion secreted correlated 1:1 with SC binding activity determined in vitro, and the IgA was released into bile with SC still attached. These results demonstrate that human IgA is normally heterovalent: it is first captured from blood by the asialoglycoprotein receptor, but escapes the usual fate of asialoglycoproteins by switching to SC during transport. Since the biliary transit times of native human and rat IgA are the same, it is probable that the receptor switching event occurs en route. This implies that the two receptors briefly share a common intracellular compartment.

Kinetic analysis of the downregulation of epidermal growth factor receptors in rats in vivo

1990 ◽  
Vol 258 (4) ◽  
pp. C593-C598 ◽  
Author(s):  
S. Yanai ◽  
Y. Sugiyama ◽  
T. Iga ◽  
T. Fuwa ◽  
M. Hanano
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cell Surface ◽  
Kinetic Analysis ◽  
Intravenous Administration ◽  
Recovery Rate ◽  
Specific Binding ◽  
Control Level ◽  
Epidermal Growth

We previously clarified the specific binding sites for epidermal growth factor (EGF) in several organs in rats based on in vivo kinetic analysis (D. C. Kim, Y. Sugiyama, H. Sato, T. Fuwa, T. Iga, and M. Hanano. J. Pharm. Sci. 77: 200-207, 1988). In the present study, we have determined the extent of the receptor downregulation and the recovery rate of the available receptors for EGF in several organs in vivo. At the specified times (30 min-24 h) after intravenous administration of excess unlabeled EGF (300 micrograms/kg), the early-phase (less than 3 min) uptake clearances (k1) of the tracer amount of 125I-EGF, which are proportional to the cell-surface available receptor densities, were determined in the liver, kidney, duodenum, jejunum, ileum, stomach, and spleen. As the result, the k1 value in each organ at 30 min after intravenous administration of unlabeled EGF was lowered close to the receptor-independent clearance value, indicating that the cell-surface receptors were almost completely downregulated, and thereafter, the k1 value showed gradual recovery to the control level. Furthermore, the recovery half-lives showed interorgan differences, namely the half-life (20 min) in the liver was much shorter than those (2-4.5 h) in other organs. These results were considered to reflect the processes of the recycling of internalized EGF receptors to the cell-surface or recruitment of new receptors. It was concluded that the recovery rate of the downregulated receptors in the liver, which is most responsible for the plasma clearance of EGF, is much faster than those in other organs.

scholarly journals Asialoglycoprotein receptor 1 is a specific cell-surface marker for isolating hepatocytes derived from human pluripotent stem cells

Development ◽  
2016 ◽  
Vol 143 (9) ◽  
pp. 1475-1481 ◽  
Author(s):  
Derek T. Peters ◽  
Christopher A. Henderson ◽  
Curtis R. Warren ◽  
Max Friesen ◽  
Fang Xia ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Surface ◽  
Pluripotent Stem Cells ◽  
Human Pluripotent Stem Cells ◽  
Surface Marker ◽  
Asialoglycoprotein Receptor ◽  
Cell Surface Marker ◽  
Specific Cell ◽  
Specific Cell Surface

scholarly journals Rapid Clearance of Sialylated Glycoproteins by the Asialoglycoprotein Receptor

2002 ◽  
Vol 278 (7) ◽  
pp. 4597-4602 ◽  
Author(s):  
Eric I. Park ◽  
Stephen M. Manzella ◽  
Jacques U. Baenziger
Keyword(s):  
Asialoglycoprotein Receptor ◽  
Rapid Clearance ◽  
Sialylated Glycoproteins

scholarly journals Reversible effects of sphingomyelin degradation on cholesterol distribution and metabolism in fibroblasts and transformed neuroblastoma cells

1990 ◽  
Vol 271 (1) ◽  
pp. 121-126 ◽  
Author(s):  
M I Pörn ◽  
J P Slotte
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Cell Line ◽  
Cholesterol Oxidase ◽  
Neuroblastoma Cell ◽  
Control Level ◽  
Neuroblastoma Cells ◽  
Long Term Effects ◽  
Human Lung Fibroblast ◽  
Acat Activity

Plasma-membrane sphingomyelin appears to be one of the major determinants of the preferential allocation of cell cholesterol into the plasma-membrane compartment, since removal of sphingomyelin leads to a dramatic redistribution of cholesterol within the cell [Slotte & Bierman (1988) Biochem. J. 250, 653-658]. In the present study we examined the long-term effects of sphingomyelin degradation on cholesterol redistribution in cells and determined the reversibility of the process. In a human lung fibroblast-cell line, removal of 80% of the sphingomyelin led to a rapid and transient up-regulation (3-fold) of acyl-CoA:cholesterol acyltransferase (ACAT) activity, and also, within 30 h, to the translocation of about 50% of the cell non-esterified cholesterol from a cholesterol oxidase-susceptible compartment (i.e. the cell surface) to oxidase-resistant compartments. At 49 h after the initial sphingomyelin degradation, the cell sphingomyelin level was back to 45% of the control level, and the direction of cell cholesterol flow was toward the cell surface, although the original distribution was not achieved. In a transformed neuroblastoma cell line (SH-SY5Y), the depletion of sphingomyelin led to a similarly rapid and transient up-regulation of ACAT activity, and to the translocation of about 25% of cell-surface cholesterol into internal membranes (within 3 h). The flow of cholesterol back to the cholesterol oxidase-susceptible pool was rapid, and a pretreatment cholesterol distribution was reached within 20-49 h. Also, the resynthesis of sphingomyelin was faster in SH-SY5Y neuroblastoma cells and reached control levels within 24 h. The findings of the present study show that the cellular redistribution of cholesterol, as induced by sphingomyelin degradation, is reversible and suggest that the normalization of cellular cholesterol distribution is linked to the re-synthesis of sphingomyelin.

scholarly journals Enhanced T cell responses to antigenic peptides targeted to B cell surface Ig, Ia, or class I molecules.

1988 ◽  
Vol 168 (1) ◽  
pp. 171-180 ◽  
Author(s):  
L A Casten ◽  
P Kaumaya ◽  
S K Pierce
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cytochrome C ◽  
Cell Surface ◽  
B Cell ◽  
Peptide Fragment ◽  
Peptide Antibody ◽  
Antibody Conjugates ◽  
Antibody Conjugate

The helper T cell recognition of soluble globular protein antigens requires that the proteins be processed by an APC, releasing a peptide that is transported to and held on the APC surface where it is recognized by the specific T cell in conjunction with Ia. When cellular processing functions are blocked, APC lose their ability to present native antigens while retaining the capacity to activate T cells when provided with a cognate peptide fragment that contains the T cell antigenic determinant. In this report, we show that a peptide fragment of the soluble globular protein antigen tobacco hornworm moth cytochrome c, residues 92-103 containing an additional NH2-terminal cysteine residue (THMcCys92-103), is effectively presented by B cells to an I-Ek-restricted, THMc-specific T cell hybrid when covalently coupled to antibodies specific for B cell surface Ig, Ia (Ak), or class I (Kk). Maximal activation of the T cells to the THMcCys92-103-antibody conjugates is achieved with 1/100-1/1,000th of the peptide required using unconjugated THMcCys92-103 or THMcCys92-103 coupled to nonspecific antibody. The T cell response to the peptide antibody conjugates is MHC restricted, but unlike native cytochrome c-antibody conjugates, THMcCys92-103-antibody conjugates do not require processing and can be presented by paraformaldehyde-fixed B cells. The THMcCys92-103-antibody conjugate are nearly as effective when incubated with B cells, and the unbound conjugates washed away before addition of T cells as when continuously present in culture with T cells and B cells, indicating that the active peptide antibody conjugate is associated at the B cell surface. The presentation of THMcCys92-103 coupled to monovalent Fab fragments of rabbit anti-Ig antibodies is less effective than that of the peptide coupled to bivalent antibody when either live or fixed B cells are APC, indicating that the avidity for the APC surface afforded by bivalent binding may be important in the conjugate's antigenicity. The results presented here indicate that a T cell-antigenic peptide, covalently coupled to a larger antibody molecule, can be readily recognized by an Ia-restricted helper T cell in the absence of processing. Moreover, the ability of the peptide to bind to B cell surfaces greatly augments the peptide's antigenicity, even when the binding is to structures distinct from the Ia molecule required for T cell activation.

scholarly journals Identification and quantification of the rat hepatocyte asialoglycoprotein receptor.

1981 ◽  
Vol 78 (6) ◽  
pp. 3348-3352 ◽  
Author(s):  
A. L. Schwartz ◽  
A. Marshak-Rothstein ◽  
D. Rup ◽  
H. F. Lodish
Keyword(s):  
Asialoglycoprotein Receptor ◽  
Rat Hepatocyte ◽  
Identification And Quantification

scholarly journals Intracellular transport of formaldehyde-treated serum albumin in liver endothelial cells after uptake via scavenger receptors

1989 ◽  
Vol 258 (2) ◽  
pp. 511-520 ◽  
Author(s):  
W Eskild ◽  
G M Kindberg ◽  
B Smedsrød ◽  
R Blomhoff ◽  
K R Norum ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Serum Albumin ◽  
Intravenous Injection ◽  
Intracellular Transport ◽  
Liver Homogenate ◽  
Scavenger Receptors ◽  
Coated Pits ◽  
Mitochondrial Fractions ◽  
Liver Endothelial Cells

Endocytosis of formaldehyde-treated serum albumin (FSA) mediated by the scavenger receptor was studied in rat liver endothelial cells. Suspended cells had about 8000 receptors/cell, whereas cultured cells had about 19,000 receptors/cell. Kd was 10(-8) M in both systems. Cell-surface scavenger receptors were found exclusively in coated pits by electron microscopy, by using ligand labelled with colloidal gold. Cell-surface-bound FSA could be released by decreasing the pH to 6.0; it was therefore possible to assess the rate of internalization of surface-bound ligand. This rate was very high: t1/2 for internalization of ligand prebound at 4 degrees C was 24 s. The endocytic rate constant at 37 degrees C, Ke, measured as described by Wiley & Cunningham [(1982) J. Biol. Chem. 257, 4222-4229], was 2.44 min-1, corresponding to t1/2 = 12 s. Uptake of FSA at 37 degrees C after destruction of one cell-surface pool of receptors by Pronase was decreased to 60%. This finding is compatible with a relatively large intracellular pool of receptors. The intracellular handling of 125I-tyramine-cellobiose-labelled FSA (125I-TC-FSA) was studied by subcellular fractionation in sucrose gradients, Nycodenz gradients or by differential centrifugation. The density distributions of degraded and undegraded 125I-TC-FSA after fractionation of isolated non-parenchymal cells and whole liver were similar, when studied in Nycodenz and sucrose gradients, suggesting that the subcellular distribution of the ligand was not influenced by the huge excess of non-endothelial material in a whole liver homogenate. Fractionation in sucrose gradients showed that the ligand was sequentially associated with organelles banding at 1.14, 1.17 and 1.21 g/ml. At 9-12 min after intravenous injection the ligand was in a degradative compartment, as indicated by the accumulation of acid-soluble radioactivity at 1.21 g/ml. A rapid transfer of ligand to the lysosomes was also indicated by the finding that a substantial proportion of the ligand could be degraded by incubating mitochondrial fractions prepared 12 min after intravenous injection of the ligand. The results indicate that FSA is very rapidly internalized and transferred through an endosomal compartment to the lysosomes. The endosomes are gradually converted into lysosomes between 9 and 12 min after injection of FSA. The rate-limiting step in the intracellular handling of 125I-TC-FSA is the degradation in the lysosomes.

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