Sc. Greenway et Kb. Storey, Discordant responses of mitogen-activated protein kinases to anoxia and freezing exposures in hatchling turtles, J COMP PH B, 169(7), 1999, pp. 521-527
Citations number
39
Categorie Soggetti
Animal Sciences",Physiology
Journal title
JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTALPHYSIOLOGY
The role of two vertebrate mitogen-activated protein kinases (MAPKs) in med
iating responses to in vivo anoxia or freezing exposures was examined in fo
ur organs (liver, heart, kidney and brain) of hatchling red-cared turtles,
Trachemys scripta elegans, which are naturally tolerant of these stresses.
The extracellular signal-regulated kinases were not stress-activated except
in brain of frozen turtles. The c-Jun NH2-terminal kinases (JNKs) were tra
nsiently activated by anoxia exposure in all four organs (after 1 h in brai
n or 5 h in other organs) but activity was suppressed during freezing excep
t in brain which showed a transient activation of JNK after 1 h. Changes in
the concentrations of the transcription factors, c-Fos and c-Myc, mere als
o stress- and organ-specific. The patterns of MAPK activation in a stress-t
olerant animal suggest the relative importance of these kinase pathways in
cellular adaptation to oxygen deprivation or freezing and identify novel na
tural activators of MAPKs in vivo. The specificity of the signaling pathway
s is also emphasized here as the general whole-body stresses, anoxia and fr
eezing, activated individual MAPKs in a tissue-, time-, and stress-dependen
t manner.