Major glycoprotein of the human erythrocyte membrane: Evidence for an amphipathic molecular structure

Segrest, Jere P.; Kahane, Itzhak; Jackson, Richard L.; Marchesi, V.

doi:10.1016/s0003-9861(73)80019-0

Cited by 272 publications

(92 citation statements)

References 19 publications

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“…1 ranks in the top one-third of the list. Each is significantly more hydrophobic than the region of the MN-glycoprotein which presumably spans the red cell membrane [4][5][6].…”

Section: Resultsmentioning

confidence: 99%

“…For example, there is an insignificant binding of cholesteryl ester by the apoproteins of human HDL * in the absence of phospholipids. We have recently presented studies describing the probable location of phospholipid-binding site(s) in the MN-glycoprotein of the human red cell membrane [4][5][6] and of plasma lipoproteins [7][8][9][10][11][12]. Phospholipid-binding regions do not appear to be uniformly distributed along the length of the polypeptide chain [7][8][9][10][11]13] ; certain fragments of apoLP-Ala, apoLP-Gln-I and apoLP-Gln-II preferentially bind phospholipid as corn-* Abbreviations: VLDL, very low density lipoproteins; HDL, high density lipoproteins; apoprotein, a lipid-free protein component from a lipoprotein; apoLP-Ala and apoLP-Ser, two apoproteins from human VLDL, with carboxyl-terminal alanine and serine, respectively; apoLP-Gln-I (A-l), and apoLP-Gln-II (A-II), the two major apoproteins of human HDL, each with carboxyl-terminal glutamine.…”

Section: Introductionmentioning

confidence: 99%

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A molecular theory of lipid—protein interactions in the plasma lipoproteins

et al. 1974

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“…1 ranks in the top one-third of the list. Each is significantly more hydrophobic than the region of the MN-glycoprotein which presumably spans the red cell membrane [4][5][6].…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A molecular theory of lipid—protein interactions in the plasma lipoproteins

et al. 1974

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“…To check the extent of amylase removal and the effect of the procedure on other proteins of the content, the supernate of the glycogenamylase precipitate was lyophilized and the resulting 184 THE JOURNAL OF CELL BIOLOGY . VOLUME 64,1975 residue was resuspended in solutions appropriate for gel electrophoresis.…”

Section: Purification Of Amylase By the Alcoholic Glycogen-precipitatmentioning

confidence: 99%

“…194 THE JOURNAL OF CELL BIOLOGY -VOLUME 64,1975 NH,HCOs, desalted over a column of Biogel P-2, lyophilization and resuspension in water). The granule membranes were harvested and diluted fivefold with lysis medium.…”

Section: Lysis Of Secretion Granules and Subsequent Separation Of Gramentioning

confidence: 99%

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Secretion granules of the rabbit parotid gland. Isolation, subfractionation, and characterization of the membrane and content subfractions.

Castle¹,

Jamieson²,

Palade³

1975

The Journal of Cell Biology

104

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A fraction of secretion granules has been isolated from rabbit parotid by a procedure which was found to be especially effective in reducing contamination resulting from aggregation and/or cosedimentation of granules with other cell particulates. The fraction, representing 15% (on the average) of the total tissue amylase activity, was homogeneous as judged by electron microscopy and contaminated to exceedingly low levels by other cellular organelles as judged by marker enzymatic and chemical assays.Lysis of the granules was achieved by their gradual exposure to hypotonic NaHCOs, containing 0.5 mM EDTA. The content and the membranes separated by centrifugation of the granule lysate were characterized primarily by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis which indicated that the content was composed of a limited number of molecular weight classes of polypeptides of which three bands (having approximate mol wt 58,000, 33,000, and 12,000) could be considered major components. The gel profile of the membrane subfraction was characterized by 20-30 Coomassie brilliant blue-staining bands of which a single species of tool wt ~40,000 was the conspicuous major polypeptide.Two types of experiments employing gel electrophoretic analysis were carried out for identifying and assessing the extent of residual secretory protein adsorbed to purified granule membranes: (a) examination of staining and radioactivity profiles after mixing of radioactive secretion granule extract with nonradioactively labeled granule membranes and (b) comparison of gel profiles of secretion granule extract and granule membranes with those of unlysed secretion granules and secretory protein discharged from lobules in vitro or collected by cannulation of parotid ducts, the last two samples being considered physiologic secretory standards. The results indicated that the membranes were contaminated to a substantial degree by residual, poorly extractable secretory protein even though assays of membrane fractions for a typical secretory enzyme activity (amylase) indicated quite thorough separation of membranes and content. Hence, detailed examination of membrane subfractions for residual content species by gel electrophoresis points to the general utility and sensitivity of this technique as a means for accurately detecting a defined set of polypeptides occurring as contaminants in cellular fractions or organelle subfractions.The secretion granule in exocrine cells represents the intracellular storage compartment for protein destined for export. Within the exocrine cell the population of accumulated granules, which can occupy as much as half of the cellular volume, is located in the apical cytoplasm between the Golgi region, where granules originate (2,13,28,29,54,55), and the apical cell membrane, where the period of storage is terminated by release of the granule contents into the extracellular space by the process of exocytosis (57).In our previous studies (13) we undertook a characterization by autoradiography of the secre...

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