Inhibition of Phagocytosis and Plasma Membrane Mobility of the Cultivated Macrophage by Cytochalasin B: Role of Subplasmalemmal Microfilaments

• Published in: The Journal of cell biology 1974-09, Vol.62 (3), p.647-659
• Main Authors: Axline, Stanton G., Reaven, Eve P.
• Format: Article
• Language: English
• Subjects: Animals; Cell Membrane - drug effects; Cell membranes; Cell motility; Cell Movement - drug effects; Cells; Cytochalasin B - pharmacology; Cytochalasins; Dose response relationship; Dose-Response Relationship, Drug; Glucose - metabolism; Hexoses; Hexoses - metabolism; Inclusion Bodies - physiology; Macrophages; Macrophages - cytology; Macrophages - drug effects; Macrophages - metabolism; Male; Mice; Microfilaments; Microscopy, Electron, Scanning; Microscopy, Phase-Contrast; Phagocytes; Phagocytosis; Phagocytosis - drug effects
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.62.3.647

Functional and morphologic effects of cytochalasin B on the cultivated macrophage were examined to determine the basis for plasma membrane movements of the type required for endocytosis and/or spreading on a substratum. Inhibition of phagocytosis and changes in cell shape by cytochalasin B exhibited nearly identical dose-response curves requiring 2-5 × 10-6 M and 1-2 × 10-5 M cytochalasin B to inhibit these functions by 50% and 100%, respectively. In contrast, hexose transport was ten times more sensitive to the drug requiring 2-3 × 10-7 M cytochalasin B to achieve 50% inhibition of 2-deoxyglucose uptake. Inhibition of phagocytosis and changes in cell shape could not be explained solely by drug effects on hexose transport. Analysis of serial thin sections showed that cytochalasin B doses inhibitory for hexose transport had no effect on distribution or organization of either of the two subplasmalemmal microfilament types. However, cytochalasin B concentrations (2.0 × 10-5 M) that inhibited phagocytosis and altered cell shape disorganized and/or disrupted oriented bundles of 40-50-Å subplasmalemmal microfilaments, but had no effect on the microfilamentous network. Comparative dose-response studies showing positive correlations among cytochalasin B effects on phagocytosis, changes in cell shape, and alterations in oriented subplasmalemmal microfilament bundles provide additional support for the hypothesis that microfilamentous structures play a role in translocation of plasma membrane required for endocytosis and cell motility.