Is AMP-Activated Protein Kinase a Better Signal for Temperature Stress Than Heat Shock Protein in the Crab Cancer irroratus?
Markus Frederich, Department of Biological Sciences, University of New England
16 Nov 2007
Marine crustaceans are exposed to frequent seasonal and diel temperature changes. Such temperature changes have a profound impact on energy metabolism and scope for activity of ectothermal animals. We have defined specific threshold temperatures: critical temperatures, that indicate the transition to anaerobic metabolism despite the presence of sufficient oxygen in the environment; as well as pejus temperatures, that indicate the transition to a reduced scope for aerobic activity during temperature stress. Our current work focuses on the metabolic master switch AMP-activated protein kinase, AMPK. AMPK regulates in mammals all major pathways of energy metabolism to ensure a contantly high ATP concentration. We have identified AMPK in various decapod crustaceans and found AMPK activity to increase with temperature much earlier than any detectable response by the well investigated HSP70 system. Additionally, the temperature that activates AMPK coincides with the upper pejus temperature in the crab Cancer irroratus. Further work will investigate whether AMPK activity or mRNA expression can be used as a cellular marker for acute and chronic temperature stress.