Glucose and urea metabolic enzymes are differentially phosphorylated during freezing, anoxia, and dehydration exposures in a freeze tolerant frog

Publication date: Available online 25 January 2019Source: Comparative Biochemistry and Physiology Part D: Genomics and ProteomicsAuthor(s): Liam J. Hawkins, Minjing Wang, Baowen Zhang, Qi Xiao, Hui Wang, Kenneth B. StoreyAbstractVertebrate freeze tolerance requires multiple adaptations underpinned by specialized biochemistry. Freezing of extracellular water leads to intracellular dehydration as pure water is incorporated into growing ice crystals and also results in the cessation of blood supply to tissues, creating an anoxic cellular environment. Hence, the freeze tolerant wood frog, Rana sylvatica, must endure both dehydration and anoxia stresses in addition to freezing. The metabolic responses to freezing, dehydration and anoxia involve both protein/enzyme adaptations and the production of metabolites with metabolic or osmotic functions, particularly glucose and urea. The present study uses a phosphoproteome analysis to examine the differential phosphorylation of metabolic enzymes involved in the production of these two metabolites in liver in response to freezing, anoxia, or dehydration exposures. Our results show stress-specific responses in the abundance of phosphopeptides retrieved from nine glycolytic enzymes and three urea cycle enzymes in liver of wood frogs exposed to 24 h freezing, 24 h anoxia, or dehydration to 40% of total body water loss, as compared with 5 °C acclimated controls. Data show changes in the abundance of phosphopeptides belonging to glycoge...
Source: Comparative Biochemistry and Physiology Part D: Genomics and Proteomics - Category: Genetics & Stem Cells Source Type: research