Browsing by Subject "Membrane skeleton"

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    Membrane skeletons in avian erythrocytes as revealed by the quick-freezing and deep-etching method
    (Murcia : F. Hernández, 1997) Terada, N.; Fuji, Y.; Kitano, K.; Ohno, S.
    Ultrastructure of chicken erythrocytes were examined by the quick-freezing and deep-etching (QFDE) method. Some erythrocytes were fixed with paraformaldehyde and prepared with erythrocytesplitting method or saponin treatment to remove soluble proteins before quick-freezing. Others were prepared in the cytosol buffer with the erythrocyte-splitting method to obtain natural state of cytoskeletons. Non-expanding membrane skeletons were highly condensed on the cytoplasmic side of lipid membrane in the paraformaldehyde- fixed specimens. Under unilateral extension of the specimens, long stretched filaments were connected alternately with condensed filamentous or granular structures under erythrocyte membranes. As the membrane skeletons got closer to the marginal bands, they become more dense network structures. Moreover, in the fresh unfixed specimens, dense networks of filaments were localized underlying erythrocyte membranes in a relatively intact state. Fine filaments connected the marginal microtubule bands to the cytoplasmic sides of erythrocyte membranes. The different distribution of each cytoskeletal component and the association of these structures may support the elliptocytic shape of chicken erythrocytes and resist the dynamic circumstance.
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    Nonerythroid membrane skeletal proteins in normal and diseased human skin
    (Murcia : F. Hernández, 1996) Shimizu, T.; Takakuwa, Y.; Koizumi, H.; Ohkawara, A.
    A number of reports have described the presence and localization of membrane skeletal proteins in nonerythroid tissues and cultured cells. Interactions of these proteins, which have been extensively characterized in erythrocytes, may be physiologically important in other cell types. This review focuses on recent developments concerning proteins analogous to erythrocyte spectrin, protein 4.1, adducin and ankyrin in epidermal keratinocytes, and discusses their significance from physiological and pathological stand points. Keratinocyte proteins are involved in a wide variety of functions such as the cell-to-cell and cell-to-substratum adhesion, stratification, and maintenance of the cell shape. In epidermal keratinocytes, these nonerythroid membrane skeletal proteins may play a role in maintaining the polarity of membrane proteins by connecting them to the cytoskeleton, regulating cell-cell interdigitations and stabilizing newly synthesized cell membranes before elaboration of cell-cell interdigitations. Furthermore, altered expression and distribution of these proteins may be important in the pathogenesis of skin disease such as psoriasis.
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