Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12202/3151
Title: GLYCOPHORIN IN ERYTHROID CELLS
Authors: SILVER, RUTH E.
Keywords: Biochemistry.
Issue Date: 1987
Publisher: ProQuest Dissertations & Theses
Citation: Source: Dissertation Abstracts International, Volume: 48-02, Section: B, page: 4280.
Abstract: Glycophorin is the major sialoglycoprotein of the human erythrocyte membrane. While no biological role has yet been found for glycophorin in the mature erythrocyte, its presence in early precursors of the erythroid cells has led some to propose that glycophorin could play a role in erythroid differentiation. The characteristics of glycophorin and its use as a model for membrane proteins are described.;The study of glycophorin was undertaken to define its chemical and biological characteristics in the immature erythroid cell. At first, we studied normal erythroid precursor cells cultured from peripheral blood, but this direction was eventually abandoned mainly because of unsatisfactory yields and other experimental difficulties. Therefore, we studied the glycophorins of K562, an erythroleukemic cell line arrested at a point in differentiation.;Glycophorins were purified from K562 cells using a combination of SDS/TCA fractionation, and hot phenol and Folch extractions. This preparation was characterized chemically, as well as by lectin binding and by binding to erythrocyte glycophorin-specific monoclonal antibodies. The carboxyl-terminal region of K562 glycophorin resembled that of erythrocyte glycophorin whereas the amino-terminal regions appeared significantly different. This difference is due to different O-linked glycosylation in this region. The O-linked oligosaccharides of erythrocyte and K562 glycophorin were similar but there were fewer tetrasaccharides per molecule of K562 glycophorin.;Two populations of glycophorin, which differed in their binding to Lens culinaris lectin, were studied in detail. The (alpha) glycophorins do not have a precursor-product relationship. Only one of the populations is present at the surface of K562 cells. The two glycophorins probably have different asparagine-linked oligosaccharide structures, and this possibility is discussed in light of what is known about the regulation of asparagine-linked oligosaccharide biosynthesis and processing. The significance of finding only one species of glycophorin at the cell surface is examined in relation to the role of carbohydrate in intracellular routing.
URI: https://ezproxy.yu.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:8711064
https://hdl.handle.net/20.500.12202/3151
Appears in Collections:Albert Einstein College of Medicine: Doctoral Dissertations

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