Relation of actin fibrils to energy metabolism of endothelial cells |
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Authors: | Utz Tillmann Prof Dr. Jürgen Bereiter-Hahn |
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Affiliation: | (1) Cinematic Cell Research Group, J.W. Goethe University, Frankfurt a.M., Federal Republic of Germany;(2) Arbeitsgruppe Kinematische Zellforschung, Fachbereich Biologie, Senckenberganlage 27, D-6000 Frankfurt am Main, Federal Republic of Germany |
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Abstract: | Summary 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. |
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Keywords: | Actin Glycolysis Respiration Cellular ATP-content Cytolchalasin D Endothelial cells Cell culture Xenopus laevis |
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