Mitogen-activated protein kinases and selected downstream targets display organ-specific responses in the hibernating ground squirrel.
The responses of mitogen-activated protein kinase (MAPK) family members, including the extracellular signal-regulated kinases (ERKs), the c-jun NH2-terminal kinases (JNKs) and p38MAPK, during mammalian hibernation were analyzed in five organs of Richardson's ground squirrels, Spermophilus richardsonii. Each kinase subfamily responded differently in torpor and each showed organ-specific patterns of response. ERK1/2 activities increased significantly in muscle and brain during hibernation but decreased in kidney and liver. JNK activity rose in four organs (except brain) during hibernation whereas active, phosphorylated p38MAPK increased only in muscle and heart. Activities of ERK-activated kinases also responded to hibernation: MAPKAPK-1 rose in muscle and brain, MAPKAPK-2 decreased in liver and kidney but rose in the other three organs, and p70S6K kinase activity decreased kidney and heart. Transcription factors, c-Jun and CREB, also showed organ-specific responses during torpor. The data suggest key roles for MAPKs in the regulation of the known organ-specific changes in gene expression and protein phosphorylation that define the hibernation phenotype.
MacDonald
Justin A
JA
Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive N.W., Calgary, AB, Canada T2N 4N1.
Storey
Kenneth B
KB
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006605:Hibernation; D048031:JNK Mitogen-Activated Protein Kinases; D007668:Kidney / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D012589:Sciuridae; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases
D017362:Cyclic AMP Response Element-Binding Protein; D016755:Proto-Oncogene Proteins c-jun; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases