摘要 : Winter survival for many insects depends on cold hardiness adaptations as well as entry into a hypometabolic diapause state that minimizes energy expenditure. We investigated whether AMP-activated protein kinase (AMPK) could be in... 展开 Winter survival for many insects depends on cold hardiness adaptations as well as entry into a hypometabolic diapause state that minimizes energy expenditure. We investigated whether AMP-activated protein kinase (AMPK) could be involved in this adaptation in larvae of two cold-hardy insects, <i>Eurosta solidaginis</i> that is freeze tolerant and <i>Epiblema scudderiana</i> that uses a freeze avoidance strategy. AMPK activity was almost 2-fold higher in winter larvae (February) compared with animals collected in September. Immunoblotting revealed that phosphorylation of AMPK in the activation loop and phosphorylation of acetyl-CoA carboxylase (ACC), a key target of AMPK, were higher in <i>Epiblema</i> during midwinter whereas no seasonal change was seen in <i>Eurosta</i>. Immunoblotting also revealed a significant increase in ribosomal protein S6 phosphorylation in overwintering <i>Epiblema</i> larvae, and in both <i>Eurosta</i> and <i>Epiblema</i>, phosphorylation of eukaryotic initiation factor 4E-binding protein-1 dramatically increased in the winter. Pyruvate dehydrogenase (PDH) E1 alpha subunit site 1 phosphorylation was 2-fold higher in extracts of <i>Eurosta</i> larvae collected in February versus September while PDH activity decreased by about 50% in <i>Eurosta</i> and 80% in February <i>Eurosta</i> larvae compared with animals collected in September. Glycogen phosphorylase phosphorylation was 3-fold higher in <i>Epiblema</i> larvae collected in February compared with September and also in these animals, triglyceride lipase activity increased by 70% during winter. Overall, our study suggests a re-sculpting of metabolism during insect diapause, which shifted to a more catabolic poise in freeze-avoiding overwintering <i>Epiblema</i> larvae, possibly involving AMPK. 收起