Mannose 6-phosphate receptor-dependent endocytosis of lysosomal enzymes is increased in sulfatide-storing kidney cells

2009 ◽  
Vol 390 (1) ◽  
Author(s):  
Diana Klein ◽  
Afshin Yaghootfam ◽  
Ullrich Matzner ◽  
Bettina Koch ◽  
Thomas Braulke ◽  
...  

Abstract Metachromatic leukodystrophy is a lysosomal disorder caused by the deficiency of arylsulfatase A (ASA). This leads to the storage of the sphingolipid 3-O-sulfogalactosylceramide (sulfatide) in various cell types, such as renal tubular cells. Examination of mannose 6-phosphate receptor (MPR300)-dependent endocytosis revealed that uptake of lysosomal enzymes is more than two-fold increased in sulfatide-storing kidney cells. Expression of MPR300 and its internalization rate is increased in these cells, whereas the recycling rate is decreased. Similar alterations can be found for the transferrin receptor, indicating that sulfatide storage leads to a general alteration of the endocytotic pathway. These data allow calculating that the endosomal pool from which receptors can recycle is 1.4- to 2-fold increased in lipid-storing cells. Immunocytochemistry demonstrates that the MPR300 in lipid-storing cells does not co-localize with accumulated sulfatide, suggesting that the kinetics of internalization and recycling appear to be altered indirectly.

1998 ◽  
Vol 334 (3) ◽  
pp. 547-551 ◽  
Author(s):  
David E. SLEAT ◽  
Istvan SOHAR ◽  
Premila S. PULLARKAT ◽  
Peter LOBEL ◽  
Raju K. PULLARKAT

Mannose 6-phosphate (Man-6-P) is a carbohydrate modification that is generated on newly synthesized lysosomal proteins. This modification is specifically recognized by two Man-6-P receptors that direct the vesicular transport of the lysosomal enzymes from the Golgi to a prelysosomal compartment. The Man-6-P is rapidly removed in the lysosome of most cell types; however, in neurons the Man-6-P modification persists. In this study we have examined the spectrum of Man-6-P-containing glycoproteins in brain specimens from patients with different neuronal ceroid lipofuscinoses (NCLs), which are progressive neurodegenerative disorders with established links to defects in lysosomal catabolism. We find characteristic alterations in the Man-6-P glycoproteins in specimens from late-infantile (LINCL), juvenile (JNCL) and adult (ANCL) patients. Man-6-P glycoproteins in LINCL patients were similar to controls, with the exception that the band corresponding to CLN2, a recently identified lysosomal enzyme whose deficiency results in this disease, was absent. In an ANCL patient, two Man-6-P glycoproteins were elevated in comparison with normal controls, suggesting that this disease also results from a perturbation in lysosomal hydrolysis. In JNCL, total levels of Man-6-P glycoproteins were 7-fold those of controls. In general this was reflected by increased lysosomal enzyme activities in JNCL but three Man-6-P glycoproteins were elevated to an even greater degree. These are CLN2 and the unidentified proteins that are also highly elevated in the ANCL.


2005 ◽  
Vol 289 (4) ◽  
pp. F742-F748 ◽  
Author(s):  
Masaru Watanabe ◽  
Masato Konishi ◽  
Ichiro Ohkido ◽  
Senya Matsufuji

To study the regulatory mechanisms of intracellular Mg2+ concentration ([Mg2+]i) in renal tubular cells as well as in other cell types, we established a mutant strain of mouse renal cortical tubular cells that can grow in culture media with very high extracellular Mg2+ concentrations ([Mg2+]o > 100 mM: 101Mg-tolerant cells). [Mg2+]i was measured with a fluorescent indicator furaptra (mag-fura 2) in wild-type and 101Mg-tolerant cells. The average level of [Mg2+]i in the 101Mg-tolerant cells was kept lower than that in the wild-type cells either at 51 mM or 1 mM [Mg2+]o. When [Mg2+]o was lowered from 51 to 1 mM, the decrease in [Mg2+]i was significantly faster in the 101Mg-tolerant cells than in the wild-type cells. These differences between the 101Mg-tolerant cells and the wild-type cells were abolished in the absence of extracellular Na+ or in the presence of imipramine, a known inhibitor of Na+/Mg2+ exchange. We conclude that Na+-dependent Mg2+ transport activity is enhanced in the 101Mg-tolerant cells. The enhanced Mg2+ extrusion may prevent [Mg2+]i increase to higher levels and may be responsible for the Mg2+ tolerance.


1979 ◽  
Vol 25 (6) ◽  
pp. 680-685 ◽  
Author(s):  
C. K. Ho ◽  
L. A. Babiuk

A Vero cell adapted Green strain of canine distemper virus (CDV) was tested for its plaque-forming capacity in different cell lines. Plaque formation was observed in HEp-2, BS-C-I, and HeLa cells but not in Vero or dog kidney cells even though replication and cytopathology were observed in the latter cell types. In the cells in which the virus was capable of producing plaques, the plaques were observed within 24 h post infection and continued to increase in size with subsequent cellular destruction such that by 72 h postinfection the size of the plaques approached 0.5 mm. With the use of the plaquing technique, it was possible to demonstrate the thermal lability of the virus as well as the kinetics of adsorption. Thus, it was shown that the half-life of the virus was 125 min at 25 °C, 75 min at 35 °C, and 65 min at 37 °C. The rate of adsorption of CDV to HEp-2 cells was 17.2% in 30 min at 37 °C and continued slowly for 4 h before completion. Application of this rapid plaque-forming assay to plaque-reduction tests for CDV antibody and for CDV-infected cells by the infectious center assay are described.


1967 ◽  
Vol 39 (4) ◽  
pp. 543-NP ◽  
Author(s):  
M. A. WILLIAMS ◽  
W. I. BABA

SUMMARY Microgram quantities of tritiated aldosterone or cortisol were injected into the aorta of rats. The kidneys were removed at various times after injection, and examined by light and electron microscope autoradiography. The mineralocorticoids or their metabolites were bound to kidney cells in amounts sufficient to give autoradiographs. Radioactivity occurred mainly in the proximal and distal convoluted tubules. Within these cells it was bound mainly to mitochondria and plasma membranes. The results are discussed in relation to the current theories of mineralocorticoid action.


1983 ◽  
Vol 97 (6) ◽  
pp. 1700-1706 ◽  
Author(s):  
D E Goldberg ◽  
C A Gabel ◽  
S Kornfeld

Phosphomannosyl residues present on lysosomal enzymes are specifically recognized by the mannose 6-phosphate receptor protein. This interaction results in the selective targeting of lysosomal enzymes to lysosomes. While this pathway is operative in many cell types, we have found four cultured cell lines that are deficient in the ability to bind lysosomal enzymes containing phosphomannosyl residues to their intracellular or surface membranes (Gabel, C., D. Goldberg, and S. Kornfeld, 1983, Proc. Natl. Acad. Sci. USA, 80:775-779). These cells appear to segregate lysosomal enzymes by an alternate intracellular pathway. To determine the basis for the lack of mannose 6-phosphate receptor activity in these cell lines, we studied the biosynthesis of the receptor in receptor-positive (BW5147) and receptor-deficient (P388D1 and MOPC 315) cells. The cells were labeled with [2-3H]mannose or [35S]methionine and the receptor was immunoprecipitated with an antireceptor antiserum. BW5147 cells synthesize a receptor protein whose size increases after translation/glycosylation. MOPC 315 cells produce an apparently normal receptor and degrade it rapidly. P388D1 cells fail to synthesize any detectable receptor. The receptor from BW5147 and MOPC 315 cells is a glycoprotein with both high mannose and complex asparagine-linked oligosaccharides. The complex-type units become fully sialylated and remain so during long periods of chase.


2002 ◽  
Vol 21 (8) ◽  
pp. 457-462 ◽  
Author(s):  
B-P Jiann ◽  
K-J Chou ◽  
H-T Chang ◽  
W-C Chen ◽  
J-K Huang ◽  
...  

The effects of the environmental toxicant, triethyltin, on Ca2 + mobilization in Madin–Darby canine kidney (MDCK) cells have been examined. Triethyltin induced an increase in cytosolic free Ca2 + levels ([Ca2 +]i) at concentrations larger than 2 mM in a concentrationdependent manner. Within 5 min, the [Ca2 +]i signal was composed of a gradual rise and a sustained phase. The [Ca2 +]i signal was partly reduced by removing extracellular Ca2 +. In Ca2 +-free medium, pretreatment with thapsigargin (1 mM), an endoplasmic reticulum Ca2 + pump inhibitor, reduced 50 mM triethyltin-induced [Ca2 +]i increase by 80%. Conversely, pretreatment with triethyltin abolished thapsigargin-induced Ca2 + release. Pretreatment with U73122 (2 mM) to inhibit phospholipase C-coupled inositol 1,4,5-trisphosphate formations failed to alter 50 mM triethyltin-induced Ca2 + release. Incubation with triethyltin at a concentration (1 mM) that did not increase basal [Ca2 +]i for 3 min did not alter ATP (10 mM)and bradykinin (1 mM)-induced [Ca2 +]i increases. Collectively, this study shows that triethyltin altered Ca2 + movement in renal tubular cells by releasing Ca2 + from multiple stores in an inositol 1,4,5-trisphosphate-independent manner, and by inducing Ca2 + influx.


1982 ◽  
Vol 95 (2) ◽  
pp. 536-542 ◽  
Author(s):  
CA Gabel ◽  
DE Goldberg ◽  
S Kornfeld

Phosphomannosyl residues on lysosomal enzymes serve as an essential component of the recognition marker necessary for binding to the mannose 6-phosphate (Man 6-P) receptor and translocation to lysosomes. The high mannose-type oligosaccharide units of lysosomal enzymes are phosphorylated by the following mechanism: N-acetylglucosamine 1-phosphate is transferred to the 6 position of a mannose residue to form a phosphodiester; then N- acetylglucosamine is removed to expose a phosphomonoester. We examined the kinetics of this phosphorylation pathway in the murine lymphoma BW5147.3 cell line to determine the state of oligosaccharide phosphorylation at the time the newly synthesized lysosomal enzymes bind to the receptor. Cells were labeled with [2-(3)H]mannose for 20 min and then chased for various times up to 4 h. The binding of newly synthesized glycoproteins to the Man 6-P receptor was followed by eluting the bound ligand with Man 6-P. Receptor-bound material was first detected at 30 min of chase and reached a maximum at 60 min of chase, at which time approximately 10 percent of the total phosphorylated oligosaccharides were associated with the receptor. During longer chase times, the total quantity of cellular phosphorylated oligosaccharides decreased with a half-time of 1.4 h, suggesting that the lysosomal enzymes had reached their destination and had been dephosphorylated. The structures of the phosphorylated aligosaccharides of the eluted ligand were then determined and compared with the phosphorylated oligosaccharides of molecules which were not bond to the receptor. The major phosphorylated oligosaccharide species present in the nonreceptor-bound material contained a single phosphosphodiester at all time examined. In contrast, receptor-bound oligosaccharides were greatly enriched in species possessing one and two phosphomonoesters. These results indicate that binding of newly synthesized lysosomal enzymes to the Man 6-P receptor occurs only after removal of the covering N- acetylglucosamine residues.


1988 ◽  
Vol 255 (4) ◽  
pp. F574-F580
Author(s):  
H. F. Cantiello ◽  
E. Chen ◽  
S. Ray ◽  
G. T. Haupert

Bovine hypothalamus contains a high affinity, specific, reversible inhibitor of mammalian Na+-K+-ATPase. Kinetic analysis using isolated membrane fractions showed binding and dissociation rates of the hypothalamic factor (HF) to be (like ouabain) relatively long (off rate = 60 min). To determine whether the kinetics of inhibition in intact cells might be more consistent with regulation of physiological processes in vivo, binding and dissociation reactions of HF in intact renal epithelial cells (LLC-PK1) were studied using 86Rb+ uptake and [3H]ouabain binding. As with membranes, a 60-min incubation with HF inhibited Na+-K+-ATPase in LLC-PK1 cells. In contrast to membrane studies, no prolonged incubation with LLC-PK1 was needed to observe inhibition of Na+-K+-ATPase. HF caused a 33% inhibition of ouabain-sensitive 86Rb+ influx within 10 min. Incubation of cells with HF followed by washout showed rapid reversal of pump inhibition and a doubling of pump activity. The dose-response curve for HF inhibition of LLC-PK1 86Rb+ uptake showed a sigmoidal shape consistent with an allosteric binding reaction. Thus HF is a potent regulator of Na+-K+-ATPase activity in intact renal cells, with binding and dissociation reactions consistent with relevant physiological processes.


Sign in / Sign up

Export Citation Format

Share Document