Eddy, S.F. and Storey, K.B. 2007. p38MAPK
regulation of transcription factor targets in muscle and heart of hibernating
bats, Myotis lucifugus. Cell Biochem.
Function 25, 759-765. DOI: 10.1002/cbf.1416
p38MAPK regulation
of transcription factor targets in muscle and heart of hibernating bats, Myotis lucifugus
Sean
F. Eddy and Kenneth B. Storey
Abstract
Mammalian hibernation combines a
profound net metabolic rate suppression with the selective up-regulation
of key genes whose protein products address specific metabolic needs of the
hibernator. The signal transduction pathways and transcription factors involved
in regulating hibernation-responsive gene expression are of great interest. The
present study suggests an important role for the p38 mitogen-activated
protein kinase (p38MAPK) and selected downstream transcription factors
under its control (CREB, ATF-2, Elk-1) in the metabolic response by skeletal
muscle during hibernation of little brown bats, Myotis lucifugus. Western blotting was
used to quantify both total protein and levels of the phosphorylated, active forms
of p38MAPK, CREB, ATF-2 and Elk-1 in both skeletal muscle and heart
of euthermic and hibernating bats. The p38MAPK pathway was not
apparently activated in heart during torpor but skeletal muscle showed strong
increases (2.2–11-fold) in the amounts of phosphorylated p38T180/Y182,
CREBS133, ATF-2T69/71 and Elk-1S383 in the
torpid versus aroused state. By contrast both total and phosphorylated levels
of Elk-1 in heart were reduced during hibernation to just 30% of the euthermic
values. These data implicate p38MAPK and its transcription factor
targets, CREB, ATF-2 and Elk-1 in skeletal muscle maintenance during
hibernation.