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Biomedical subjects

W Ness

Publications and source records attributed to W Ness.

4 recordsLinked to original sources
PubMed1994

Localization of protein kinase C in primary cultures of human keratinocytes in relation to cell contact proteins.

To investigate the role of protein kinase C (PKC), one of the key factors in cellular signalling, in the integrity of cell contacts, we studied the effects of PKC activation and inhibition on cell-cell and cell-substratum contacts. We localized PKC, actin and two major elements of zonula adherens (vinculin, E-cadherin) and focal contacts (vinculin) in primary cultures of normal human keratinocytes (nHEK) by fluorescent analogue cytochemistry. The activity of PKC was influenced by administration of TPA (12-O-tetradecanoylphorbol-13-acetate, a specific PKC activator) and H-7 [1-(5-isoquinolinesulphonyl)-2-methylpiperazine, a PKC inhibitor] for various periods of time. Our results show varying effects of TPA and H-7 on zonula adherens and focal contacts, suggesting differences in modulation of both types of adherens junctions by mechanisms partially involving PKC. In addition, TPA treatment of nHEK leads to changes in actin cytoskeletal organization.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Localization of adducin in epidermis.

On the cytoplasmic side of the plasma membrane of erythrocytes there is a dense protein filament matrix that maintains the shape of the cells. The main constituents of this system, actin and spectrin, which have also been detected in keratinocytes and fibroblasts, are known to be linked in erythrocytes in a network structure by additional proteins such as band 4.1 and adducin. The interaction between actin and spectrin, mediated by adducin, is regulated by calmodulin and protein kinase C. Because we have previously found adducin in cultured keratinocytes, we investigated epidermis by immunochemical techniques. We found adducin to be localized at cell-cell contact sites in epidermis using affinity-purified antibodies against human erythrocyte adducin. Immunofluorescence of epidermis revealed an intense fluorescence in the basal layer, whereas stratum spinosum and stratum granulosum showed moderate staining. There was intense staining at sites of cell-cell contact in cultured human keratinocytes. Immunoblot analysis indicated the presence of adducin polypeptides of 103 kd and 97 kd in epidermis, but in cultured keratinocytes only the higher molecular weight form could be detected. This study indicates adducin, a regulatory protein in erythrocytes, is also present in epidermis. Its localization suggests that it may be involved in the formation of the microfilament matrix of the membrane skeleton at cell-cell contact sites.

Actins↗
PubMed1993

Talin: adherens junction protein is localized at the epidermal-dermal interface in skin.

The interaction between cells of the epidermis and the basal lamina is important for the integrity of the skin. Several hereditary and acquired diseases show changes at the dermal-epidermal interface due to loss of adhesion between basal cells and the basement membrane. The structures mediating this interaction are hemidesmosomes, which have been extensively characterized by biochemical, molecular biologic, and morphologic techniques. Recently, however, a group of adhesion molecules that are distinct from hemidesmosomes and that mediate cell-matrix interactions was described in cultured fibroblasts, keratinocytes, and skin. These adhesion molecules, beta 1 integrins, have been shown to be present in the focal adhesion, a cell-matrix contact associated with microfilaments rather than intermediate filaments characteristic of hemidesmosomes. In cultured cells, integrins of the beta 1 family have been shown to be linked by a protein complex to actin filaments. In this study we describe the localization of talin, the binding protein for beta 1 integrins, and vinculin at the dermal-epidermal interface in skin with immunofluorescence and immunoblotting techniques. These data suggest the presence of a link between the cytoplasmic actin filament system in basal keratinocytes and the extracellular matrix.

Desmosomes↗