Relation of actin fibrils to energy metabolism of endothelial cells
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- Tillmann, U. & Bereiter-Hahn, J. Cell Tissue Res. (1986) 243: 579. doi:10.1007/BF00218065
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The physiological significance of the association of glycolytic enzymes with actin fibrils was investigated in cell culture. Cytochalasin D (CD) was used to induce the known actin-based sequence of events in a culture of an endothelial-cell line (XTH-2) derived from hearts from tadpoles of Xenopus laevis. 1 min following addition of CD, ruptures in the cortical fibrillar meshwork and in stress fibres are seen. At the same time the cellular ATP level decreases by ca. 25%. This and the following reactions resulting in a kind of arborization depend on a continuous supply with metabolic energy. As shown by measurements of oxygen consumption, cells with intact energy metabolism provide the ATP needed from glycolysis; ATP produced by oxidative phosphorylation is not ultilized as long as lactate dehydrogenase (LDH) reoxidizes NADH2. After inhibition of LDH, respiration in XTH-2 cells doubles. CD treatment induces a transient increase in oxygen consumption, indicating an increased energy supply by respiration. From these results we conclude: The energy needed by the actomyosin system is — under normal metabolic conditions — supplied from ATP phosphorylated in glycolysis. The processes of energy metabolism seem to be highly compartmentalized; ATP is not a parameter that is kept constant in time intervals of minutes up to one hour.