On the attachment of ribosomes to microsomal membranes

Sabatini, David D.; Tashiro, Yutaka; Palade, George E.

doi:10.1016/s0022-2836(66)80019-0

Cited by 297 publications

(111 citation statements)

References 26 publications

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“…A few residual particles can be seen on the outer surface of some vesicles, but they are much less numerous and smaller than in untreated microsomes. Our biochemical and morphological data are in full agreement with previous reports by Palade and Siekevitz (21) and Sabatini et al (22).…”

Section: Modification Of Microsomes By Treatment With Ppi or Ed Tasupporting

confidence: 93%

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Analytical Study of Microsomes and Isolated Subcellular Membranes From Rat Liver

Amar-Costesec

Wibo

Thinessempoux

et al. 1974

The Journal of Cell Biology

215

112

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lsopycnic equilibration and sedimentation rate studies of rat liver microsomes led previously to the assignment of microsomal constituents into group al (monoamine oxidase), group a2 (5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase and cholesterol), group a3 (galactosyltransferase), group b (NADH cytochrome ¢ reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b5 and P 450), and group c (glucose 6-phosphatase, esterase, nucleoside diphosphatase, 13-glucuronidase and glucuronyltransferase).Confirmation and extension of the assignment into groups has been obtained by studying the differential effect of the reagents digitonin, EDTA, and PPi. Digitonin specifically affected the equilibrium density only of the group a2 and (to a lesser extent) group a3, and not of groups b and c under conditions which preserved the structure-linked latency of nucleoside diphosphatase and galactosyltransferase. Within experimental error the rate of sedimentation of all microsomal constituents was unaffected. The morphological appearance under the electron microscope was indistinguishable from that of nondigitonin-treated microsomes, except that a few smooth membranes (< 10%) exhibited broken-looking profiles.Treatment of microsomes with EDTA or PPi detached a substantial part of RNA and released protein in excess over the amount accountable for by detachment of ribosome constituents. This detachment was confirmed by electron microscopy. EDTA and PPi decreased markedly the equilibrium density and the density dispersion of groups b and c, due mainly to the uncoating of rough

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Section: Modification Of Microsomes By Treatment With Ppi or Ed Tasupporting

confidence: 93%

“…membranes in vitro. This matter is already well documented for E D T A (22) and, to a lesser extent, for PPi (23). Our biochemical and morphological data agree satisfactorily with these reports.…”

Section: Action Of Edta and Ppi On Microsomal Componentssupporting

confidence: 92%

Analytical Study of Microsomes and Isolated Subcellular Membranes From Rat Liver

Amar-Costesec

Wibo

Thinessempoux

et al. 1974

The Journal of Cell Biology

215

112

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“…Electron micrographs of cells of castor bean endosperm have shown that the endoplasmic reticulum is richly endowed with ribosomes and is predominantly "rough" in character (29,42) . Studies on cell-free preparations from rat liver have shown that the controlled use of EDTA results in dissociation of the ribosomes from the membranes and further that the attachment can be maintained by appropriate concentrations of Mg++ (38) .…”

Section: Effect Of Mg++ On Sedimentation Behaviormentioning

confidence: 99%

Endoplasmic Reticulum as the Site of Lecithin Formation in Castor Bean Endosperm

Lord

Kagawa

Moore

et al. 1973

The Journal of Cell Biology

320

201

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The properties of a discrete membranous fraction isolated on sucrose gradients from castor bean endosperm have been examined . This fraction was previously shown to be the exclusive site of phosphorylcholine-glyceride transferase . The distribution of NADPH-cytochrome c reductase and antimycin insensitive NADH-cytochrome c reductase across the gradient followed closely that of the phosphorylcholine-glyceride transferase . This fraction also had NADH diaphorase activity and contained cytochromes b5 and P 450. On sucrose gradients containing 1 mM EDTA this fraction had a mean isopycnic density of 1 .12 g/cma and sedimented separately from the ribosomes ; electron micrographs showed that it was comprised of smooth membranes . When magnesium was included in the gradients to prevent the dissociation of membrane-bound ribosomes, the isopycnic density of the membrane fraction with its associated enzymes was increased to 1 .16 g/cma and under these conditions the electron micrographs showed that the membranes had the typical appearance of rough endoplasmic reticulum . Together these data show that the endoplasmic reticulum is the exclusive site of lecithin formation in the castor bean endosperm and establish a central role for this cytoplasmic component in the biogenesis of cell membranes .

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“…In such polysomes the large ribosomal subunit, which contains the nascent polypeptide chain, is specifically bound to the endoplasmic reticulum membrane, and the nascent chain passes through the membrane (18,(37)(38)(39).…”

Section: Proteins Synthesized By Intact Reticulocytesmentioning

confidence: 99%

Biosynthesis of Reticulocyte Membrane Proteins by Membrane-Free Polyribosomes

Lodish

1973

Proc. Natl. Acad. Sci. U.S.A.

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Intact rabbit reticulocyte cells synthesize two predominant species of membrane polypeptides; at least 10 reticulocyte membrane polypeptide species are not produced by the cells. Cell-free extracts of reticulocytes, free of any membranes or membrane-bound polyribosomes, synthesize large amounts of these two membrane polypeptides; one of these polypeptides appears to be modified, probably by loss of 20-40 amino acids, after it is incorporated into the membrane. Deprivation of hemin results in inhibition of synthesis by lysates of membrane proteins, globin, and all other cytoplasmic proteins.The protein composition of mammalian erythrocyte membrane is now fairly well established. There exist 7-9 main components (1-8); the major species include two polypeptides of molecular weight greater than 200,000 (4), a protein of molecular weight 100,000, and a sialoylgylcoprotein which contains the MN, A, and B blood-group activities (8). The latter two species are the only membrane proteins found on the cell surface (3, 9-12); they may also penetrate to the interior surface of the membrane (13-15). Little is known, however, about the biosynthesis of erythrocyte membrane proteins: the types of erythropoetic cells that synthesize each protein, the type of polysome (free or membrane-attached) that synthesizes the proteins, and the factors that regulate their synthesis.The reticulocyte is the penultimate cell in the erythropoetic series; it has no nucleus, and makes no RNA or DNA.About 90% of protein produced is a and ,3-globin chains (16,17). The protein composition of reticulocyte membranes is very similar to that of erythrocyte membranes (my unpublished observations). In this paper, I show that reticulocytes synthesize only 2 major and 2-3 minor membrane proteins; most of the membrane proteins are no longer being synthesized in significant amounts at this stage.In most mammalian cells a fraction of the polyribosomes are firmly attached to membranes; these are the site of synthesis of most, if not all, proteins that are eventually transported out of the cell, such as trypsinogen, chymotrypsinogen, albumin, and other serum proteins (18-22). It is not at all clear that this is the sole function of these polysomes.Burka has claimed that rabbit reticulocytes contain membrane-bound polyribosomes (23) that synthesize most of the nonglobin proteins made by the cell (24). By contrast, we showed recently that membrane-free reticulocyte polyribosomes will produce precisely the same globin and nonglobin proteins as does the intact cell (17). In this paper I show, using dodecyl sulfate-gel electrophoresis and peptide map-1526 ping procedures, that a membrane-free lysate makes large amounts of the two membrane polypeptides produced by the intact cell; one of these proteins appears to be modified, probably by removal of 20-40 amino acids when it is incorporated into the membrane. MATERIALS AND METHODSMaterials. Acetylphenylhydrazine was purchased from Sigma, and [35S]methionine (30,000 Ci/mol) from Amersham/Searle. Sources of all o...

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On the attachment of ribosomes to microsomal membranes

Cited by 297 publications

References 26 publications

Analytical Study of Microsomes and Isolated Subcellular Membranes From Rat Liver

Analytical Study of Microsomes and Isolated Subcellular Membranes From Rat Liver

Endoplasmic Reticulum as the Site of Lecithin Formation in Castor Bean Endosperm

Biosynthesis of Reticulocyte Membrane Proteins by Membrane-Free Polyribosomes

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