The distribution of protein-bound carbohydrates in submicrosomal fractions from rat liver

Helgeland, L.; Christensen, Terje; Janson, T.L.

doi:10.1016/0304-4165(72)90088-8

Cited by 31 publications

(7 citation statements)

References 31 publications

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“…Our conclusion is consistent with the demonstration made by using iodinated lectins that, in the liver endoplasmic reticulum, membrane glycoproteins do not have the terminal trisaccharide : N-acetylglucosamine-galactose-sialic acid (32) . It is at variance with the reports of others describing sialoglycoprotein as a genuine constituent of the endoplasmic reticulum (5,7,12,19,23,28) . However, this latter conclusion is based upon the biochemical properties of microsomal fractions in which the vesicles derived from the endoplasmic reticulum were probably contaminated by sialoglycoprotein-rich components .…”

Section: Discussioncontrasting

confidence: 54%

“…Several publications have reported that protein-bound sialic acid (sialoglycoprotein) is not confmed to the pericellular membrane but also occurs within the cell, in the nuclear membrane (21,22,26), mitochondria (13,14,35), lysosomal membrane (20), Golgi complex (5,23), endoplasmic reticulum (5,7,19,24,28), and cytosol (7) (see also reference 41 for a review) . However, in most of these publications it has not been unequivocally established that sialoglycoprotein belongs to the main cell component of the preparation analyzed rather than to a sialoglycoprotein-rich contaminant, for instance the plasma membrane .…”

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confidence: 99%

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Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

Amar-Costesec¹

1981

The Journal of Cell Biology

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Detailed investigations by quantitative centrifugal fractionation were conducted to determine the subcellular distribution of protein-bound sialic acid in rat liver. Homogenates obtained from perfused livers were fractionated by differential centrifugation into nuclear fraction, large granules, microsomes, and final supernate fraction, or were used to isolate membrane preparations enriched in either plasma membranes or Golgi complex elements . Large granule fractions, microsome fractions, and plasma membrane preparations were subfractionated by density equilibration in linear gradients of sucrose . In some experiments, microsomes or plasma membrane preparations were treated with digitonin before isopycnic centrifugation to better distinguish subcellular elements related to the plasma membrane or the Golgi complex from the other cell components ; in other experiments, large granule fractions were obtained from Triton WR-1339-loaded livers, which effectively resolve lysosomes from mitochondria and peroxisomes in density gradient analysis . Protein-bound sialic acid and marker enzymes were assayed in the various subcellular fractions. The distributions obtained show that sialoglycoprotein is restricted to some particular domains of the cell, which include the plasma membrane, phagolysosomes, and possibly the Golgi complex. Although sialoglycoprotein is largely recovered in the microsome fraction, it has not been detected in the endoplasmic reticulum-derived elements of this subcellular fraction . In addition, it has not been detected either in mitochondria or in peroxisomes. Because the sialyltransferase activities are associated with the Golgi complex, the cytoplasm appears compartmentalized into components which biogenetically involve the Golgi apparatus and components which do not.Sialic acid is found within rat liver cells mainly as the terminal sugar of the saccharide chains of glycoproteins and glycolipids. These constituents are abundant at the cell surface, with their sugar residues externally disposed (45) .Several publications have reported that protein-bound sialic acid (sialoglycoprotein) is not confmed to the pericellular membrane but also occurs within the cell, in the nuclear membrane (21, 22, 26), mitochondria (13, 14, 35), lysosomal membrane (20), Golgi complex (5, 23), endoplasmic reticulum (5,7,19,24,28), and cytosol (7) (see also reference 41 for a review) . However, in most of these publications it has not been unequivocally established that sialoglycoprotein belongs to the main cell component of the preparation analyzed rather than to a sialoglycoprotein-rich contaminant, for instance the plasma membrane . Whether sialoglycoproteins are confmed to the cell surface or also occur in cell organelles raises key questions concerning both their function and their route of biosynthesis . It is generally accepted that after passage through the Golgi complex, which is the sole subcellular organelle unambiguously established as being endowed with sialyltransferase activities (33, 43), glycoprot...

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Section: Discussioncontrasting

confidence: 54%

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confidence: 99%

Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

Amar-Costesec¹

1981

The Journal of Cell Biology

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“…6 , adult) is similar to some of these findings (38)(39)(40)(41) in that the membrane proteins cover the range of molecular weight from -15,000 to over 100,000. Except for a larger amount of material in the ribosomal protein region, the patterns obtained from rough microsomes were nearly identical to those obtained from smooth microsomes, confirming earlier work (32,33,(42)(43)(44) on the protein* (and enzymatic) identity of these two membranes; differing results (37,38) can be ascribed to cross-contamination of the preparations (cf. 33).…”

Section: Electrophoresis Of Membrane Proteins On Sds Gelssupporting

confidence: 89%

“…There has been much work on the electrophoresis of solubilized ER membrane proteins from various sources, using either urea (35) or SDS (32,(36)(37)(38)(39)(40)(41)(42) electrophoresis. Our electrophoretic pattern (cf.…”

Section: Electrophoresis Of Membrane Proteins On Sds Gelsmentioning

confidence: 99%

The differentiation of rat liver endoplasmic reticulum membranes: Apo–cytochrome P₄₅₀ as a membrane protein

Siekevitz

1973

J Supramol Struct

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The proteins of washed microsomal membranes from adult rat liver were solubilized by 2% SDS and electrophoresed o n polyacrylamide gels. Confirming earlier reports, a large Coomassie-Blue staining band in the -50,000 MW region was identified as cytochrome P450 by four criteria: similar electrophoretic mobility to a purified cytochrome P,,, preparation, an increase in this band after in vivo phenobarbital administration, a decrease in this band after in vivo allylisopropylacetamide administration, and direct specific binding of added purified heme to this region of a washed, unfixed gel. Although cyt P450 is not spectrally evident until just at the time of birth of the rats, a large band in this region was detectable in gels of microsoma1 membrane protein at all times, from three days before birth onward; this band also bound added heme after membrane proteins from fetal rat liver microsomes were electrophoresed on the gels. The conclusion was that apo-cyt P450 is present in microsomal membranes at these times during differentiation, and that, regarding this protein, during differentiation heme is bound t o the apo-protein already there, concomitant with a synthesis of more cyt P,, molecules. The process of differentiation of this membrane type is also discussed.

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“…T o obtain results directly pertinent to the membrane phospholipids, the rough microsomal and Golgi-rich fractions have been sonicated to release intravesicular contents which are functionally and chemically different from the membrane (16)(17)(18)(19). Contamination of each membrane fraction has been minimized and characterized by assays for marker enzymes and by morphometric analysis with the electron microscope.…”

Section: Introduction Materials and Methodsmentioning

confidence: 99%

Incorporation in vivo of [³²P]orthophosphate and [Me-³H]choline into rough microsomal, Golgi, and plasma membranes of rat liver

Chang¹,

Riordan²,

Moscarello³

et al. 1977

Can. J. Biochem.

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Sturgess, J. M. (1977) Incorporation in vivo of [32P]orthophosphate and [Me-3H]choline into rough microsomal, Golgi, and plasma membranes of rat liver. Clin. J. Biochem. 55,876-885T o study membrane biogenesis and t o test the validity of the endomembrane flow hypothesis, incorporation of 32P and [Me-3H]choline in vivo into membranes of the rat liver was followed. Rough microsomal, Golgi-rich, and plasma membrane fractions were monitored with marker enzyme assays and shown with morphometric analysis t o contain 82% rough microsomes, at least 70% Golgi complexes, and 88% plasma membranes, respectively. Membrane subfractions from the rough microsomal and Golgi-rich fractions were prepared by sonic disruption.At 5 t o 30 min after 32P injection, the specific radioactivity of phosphatidylcholine was higher in the rough microsomal membranes than in the Golgi membranes. From 1 to 3 h , the specific activity of phosphatidylcholine in Golgi membranes became higher and reached the maximum at about 3 h. Although the plasma membrane had the lowest specific radioactivity throughout 0.25-3 h, it increased rapidly thereafter t o attain the highest specific activity at 5 h. Both rough microsomal and plasma membranes reached their maxima at 5 h.The specific radioactivity of [32P]phosphatidylethanolamine in the three membrane fractions was similar t o that of [32Plphosphatidylcholine except from 5 to 30 min, when the specific radioactivity of phosphatidylethanolamine in the Golgi membranes was similar t o the rough microsomal membranes.At 15 min t o 5 h after [Me-3H]choline injection, more than 90% of the radioactivity in all the membranes was acid-precipitable. The specific radioactivities of the acid-precipitated membranes, expressed as dpm per milligram protein, reached the maximum at 3 h. After [Me-3H]choline injection, the specific radioactivity of phosphatidylcholine separated from the lipid extract of the acid-precipitated membranes (dpm per micromole phosphorus) did not differ significantly in the three membrane fractions. The results indicated rapid incorporation of choline into membrane phosphatidylcholine by the rough endoplasmic reticulum, Golgi, and plasma membranes simultaneously.The data with both 32P and [Me-3H]choline precursors did not support the endomembrane flow hypothesis. The Golgi complexes apparently synthesized phosphatidylethanolamine and incorporated choline into phosphatidylcholine as well a s the endoplasmic reticulum. The results are discussed with relevance t o current hypotheses on the biogenesis and transfer of membrane phospholipids. Chang, P. L., Riordan, J. R., Moscarello, M. A. & Sturgess, J. M. (1977) Incorporation in vivo of [32P]orthophosphate and [Me-3H]choline into rough microsomal, Golgi, and plasma membranes of rat liver. Can. J. Biochem. 55.876-885 Dans le but d'etudier la biogenese des membranes et d e verifier la validite d e l'hypothese du mouvement endomembranaire, nous avons suivi l'incorporation in vivo du 32P et de la [Me-3H]choline dans les membranes du foie de rat. Nous avons...

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The distribution of protein-bound carbohydrates in submicrosomal fractions from rat liver

Cited by 31 publications

References 31 publications

Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

The differentiation of rat liver endoplasmic reticulum membranes: Apo–cytochrome P₄₅₀ as a membrane protein

Incorporation in vivo of [³²P]orthophosphate and [Me-³H]choline into rough microsomal, Golgi, and plasma membranes of rat liver

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The distribution of protein-bound carbohydrates in submicrosomal fractions from rat liver

Cited by 31 publications

References 31 publications

Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

Analytical study of microsomes and isolated subcellular membranes from rat liver. VII. Distribution of protein-bound sialic acid.

The differentiation of rat liver endoplasmic reticulum membranes: Apo–cytochrome P450 as a membrane protein

Incorporation in vivo of [32P]orthophosphate and [Me-3H]choline into rough microsomal, Golgi, and plasma membranes of rat liver

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The differentiation of rat liver endoplasmic reticulum membranes: Apo–cytochrome P₄₅₀ as a membrane protein

Incorporation in vivo of [³²P]orthophosphate and [Me-³H]choline into rough microsomal, Golgi, and plasma membranes of rat liver