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Stuart H. Yuspa, Henry Hennings, Ulrike Lichti
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 245-257; https://doi.org/10.1002/jsscb.380170306

Abstract:
Mouse epidermal basal cells can be selectively cultivated in medium with a calcium concentration of 0.02–0.09 mM. Terminal differentiation and slouching of mature kcratinocytes occur when the calcium concentration is increased to 1.2–1.4 mM. When basal cell cultures are exposed to chemical initiators of carcinogenesis, colonies of cells that resist calcium‐induced differentiation evolve. Likewise, basal cells derived from mouse skin initiated in vivo yield foci that resist terminal differentiation. This defect in the commitment to terminal differentiation appears to be an essential change in initiated cells in skin and is also characteristic of malignant epidermal cells. This model system has also provided a means to determine if basal cells are more responsive to phorbol esters than other cells in epidermis and to explore the possibility that heterogeneity of response exists within subpopulations of basal cells. The induction of the enzyme ornithine decarboxylase (ODC) was used as a marker for responsiveness to phorbol esters. ODC induction after exposure to 12‐0‐tetradccanoylphorbol‐13‐acetate (TPA) in basal cells is enhanced 20‐fold over the response of a culture population containing both differentiating and basal cells. When basal cells are induced to differentiate by increased calcium, responsiveness to TPA is lost within several hours. In basal cell cultures, two ODC responses can be distinguished. After exposure to low concentrations of TPA or to weak promoters of the phorbol ester series, ODC activity is maximal at 3 hr. With higher concentrations of TPA, the ODC maximum is at 9 hr. These results arc consistent with the presence of subpopulations of basal cells with differing sensitivities to TPA. Other studies that use the enzyme epidermal transglutaminase as a marker for differentiation support this conclusion. In basal cell culture TPA exposure rapidly increases transglutaminase activity and cornified envelope development, reflecting induced differentiation in some cells. As differentiated cells arc sloughed from the dish, the remaining basal cells proliferate and become resitant to induced differentiation by 1.2 m M calcium. These data provide additional evidence of basal cell heterogeneity in which TPA induces one subpopulation to differentiate while another is stimulated to proliferate and resists a differentiation signal. Tumor promoters, by their ability to produce heterogeneous responses with regard to terminal differentiation and proliferation, would cause redistribution of subpopulations of epidermal cells in skin. Cells that resist signals for terminal differentiation, such as initiated cell, would be expected to increase in number during remodeling. Clonal expansion of the intitiated population could result in a benign tumor with an altered program of differentiation. In skin, benign tumors are the principal product of 2‐stage carcinogenesis. Subsequent progression to malignancy may involve an additional step, probably a genetic alteration, that is independent of the tumor promoter.
George J. Todaro, Joseph E. De Larco, Charlotte Fryling, Patricia A. Johnson, Michael B. Sporn
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 287-301; https://doi.org/10.1002/jsscb.1981.380150306

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Thérèse M. Coquerelle, Karl F. Weibezahn
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 369-376; https://doi.org/10.1002/jsscb.380170408

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A. Christie King, Pedro Cuatrecasas
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 377-387; https://doi.org/10.1002/jsscb.380170409

Abstract:
Epidermal growth factor is internalized into cells and concomitantly induces a massive clearance of up to 90% of its total surface receptors. The hormone‐receptor complex is delivered to lysosomes and degraded or inactivated. Lysosomotropic alkylamines block the degradation but not the binding‐or internalization of ligand‐receptor complexes and thus their presence results in a marked potentiation of intracellular accumulation of epidermal growth factor. We have used these alkylamines as pharmacological tools to trap internalized 125I‐labeled epidermal growth factor and now report that the residual population of epidermal growth factor receptors remaining on human fibroblasts after completion of the receptor clearance process is not only accessible for ligand binding but also directs the continued internalization and degradation of this growth factor over prolonged periods of time. We also show that down regulation of epidermal growth factor receptors does not result in desensitization of cells to the mitogenic response.
Dov Zipori
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 347-357; https://doi.org/10.1002/jsscb.380170406

Abstract:
Adherent stromal cells from mouse bone marrow inhibited the formation of granulocyte/monocyte (G/M) colonies induced in vitro by colony‐stimulating factor (CSF), This inhibition occurred both when crude conditioned media obtained from various sources were used to induce colony formation or when a pure CSF preparation from mouse lung origin was tested. The inhibition did not appear to be toxic in nature since despite the lack of colony formation, progenitor CFU‐C proliferated in the presence of stromal cells. Medium conditioned by adherent stromal cells was devoid of inhibitory activity when incorporated into the culture medium used for G/M colony formation, indicating that the inhibitory activity may not be present in a soluble form. Inhibitors of prostaglandins did not affect G/M colony formation. In contrast, D‐glucose and a number of other free monosaccharides but not pyruvate lactate or glycerol induced formation fo myeloid colonies in the presence of stromal cells. This did not require addition of exogenous CSF. Released factors concentrated from serum‐free medium conditioned by stromal cells exhibited colony‐stimulating activity provided that the medium contained a high glucose concentration during incubation. It is proposed that stromal cells produce a resident CSF that, in contrast to exogenous CSF species, is capable of inducing myelopoiesis within the bone marrow stroma.
Blair T. Atherton, Deena M. Taylor, Richard O. Hynes
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 153-161; https://doi.org/10.1002/jsscb.380170206

Abstract:
The reactivity of six monoclonal antibodies with fragments of fibronectin produced with trypsin, chymotrypsin, and Staphylococcus aureus V8 protease is described. All these antibodies reacted with fragments derived from the C‐terminal one‐third of fibronectin. This region probably contains sites for the binding of fibronectin to cells, and to heparin and may also contain active sites for the reattachment, spreading, and alignment of transformed cells. Analysis of the reactivities of different sets of proteolytic fragments with the antibodies and with other ligands (eg. heparin) allows one to determine overlaps between the fragments and to locate the positions of the different binding sites for antibodies and ligands. One of the antibodies has allowed us to identify a site of structural difference between cellular and plasma fibronectins from hamsters. The site recognized by this antibody is located near to, but not at, the C‐terminal end and docs not involve carbohydrate groups. Because of its internal location in fibronectin, this difference suggests that there are probably different genes for cellular and plasma fibronectin. These monoclonal antibodies should be useful for further probing the functions present in the C‐terminal regions of fibronectin and for determining their locations.
Steven K. Akiyama, , Masao Hayashi
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 345-358; https://doi.org/10.1002/jsscb.1981.380160405

Abstract:
Fibronectin is a large, adhesive glycoprotein which is found in a number of locations, most notably on cell surfaces, in extracellular matrixes, and in blood. Fibronectin has been detected in all vertebrates tested and in many invertebrates. Its presence in sponges is significant because this suggests that fibronectin may have appeared very early in evolution, possibly with the most primitive multicellular organisms. Cellular and plasma fibronectins have many striking similarities. However, the locations of the polypcptide chain differences between these two proteins indicate that plasma fibronectin cannot be derived from cellular fibronectin by means of simple post‐translational proteolysis. Instead, these different types of fibronectin may be products of different genes or of differentially spliced messenger RNA molecules. Amniotic fluid fibronectin is possibly a third form of the protein. Cellular and plasma fibronectins are composed of at least six protcaseresistant domains which contain specific binding sites for actin, gelatin, heparin, Staphylococcus aureus, transglutarninase, fibrin, DNA, and a cell surface receptor. The relative locations of these domains have been mapped in the primary structure of fibronectin. The cell surface receptor for fibronectin has not been positively identified, but may be a glycoprotein, a glycolipid, or a complex of the two. Although cell‐substratum adhesion is mediated by fibronectin, the locations of the areas of closest approach of the cell to the substratum (the adhesion plaques) and fibronectin are not coincident under conditions of active cell growth. Under conditions of cell growth arrest in low scrum concentrations, some fibronectin may become localized at the adhesion plaques. Models describing the domain structure of fibronectin and the molecular organization of the adhesion plaque area are presented.
Samuel H. Barondes, , Wayne R. Springer, Douglas N. Cooper
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 233-242; https://doi.org/10.1002/jsscb.1981.380160304

Abstract:
Endogenous lectins in both cellular slime molds and chicken tissues have been localized primarily intracellularly, in contrast with the predominantly extracellular localization of the glycoproteins, glycolipids, and glycosaminoglycans with which they might interact. Here we present evidence that lectins in both of these organisms may be externalized and become associated with the cell surface and/or extracellular materials. In chicken intestine, chicken‐lactose‐lectin‐II is shown to be localized in the secretory granules of the goblet cells, along with mucin, and to be secreted onto the intestinal surface. In embryonic muscle, chicken‐lactose‐lectin‐I is shown to be externalized with differentiation, ultimately becoming localized on the surface of myotubes and in the extracellular spaces. In a cellular slime mold, Dictyostelium purpureum, externalization of lectin is elicited by either polyvalent glycoproteins that bind the small amount of endogenous cell surface lectin, or by slime mold or plant lectins that bind unoccupied complementary cell surface oligosaccharides. These results suggest that externalization of endogenous lectin may be a response to specific external signals. We conclude that lectins are frequently held in intracellular reserves awaiting release for specific external functions.
Matthew M. Rechler, S. Peter Nissley, George L. King, Alan C. Moses, Ellen E. Van Obberghen-Schilling, Joyce A. Romanus, Alfred B. Knight, Patricia A. Short, Robert M. White
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 253-286; https://doi.org/10.1002/jsscb.1981.380150305

Abstract:
The properties of multiplication stimulating activity (MSA), an insulin‐like growth factor (somatomedin) purified from culture medium conditioned by the BRL 3A rat liver cell line are summarized. The relationship of MSA to somatomedins purified from human and rat plasma are considered. MSA appears to be the predominant somatomedin in fetal rat serum, but a minor component ot adult rat somatomedin. In vitro biological effects of MSA and insulin in adipocytes, fibroblasts and chondrocytes are examined to determine whether they are mediated by insulin receptors or insulin‐like growth factor receptors. The possible relationship of a primary defect of insulin receptors observed in fibroblasts from a patient with the rare genetic disorder, leprechaunism, to intrauterine growth retardation is discussed.
Daniel J. Knauer, Fred W. Wagner, Gary L. Smith
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 177-191; https://doi.org/10.1002/jsscb.1981.380150209

Abstract:
The rat liver cell line, BRL‐3A, is known to produce a family of polypeptides referred to as multiplication‐stimulating‐activity (MSA). Serum‐free conditioned medium from this cell line is a rich source for the purification of these somatomedin‐like molecules. Somatomedins in serum, as well as MSA produced by BRL‐3A cells in culture, exist primarily as a high molecular weight complex bound to specific carrier proteins. This study describes the purification of the MSA carrier protein (MCP) from conditioned medium using affinity chromatographic procedures. The purified carrier protein is shown to specifically bind labeled MSA and generates a complex with an apparent molecular weight of 60,000–70,000 daltons. Characterization of the carrier protein indicates that it consists of two different noncovalently linked protein chains with apparent molecular weights of 30,000 and 31,500 daltons. The availability of a pure carrier protein should provide a unique opportunity to investigate the functional significance of the carrier protein in the biological activity of the somatomedins.
Tatsuro Irimura, Garth L. Nicolson
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 325-336; https://doi.org/10.1002/jsscb.380170404

Abstract:
The role of glycoconjugates in cell surface and blood‐borne implantation properties of murine metastatic melanoma sublines of low (B16‐F1) or high (B 16‐F10) potential to colonize lungs was investigated by treating melanoma cells with the antibiotic tunicamycin. This drug prevents glycosylation of glycoproteins by inhibiting the formation of lipid‐linked oligosaccharide precursors. The degree of tunicamycin‐mediated modifications in glycoproteins was assessed by monitoring the decrease in cell surface sialogalactoproteins by binding of 125I‐labeled Ricinus communis agglutinin I. Scanning electron microscopy of tunicamycin‐treated B16‐F1 and B16‐F10 cells showed morphologic changes such as cell rounding and formation of numerous surface blebs. Tunicamycin‐treated B16‐F1 and B16‐F10 cells lost their lung colonization abilities when injected intravenously into C57BL/6 mice, concomitant with lowered rates of adhesion to endothelial cell monolayers, endothelial extracellular matrix (basal lamina), and polyvinyl‐immobilized fibronectin in vitro, suggesting that this drug inhibits experimental metastasis by modifying the surface glycoproteins involved in determining the adhesive properties of malignant cells.
Judith Lahav, Richard O. Hynes
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 299-311; https://doi.org/10.1002/jsscb.380170402

Abstract:
The proteins fibronectin (FN), Von Willebrand factor (VWF), and fibrinogen are believed to play a role in platelet function. They arc distributed between the plasma and the platelet pool in the resting state and undergo redistribution upon platelet activation. We have studied their expression on the surface of the platelet and their mobilization following platelet binding to substrata. For the purpose of studying protein expression on the surface of intact platelets either adherent to a substratum or in suspension, the enzyme‐linked immunosorbent assay (ELISA) was elaborated and modified. Using this technique as well as immunofluorescence, we found that antiserum raised against carefully washed human platelets recognized FN, VWF, and fibrinogen as well as platelet surfaces. However, specific antisera against these three proteins failed to bind to the surface of unactivated gel‐filtered platelets. When gel‐filtered platelets were exposed to plastic or fibrillar collagen, they adhered and spread. Such platelets did bind antibodies against FN, VWF, and fibrinogen, Moreover, when the adherent platelets were incubated with FN or with VWF in the absence of ristocetin, they bound these proteins in a concentration‐dependent fashion. The patterns of the bound proteins were not similar, suggesting a different spatial distribution of binding sites. These findings indicate that platelet activation by adhesion to substrata mobilize both endogenous and exogenous pools of these proteins, thereby making them surface associated and probable participants in further binding properties of the activated platelet.
C. Lagenaur, M. Schachner
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 335-346; https://doi.org/10.1002/jsscb.1981.380150404

Abstract:
A monoclonal antibody designated M2 arose from the fusion of mouse myeloma cells with splenocytes from a rat immunized with particulate fraction from early postnatal mouse cerebellum. Expression of M2 antigen was examined by indirect immunofluorescence on frozen sections of developing and adult mouse cerebellum and on monolayer cultures of early postnatal mouse cerebellar cells. In adult cerebellum, M2 staining outlines the cell bodies of granule and Purkinje cells. A weaker, more diffuse staining is seen in the molecular layer and white matter. In sections of newborn cerebellum, M2 antigen is weakly detectable surrounding cells of the external granular layer and Purkinje cells. The expression of M2 antigen increases during development in both cell types, reaching adult levels by postnatal day 14. At all stages of postnatal cerebellar development, granule cells that have completed migration to the internal granule layer are more heavily stained by M2 antibodies than are those before and in process of migration. In monolayer cultures, M2 antigen is detected on the cell surface of all GFA protein-positive astrocytes and on more immature oligodendrocytes that express 04 antigen but not 01 antigen. After 3 days in culture, tetanus toxin positive neurons begin to express M2 antigen. The same delayed expression of M2 antigen on neurons is observed in cultures derived from mice ranging in age from postnatal day 0 to 10.
Umbert A. Urch, Jerry L. Hedrick
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 111-117; https://doi.org/10.1002/jsscb.1981.380150202

The publisher has not yet granted permission to display this abstract.
Edward J. O'Keefe, Teresa K. Battin, Vann Bennett
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 15-27; https://doi.org/10.1002/jsscb.1981.380150103

Abstract:
Microsomal membranes from human placenta, which bind 5–20 pmol of 125I-epidermal growth factor (EGF) per mg protein, have been affinity-labeled with 125I-EGF either spontaneously or with dimethylsuberimidate. Coomassie blue staining patterns on SDS polyacrylamide gels are minimally altered, and the EGF-receptor complex appears as a specifically labeled band of 180,000 daltons which is not removed by urea, neutral buffers, or chaotropic salts but is partially extracted by mild detergents. Limited proteolysis by alpha chymotrypsin and several other serine proteases yields labeled fragments of 170,000, 130,000, 85,000, and 48,000 daltons. More facile cleavage by papain or bromelain rapidly degrades the hormone-receptor complex to smaller labeled fragments of about 35,000 and 25,000 daltons. These fragments retain the binding site for EGF, are capable of binding EGF, and remain associated with the membrane. Alpha chymotryptic digestion of receptor solubilized by detergents yields the same fragments obtained with intact vesicles, suggesting that the fragments may represent intrinsic proteolytic domains of the receptor.
Jon S. Morrow, Wallace B. Haigh, Vincent T. Marchesi
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 275-287; https://doi.org/10.1002/jsscb.380170308

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Zoltan A. Tokes, Sandra J. Gendler, Gerald B. Dermer
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 69-77; https://doi.org/10.1002/jsscb.380170108

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Frank B. Dazzo, Estelle M. Hrabak
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 133-138; https://doi.org/10.1002/jsscb.1981.380160204

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, Patrick Machy, Lee D. Leserman
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 243-258; https://doi.org/10.1002/jsscb.1981.380160305

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Steven H. Herrmann, Matthew F. Mescher
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 121-131; https://doi.org/10.1002/jsscb.1981.380160203

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Marie M. Roberson, Howard Ceri, Paula J. Shadle, Samuel H. Barondes
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 395-402; https://doi.org/10.1002/jsscb.1981.380150409

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Terry W. Moody, Duncan P. Taylor, Candace B. Pert
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 153-159; https://doi.org/10.1002/jsscb.1981.380150206

Abstract:
The effect of nucleotides on central nervous system neuropeptide receptor binding was investigated. The guanine nucleotides, guanosine-5′-triphosphate and guanylyl-5′-imidodiphosphate, significantly inhibited the binding of radiolabeled vasoactive intestinal polypeptide but not that of [Tyr4]bombesin to rat brain membranes. Vasoactive intestinal polypeptide binding was inhibited by guanine nucleotides in a dose-dependent manner. Using a 20 μM dose, 60% of the specific vasoactive intestinal polypeptide binding was inhibited by guanylyl-5′-imidodiphosphate, which was more potent than guanosine-5′-triphosphate, whereas other nucleotides were not effective. This reduction in binding was a consequence of lower affinity of the receptor for vasoactive intestinal polypeptide, which in turn resulted from an increased rate of dissociation.
James L. Sims, Sosamma J. Berger, Nathan A. Berger
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 281-288; https://doi.org/10.1002/jsscb.1981.380160308

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Jerry W. Shay, Gay Lorkowski, Mike A. Clark
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 75-82; https://doi.org/10.1002/jsscb.1981.380160107

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Mojtaba Esfahani, Elise M. Kucirka, Frank X. Timmons, Somdev Tyagi, Arthur E. Lord Jr., Susan A. Henry
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 119-128; https://doi.org/10.1002/jsscb.1981.380150203

Abstract:
The growth response of a double-mutant fatty acid auxotroph of yeast Saccharomyces cerevisiae to exogenous saturated fatty acids of a homologous series from 12:0 to 16:0, each supplied with oleate, linoleate, linolenate, or cis11- eicosenoate, cannot be explained in terms of the efficiency of incorporation of the fatty acids into phospholipids or alteration of membrane fluidity. There is, however, a negative correlation between growth and levels of 12:0 plus 13:0 in phospholipids, as well as a positive correlation between growth and levels of 14:0, 1 5:0, and 1 6:0. We, therefore, conclude that the predominant factor in these phospholipid fatty acyl chain modifications is maintenance of an optimal concentration of C14:0 through C16:0 in phospholipids of this organism.
Peter H. Burrill, Isa Bernardini, Hynda K. Kleinman, Norman Kretchmer
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 385-392; https://doi.org/10.1002/jsscb.1981.380160409

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, M. Schachner
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 53-74; https://doi.org/10.1002/jsscb.1981.380160106

Abstract:
The distribution of two glial antigens (C1 and M1) has been studied by indirect immunofluorescence during postnatal development of the cerebella of normal and neurologically mutant mice (weaver, staggerer, reeler, Purkinje cell degeneration, and wobbler). During the first postnatal week of normal development, C1 antigen is expressed in ependyma. Bergmann glial fibers (BG), and astrocytes of the internal granular layer and white matter. After day 10, C1 antigen is restricted to BG and ependymal cells. During the second and third week. BG undergo a transient loss of C1 antigen that starts in medioventral areas and spreads in a gradient dorsally and laterally. In reeler, weaver, and staggerer, C1 antigen expression is normal during the first postnatal week, and subsides in BG in a similar spatial gradient as described for the normal littermates. However, the loss of C1 antigen in BG occurs earlier (first in reeler, then in weaver, and last in staggerer) and is not reversible as it is in normal mice. In Purkinje cell degeneration, C1 antigen expression is diminished in BG after the onset of behavioral abnormalities. Wobbler is normal with respect to C1 antigen expression at adult ages. M1 antigen is detectable in white matter astrocytes from postnatal day 7 on, and persists in these cells into adulthood. Astrocytes if the internal granular layer and BG express M1 antigen only transiently in normal mice during the second and third weeks. The appearance of M1 antigen in BG occurs in a spatiotemporal gradient, matching the one in which C1 antigen disappears. M1 antigen expression is abnormally maintained in BG of reeler, staggerer, and weaver. In Purkinje cell degeneration. M1 antigen is expressed abnormally at the onset of behavioral abnormalities first in astrocytes of the internal granular layer and, with growing age, increasingly also in BG. In wobbler, BG do not express M1 antigen. However, astrocytes of the granular layer are abnormally M1 antigen-positive.
, Ben Ü, Lorraine Chuman, Michael J. Rindler, , Gordon Sato
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 63-72; https://doi.org/10.1002/jsscb.1981.380150107

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Steven P. Balk, Matthew F. Mescher
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 43-52; https://doi.org/10.1002/jsscb.1981.380160105

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Diane Chang Lin
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 129-138; https://doi.org/10.1002/jsscb.1981.380150204

Abstract:
The spectrin-4.1-actin complex isolated from the cytoskeleton of human erythrocyte [3] was found to be similar to muscle F-actin in several aspects: Both the complex and F-actin nucleate cytochalasin-sensitive actin polymerization; both bind dihydrocytochalasin B with similar binding constants; both can be depolymerized by DNase I with loss of cytochalasin binding activity. From these results, we conclude that the actin in the complex is in an oligomeric form. However, the presence of spectrin and band 4.1 in the complex not only stabilized the actin in the complex as evidenced by its resistance to depolymerization in low-ionic-strength conditions and to DNase I as compared with F-actin, but also altered the characteristics of the binding site(s) for cytochalasins believed to be located at the “barbed” (polymerizing) end of the oligomeric actin.
Carmia Borek
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 311-336; https://doi.org/10.1002/jsscb.1981.380160403

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Donald R. Bertolini, Michiko Watanabe, Robert S. Turner Jr.
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 327-333; https://doi.org/10.1002/jsscb.1981.380150403

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Cecilia Hofmann, Tae H. Ji, Bonnie Miller, Donald F. Steiner
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 1-13; https://doi.org/10.1002/jsscb.1981.380150102

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S. Barbara Yancey, , Jean-Paul Revel
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 221-232; https://doi.org/10.1002/jsscb.1981.380160303

Abstract:
By the use of a simple, rapid method for the isolation of gap junctions from small amounts of rat liver (2–3 g), we have followed the incorporation of the radiolabeled amino acid precursors 3H-leucine and 35S-methionine into the gap junction protein. In timed studies with 35S-methionine as precursor, the specific activity in the protein is maximal by 4 h after a single injection of 300 μCi/100 g body weight. From the decay in the specific activity with time after a single injection, the gap junction protein has an apparent half-life of about 19 h. Because of problems of reutilization of radiolabeled amino acid with 35S-methionine as precursor, this apparent halflife probably overestimates the true half-life and indicates a surprisingly rapid turnover of the gap junction protein. This short half-life suggests that, in rat liver, the gap junctions may be very responsive to alterations in physiological demands.
Raymond J. Ivatt, O. Prem Das, Ellen J. Henderson, Phillips W. Robbins
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 359-368; https://doi.org/10.1002/jsscb.380170407

Abstract:
We have examined the glycoprotein-linked oligosaccharides assembled during the life cycle of Dictyostelium discoideum, and found their expression to be dramatically dependent upon the stage of development. During early development mature glycans have a high mannose character, and a substantial proportion acquire a fucose residue that correlates with endo-H resistance. One-third of the glycans also acquire sulfate residues. These glycans diminish in importance during aggregation. The mature glycans expressed during late development contain fewer mannose residues, from five to ten mannose residues, and are characterized by the absence of sulfate residues and by the presence of fucose residues on endo-H-sensitive glycans. These glycans make their appearance coincident with the construction of tips on tight cell mounds. At this stage glycans characteristic of both early and late stages occur simultaneously. Developmental regulation of the wide array of protein-linked glycans expressed during the life cycle of Dictyostelium discoideum may be as simple as the controlled transition from a group of structures that are assembled by the vegetative cells to a group of structures that are assembled by the terminally differentiating cells. The potential biological significance of this transition is discussed.
Richard E. Fine, Richard Goldenberg, Joseph Sorrentino, Harvey R. Herschman
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 235-251; https://doi.org/10.1002/jsscb.1981.380150304

Abstract:
Epidermal Growth Factor (EGF), a small polypeptide which acts as a mitogen for many cell types, has previously been shown to bind to a specific plasma membrane receptor on 3T3 cells. If 125I-EGF is bound to 3T3 cells for one hour at 4°C, it remains predominantly associated with the plasma membrane-containing fractions obtained by subjecting cell supernatants to equilibrium sedimentation on sucrose gradients. When binding is followed by a 10-minute incubation at 37°C, over 50% of the 125I-EGF is associated with two internal membrane-containing peaks having higher densities than the plasma membrane. After one hour at 37°C, over 80% of the 125I-EGF is degraded and removed from the cells. The most rapidly labeled internal peak corresponds in density to brain-coated vesicles (CVs). Antiserum prepared against coated vehicles from brain precipitates the 125I-EGF in this peak. In addition, CVs containing 125I-EGF can be co-purified from 3T3 cells exposed to 125I-EGF, using brain as a carrier. Several lines of evidence suggest that the other 125I-EGF-labeled intracellular peak is 125I-EGF in lysosomes. These results provide kinetic and biochemical evidence for a unidirectional pathway for EGF catabolism by 3T3 cells. EGF first binds to the plasma membrane bound receptors, is then moved to the cytoplasm in CVs, and finally appears in lysosomes, where it is degraded and released from the cells. Ten-millimolar NH4Cl blocks lysosomal hydrolysis of EGF almost completely. Subsequently, EGF internalization is inhibited. This finding suggests that the pathway for EGF internalization and degradation is tightly coupled.
Stephen E. Zweig, K. T. Tokuyasu, S. J. Singer
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 163-181; https://doi.org/10.1002/jsscb.380170207

Abstract:
The mature mammalian erythrocyte has a unique membranoskeleton, the spectrin-actin complex, which is responsible for many of the unusual membrane properties of the erythrocyte. Previous studies have shown that in successive stages of differentiation of the erythropoietic series leading to the mature erythrocyte there is a progressive increase in the density of spectrin associated with the membranes of these cells. An important stage of this progression occurs during the enucleation of the late erythroblast to produce the incipient reticulocyte, when all of the spectrin of the former cell is sequestered to the membrane of the reticulocyte. The reticulocyte itself, however, does not exhibit a fully formed membranoskeleton. In particular, the in vitro binding of multivalent ligands to specific membrane receptors on the reticulocyte was shown to cause a clustering of some fractions of these ligand-receptor complexes into special mobile domains on the cell surface. These domains of clustered ligand-receptor complexes became invaginated and endocytosed as small vesicles. By immunoelectron microscopic experiments, these invaginations and endocytosed vesicles were found to be specifically free of spectrin on their cytoplasmic surfaces. These earlier findings then raised the possibility that the maturation of reticulocytes to mature erythrocytes in vivo might involve a progressive loss of reticulocyte membrane free of spectrin, thereby producing a still more concentrated spectrin-actin membranoskeleton in the erythrocyte than in the reticulocyte. This proposal is tested experimentally in this paper. In vivo reticulocytes were observed in ultrathin frozen sections of spleens from rabbits rendered anemic by phenylhydrazine treatment. These sections were indirectly immunolabeled with ferritin-antibody reagents directed to rabbit spectrin. Most reticulocytes in a section had one or more surface invaginations and one or more intracellular vesicles that were devoid of spectrin labeling. The erythrocytes in the same sections did not exhibit these features, and their membranes were everywhere uniformly labeled for spectrin. Spectrin-free surface invaginations and intracellular vesicle were also observed with reticulocytes within normal rabbit spleens. Based on these results, a scheme for membrane remodeling during reticulocyte maturation in vivo is proposed.
Mark H. Ginsberg, Edward F. Plow, Jane Forsyth
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 91-98; https://doi.org/10.1002/jsscb.380170111

Abstract:
Thrombin stimulation of human platelets causes increased cellular adhesiveness for other platelets (aggregation) and surfaces and increased surface expression of platelet fibronectin antigen. Aggregation occurs concurrently with secretion. In these studies, the threshold thrombin dose for surface expression of fibronectin, as measured by binding of F(ab′)2 antifibronectin, was similar to that for serotonin secretion. Moreover, both processes occurred at similar rates, and inhibition of secretion was associated with inhibition of antifibronectin binding. Thus a hypothesis is proposed in which adhesive proteins within platelet granules become expressed on the platelet surface as a direct consequence of the secretory process. This cluster of adhesive proteins may then contribute to increased cellular adhesiveness.
Dennis E. Koppel
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 61-67; https://doi.org/10.1002/jsscb.380170107

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John I. Toohey
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 17, pp 11-25; https://doi.org/10.1002/jsscb.380170103

Abstract:
Macrophages are shown to replace methylthio disulfides in supporting in vitro proliferation of three cell lines previously characterized as methylthio-dependent. Macrophages have the capacity to generate methylthio groups from methylthioadenosine. It is hypothesized that macrophages stimulate cell proliferation both in normal immune systems and in certain cancers by providing an abundance of methylthio groups. Fetal calf serum is shown to contain methylthio groups. It appears that, in cell cultures containing fetal calf serum, sulfhydryl compounds stimulate cell proliferation by making the methylthio groups in the serum available to the cells.
O.J. Bjerrum, M. Hawkins, P. Swanson, , L. Lorand
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 289-301; https://doi.org/10.1002/jsscb.1981.380160309

Abstract:
An increase in the intracellular concentration of Ca2+ in human erythrocytes results in the formation of γ-glutamyl-ϵ-lysine cross-linked membrane protein polymers. Following solubilization of the membranes with SDS, these polymers can be isolated on a Lubrol-containing sucrose gradient. Immunoelectrophoresis of the polymeric material with a polyspecific rabbit antibody against human ghosts gave rise to a single, but heterogeneous, precipitate. The polymer was amphiphilic and, on addition to Triton-solubilized erythrocyte membrane proteins, it coprecipitated with spectrin. When the antighost antibody was absorbed with the polymer prior to cross immunoelectrophoresis of normal erythrocyte membrane proteins, the precipitates of glycophorin, acetylcholinesterase, and hemoglobin were normal, whereas the anti-body liters against band 3 protein, spectrin, and ankyrin became reduced. Furthermore, a rabbit antibody raised against the isolated human polymer reacted selectively with the same three membrane proteins. No reactions occurred with lysate proteins.
David V. Godin, F. Geoffrey Herring
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 213-218; https://doi.org/10.1002/jsscb.1981.380150302

Abstract:
Erythrocytes from patients with familial lecithin : cholesterol acyltransferase (LCAT) deficiency have been shown to exhibit an increase in membrane fluidity which is surprisingly small in view of the extensive alterations both in membrane lipid composition (namely, an elevation in cholesterol and phosphatidylcholine contents as well as a decrease in phosphatidylethanolamine) and in the functional properties of these cells. In the hope of deriving some information concerning the interrelationship between the structural and functional abnormalities, we have used the spin probe 5-doxyl stearic acid to investigate the temperature-dependent fluidity properties of red cells from two patients with a hereditary hemolytic syndrome (HHS) whose red cells are also characterized by qualitatively similar alterations in phosphatidylcholine and phosphatidylethanolamine but, unlike those in LCAT deficiency, have relatively normal levels of membrane cholesterol. A small increase in membrane fluidity of HHS erythrocytes equivalent to that previously observed in LCAT deficiency was found, indicating that membrane cholesterol level does not exert an important modulatory influence on membrane fluidity in these cells. It is concluded that while the distinct patterns of structural and functional erythrocyte alterations in these two disorders cannot be explained on the basis of differences in bulk membrane fluidity, the marginally increased fluidity may underlie the abnormalities in osmotic fragility and membrane p-nitrophenylphosphatase activity which are shared in common by both types of modified red cells.
D. S. Coffman, Ben H. Leichtling, H. V. Rickenberg
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 15, pp 369-385; https://doi.org/10.1002/jsscb.1981.380150407

Abstract:
The phosphoproteins of Dictyostelium discoideum were compared at different stages of development by polyacrylamide gel electrophoresis. Certain phosphoproteins of vegetative amoebae were conserved while others appeared and disappeared during development. Four major phosphoproteins with apparent subunit molecular weights of 50,000, 47,000, 38,000, and 34,000 disappeared precociously in response to exogenous cAMP. Two membranal phosphoproteins, with apparent subunit molecular weights of 80,000 and 81,000, appeared precociously in response to added cAMP. One of these phosphoproteins, molecular weight of 80,000, has been identified tentatively as the “contact site A” glycoprotein. Another membranal protein, with apparent subunit molecular weight of 42,000, unaffected in its appearance by cAMP, has been identified tentatively as phosphoactin.
, Philip C. Hanawalt, James A. Miller, Elizabeth C. Miller
Journal of Supramolecular Structure and Cellular Biochemistry, Volume 16, pp 83-90; https://doi.org/10.1002/jsscb.1981.380160108

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