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Antibodies to tubulin and actin bind to the surface of a human monocytic cell line, U937

journal contribution
posted on 2023-05-17, 16:58 authored by Por, SB, Cooley, MA, Breit, SN, Penny, R, French, PW
Intermittent reports of cytoskeleton proteins (actin and tubulin) on the cell surface have appeared over the last 13 years. Whereas most have concentrated on lymphocytes, this study provides evidence for the presence of these proteins on the surface of a human cultured monocyte-like cell line, U937. Both actin and tubulin were detected on the surface of U937 cells by flow cytometry, using an indirect staining procedure based on biotin-streptavidin-phycoerythrin, chosen for greater sensitivity. By use of this procedure, the majority of viable unstimulated U937 cells stained positively for actin and tubulin, although the level of fluorescence intensity was low. With an antibody specific for tyrosine-tubulin, most of the surface tubulin was also found to be tyrosinylated. For vimentin, an intermediate filament protein abundantly present in the cytoplasm of U937 cells, no staining could be detected. Confirmation of the flow cytometry data for surface actin and tubulin on unstimulated U937 cells was achieved by direct vesualization using a confocal laser scanning microscope. When U937 cells were activated with PMA and LPS, a marked reduction in the level of cell surface actin and tubulin occurred. The role of cell surface actin and tubulin on unstimulated U937 cells, in terms of monocyte function, remains to be elucidated


Publication title

Journal of Histochemistry and Cytochemistry










Tasmanian School of Medicine


Histochemical Soc Inc

Place of publication

Univ Washington, Dept Biostructure, Box 357420, Seattle, USA, Wa, 98195

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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