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ERK activation in progressively dehydrated anuran amphibians.
Author(s) -
Duerr Jeffrey M
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1395
Subject(s) - mapk/erk pathway , amphibian , ectotherm , p38 mitogen activated protein kinases , bufo , biology , osmotic shock , microbiology and biotechnology , rana , toad , dehydration , phosphorylation , heat shock protein , mitogen activated protein kinase , kinase , endocrinology , ecology , biochemistry , gene
Comparative vertebrate studies into physiological responses to adverse conditions can yield great insight into the design of robust systems and the provide fundamental knowledge of stress adaptations. The classically studied cellular stress response is the mitogen‐activated protein kinase (MAPK) pathway. In mammals, there are four known MAPKs: JNK, p38, BMK, and ERK. p38 is a MAPK which responds to environmental stresses such as heat, oxidation, ionizing radiation, and hyper‐osmotic shock. The ERK MAPK is known to respond to growth factors and other mitogens by triggering cascades which activate transcription (Cowan and Storey, 2003). JNK is known to be activated when an organism is confronted with osmotic stress, heat shock, and UV exposure. Generally JNK activation leads to apoptosis, although occasionally it may trigger cell survival pathways. The effects of dehydration on anuran amphibian blood flow rates have been previously investigated and suggested that a terrestrial toad ( Bufo marinus ) possessed a greater tolerance of dehydration as measure by cardiovascular performance relative to a more aquatic species ( Rana catesbeiana ). The initial goal of this study was to examine the effect of progressive dehydration on MAPK family activation in cardiac tissue from two species of anuran amphibians: Rana catesbeiana and Bufo marinus . Western blot analysis indicated that the pERK increase by three‐fold in Bufo and 2‐fold in Rana . pJNK levels remained unaffected in Bufo whereas in Rana they initially decreased, but then rebounded to baseline levels. pp38 did exhibit any change in phosphorylation levels over the range of dehydration examined. The physiological consequences of ERK activation in response to osmotic stress in anuran cardiomyocytes remains to be investigated.