Molecular Mechanisms of Metabolic Suppression: Protein Synthesis and Mitochondrial Respiration in a Hibernating Ground Squirrel Model

摘要

We have discovered that mitochondrial proton conductance is unchanged during hibernation and that the reduced metabolism observed in hibernators is a partial consequence of tissue specific depression of substrate oxidation. Using proton leak analyses we show that increases in uncoupling protein 3 expression do not serve a thermogenic function. Rather uncoupling protein 3 likely protects against the accumulation of fatty acids in the mitochondrial matrix. The polyA binding protein-mRNA interactions observed previously in hibernating animals are also observed in explants from squirrels not hibernating. These data suggest that PABP-mRNA interactions are a consequence of cold temperature. Using a mouse cDNA array, we have discovered several additional candidate genes that appear upregulated during hibernation. The functional significance of this result is currently being determined. We have developed black bear cDNA libraries for the ultimate construction of a bear array that will be used in future comparative studies of hibernation.