Significant modulation of the hepatic proteome induced by exposure to low temperature in Xenopus laevis

Kazumichi Nagasawa, Yuta Tanizaki, Takehito Okui, Atsuko Watarai, Shinobu Ueda, Takashi Kato

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    13 Citations (Scopus)

    Abstract

    The African clawed frog, Xenopus laevis, is an ectothermic vertebrate that can survive at low environmental temperatures. To gain insight into the molecular events induced by low body temperature, liver proteins were evaluated at the standard laboratory rearing temperature (22°C, control) and a low environmental temperature (5°C, cold exposure). Using nano-flow liquid chromatography coupled with tandem mass spectrometry, we identified 58 proteins that differed in abundance. A subsequent Gene Ontology analysis revealed that the tyrosine and phenylalanine catabolic processes were modulated by cold exposure, which resulted in decreases in hepatic tyrosine and phenylalanine, respectively. Similarly, levels of pyruvate kinase and enolase, which are involved in glycolysis and glycogen synthesis, were also decreased, whereas levels of glycogen phosphorylase, which participates in glycogenolysis, were increased. Therefore, we measured metabolites in the respective pathways and found that levels of hepatic glycogen and glucose were decreased. Although the liver was under oxidative stress because of iron accumulation caused by hepatic erythrocyte destruction, the hepatic NADPH/NADP ratio was not changed. Thus, glycogen is probably utilized mainly for NADPH supply rather than for energy or glucose production. In conclusion, X. laevis responds to low body temperature by modulating its hepatic proteome, which results in altered carbohydrate metabolism.

    Original languageEnglish
    Pages (from-to)1057-1069
    Number of pages13
    JournalBiology Open
    Volume2
    Issue number10
    DOIs
    Publication statusPublished - 2013 Oct 15

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    Keywords

    • Animal model
    • Liver
    • Low temperature
    • Pathway
    • Proteomics
    • Xenopus laevis

    ASJC Scopus subject areas

    • Biochemistry, Genetics and Molecular Biology(all)
    • Agricultural and Biological Sciences(all)

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