Fig. 1.

Hypoxia and STOX1 overexpression affect the fumarate-dependentl-malate pathway. (A) Characteristics of control, STOX1A and STOX1B over-expressing human trophoblast cell lines, and experimental plan in the presence and in the absence of the hypoxia-mimetic agent CoCl₂. (B) Immunoblot of the hypoxia marker HIF1A and the internal reference GAPDH from whole-cell extracts. The immunoblot is representative of 3 independent experiments. (C) Schematic representation of the Krebs cycle where the reaction catalyzed by the enzyme fumarase from fumarate (substrate) to l-malate (product) is framed. Levels of the (D) fumarate and (E)l-malate metabolites expressed in nmol/mg of protein. (F) Fumarase specific activity (fumarase activity/fumarase protein content) expressed as percent of untreated control BD3 cell line. Dosages (fumarate, malate) and enzyme activity (fumarase), n = 3 independent experiments, mean ± SD. *p ≤ 0.05 **p ≤ 0.01 ***p ≤ 0.001 based on one-way ANOVA versus the untreated control (red stars) or the corresponding untreated condition (blue stars). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)