The Correlation Between UCP Expression UND Cellular Metabolism

Mitochondrial anion carriers transport components of cellular metabolic pathways across the inner mitochondrial membrane. In contrast, the members of the uncoupling protein subfamily (UCP1-UCP5) were shown to transport protons, that is, in case of UCP1, a molecular basis of non-shivering thermogenesis. The exact biological functions of the other UCPs still remain elusive. However, there is increasing evidence that the UCPs' function may be linked to the cell metabolism. In our previous work 1,2,3, we have shown that the tissue distribution of particular UCPs are strikingly different. Here, we hypothesized that their expression is tightly connected to a certain type of cell metabolism. To prove this hypothesis, we employ mouse embryonic stem cells (mESC) which only express UCP2. After initiation of the neuronal differentiation, the UCP2 expression drops abruptly. In contrast, the expression of UCP4 starts with the beginning of neuronal differentiation and lasts throughout neuronal development in embryonic mouse tissue as the expression of other neuronal markers simultaneously takes place. Notably, UCP4 is not present in neuroblastoma cells, which instead prominently express UCP2. To elucidate the role of UCP2 and UCP4 we analyse the regulation of UCP2 expression in cultivated neuroblastoma cells and UCP4 in primary neuronal culture under different growing conditions. The results support our hypothesis that both proteins are a fixed part of the respective cell metabolism.1. Smorodchenko, A et al. Biochim Biophys Acta. 2009 Oct;1788(10):2309-19.2. Smorodchenko, A et al. Mol Cell Neurosci. 2011 Aug;47(4):244-53.3. Rupprecht, A. et al. PLoS One. 2012;7(8):e41406.