Transcriptional and post-translational activation of AMPKα by oxidative, heat, and cold stresses in the red flour beetle, Tribolium castaneum

The AMP-activated protein kinase (AMPK) has important roles in the regulation of energy metabolism, and AMPK activity and its regulation have been the focus of relevant investigations. However, functional characterization of AMPK is still limited in insects. In this study, the full-length cDNA coding AMPK alpha (TcAMPK alpha) was isolated from the red flour beetle, Tribolium castaneum. The TcAMPK alpha gene contains an ORF of 1581 bp encoding a protein of 526 amino acid residues, which shared conserved domain structure with Drosophila melanogaster and mammalian orthologs. Exposure of female adults to oxidative, heat, and cold stresses caused an increase in TcAMPK alpha mRNA expression levels and phosphorylation of Thr-173 in the activation loop. The RNAi-mediated knockdown of TcAMPK alpha resulted in the increased sensitivity of T. castaneum to oxidative, heat, and cold stresses. These results suggest that stress signals regulate TcAMPK alpha activity, and TcAMPK alpha plays an important role in enabling protective mechanisms and processes that confer resistance to environmental stress.